1591804560
Build a Docker image using Maven and Spring Boot
This tutorial will introduce three techniques for building a Spring Boot java application into a Docker image using Maven.
We walked through using Spring Boot natively, and the Jib plugin from Google, both of which will work without needing to create a Dockerfile. Finally, we looked briefly at the Dockerfile-maven plugin written by Spotify which is now mature and stable, but no longer being actively enhanced.
#spring-boot #java
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Enhance Amazon Aurora Read/Write Capability with ShardingSphere-JDBC
1. Introduction
Amazon Aurora is a relational database management system (RDBMS) developed by AWS(Amazon Web Services). Aurora gives you the performance and availability of commercial-grade databases with full MySQL and PostgreSQL compatibility. In terms of high performance, Aurora MySQL and Aurora PostgreSQL have shown an increase in throughput of up to 5X over stock MySQL and 3X over stock PostgreSQL respectively on similar hardware. In terms of scalability, Aurora achieves enhancements and innovations in storage and computing, horizontal and vertical functions.
Aurora supports up to 128TB of storage capacity and supports dynamic scaling of storage layer in units of 10GB. In terms of computing, Aurora supports scalable configurations for multiple read replicas. Each region can have an additional 15 Aurora replicas. In addition, Aurora provides multi-primary architecture to support four read/write nodes. Its Serverless architecture allows vertical scaling and reduces typical latency to under a second, while the Global Database enables a single database cluster to span multiple AWS Regions in low latency.
Aurora already provides great scalability with the growth of user data volume. Can it handle more data and support more concurrent access? You may consider using sharding to support the configuration of multiple underlying Aurora clusters. To this end, a series of blogs, including this one, provides you with a reference in choosing between Proxy and JDBC for sharding.
1.1 Why sharding is needed
AWS Aurora offers a single relational database. Primary-secondary, multi-primary, and global database, and other forms of hosting architecture can satisfy various architectural scenarios above. However, Aurora doesn’t provide direct support for sharding scenarios, and sharding has a variety of forms, such as vertical and horizontal forms. If we want to further increase data capacity, some problems have to be solved, such as cross-node database Join, associated query, distributed transactions, SQL sorting, page turning, function calculation, database global primary key, capacity planning, and secondary capacity expansion after sharding.
1.2 Sharding methods
It is generally accepted that when the capacity of a MySQL table is less than 10 million, the time spent on queries is optimal because at this time the height of its BTREE index is between 3 and 5. Data sharding can reduce the amount of data in a single table and distribute the read and write loads to different data nodes at the same time. Data sharding can be divided into vertical sharding and horizontal sharding.
1. Advantages of vertical sharding
- Address the coupling of business system and make clearer.
- Implement hierarchical management, maintenance, monitoring, and expansion to data of different businesses, like micro-service governance.
- In high concurrency scenarios, vertical sharding removes the bottleneck of IO, database connections, and hardware resources on a single machine to some extent.
2. Disadvantages of vertical sharding
- After splitting the library,
Joincan only be implemented by interface aggregation, which will increase the complexity of development. - After splitting the library, it is complex to process distributed transactions.
- There is a large amount of data on a single table and horizontal sharding is required.
3. Advantages of horizontal sharding
- There is no such performance bottleneck as a large amount of data on a single database and high concurrency, and it increases system stability and load capacity.
- The business modules do not need to be split due to minor modification on the application client.
4. Disadvantages of horizontal sharding
- Transaction consistency across shards is hard to be guaranteed;
- The performance of associated query in cross-library
Joinis poor. - It’s difficult to scale the data many times and maintenance is a big workload.
Based on the analysis above, and the available studis on popular sharding middleware, we selected ShardingSphere, an open source product, combined with Amazon Aurora to introduce how the combination of these two products meets various forms of sharding and how to solve the problems brought by sharding.
ShardingSphere is an open source ecosystem including a set of distributed database middleware solutions, including 3 independent products, Sharding-JDBC, Sharding-Proxy & Sharding-Sidecar.
2. ShardingSphere introduction:
The characteristics of Sharding-JDBC are:
- With the client end connecting directly to the database, it provides service in the form of jar and requires no extra deployment and dependence.
- It can be considered as an enhanced JDBC driver, which is fully compatible with JDBC and all kinds of ORM frameworks.
- Applicable in any ORM framework based on JDBC, such as JPA, Hibernate, Mybatis, Spring JDBC Template or direct use of JDBC.
- Support any third-party database connection pool, such as DBCP, C3P0, BoneCP, Druid, HikariCP;
- Support any kind of JDBC standard database: MySQL, Oracle, SQLServer, PostgreSQL and any databases accessible to JDBC.
- Sharding-JDBC adopts decentralized architecture, applicable to high-performance light-weight OLTP application developed with Java
Hybrid Structure Integrating Sharding-JDBC and Applications
Sharding-JDBC’s core concepts
Data node: The smallest unit of a data slice, consisting of a data source name and a data table, such as ds_0.product_order_0.
Actual table: The physical table that really exists in the horizontal sharding database, such as product order tables: product_order_0, product_order_1, and product_order_2.
Logic table: The logical name of the horizontal sharding databases (tables) with the same schema. For instance, the logic table of the order product_order_0, product_order_1, and product_order_2 is product_order.
Binding table: It refers to the primary table and the joiner table with the same sharding rules. For example, product_order table and product_order_item are sharded by order_id, so they are binding tables with each other. Cartesian product correlation will not appear in the multi-tables correlating query, so the query efficiency will increase greatly.
Broadcast table: It refers to tables that exist in all sharding database sources. The schema and data must consist in each database. It can be applied to the small data volume that needs to correlate with big data tables to query, dictionary table and configuration table for example.
3. Testing ShardingSphere-JDBC
3.1 Example project
Download the example project code locally. In order to ensure the stability of the test code, we choose shardingsphere-example-4.0.0 version.
git clone https://github.com/apache/shardingsphere-example.git
Project description：
shardingsphere-example
├── example-core
│ ├── config-utility
│ ├── example-api
│ ├── example-raw-jdbc
│ ├── example-spring-jpa #spring+jpa integration-based entity，repository
│ └── example-spring-mybatis
├── sharding-jdbc-example
│ ├── sharding-example
│ │ ├── sharding-raw-jdbc-example
│ │ ├── sharding-spring-boot-jpa-example #integration-based sharding-jdbc functions
│ │ ├── sharding-spring-boot-mybatis-example
│ │ ├── sharding-spring-namespace-jpa-example
│ │ └── sharding-spring-namespace-mybatis-example
│ ├── orchestration-example
│ │ ├── orchestration-raw-jdbc-example
│ │ ├── orchestration-spring-boot-example #integration-based sharding-jdbc governance function
│ │ └── orchestration-spring-namespace-example
│ ├── transaction-example
│ │ ├── transaction-2pc-xa-example #sharding-jdbc sample of two-phase commit for a distributed transaction
│ │ └──transaction-base-seata-example #sharding-jdbc distributed transaction seata sample
│ ├── other-feature-example
│ │ ├── hint-example
│ │ └── encrypt-example
├── sharding-proxy-example
│ └── sharding-proxy-boot-mybatis-example
└── src/resources
└── manual_schema.sql
Configuration file description:
application-master-slave.properties #read/write splitting profile
application-sharding-databases-tables.properties #sharding profile
application-sharding-databases.properties #library split profile only
application-sharding-master-slave.properties #sharding and read/write splitting profile
application-sharding-tables.properties #table split profile
application.properties #spring boot profile
Code logic description:
The following is the entry class of the Spring Boot application below. Execute it to run the project.
The execution logic of demo is as follows:
3.2 Verifying read/write splitting
As business grows, the write and read requests can be split to different database nodes to effectively promote the processing capability of the entire database cluster. Aurora uses a reader/writer endpoint to meet users' requirements to write and read with strong consistency, and a read-only endpoint to meet the requirements to read without strong consistency. Aurora's read and write latency is within single-digit milliseconds, much lower than MySQL's binlog-based logical replication, so there's a lot of loads that can be directed to a read-only endpoint.
Through the one primary and multiple secondary configuration, query requests can be evenly distributed to multiple data replicas, which further improves the processing capability of the system. Read/write splitting can improve the throughput and availability of system, but it can also lead to data inconsistency. Aurora provides a primary/secondary architecture in a fully managed form, but applications on the upper-layer still need to manage multiple data sources when interacting with Aurora, routing SQL requests to different nodes based on the read/write type of SQL statements and certain routing policies.
ShardingSphere-JDBC provides read/write splitting features and it is integrated with application programs so that the complex configuration between application programs and database clusters can be separated from application programs. Developers can manage the Shard through configuration files and combine it with ORM frameworks such as Spring JPA and Mybatis to completely separate the duplicated logic from the code, which greatly improves the ability to maintain code and reduces the coupling between code and database.
3.2.1 Setting up the database environment
Create a set of Aurora MySQL read/write splitting clusters. The model is db.r5.2xlarge. Each set of clusters has one write node and two read nodes.
3.2.2 Configuring Sharding-JDBC
application.properties spring boot Master profile description:
You need to replace the green ones with your own environment configuration.
# Jpa automatically creates and drops data tables based on entities
spring.jpa.properties.hibernate.hbm2ddl.auto=create-drop
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
spring.jpa.properties.hibernate.show_sql=true
#spring.profiles.active=sharding-databases
#spring.profiles.active=sharding-tables
#spring.profiles.active=sharding-databases-tables
#Activate master-slave configuration item so that sharding-jdbc can use master-slave profile
spring.profiles.active=master-slave
#spring.profiles.active=sharding-master-slave
application-master-slave.properties sharding-jdbc profile description:
spring.shardingsphere.datasource.names=ds_master,ds_slave_0,ds_slave_1
# data souce-master
spring.shardingsphere.datasource.ds_master.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds_master.password=Your master DB password
spring.shardingsphere.datasource.ds_master.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds_master.jdbc-url=Your primary DB data sourceurl spring.shardingsphere.datasource.ds_master.username=Your primary DB username
# data source-slave
spring.shardingsphere.datasource.ds_slave_0.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds_slave_0.password= Your slave DB password
spring.shardingsphere.datasource.ds_slave_0.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds_slave_0.jdbc-url=Your slave DB data source url
spring.shardingsphere.datasource.ds_slave_0.username= Your slave DB username
# data source-slave
spring.shardingsphere.datasource.ds_slave_1.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds_slave_1.password= Your slave DB password
spring.shardingsphere.datasource.ds_slave_1.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds_slave_1.jdbc-url= Your slave DB data source url
spring.shardingsphere.datasource.ds_slave_1.username= Your slave DB username
# Routing Policy Configuration
spring.shardingsphere.masterslave.load-balance-algorithm-type=round_robin
spring.shardingsphere.masterslave.name=ds_ms
spring.shardingsphere.masterslave.master-data-source-name=ds_master
spring.shardingsphere.masterslave.slave-data-source-names=ds_slave_0,ds_slave_1
# sharding-jdbc configures the information storage mode
spring.shardingsphere.mode.type=Memory
# start shardingsphere log，and you can see the conversion from logical SQL to actual SQL from the print
spring.shardingsphere.props.sql.show=true
3.2.3 Test and verification process description
- Test environment data initialization: Spring JPA initialization automatically creates tables for testing.
- Write data to the master instance
As shown in the ShardingSphere-SQL log figure below, the write SQL is executed on the ds_master data source.
- Data query operations are performed on the slave library.
As shown in the ShardingSphere-SQL log figure below, the read SQL is executed on the ds_slave data source in the form of polling.
[INFO ] 2022-04-02 19:43:39,376 --main-- [ShardingSphere-SQL] Rule Type: master-slave
[INFO ] 2022-04-02 19:43:39,376 --main-- [ShardingSphere-SQL] SQL: select orderentit0_.order_id as order_id1_1_, orderentit0_.address_id as address_2_1_,
orderentit0_.status as status3_1_, orderentit0_.user_id as user_id4_1_ from t_order orderentit0_ ::: DataSources: ds_slave_0
---------------------------- Print OrderItem Data -------------------
Hibernate: select orderiteme1_.order_item_id as order_it1_2_, orderiteme1_.order_id as order_id2_2_, orderiteme1_.status as status3_2_, orderiteme1_.user_id
as user_id4_2_ from t_order orderentit0_ cross join t_order_item orderiteme1_ where orderentit0_.order_id=orderiteme1_.order_id
[INFO ] 2022-04-02 19:43:40,898 --main-- [ShardingSphere-SQL] Rule Type: master-slave
[INFO ] 2022-04-02 19:43:40,898 --main-- [ShardingSphere-SQL] SQL: select orderiteme1_.order_item_id as order_it1_2_, orderiteme1_.order_id as order_id2_2_, orderiteme1_.status as status3_2_,
orderiteme1_.user_id as user_id4_2_ from t_order orderentit0_ cross join t_order_item orderiteme1_ where orderentit0_.order_id=orderiteme1_.order_id ::: DataSources: ds_slave_1
Note: As shown in the figure below, if there are both reads and writes in a transaction, Sharding-JDBC routes both read and write operations to the master library. If the read/write requests are not in the same transaction, the corresponding read requests are distributed to different read nodes according to the routing policy.
@Override
@Transactional // When a transaction is started, both read and write in the transaction go through the master library. When closed, read goes through the slave library and write goes through the master library
public void processSuccess() throws SQLException {
System.out.println("-------------- Process Success Begin ---------------");
List<Long> orderIds = insertData();
printData();
deleteData(orderIds);
printData();
System.out.println("-------------- Process Success Finish --------------");
}
3.2.4 Verifying Aurora failover scenario
The Aurora database environment adopts the configuration described in Section 2.2.1.
3.2.4.1 Verification process description
- Start the
Spring-Bootproject
2. Perform a failover on Aurora’s console
3. Execute the Rest API request
4. Repeatedly execute POST (http://localhost:8088/save-user) until the call to the API failed to write to Aurora and eventually recovered successfully.
5. The following figure shows the process of executing code failover. It takes about 37 seconds from the time when the latest SQL write is successfully performed to the time when the next SQL write is successfully performed. That is, the application can be automatically recovered from Aurora failover, and the recovery time is about 37 seconds.
3.3 Testing table sharding-only function
3.3.1 Configuring Sharding-JDBC
application.properties spring boot master profile description
# Jpa automatically creates and drops data tables based on entities
spring.jpa.properties.hibernate.hbm2ddl.auto=create-drop
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
spring.jpa.properties.hibernate.show_sql=true
#spring.profiles.active=sharding-databases
#Activate sharding-tables configuration items
#spring.profiles.active=sharding-tables
#spring.profiles.active=sharding-databases-tables
# spring.profiles.active=master-slave
#spring.profiles.active=sharding-master-slave
application-sharding-tables.properties sharding-jdbc profile description
## configure primary-key policy
spring.shardingsphere.sharding.tables.t_order.key-generator.column=order_id
spring.shardingsphere.sharding.tables.t_order.key-generator.type=SNOWFLAKE
spring.shardingsphere.sharding.tables.t_order.key-generator.props.worker.id=123
spring.shardingsphere.sharding.tables.t_order_item.actual-data-nodes=ds.t_order_item_$->{0..1}
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.sharding-column=order_id
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.algorithm-expression=t_order_item_$->{order_id % 2}
spring.shardingsphere.sharding.tables.t_order_item.key-generator.column=order_item_id
spring.shardingsphere.sharding.tables.t_order_item.key-generator.type=SNOWFLAKE
spring.shardingsphere.sharding.tables.t_order_item.key-generator.props.worker.id=123
# configure the binding relation of t_order and t_order_item
spring.shardingsphere.sharding.binding-tables[0]=t_order,t_order_item
# configure broadcast tables
spring.shardingsphere.sharding.broadcast-tables=t_address
# sharding-jdbc mode
spring.shardingsphere.mode.type=Memory
# start shardingsphere log
spring.shardingsphere.props.sql.show=true
3.3.2 Test and verification process description
1. DDL operation
JPA automatically creates tables for testing. When Sharding-JDBC routing rules are configured, the client executes DDL, and Sharding-JDBC automatically creates corresponding tables according to the table splitting rules. If t_address is a broadcast table, create a t_address because there is only one master instance. Two physical tables t_order_0 and t_order_1 will be created when creating t_order.
2. Write operation
As shown in the figure below, Logic SQL inserts a record into t_order. When Sharding-JDBC is executed, data will be distributed to t_order_0 and t_order_1 according to the table splitting rules.
When t_order and t_order_item are bound, the records associated with order_item and order are placed on the same physical table.
3. Read operation
As shown in the figure below, perform the join query operations to order and order_item under the binding table, and the physical shard is precisely located based on the binding relationship.
The join query operations on order and order_item under the unbound table will traverse all shards.
3.4 Testing database sharding-only function
3.4.1 Setting up the database environment
Create two instances on Aurora: ds_0 and ds_1
When the sharding-spring-boot-jpa-example project is started, tables t_order, t_order_item，t_address will be created on two Aurora instances.
3.4.2 Configuring Sharding-JDBC
application.properties springboot master profile description
# Jpa automatically creates and drops data tables based on entities
spring.jpa.properties.hibernate.hbm2ddl.auto=create
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
spring.jpa.properties.hibernate.show_sql=true
# Activate sharding-databases configuration items
spring.profiles.active=sharding-databases
#spring.profiles.active=sharding-tables
#spring.profiles.active=sharding-databases-tables
#spring.profiles.active=master-slave
#spring.profiles.active=sharding-master-slave
application-sharding-databases.properties sharding-jdbc profile description
spring.shardingsphere.datasource.names=ds_0,ds_1
# ds_0
spring.shardingsphere.datasource.ds_0.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds_0.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds_0.jdbc-url= spring.shardingsphere.datasource.ds_0.username=
spring.shardingsphere.datasource.ds_0.password=
# ds_1
spring.shardingsphere.datasource.ds_1.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds_1.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds_1.jdbc-url=
spring.shardingsphere.datasource.ds_1.username=
spring.shardingsphere.datasource.ds_1.password=
spring.shardingsphere.sharding.default-database-strategy.inline.sharding-column=user_id
spring.shardingsphere.sharding.default-database-strategy.inline.algorithm-expression=ds_$->{user_id % 2}
spring.shardingsphere.sharding.binding-tables=t_order,t_order_item
spring.shardingsphere.sharding.broadcast-tables=t_address
spring.shardingsphere.sharding.default-data-source-name=ds_0
spring.shardingsphere.sharding.tables.t_order.actual-data-nodes=ds_$->{0..1}.t_order
spring.shardingsphere.sharding.tables.t_order.key-generator.column=order_id
spring.shardingsphere.sharding.tables.t_order.key-generator.type=SNOWFLAKE
spring.shardingsphere.sharding.tables.t_order.key-generator.props.worker.id=123
spring.shardingsphere.sharding.tables.t_order_item.actual-data-nodes=ds_$->{0..1}.t_order_item
spring.shardingsphere.sharding.tables.t_order_item.key-generator.column=order_item_id
spring.shardingsphere.sharding.tables.t_order_item.key-generator.type=SNOWFLAKE
spring.shardingsphere.sharding.tables.t_order_item.key-generator.props.worker.id=123
# sharding-jdbc mode
spring.shardingsphere.mode.type=Memory
# start shardingsphere log
spring.shardingsphere.props.sql.show=true
3.4.3 Test and verification process description
1. DDL operation
JPA automatically creates tables for testing. When Sharding-JDBC’s library splitting and routing rules are configured, the client executes DDL, and Sharding-JDBC will automatically create corresponding tables according to table splitting rules. If t_address is a broadcast table, physical tables will be created on ds_0 and ds_1. The three tables, t_address, t_order and t_order_item will be created on ds_0 and ds_1 respectively.
2. Write operation
For the broadcast table t_address, each record written will also be written to the t_address tables of ds_0 and ds_1.
The tables t_order and t_order_item of the slave library are written on the table in the corresponding instance according to the slave library field and routing policy.
3. Read operation
Query order is routed to the corresponding Aurora instance according to the routing rules of the slave library .
Query Address. Since address is a broadcast table, an instance of address will be randomly selected and queried from the nodes used.
As shown in the figure below, perform the join query operations to order and order_item under the binding table, and the physical shard is precisely located based on the binding relationship.
3.5 Verifying sharding function
3.5.1 Setting up the database environment
As shown in the figure below, create two instances on Aurora: ds_0 and ds_1
When the sharding-spring-boot-jpa-example project is started, physical tables t_order_01, t_order_02, t_order_item_01，and t_order_item_02 and global table t_address will be created on two Aurora instances.
3.5.2 Configuring Sharding-JDBC
application.properties springboot master profile description
# Jpa automatically creates and drops data tables based on entities
spring.jpa.properties.hibernate.hbm2ddl.auto=create
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
spring.jpa.properties.hibernate.show_sql=true
# Activate sharding-databases-tables configuration items
#spring.profiles.active=sharding-databases
#spring.profiles.active=sharding-tables
spring.profiles.active=sharding-databases-tables
#spring.profiles.active=master-slave
#spring.profiles.active=sharding-master-slave
application-sharding-databases.properties sharding-jdbc profile description
spring.shardingsphere.datasource.names=ds_0,ds_1
# ds_0
spring.shardingsphere.datasource.ds_0.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds_0.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds_0.jdbc-url= 306/dev?useSSL=false&characterEncoding=utf-8
spring.shardingsphere.datasource.ds_0.username=
spring.shardingsphere.datasource.ds_0.password=
spring.shardingsphere.datasource.ds_0.max-active=16
# ds_1
spring.shardingsphere.datasource.ds_1.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds_1.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds_1.jdbc-url=
spring.shardingsphere.datasource.ds_1.username=
spring.shardingsphere.datasource.ds_1.password=
spring.shardingsphere.datasource.ds_1.max-active=16
# default library splitting policy
spring.shardingsphere.sharding.default-database-strategy.inline.sharding-column=user_id
spring.shardingsphere.sharding.default-database-strategy.inline.algorithm-expression=ds_$->{user_id % 2}
spring.shardingsphere.sharding.binding-tables=t_order,t_order_item
spring.shardingsphere.sharding.broadcast-tables=t_address
# Tables that do not meet the library splitting policy are placed on ds_0
spring.shardingsphere.sharding.default-data-source-name=ds_0
# t_order table splitting policy
spring.shardingsphere.sharding.tables.t_order.actual-data-nodes=ds_$->{0..1}.t_order_$->{0..1}
spring.shardingsphere.sharding.tables.t_order.table-strategy.inline.sharding-column=order_id
spring.shardingsphere.sharding.tables.t_order.table-strategy.inline.algorithm-expression=t_order_$->{order_id % 2}
spring.shardingsphere.sharding.tables.t_order.key-generator.column=order_id
spring.shardingsphere.sharding.tables.t_order.key-generator.type=SNOWFLAKE
spring.shardingsphere.sharding.tables.t_order.key-generator.props.worker.id=123
# t_order_item table splitting policy
spring.shardingsphere.sharding.tables.t_order_item.actual-data-nodes=ds_$->{0..1}.t_order_item_$->{0..1}
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.sharding-column=order_id
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.algorithm-expression=t_order_item_$->{order_id % 2}
spring.shardingsphere.sharding.tables.t_order_item.key-generator.column=order_item_id
spring.shardingsphere.sharding.tables.t_order_item.key-generator.type=SNOWFLAKE
spring.shardingsphere.sharding.tables.t_order_item.key-generator.props.worker.id=123
# sharding-jdbc mdoe
spring.shardingsphere.mode.type=Memory
# start shardingsphere log
spring.shardingsphere.props.sql.show=true
3.5.3 Test and verification process description
1. DDL operation
JPA automatically creates tables for testing. When Sharding-JDBC’s sharding and routing rules are configured, the client executes DDL, and Sharding-JDBC will automatically create corresponding tables according to table splitting rules. If t_address is a broadcast table, t_address will be created on both ds_0 and ds_1. The three tables, t_address, t_order and t_order_item will be created on ds_0 and ds_1 respectively.
2. Write operation
For the broadcast table t_address, each record written will also be written to the t_address tables of ds_0 and ds_1.
The tables t_order and t_order_item of the sub-library are written to the table on the corresponding instance according to the slave library field and routing policy.
3. Read operation
The read operation is similar to the library split function verification described in section2.4.3.
3.6 Testing database sharding, table sharding and read/write splitting function
3.6.1 Setting up the database environment
The following figure shows the physical table of the created database instance.
3.6.2 Configuring Sharding-JDBC
application.properties spring boot master profile description
# Jpa automatically creates and drops data tables based on entities
spring.jpa.properties.hibernate.hbm2ddl.auto=create
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
spring.jpa.properties.hibernate.show_sql=true
# activate sharding-databases-tables configuration items
#spring.profiles.active=sharding-databases
#spring.profiles.active=sharding-tables
#spring.profiles.active=sharding-databases-tables
#spring.profiles.active=master-slave
spring.profiles.active=sharding-master-slave
application-sharding-master-slave.properties sharding-jdbc profile description
The url, name and password of the database need to be changed to your own database parameters.
spring.shardingsphere.datasource.names=ds_master_0,ds_master_1,ds_master_0_slave_0,ds_master_0_slave_1,ds_master_1_slave_0,ds_master_1_slave_1
spring.shardingsphere.datasource.ds_master_0.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds_master_0.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds_master_0.jdbc-url= spring.shardingsphere.datasource.ds_master_0.username=
spring.shardingsphere.datasource.ds_master_0.password=
spring.shardingsphere.datasource.ds_master_0.max-active=16
spring.shardingsphere.datasource.ds_master_0_slave_0.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds_master_0_slave_0.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds_master_0_slave_0.jdbc-url= spring.shardingsphere.datasource.ds_master_0_slave_0.username=
spring.shardingsphere.datasource.ds_master_0_slave_0.password=
spring.shardingsphere.datasource.ds_master_0_slave_0.max-active=16
spring.shardingsphere.datasource.ds_master_0_slave_1.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds_master_0_slave_1.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds_master_0_slave_1.jdbc-url= spring.shardingsphere.datasource.ds_master_0_slave_1.username=
spring.shardingsphere.datasource.ds_master_0_slave_1.password=
spring.shardingsphere.datasource.ds_master_0_slave_1.max-active=16
spring.shardingsphere.datasource.ds_master_1.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds_master_1.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds_master_1.jdbc-url=
spring.shardingsphere.datasource.ds_master_1.username=
spring.shardingsphere.datasource.ds_master_1.password=
spring.shardingsphere.datasource.ds_master_1.max-active=16
spring.shardingsphere.datasource.ds_master_1_slave_0.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds_master_1_slave_0.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds_master_1_slave_0.jdbc-url=
spring.shardingsphere.datasource.ds_master_1_slave_0.username=
spring.shardingsphere.datasource.ds_master_1_slave_0.password=
spring.shardingsphere.datasource.ds_master_1_slave_0.max-active=16
spring.shardingsphere.datasource.ds_master_1_slave_1.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds_master_1_slave_1.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds_master_1_slave_1.jdbc-url= spring.shardingsphere.datasource.ds_master_1_slave_1.username=admin
spring.shardingsphere.datasource.ds_master_1_slave_1.password=
spring.shardingsphere.datasource.ds_master_1_slave_1.max-active=16
spring.shardingsphere.sharding.default-database-strategy.inline.sharding-column=user_id
spring.shardingsphere.sharding.default-database-strategy.inline.algorithm-expression=ds_$->{user_id % 2}
spring.shardingsphere.sharding.binding-tables=t_order,t_order_item
spring.shardingsphere.sharding.broadcast-tables=t_address
spring.shardingsphere.sharding.default-data-source-name=ds_master_0
spring.shardingsphere.sharding.tables.t_order.actual-data-nodes=ds_$->{0..1}.t_order_$->{0..1}
spring.shardingsphere.sharding.tables.t_order.table-strategy.inline.sharding-column=order_id
spring.shardingsphere.sharding.tables.t_order.table-strategy.inline.algorithm-expression=t_order_$->{order_id % 2}
spring.shardingsphere.sharding.tables.t_order.key-generator.column=order_id
spring.shardingsphere.sharding.tables.t_order.key-generator.type=SNOWFLAKE
spring.shardingsphere.sharding.tables.t_order.key-generator.props.worker.id=123
spring.shardingsphere.sharding.tables.t_order_item.actual-data-nodes=ds_$->{0..1}.t_order_item_$->{0..1}
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.sharding-column=order_id
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.algorithm-expression=t_order_item_$->{order_id % 2}
spring.shardingsphere.sharding.tables.t_order_item.key-generator.column=order_item_id
spring.shardingsphere.sharding.tables.t_order_item.key-generator.type=SNOWFLAKE
spring.shardingsphere.sharding.tables.t_order_item.key-generator.props.worker.id=123
# master/slave data source and slave data source configuration
spring.shardingsphere.sharding.master-slave-rules.ds_0.master-data-source-name=ds_master_0
spring.shardingsphere.sharding.master-slave-rules.ds_0.slave-data-source-names=ds_master_0_slave_0, ds_master_0_slave_1
spring.shardingsphere.sharding.master-slave-rules.ds_1.master-data-source-name=ds_master_1
spring.shardingsphere.sharding.master-slave-rules.ds_1.slave-data-source-names=ds_master_1_slave_0, ds_master_1_slave_1
# sharding-jdbc mode
spring.shardingsphere.mode.type=Memory
# start shardingsphere log
spring.shardingsphere.props.sql.show=true
3.6.3 Test and verification process description
1. DDL operation
JPA automatically creates tables for testing. When Sharding-JDBC’s library splitting and routing rules are configured, the client executes DDL, and Sharding-JDBC will automatically create corresponding tables according to table splitting rules. If t_address is a broadcast table, t_address will be created on both ds_0 and ds_1. The three tables, t_address, t_order and t_order_item will be created on ds_0 and ds_1 respectively.
2. Write operation
For the broadcast table t_address, each record written will also be written to the t_address tables of ds_0 and ds_1.
The tables t_order and t_order_item of the slave library are written to the table on the corresponding instance according to the slave library field and routing policy.
3. Read operation
The join query operations on order and order_item under the binding table are shown below.
3. Conclusion
As an open source product focusing on database enhancement, ShardingSphere is pretty good in terms of its community activitiy, product maturity and documentation richness.
Among its products, ShardingSphere-JDBC is a sharding solution based on the client-side, which supports all sharding scenarios. And there’s no need to introduce an intermediate layer like Proxy, so the complexity of operation and maintenance is reduced. Its latency is theoretically lower than Proxy due to the lack of intermediate layer. In addition, ShardingSphere-JDBC can support a variety of relational databases based on SQL standards such as MySQL/PostgreSQL/Oracle/SQL Server, etc.
However, due to the integration of Sharding-JDBC with the application program, it only supports Java language for now, and is strongly dependent on the application programs. Nevertheless, Sharding-JDBC separates all sharding configuration from the application program, which brings relatively small changes when switching to other middleware.
In conclusion, Sharding-JDBC is a good choice if you use a Java-based system and have to to interconnect with different relational databases — and don’t want to bother with introducing an intermediate layer.
Author
Sun Jinhua
A senior solution architect at AWS, Sun is responsible for the design and consult on cloud architecture. for providing customers with cloud-related design and consulting services. Before joining AWS, he ran his own business, specializing in building e-commerce platforms and designing the overall architecture for e-commerce platforms of automotive companies. He worked in a global leading communication equipment company as a senior engineer, responsible for the development and architecture design of multiple subsystems of LTE equipment system. He has rich experience in architecture design with high concurrency and high availability system, microservice architecture design, database, middleware, IOT etc.
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EasyMDE: Simple, Beautiful and Embeddable JavaScript Markdown Editor
EasyMDE - Markdown Editor
This repository is a fork of SimpleMDE, made by Sparksuite. Go to the dedicated section for more information.
A drop-in JavaScript text area replacement for writing beautiful and understandable Markdown. EasyMDE allows users who may be less experienced with Markdown to use familiar toolbar buttons and shortcuts.
In addition, the syntax is rendered while editing to clearly show the expected result. Headings are larger, emphasized words are italicized, links are underlined, etc.
EasyMDE also features both built-in auto saving and spell checking. The editor is entirely customizable, from theming to toolbar buttons and javascript hooks.
Quick access
Install EasyMDE
Via npm:
npm install easymde
Via the UNPKG CDN:
<link rel="stylesheet" href="https://unpkg.com/easymde/dist/easymde.min.css">
<script src="https://unpkg.com/easymde/dist/easymde.min.js"></script>
Or jsDelivr:
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/easymde/dist/easymde.min.css">
<script src="https://cdn.jsdelivr.net/npm/easymde/dist/easymde.min.js"></script>
How to use
Loading the editor
After installing and/or importing the module, you can load EasyMDE onto the first textarea element on the web page:
<textarea></textarea>
<script>
const easyMDE = new EasyMDE();
</script>
Alternatively you can select a specific textarea, via JavaScript:
<textarea id="my-text-area"></textarea>
<script>
const easyMDE = new EasyMDE({element: document.getElementById('my-text-area')});
</script>
Editor functions
Use easyMDE.value() to get the content of the editor:
<script>
easyMDE.value();
</script>
Use easyMDE.value(val) to set the content of the editor:
<script>
easyMDE.value('New input for **EasyMDE**');
</script>
Configuration
Options list
- autoDownloadFontAwesome: If set to
true, force downloads Font Awesome (used for icons). If set tofalse, prevents downloading. Defaults toundefined, which will intelligently check whether Font Awesome has already been included, then download accordingly. - autofocus: If set to
true, focuses the editor automatically. Defaults tofalse. - autosave: Saves the text that's being written and will load it back in the future. It will forget the text when the form it's contained in is submitted.
- enabled: If set to
true, saves the text automatically. Defaults tofalse. - delay: Delay between saves, in milliseconds. Defaults to
10000(10 seconds). - submit_delay: Delay before assuming that submit of the form failed and saving the text, in milliseconds. Defaults to
autosave.delayor10000(10 seconds). - uniqueId: You must set a unique string identifier so that EasyMDE can autosave. Something that separates this from other instances of EasyMDE elsewhere on your website.
- timeFormat: Set DateTimeFormat. More information see DateTimeFormat instances. Default
locale: en-US, format: hour:minute. - text: Set text for autosave.
- enabled: If set to
- autoRefresh: Useful, when initializing the editor in a hidden DOM node. If set to
{ delay: 300 }, it will check every 300 ms if the editor is visible and if positive, call CodeMirror'srefresh(). - blockStyles: Customize how certain buttons that style blocks of text behave.
- bold: Can be set to
**or__. Defaults to**. - code: Can be set to
```or~~~. Defaults to```. - italic: Can be set to
*or_. Defaults to*.
- bold: Can be set to
- unorderedListStyle: can be
*,-or+. Defaults to*. - scrollbarStyle: Chooses a scrollbar implementation. The default is "native", showing native scrollbars. The core library also provides the "null" style, which completely hides the scrollbars. Addons can implement additional scrollbar models.
- element: The DOM element for the
textareaelement to use. Defaults to the firsttextareaelement on the page. - forceSync: If set to
true, force text changes made in EasyMDE to be immediately stored in original text area. Defaults tofalse. - hideIcons: An array of icon names to hide. Can be used to hide specific icons shown by default without completely customizing the toolbar.
- indentWithTabs: If set to
false, indent using spaces instead of tabs. Defaults totrue. - initialValue: If set, will customize the initial value of the editor.
- previewImagesInEditor: - EasyMDE will show preview of images,
falseby default, preview for images will appear only for images on separate lines. - imagesPreviewHandler: - A custom function for handling the preview of images. Takes the parsed string between the parantheses of the image markdown
as argument and returns a string that serves as thesrcattribute of the<img>tag in the preview. Enables dynamic previewing of images in the frontend without having to upload them to a server, allows copy-pasting of images to the editor with preview. - insertTexts: Customize how certain buttons that insert text behave. Takes an array with two elements. The first element will be the text inserted before the cursor or highlight, and the second element will be inserted after. For example, this is the default link value:
["[", "](http://)"].- horizontalRule
- image
- link
- table
- lineNumbers: If set to
true, enables line numbers in the editor. - lineWrapping: If set to
false, disable line wrapping. Defaults totrue. - minHeight: Sets the minimum height for the composition area, before it starts auto-growing. Should be a string containing a valid CSS value like
"500px". Defaults to"300px". - maxHeight: Sets fixed height for the composition area.
minHeightoption will be ignored. Should be a string containing a valid CSS value like"500px". Defaults toundefined. - onToggleFullScreen: A function that gets called when the editor's full screen mode is toggled. The function will be passed a boolean as parameter,
truewhen the editor is currently going into full screen mode, orfalse. - parsingConfig: Adjust settings for parsing the Markdown during editing (not previewing).
- allowAtxHeaderWithoutSpace: If set to
true, will render headers without a space after the#. Defaults tofalse. - strikethrough: If set to
false, will not process GFM strikethrough syntax. Defaults totrue. - underscoresBreakWords: If set to
true, let underscores be a delimiter for separating words. Defaults tofalse.
- allowAtxHeaderWithoutSpace: If set to
- overlayMode: Pass a custom codemirror overlay mode to parse and style the Markdown during editing.
- mode: A codemirror mode object.
- combine: If set to
false, will replace CSS classes returned by the default Markdown mode. Otherwise the classes returned by the custom mode will be combined with the classes returned by the default mode. Defaults totrue.
- placeholder: If set, displays a custom placeholder message.
- previewClass: A string or array of strings that will be applied to the preview screen when activated. Defaults to
"editor-preview". - previewRender: Custom function for parsing the plaintext Markdown and returning HTML. Used when user previews.
- promptURLs: If set to
true, a JS alert window appears asking for the link or image URL. Defaults tofalse. - promptTexts: Customize the text used to prompt for URLs.
- image: The text to use when prompting for an image's URL. Defaults to
URL of the image:. - link: The text to use when prompting for a link's URL. Defaults to
URL for the link:.
- image: The text to use when prompting for an image's URL. Defaults to
- uploadImage: If set to
true, enables the image upload functionality, which can be triggered by drag and drop, copy-paste and through the browse-file window (opened when the user click on the upload-image icon). Defaults tofalse. - imageMaxSize: Maximum image size in bytes, checked before upload (note: never trust client, always check the image size at server-side). Defaults to
1024 * 1024 * 2(2 MB). - imageAccept: A comma-separated list of mime-types used to check image type before upload (note: never trust client, always check file types at server-side). Defaults to
image/png, image/jpeg. - imageUploadFunction: A custom function for handling the image upload. Using this function will render the options
imageMaxSize,imageAccept,imageUploadEndpointandimageCSRFTokenineffective.- The function gets a file and
onSuccessandonErrorcallback functions as parameters.onSuccess(imageUrl: string)andonError(errorMessage: string)
- The function gets a file and
- imageUploadEndpoint: The endpoint where the images data will be sent, via an asynchronous POST request. The server is supposed to save this image, and return a JSON response.
- if the request was successfully processed (HTTP 200 OK):
{"data": {"filePath": "<filePath>"}}where filePath is the path of the image (absolute ifimagePathAbsoluteis set to true, relative if otherwise); - otherwise:
{"error": "<errorCode>"}, where errorCode can benoFileGiven(HTTP 400 Bad Request),typeNotAllowed(HTTP 415 Unsupported Media Type),fileTooLarge(HTTP 413 Payload Too Large) orimportError(see errorMessages below). If errorCode is not one of the errorMessages, it is alerted unchanged to the user. This allows for server-side error messages. No default value.
- if the request was successfully processed (HTTP 200 OK):
- imagePathAbsolute: If set to
true, will treatimageUrlfromimageUploadFunctionand filePath returned fromimageUploadEndpointas an absolute rather than relative path, i.e. not prependwindow.location.originto it. - imageCSRFToken: CSRF token to include with AJAX call to upload image. For various instances like Django, Spring and Laravel.
- imageCSRFName: CSRF token filed name to include with AJAX call to upload image, applied when
imageCSRFTokenhas value, defaults tocsrfmiddlewaretoken. - imageCSRFHeader: If set to
true, passing CSRF token via header. Defaults tofalse, which pass CSRF through request body. - imageTexts: Texts displayed to the user (mainly on the status bar) for the import image feature, where
#image_name#,#image_size#and#image_max_size#will replaced by their respective values, that can be used for customization or internationalization:- sbInit: Status message displayed initially if
uploadImageis set totrue. Defaults toAttach files by drag and dropping or pasting from clipboard.. - sbOnDragEnter: Status message displayed when the user drags a file to the text area. Defaults to
Drop image to upload it.. - sbOnDrop: Status message displayed when the user drops a file in the text area. Defaults to
Uploading images #images_names#. - sbProgress: Status message displayed to show uploading progress. Defaults to
Uploading #file_name#: #progress#%. - sbOnUploaded: Status message displayed when the image has been uploaded. Defaults to
Uploaded #image_name#. - sizeUnits: A comma-separated list of units used to display messages with human-readable file sizes. Defaults to
B, KB, MB(example:218 KB). You can useB,KB,MBinstead if you prefer without whitespaces (218KB).
- sbInit: Status message displayed initially if
- errorMessages: Errors displayed to the user, using the
errorCallbackoption, where#image_name#,#image_size#and#image_max_size#will replaced by their respective values, that can be used for customization or internationalization:- noFileGiven: The server did not receive any file from the user. Defaults to
You must select a file.. - typeNotAllowed: The user send a file type which doesn't match the
imageAcceptlist, or the server returned this error code. Defaults toThis image type is not allowed.. - fileTooLarge: The size of the image being imported is bigger than the
imageMaxSize, or if the server returned this error code. Defaults toImage #image_name# is too big (#image_size#).\nMaximum file size is #image_max_size#.. - importError: An unexpected error occurred when uploading the image. Defaults to
Something went wrong when uploading the image #image_name#..
- noFileGiven: The server did not receive any file from the user. Defaults to
- errorCallback: A callback function used to define how to display an error message. Defaults to
(errorMessage) => alert(errorMessage). - renderingConfig: Adjust settings for parsing the Markdown during previewing (not editing).
- codeSyntaxHighlighting: If set to
true, will highlight using highlight.js. Defaults tofalse. To use this feature you must include highlight.js on your page or pass in using thehljsoption. For example, include the script and the CSS files like:<script src="https://cdn.jsdelivr.net/highlight.js/latest/highlight.min.js"></script><link rel="stylesheet" href="https://cdn.jsdelivr.net/highlight.js/latest/styles/github.min.css"> - hljs: An injectible instance of highlight.js. If you don't want to rely on the global namespace (
window.hljs), you can provide an instance here. Defaults toundefined. - markedOptions: Set the internal Markdown renderer's options. Other
renderingConfigoptions will take precedence. - singleLineBreaks: If set to
false, disable parsing GitHub Flavored Markdown (GFM) single line breaks. Defaults totrue. - sanitizerFunction: Custom function for sanitizing the HTML output of Markdown renderer.
- codeSyntaxHighlighting: If set to
- shortcuts: Keyboard shortcuts associated with this instance. Defaults to the array of shortcuts.
- showIcons: An array of icon names to show. Can be used to show specific icons hidden by default without completely customizing the toolbar.
- spellChecker: If set to
false, disable the spell checker. Defaults totrue. Optionally pass a CodeMirrorSpellChecker-compliant function. - inputStyle:
textareaorcontenteditable. Defaults totextareafor desktop andcontenteditablefor mobile.contenteditableoption is necessary to enable nativeSpellcheck. - nativeSpellcheck: If set to
false, disable native spell checker. Defaults totrue. - sideBySideFullscreen: If set to
false, allows side-by-side editing without going into fullscreen. Defaults totrue. - status: If set to
false, hide the status bar. Defaults to the array of built-in status bar items.- Optionally, you can set an array of status bar items to include, and in what order. You can even define your own custom status bar items.
- styleSelectedText: If set to
false, remove theCodeMirror-selectedtextclass from selected lines. Defaults totrue. - syncSideBySidePreviewScroll: If set to
false, disable syncing scroll in side by side mode. Defaults totrue. - tabSize: If set, customize the tab size. Defaults to
2. - theme: Override the theme. Defaults to
easymde. - toolbar: If set to
false, hide the toolbar. Defaults to the array of icons. - toolbarTips: If set to
false, disable toolbar button tips. Defaults totrue. - direction:
rtlorltr. Changes text direction to support right-to-left languages. Defaults toltr.
Options example
Most options demonstrate the non-default behavior:
const editor = new EasyMDE({
autofocus: true,
autosave: {
enabled: true,
uniqueId: "MyUniqueID",
delay: 1000,
submit_delay: 5000,
timeFormat: {
locale: 'en-US',
format: {
year: 'numeric',
month: 'long',
day: '2-digit',
hour: '2-digit',
minute: '2-digit',
},
},
text: "Autosaved: "
},
blockStyles: {
bold: "__",
italic: "_",
},
unorderedListStyle: "-",
element: document.getElementById("MyID"),
forceSync: true,
hideIcons: ["guide", "heading"],
indentWithTabs: false,
initialValue: "Hello world!",
insertTexts: {
horizontalRule: ["", "\n\n-----\n\n"],
image: ["![](http://", ")"],
link: ["[", "](https://)"],
table: ["", "\n\n| Column 1 | Column 2 | Column 3 |\n| -------- | -------- | -------- |\n| Text | Text | Text |\n\n"],
},
lineWrapping: false,
minHeight: "500px",
parsingConfig: {
allowAtxHeaderWithoutSpace: true,
strikethrough: false,
underscoresBreakWords: true,
},
placeholder: "Type here...",
previewClass: "my-custom-styling",
previewClass: ["my-custom-styling", "more-custom-styling"],
previewRender: (plainText) => customMarkdownParser(plainText), // Returns HTML from a custom parser
previewRender: (plainText, preview) => { // Async method
setTimeout(() => {
preview.innerHTML = customMarkdownParser(plainText);
}, 250);
return "Loading...";
},
promptURLs: true,
promptTexts: {
image: "Custom prompt for URL:",
link: "Custom prompt for URL:",
},
renderingConfig: {
singleLineBreaks: false,
codeSyntaxHighlighting: true,
sanitizerFunction: (renderedHTML) => {
// Using DOMPurify and only allowing <b> tags
return DOMPurify.sanitize(renderedHTML, {ALLOWED_TAGS: ['b']})
},
},
shortcuts: {
drawTable: "Cmd-Alt-T"
},
showIcons: ["code", "table"],
spellChecker: false,
status: false,
status: ["autosave", "lines", "words", "cursor"], // Optional usage
status: ["autosave", "lines", "words", "cursor", {
className: "keystrokes",
defaultValue: (el) => {
el.setAttribute('data-keystrokes', 0);
},
onUpdate: (el) => {
const keystrokes = Number(el.getAttribute('data-keystrokes')) + 1;
el.innerHTML = `${keystrokes} Keystrokes`;
el.setAttribute('data-keystrokes', keystrokes);
},
}], // Another optional usage, with a custom status bar item that counts keystrokes
styleSelectedText: false,
sideBySideFullscreen: false,
syncSideBySidePreviewScroll: false,
tabSize: 4,
toolbar: false,
toolbarTips: false,
});
Toolbar icons
Below are the built-in toolbar icons (only some of which are enabled by default), which can be reorganized however you like. "Name" is the name of the icon, referenced in the JavaScript. "Action" is either a function or a URL to open. "Class" is the class given to the icon. "Tooltip" is the small tooltip that appears via the title="" attribute. Note that shortcut hints are added automatically and reflect the specified action if it has a key bind assigned to it (i.e. with the value of action set to bold and that of tooltip set to Bold, the final text the user will see would be "Bold (Ctrl-B)").
Additionally, you can add a separator between any icons by adding "|" to the toolbar array.
| Name | Action | Tooltip Class |
|---|---|---|
| bold | toggleBold | Bold fa fa-bold |
| italic | toggleItalic | Italic fa fa-italic |
| strikethrough | toggleStrikethrough | Strikethrough fa fa-strikethrough |
| heading | toggleHeadingSmaller | Heading fa fa-header |
| heading-smaller | toggleHeadingSmaller | Smaller Heading fa fa-header |
| heading-bigger | toggleHeadingBigger | Bigger Heading fa fa-lg fa-header |
| heading-1 | toggleHeading1 | Big Heading fa fa-header header-1 |
| heading-2 | toggleHeading2 | Medium Heading fa fa-header header-2 |
| heading-3 | toggleHeading3 | Small Heading fa fa-header header-3 |
| code | toggleCodeBlock | Code fa fa-code |
| quote | toggleBlockquote | Quote fa fa-quote-left |
| unordered-list | toggleUnorderedList | Generic List fa fa-list-ul |
| ordered-list | toggleOrderedList | Numbered List fa fa-list-ol |
| clean-block | cleanBlock | Clean block fa fa-eraser |
| link | drawLink | Create Link fa fa-link |
| image | drawImage | Insert Image fa fa-picture-o |
| table | drawTable | Insert Table fa fa-table |
| horizontal-rule | drawHorizontalRule | Insert Horizontal Line fa fa-minus |
| preview | togglePreview | Toggle Preview fa fa-eye no-disable |
| side-by-side | toggleSideBySide | Toggle Side by Side fa fa-columns no-disable no-mobile |
| fullscreen | toggleFullScreen | Toggle Fullscreen fa fa-arrows-alt no-disable no-mobile |
| guide | This link | Markdown Guide fa fa-question-circle |
| undo | undo | Undo fa fa-undo |
| redo | redo | Redo fa fa-redo |
Toolbar customization
Customize the toolbar using the toolbar option.
Only the order of existing buttons:
const easyMDE = new EasyMDE({
toolbar: ["bold", "italic", "heading", "|", "quote"]
});
All information and/or add your own icons
const easyMDE = new EasyMDE({
toolbar: [
{
name: "bold",
action: EasyMDE.toggleBold,
className: "fa fa-bold",
title: "Bold",
},
"italics", // shortcut to pre-made button
{
name: "custom",
action: (editor) => {
// Add your own code
},
className: "fa fa-star",
title: "Custom Button",
attributes: { // for custom attributes
id: "custom-id",
"data-value": "custom value" // HTML5 data-* attributes need to be enclosed in quotation marks ("") because of the dash (-) in its name.
}
},
"|" // Separator
// [, ...]
]
});
Put some buttons on dropdown menu
const easyMDE = new EasyMDE({
toolbar: [{
name: "heading",
action: EasyMDE.toggleHeadingSmaller,
className: "fa fa-header",
title: "Headers",
},
"|",
{
name: "others",
className: "fa fa-blind",
title: "others buttons",
children: [
{
name: "image",
action: EasyMDE.drawImage,
className: "fa fa-picture-o",
title: "Image",
},
{
name: "quote",
action: EasyMDE.toggleBlockquote,
className: "fa fa-percent",
title: "Quote",
},
{
name: "link",
action: EasyMDE.drawLink,
className: "fa fa-link",
title: "Link",
}
]
},
// [, ...]
]
});
Keyboard shortcuts
EasyMDE comes with an array of predefined keyboard shortcuts, but they can be altered with a configuration option. The list of default ones is as follows:
| Shortcut (Windows / Linux) | Shortcut (macOS) | Action |
|---|---|---|
| Ctrl-' | Cmd-' | "toggleBlockquote" |
| Ctrl-B | Cmd-B | "toggleBold" |
| Ctrl-E | Cmd-E | "cleanBlock" |
| Ctrl-H | Cmd-H | "toggleHeadingSmaller" |
| Ctrl-I | Cmd-I | "toggleItalic" |
| Ctrl-K | Cmd-K | "drawLink" |
| Ctrl-L | Cmd-L | "toggleUnorderedList" |
| Ctrl-P | Cmd-P | "togglePreview" |
| Ctrl-Alt-C | Cmd-Alt-C | "toggleCodeBlock" |
| Ctrl-Alt-I | Cmd-Alt-I | "drawImage" |
| Ctrl-Alt-L | Cmd-Alt-L | "toggleOrderedList" |
| Shift-Ctrl-H | Shift-Cmd-H | "toggleHeadingBigger" |
| F9 | F9 | "toggleSideBySide" |
| F11 | F11 | "toggleFullScreen" |
Here is how you can change a few, while leaving others untouched:
const editor = new EasyMDE({
shortcuts: {
"toggleOrderedList": "Ctrl-Alt-K", // alter the shortcut for toggleOrderedList
"toggleCodeBlock": null, // unbind Ctrl-Alt-C
"drawTable": "Cmd-Alt-T", // bind Cmd-Alt-T to drawTable action, which doesn't come with a default shortcut
}
});
Shortcuts are automatically converted between platforms. If you define a shortcut as "Cmd-B", on PC that shortcut will be changed to "Ctrl-B". Conversely, a shortcut defined as "Ctrl-B" will become "Cmd-B" for Mac users.
The list of actions that can be bound is the same as the list of built-in actions available for toolbar buttons.
Advanced use
Event handling
You can catch the following list of events: https://codemirror.net/doc/manual.html#events
const easyMDE = new EasyMDE();
easyMDE.codemirror.on("change", () => {
console.log(easyMDE.value());
});
Removing EasyMDE from text area
You can revert to the initial text area by calling the toTextArea method. Note that this clears up the autosave (if enabled) associated with it. The text area will retain any text from the destroyed EasyMDE instance.
const easyMDE = new EasyMDE();
// ...
easyMDE.toTextArea();
easyMDE = null;
If you need to remove registered event listeners (when the editor is not needed anymore), call easyMDE.cleanup().
Useful methods
The following self-explanatory methods may be of use while developing with EasyMDE.
const easyMDE = new EasyMDE();
easyMDE.isPreviewActive(); // returns boolean
easyMDE.isSideBySideActive(); // returns boolean
easyMDE.isFullscreenActive(); // returns boolean
easyMDE.clearAutosavedValue(); // no returned value
How it works
EasyMDE is a continuation of SimpleMDE.
SimpleMDE began as an improvement of lepture's Editor project, but has now taken on an identity of its own. It is bundled with CodeMirror and depends on Font Awesome.
CodeMirror is the backbone of the project and parses much of the Markdown syntax as it's being written. This allows us to add styles to the Markdown that's being written. Additionally, a toolbar and status bar have been added to the top and bottom, respectively. Previews are rendered by Marked using GitHub Flavored Markdown (GFM).
SimpleMDE fork
I originally made this fork to implement FontAwesome 5 compatibility into SimpleMDE. When that was done I submitted a pull request, which has not been accepted yet. This, and the project being inactive since May 2017, triggered me to make more changes and try to put new life into the project.
Changes include:
- FontAwesome 5 compatibility
- Guide button works when editor is in preview mode
- Links are now
https://by default - Small styling changes
- Support for Node 8 and beyond
- Lots of refactored code
- Links in preview will open in a new tab by default
- TypeScript support
My intention is to continue development on this project, improving it and keeping it alive.
Hacking EasyMDE
You may want to edit this library to adapt its behavior to your needs. This can be done in some quick steps:
- Follow the prerequisites and installation instructions in the contribution guide;
- Do your changes;
- Run
gulpcommand, which will generate files:dist/easymde.min.cssanddist/easymde.min.js; - Copy-paste those files to your code base, and you are done.
Contributing
Want to contribute to EasyMDE? Thank you! We have a contribution guide just for you!
Author: Ionaru
Source Code: https://github.com/Ionaru/easy-markdown-editor
License: MIT license
1679035563
How to Add Splash Screen in Android and iOS with Flutter
When your app is opened, there is a brief time while the native app loads Flutter. By default, during this time, the native app displays a white splash screen. This package automatically generates iOS, Android, and Web-native code for customizing this native splash screen background color and splash image. Supports dark mode, full screen, and platform-specific options.
What's New
[BETA] Support for flavors is in beta. Currently only Android and iOS are supported. See instructions below.
You can now keep the splash screen up while your app initializes! No need for a secondary splash screen anymore. Just use the preserve and remove methods together to remove the splash screen after your initialization is complete. See details below.
Usage
Would you prefer a video tutorial instead? Check out Johannes Milke's tutorial.
First, add flutter_native_splash as a dependency in your pubspec.yaml file.
dependencies:
flutter_native_splash: ^2.2.19
Don't forget to flutter pub get.
1. Setting the splash screen
Customize the following settings and add to your project's pubspec.yaml file or place in a new file in your root project folder named flutter_native_splash.yaml.
flutter_native_splash:
# This package generates native code to customize Flutter's default white native splash screen
# with background color and splash image.
# Customize the parameters below, and run the following command in the terminal:
# flutter pub run flutter_native_splash:create
# To restore Flutter's default white splash screen, run the following command in the terminal:
# flutter pub run flutter_native_splash:remove
# color or background_image is the only required parameter. Use color to set the background
# of your splash screen to a solid color. Use background_image to set the background of your
# splash screen to a png image. This is useful for gradients. The image will be stretch to the
# size of the app. Only one parameter can be used, color and background_image cannot both be set.
color: "#42a5f5"
#background_image: "assets/background.png"
# Optional parameters are listed below. To enable a parameter, uncomment the line by removing
# the leading # character.
# The image parameter allows you to specify an image used in the splash screen. It must be a
# png file and should be sized for 4x pixel density.
#image: assets/splash.png
# The branding property allows you to specify an image used as branding in the splash screen.
# It must be a png file. It is supported for Android, iOS and the Web. For Android 12,
# see the Android 12 section below.
#branding: assets/dart.png
# To position the branding image at the bottom of the screen you can use bottom, bottomRight,
# and bottomLeft. The default values is bottom if not specified or specified something else.
#branding_mode: bottom
# The color_dark, background_image_dark, image_dark, branding_dark are parameters that set the background
# and image when the device is in dark mode. If they are not specified, the app will use the
# parameters from above. If the image_dark parameter is specified, color_dark or
# background_image_dark must be specified. color_dark and background_image_dark cannot both be
# set.
#color_dark: "#042a49"
#background_image_dark: "assets/dark-background.png"
#image_dark: assets/splash-invert.png
#branding_dark: assets/dart_dark.png
# Android 12 handles the splash screen differently than previous versions. Please visit
# https://developer.android.com/guide/topics/ui/splash-screen
# Following are Android 12 specific parameter.
android_12:
# The image parameter sets the splash screen icon image. If this parameter is not specified,
# the app's launcher icon will be used instead.
# Please note that the splash screen will be clipped to a circle on the center of the screen.
# App icon with an icon background: This should be 960×960 pixels, and fit within a circle
# 640 pixels in diameter.
# App icon without an icon background: This should be 1152×1152 pixels, and fit within a circle
# 768 pixels in diameter.
#image: assets/android12splash.png
# Splash screen background color.
#color: "#42a5f5"
# App icon background color.
#icon_background_color: "#111111"
# The branding property allows you to specify an image used as branding in the splash screen.
#branding: assets/dart.png
# The image_dark, color_dark, icon_background_color_dark, and branding_dark set values that
# apply when the device is in dark mode. If they are not specified, the app will use the
# parameters from above.
#image_dark: assets/android12splash-invert.png
#color_dark: "#042a49"
#icon_background_color_dark: "#eeeeee"
# The android, ios and web parameters can be used to disable generating a splash screen on a given
# platform.
#android: false
#ios: false
#web: false
# Platform specific images can be specified with the following parameters, which will override
# the respective parameter. You may specify all, selected, or none of these parameters:
#color_android: "#42a5f5"
#color_dark_android: "#042a49"
#color_ios: "#42a5f5"
#color_dark_ios: "#042a49"
#color_web: "#42a5f5"
#color_dark_web: "#042a49"
#image_android: assets/splash-android.png
#image_dark_android: assets/splash-invert-android.png
#image_ios: assets/splash-ios.png
#image_dark_ios: assets/splash-invert-ios.png
#image_web: assets/splash-web.png
#image_dark_web: assets/splash-invert-web.png
#background_image_android: "assets/background-android.png"
#background_image_dark_android: "assets/dark-background-android.png"
#background_image_ios: "assets/background-ios.png"
#background_image_dark_ios: "assets/dark-background-ios.png"
#background_image_web: "assets/background-web.png"
#background_image_dark_web: "assets/dark-background-web.png"
#branding_android: assets/brand-android.png
#branding_dark_android: assets/dart_dark-android.png
#branding_ios: assets/brand-ios.png
#branding_dark_ios: assets/dart_dark-ios.png
# The position of the splash image can be set with android_gravity, ios_content_mode, and
# web_image_mode parameters. All default to center.
#
# android_gravity can be one of the following Android Gravity (see
# https://developer.android.com/reference/android/view/Gravity): bottom, center,
# center_horizontal, center_vertical, clip_horizontal, clip_vertical, end, fill, fill_horizontal,
# fill_vertical, left, right, start, or top.
#android_gravity: center
#
# ios_content_mode can be one of the following iOS UIView.ContentMode (see
# https://developer.apple.com/documentation/uikit/uiview/contentmode): scaleToFill,
# scaleAspectFit, scaleAspectFill, center, top, bottom, left, right, topLeft, topRight,
# bottomLeft, or bottomRight.
#ios_content_mode: center
#
# web_image_mode can be one of the following modes: center, contain, stretch, and cover.
#web_image_mode: center
# The screen orientation can be set in Android with the android_screen_orientation parameter.
# Valid parameters can be found here:
# https://developer.android.com/guide/topics/manifest/activity-element#screen
#android_screen_orientation: sensorLandscape
# To hide the notification bar, use the fullscreen parameter. Has no effect in web since web
# has no notification bar. Defaults to false.
# NOTE: Unlike Android, iOS will not automatically show the notification bar when the app loads.
# To show the notification bar, add the following code to your Flutter app:
# WidgetsFlutterBinding.ensureInitialized();
# SystemChrome.setEnabledSystemUIOverlays([SystemUiOverlay.bottom, SystemUiOverlay.top]);
#fullscreen: true
# If you have changed the name(s) of your info.plist file(s), you can specify the filename(s)
# with the info_plist_files parameter. Remove only the # characters in the three lines below,
# do not remove any spaces:
#info_plist_files:
# - 'ios/Runner/Info-Debug.plist'
# - 'ios/Runner/Info-Release.plist'
2. Run the package
After adding your settings, run the following command in the terminal:
flutter pub run flutter_native_splash:create
When the package finishes running, your splash screen is ready.
To specify the YAML file location just add --path with the command in the terminal:
flutter pub run flutter_native_splash:create --path=path/to/my/file.yaml
3. Set up app initialization (optional)
By default, the splash screen will be removed when Flutter has drawn the first frame. If you would like the splash screen to remain while your app initializes, you can use the preserve() and remove() methods together. Pass the preserve() method the value returned from WidgetsFlutterBinding.ensureInitialized() to keep the splash on screen. Later, when your app has initialized, make a call to remove() to remove the splash screen.
import 'package:flutter_native_splash/flutter_native_splash.dart';
void main() {
WidgetsBinding widgetsBinding = WidgetsFlutterBinding.ensureInitialized();
FlutterNativeSplash.preserve(widgetsBinding: widgetsBinding);
runApp(const MyApp());
}
// whenever your initialization is completed, remove the splash screen:
FlutterNativeSplash.remove();
NOTE: If you do not need to use the preserve() and remove() methods, you can place the flutter_native_splash dependency in the dev_dependencies section of pubspec.yaml.
4. Support the package (optional)
If you find this package useful, you can support it for free by giving it a thumbs up at the top of this page. Here's another option to support the package:
Android 12+ Support
Android 12 has a new method of adding splash screens, which consists of a window background, icon, and the icon background. Note that a background image is not supported.
Be aware of the following considerations regarding these elements:
1: image parameter. By default, the launcher icon is used:
- App icon without an icon background, as shown on the left: This should be 1152×1152 pixels, and fit within a circle 768 pixels in diameter.
- App icon with an icon background, as shown on the right: This should be 960×960 pixels, and fit within a circle 640 pixels in diameter.
2: icon_background_color is optional, and is useful if you need more contrast between the icon and the window background.
3: One-third of the foreground is masked.
4: color the window background consists of a single opaque color.
PLEASE NOTE: The splash screen may not appear when you launch the app from Android Studio on API 31. However, it should appear when you launch by clicking on the launch icon in Android. This seems to be resolved in API 32+.
PLEASE NOTE: There are a number of reports that non-Google launchers do not display the launch image correctly. If the launch image does not display correctly, please try the Google launcher to confirm that this package is working.
PLEASE NOTE: The splash screen does not appear when you launch the app from a notification. Apparently this is the intended behavior on Android 12: core-splashscreen Icon not shown when cold launched from notification.
Flavor Support
If you have a project setup that contains multiple flavors or environments, and you created more than one flavor this would be a feature for you.
Instead of maintaining multiple files and copy/pasting images, you can now, using this tool, create different splash screens for different environments.
Pre-requirements
In order to use the new feature, and generate the desired splash images for you app, a couple of changes are required.
If you want to generate just one flavor and one file you would use either options as described in Step 1. But in order to setup the flavors, you will then be required to move all your setup values to the flutter_native_splash.yaml file, but with a prefix.
Let's assume for the rest of the setup that you have 3 different flavors, Production, Acceptance, Development.
First this you will need to do is to create a different setup file for all 3 flavors with a suffix like so:
flutter_native_splash-production.yaml
flutter_native_splash-acceptance.yaml
flutter_native_splash-development.yaml
You would setup those 3 files the same way as you would the one, but with different assets depending on which environment you would be generating. For example (Note: these are just examples, you can use whatever setup you need for your project that is already supported by the package):
# flutter_native_splash-development.yaml
flutter_native_splash:
color: "#ffffff"
image: assets/logo-development.png
branding: assets/branding-development.png
color_dark: "#121212"
image_dark: assets/logo-development.png
branding_dark: assets/branding-development.png
android_12:
image: assets/logo-development.png
icon_background_color: "#ffffff"
image_dark: assets/logo-development.png
icon_background_color_dark: "#121212"
web: false
# flutter_native_splash-acceptance.yaml
flutter_native_splash:
color: "#ffffff"
image: assets/logo-acceptance.png
branding: assets/branding-acceptance.png
color_dark: "#121212"
image_dark: assets/logo-acceptance.png
branding_dark: assets/branding-acceptance.png
android_12:
image: assets/logo-acceptance.png
icon_background_color: "#ffffff"
image_dark: assets/logo-acceptance.png
icon_background_color_dark: "#121212"
web: false
# flutter_native_splash-production.yaml
flutter_native_splash:
color: "#ffffff"
image: assets/logo-production.png
branding: assets/branding-production.png
color_dark: "#121212"
image_dark: assets/logo-production.png
branding_dark: assets/branding-production.png
android_12:
image: assets/logo-production.png
icon_background_color: "#ffffff"
image_dark: assets/logo-production.png
icon_background_color_dark: "#121212"
web: false
Great, now comes the fun part running the new command!
The new command is:
# If you have a flavor called production you would do this:
flutter pub run flutter_native_splash:create --flavor production
# For a flavor with a name staging you would provide it's name like so:
flutter pub run flutter_native_splash:create --flavor staging
# And if you have a local version for devs you could do that:
flutter pub run flutter_native_splash:create --flavor development
Android setup
You're done! No, really, Android doesn't need any additional setup.
Note: If it didn't work, please make sure that your flavors are named the same as your config files, otherwise the setup will not work.
iOS setup
iOS is a bit tricky, so hang tight, it might look scary but most of the steps are just a single click, explained as much as possible to lower the possibility of mistakes.
When you run the new command, you will need to open xCode and follow the steps bellow:
Assumption
- In order for this setup to work, you would already have 3 different
schemessetup; production, acceptance and development.
Preparation
- Open the iOS Flutter project in Xcode (open the Runner.xcworkspace)
- Find the newly created Storyboard files at the same location where the original is
{project root}/ios/Runner/Base.lproj - Select all of them and drag and drop into Xcode, directly to the left hand side where the current LaunchScreen.storyboard is located already
- After you drop your files there Xcode will ask you to link them, make sure you select 'Copy if needed'
- This part is done, you have linked the newly created storyboards in your project.
xCode
Xcode still doesn't know how to use them, so we need to specify for all the current flavors (schemes) which file to use and to use that value inside the Info.plist file.
- Open the iOS Flutter project in Xcode (open the Runner.xcworkspace)
- Click the Runner project in the top left corner (usually the first item in the list)
- In the middle part of the screen, on the left side, select the Runner target
- On the top part of the screen select Build Settings
- Make sure that 'All' and 'Combined' are selected
- Next to 'Combine' you have a '+' button, press it and select 'Add User-Defined Setting'
- Once you do that Xcode will create a new variable for you to name. Suggestion is to name it
LAUNCH_SCREEN_STORYBOARD - Once you do that, you will have the option to define a specific name for each flavor (scheme) that you have defined in the project. Make sure that you input the exact name of the LaunchScreen.storyboard that was created by this tool
- Example: If you have a flavor Development, there is a Storyboard created name LaunchScreenDevelopment.storyboard, please add that name (without the storyboard part) to the variable value next to the flavor value
- After you finish with that, you need to update Info.plist file to link the newly created variable so that it's used correctly
- Open the Info.plist file
- Find the entry called 'Launch screen interface file base name'
- The default value is 'LaunchScreen', change that to the variable name that you create previously. If you follow these steps exactly, it would be LAUNCH_SCREEN_STORYBOARD, so input this
$(LAUNCH_SCREEN_STORYBOARD) - And your done!
Congrats you finished your setup for multiple flavors,
FAQs
I got the error "A splash screen was provided to Flutter, but this is deprecated."
This message is not related to this package but is related to a change in how Flutter handles splash screens in Flutter 2.5. It is caused by having the following code in your android/app/src/main/AndroidManifest.xml, which was included by default in previous versions of Flutter:
<meta-data
android:name="io.flutter.embedding.android.SplashScreenDrawable"
android:resource="@drawable/launch_background"
/>
The solution is to remove the above code. Note that this will also remove the fade effect between the native splash screen and your app.
Are animations/lottie/GIF images supported?
Not at this time. PRs are always welcome!
I got the error AAPT: error: style attribute 'android:attr/windowSplashScreenBackground' not found
This attribute is only found in Android 12, so if you are getting this error, it means your project is not fully set up for Android 12. Did you update your app's build configuration?
I see a flash of the wrong splash screen on iOS
This is caused by an iOS splash caching bug, which can be solved by uninstalling your app, powering off your device, power back on, and then try reinstalling.
I see a white screen between splash screen and app
- It may be caused by an iOS splash caching bug, which can be solved by uninstalling your app, powering off your device, power back on, and then try reinstalling.
- It may be caused by the delay due to initialization in your app. To solve this, put any initialization code in the
removeAftermethod.
Can I base light/dark mode on app settings?
No. This package creates a splash screen that is displayed before Flutter is loaded. Because of this, when the splash screen loads, internal app settings are not available to the splash screen. Unfortunately, this means that it is impossible to control light/dark settings of the splash from app settings.
Notes
If the splash screen was not updated correctly on iOS or if you experience a white screen before the splash screen, run flutter clean and recompile your app. If that does not solve the problem, delete your app, power down the device, power up the device, install and launch the app as per this StackOverflow thread.
This package modifies launch_background.xml and styles.xml files on Android, LaunchScreen.storyboard and Info.plist on iOS, and index.html on Web. If you have modified these files manually, this plugin may not work properly. Please open an issue if you find any bugs.
How it works
Android
- Your splash image will be resized to
mdpi,hdpi,xhdpi,xxhdpiandxxxhdpidrawables. - An
<item>tag containing a<bitmap>for your splash image drawable will be added inlaunch_background.xml - Background color will be added in
colors.xmland referenced inlaunch_background.xml. - Code for full screen mode toggle will be added in
styles.xml. - Dark mode variants are placed in
drawable-night,values-night, etc. resource folders.
iOS
- Your splash image will be resized to
@3xand@2ximages. - Color and image properties will be inserted in
LaunchScreen.storyboard. - The background color is implemented by using a single-pixel png file and stretching it to fit the screen.
- Code for hidden status bar toggle will be added in
Info.plist.
Web
- A
web/splashfolder will be created for splash screen images and CSS files. - Your splash image will be resized to
1x,2x,3x, and4xsizes and placed inweb/splash/img. - The splash style sheet will be added to the app's
web/index.html, as well as the HTML for the splash pictures.
Acknowledgments
This package was originally created by Henrique Arthur and it is currently maintained by Jon Hanson.
Bugs or Requests
If you encounter any problems feel free to open an issue. If you feel the library is missing a feature, please raise a ticket. Pull request are also welcome.
Use this package as a library
Depend on it
Run this command:
With Flutter:
$ flutter pub add flutter_native_splashThis will add a line like this to your package's pubspec.yaml (and run an implicit flutter pub get):
dependencies:
flutter_native_splash: ^2.2.19Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more.
Import it
Now in your Dart code, you can use:
import 'package:flutter_native_splash/flutter_native_splash.dart';example/lib/main.dart
import 'package:flutter/material.dart';
import 'package:flutter_native_splash/flutter_native_splash.dart';
void main() {
WidgetsBinding widgetsBinding = WidgetsFlutterBinding.ensureInitialized();
FlutterNativeSplash.preserve(widgetsBinding: widgetsBinding);
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key, required this.title});
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
});
}
@override
void initState() {
super.initState();
initialization();
}
void initialization() async {
// This is where you can initialize the resources needed by your app while
// the splash screen is displayed. Remove the following example because
// delaying the user experience is a bad design practice!
// ignore_for_file: avoid_print
print('ready in 3...');
await Future.delayed(const Duration(seconds: 1));
print('ready in 2...');
await Future.delayed(const Duration(seconds: 1));
print('ready in 1...');
await Future.delayed(const Duration(seconds: 1));
print('go!');
FlutterNativeSplash.remove();
}
@override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child: Column(
// Column is also a layout widget. It takes a list of children and
// arranges them vertically. By default, it sizes itself to fit its
// children horizontally, and tries to be as tall as its parent.
//
// Invoke "debug painting" (press "p" in the console, choose the
// "Toggle Debug Paint" action from the Flutter Inspector in Android
// Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
// to see the wireframe for each widget.
//
// Column has various properties to control how it sizes itself and
// how it positions its children. Here we use mainAxisAlignment to
// center the children vertically; the main axis here is the vertical
// axis because Columns are vertical (the cross axis would be
// horizontal).
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headlineMedium,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: const Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
Download Details:
Author: jonbhanson
Download Link: Download The Source Code
Official Website: https://github.com/jonbhanson/flutter_native_splash
License: MIT license
1667425440
Pdf2gerb: Perl Script Converts PDF Files to Gerber format
pdf2gerb
Perl script converts PDF files to Gerber format
Pdf2Gerb generates Gerber 274X photoplotting and Excellon drill files from PDFs of a PCB. Up to three PDFs are used: the top copper layer, the bottom copper layer (for 2-sided PCBs), and an optional silk screen layer. The PDFs can be created directly from any PDF drawing software, or a PDF print driver can be used to capture the Print output if the drawing software does not directly support output to PDF.
The general workflow is as follows:
- Design the PCB using your favorite CAD or drawing software.
- Print the top and bottom copper and top silk screen layers to a PDF file.
- Run Pdf2Gerb on the PDFs to create Gerber and Excellon files.
- Use a Gerber viewer to double-check the output against the original PCB design.
- Make adjustments as needed.
- Submit the files to a PCB manufacturer.
Please note that Pdf2Gerb does NOT perform DRC (Design Rule Checks), as these will vary according to individual PCB manufacturer conventions and capabilities. Also note that Pdf2Gerb is not perfect, so the output files must always be checked before submitting them. As of version 1.6, Pdf2Gerb supports most PCB elements, such as round and square pads, round holes, traces, SMD pads, ground planes, no-fill areas, and panelization. However, because it interprets the graphical output of a Print function, there are limitations in what it can recognize (or there may be bugs).
See docs/Pdf2Gerb.pdf for install/setup, config, usage, and other info.
pdf2gerb_cfg.pm
#Pdf2Gerb config settings:
#Put this file in same folder/directory as pdf2gerb.pl itself (global settings),
#or copy to another folder/directory with PDFs if you want PCB-specific settings.
#There is only one user of this file, so we don't need a custom package or namespace.
#NOTE: all constants defined in here will be added to main namespace.
#package pdf2gerb_cfg;
use strict; #trap undef vars (easier debug)
use warnings; #other useful info (easier debug)
##############################################################################################
#configurable settings:
#change values here instead of in main pfg2gerb.pl file
use constant WANT_COLORS => ($^O !~ m/Win/); #ANSI colors no worky on Windows? this must be set < first DebugPrint() call
#just a little warning; set realistic expectations:
#DebugPrint("${\(CYAN)}Pdf2Gerb.pl ${\(VERSION)}, $^O O/S\n${\(YELLOW)}${\(BOLD)}${\(ITALIC)}This is EXPERIMENTAL software. \nGerber files MAY CONTAIN ERRORS. Please CHECK them before fabrication!${\(RESET)}", 0); #if WANT_DEBUG
use constant METRIC => FALSE; #set to TRUE for metric units (only affect final numbers in output files, not internal arithmetic)
use constant APERTURE_LIMIT => 0; #34; #max #apertures to use; generate warnings if too many apertures are used (0 to not check)
use constant DRILL_FMT => '2.4'; #'2.3'; #'2.4' is the default for PCB fab; change to '2.3' for CNC
use constant WANT_DEBUG => 0; #10; #level of debug wanted; higher == more, lower == less, 0 == none
use constant GERBER_DEBUG => 0; #level of debug to include in Gerber file; DON'T USE FOR FABRICATION
use constant WANT_STREAMS => FALSE; #TRUE; #save decompressed streams to files (for debug)
use constant WANT_ALLINPUT => FALSE; #TRUE; #save entire input stream (for debug ONLY)
#DebugPrint(sprintf("${\(CYAN)}DEBUG: stdout %d, gerber %d, want streams? %d, all input? %d, O/S: $^O, Perl: $]${\(RESET)}\n", WANT_DEBUG, GERBER_DEBUG, WANT_STREAMS, WANT_ALLINPUT), 1);
#DebugPrint(sprintf("max int = %d, min int = %d\n", MAXINT, MININT), 1);
#define standard trace and pad sizes to reduce scaling or PDF rendering errors:
#This avoids weird aperture settings and replaces them with more standardized values.
#(I'm not sure how photoplotters handle strange sizes).
#Fewer choices here gives more accurate mapping in the final Gerber files.
#units are in inches
use constant TOOL_SIZES => #add more as desired
(
#round or square pads (> 0) and drills (< 0):
.010, -.001, #tiny pads for SMD; dummy drill size (too small for practical use, but needed so StandardTool will use this entry)
.031, -.014, #used for vias
.041, -.020, #smallest non-filled plated hole
.051, -.025,
.056, -.029, #useful for IC pins
.070, -.033,
.075, -.040, #heavier leads
# .090, -.043, #NOTE: 600 dpi is not high enough resolution to reliably distinguish between .043" and .046", so choose 1 of the 2 here
.100, -.046,
.115, -.052,
.130, -.061,
.140, -.067,
.150, -.079,
.175, -.088,
.190, -.093,
.200, -.100,
.220, -.110,
.160, -.125, #useful for mounting holes
#some additional pad sizes without holes (repeat a previous hole size if you just want the pad size):
.090, -.040, #want a .090 pad option, but use dummy hole size
.065, -.040, #.065 x .065 rect pad
.035, -.040, #.035 x .065 rect pad
#traces:
.001, #too thin for real traces; use only for board outlines
.006, #minimum real trace width; mainly used for text
.008, #mainly used for mid-sized text, not traces
.010, #minimum recommended trace width for low-current signals
.012,
.015, #moderate low-voltage current
.020, #heavier trace for power, ground (even if a lighter one is adequate)
.025,
.030, #heavy-current traces; be careful with these ones!
.040,
.050,
.060,
.080,
.100,
.120,
);
#Areas larger than the values below will be filled with parallel lines:
#This cuts down on the number of aperture sizes used.
#Set to 0 to always use an aperture or drill, regardless of size.
use constant { MAX_APERTURE => max((TOOL_SIZES)) + .004, MAX_DRILL => -min((TOOL_SIZES)) + .004 }; #max aperture and drill sizes (plus a little tolerance)
#DebugPrint(sprintf("using %d standard tool sizes: %s, max aper %.3f, max drill %.3f\n", scalar((TOOL_SIZES)), join(", ", (TOOL_SIZES)), MAX_APERTURE, MAX_DRILL), 1);
#NOTE: Compare the PDF to the original CAD file to check the accuracy of the PDF rendering and parsing!
#for example, the CAD software I used generated the following circles for holes:
#CAD hole size: parsed PDF diameter: error:
# .014 .016 +.002
# .020 .02267 +.00267
# .025 .026 +.001
# .029 .03167 +.00267
# .033 .036 +.003
# .040 .04267 +.00267
#This was usually ~ .002" - .003" too big compared to the hole as displayed in the CAD software.
#To compensate for PDF rendering errors (either during CAD Print function or PDF parsing logic), adjust the values below as needed.
#units are pixels; for example, a value of 2.4 at 600 dpi = .0004 inch, 2 at 600 dpi = .0033"
use constant
{
HOLE_ADJUST => -0.004 * 600, #-2.6, #holes seemed to be slightly oversized (by .002" - .004"), so shrink them a little
RNDPAD_ADJUST => -0.003 * 600, #-2, #-2.4, #round pads seemed to be slightly oversized, so shrink them a little
SQRPAD_ADJUST => +0.001 * 600, #+.5, #square pads are sometimes too small by .00067, so bump them up a little
RECTPAD_ADJUST => 0, #(pixels) rectangular pads seem to be okay? (not tested much)
TRACE_ADJUST => 0, #(pixels) traces seemed to be okay?
REDUCE_TOLERANCE => .001, #(inches) allow this much variation when reducing circles and rects
};
#Also, my CAD's Print function or the PDF print driver I used was a little off for circles, so define some additional adjustment values here:
#Values are added to X/Y coordinates; units are pixels; for example, a value of 1 at 600 dpi would be ~= .002 inch
use constant
{
CIRCLE_ADJUST_MINX => 0,
CIRCLE_ADJUST_MINY => -0.001 * 600, #-1, #circles were a little too high, so nudge them a little lower
CIRCLE_ADJUST_MAXX => +0.001 * 600, #+1, #circles were a little too far to the left, so nudge them a little to the right
CIRCLE_ADJUST_MAXY => 0,
SUBST_CIRCLE_CLIPRECT => FALSE, #generate circle and substitute for clip rects (to compensate for the way some CAD software draws circles)
WANT_CLIPRECT => TRUE, #FALSE, #AI doesn't need clip rect at all? should be on normally?
RECT_COMPLETION => FALSE, #TRUE, #fill in 4th side of rect when 3 sides found
};
#allow .012 clearance around pads for solder mask:
#This value effectively adjusts pad sizes in the TOOL_SIZES list above (only for solder mask layers).
use constant SOLDER_MARGIN => +.012; #units are inches
#line join/cap styles:
use constant
{
CAP_NONE => 0, #butt (none); line is exact length
CAP_ROUND => 1, #round cap/join; line overhangs by a semi-circle at either end
CAP_SQUARE => 2, #square cap/join; line overhangs by a half square on either end
CAP_OVERRIDE => FALSE, #cap style overrides drawing logic
};
#number of elements in each shape type:
use constant
{
RECT_SHAPELEN => 6, #x0, y0, x1, y1, count, "rect" (start, end corners)
LINE_SHAPELEN => 6, #x0, y0, x1, y1, count, "line" (line seg)
CURVE_SHAPELEN => 10, #xstart, ystart, x0, y0, x1, y1, xend, yend, count, "curve" (bezier 2 points)
CIRCLE_SHAPELEN => 5, #x, y, 5, count, "circle" (center + radius)
};
#const my %SHAPELEN =
#Readonly my %SHAPELEN =>
our %SHAPELEN =
(
rect => RECT_SHAPELEN,
line => LINE_SHAPELEN,
curve => CURVE_SHAPELEN,
circle => CIRCLE_SHAPELEN,
);
#panelization:
#This will repeat the entire body the number of times indicated along the X or Y axes (files grow accordingly).
#Display elements that overhang PCB boundary can be squashed or left as-is (typically text or other silk screen markings).
#Set "overhangs" TRUE to allow overhangs, FALSE to truncate them.
#xpad and ypad allow margins to be added around outer edge of panelized PCB.
use constant PANELIZE => {'x' => 1, 'y' => 1, 'xpad' => 0, 'ypad' => 0, 'overhangs' => TRUE}; #number of times to repeat in X and Y directions
# Set this to 1 if you need TurboCAD support.
#$turboCAD = FALSE; #is this still needed as an option?
#CIRCAD pad generation uses an appropriate aperture, then moves it (stroke) "a little" - we use this to find pads and distinguish them from PCB holes.
use constant PAD_STROKE => 0.3; #0.0005 * 600; #units are pixels
#convert very short traces to pads or holes:
use constant TRACE_MINLEN => .001; #units are inches
#use constant ALWAYS_XY => TRUE; #FALSE; #force XY even if X or Y doesn't change; NOTE: needs to be TRUE for all pads to show in FlatCAM and ViewPlot
use constant REMOVE_POLARITY => FALSE; #TRUE; #set to remove subtractive (negative) polarity; NOTE: must be FALSE for ground planes
#PDF uses "points", each point = 1/72 inch
#combined with a PDF scale factor of .12, this gives 600 dpi resolution (1/72 * .12 = 600 dpi)
use constant INCHES_PER_POINT => 1/72; #0.0138888889; #multiply point-size by this to get inches
# The precision used when computing a bezier curve. Higher numbers are more precise but slower (and generate larger files).
#$bezierPrecision = 100;
use constant BEZIER_PRECISION => 36; #100; #use const; reduced for faster rendering (mainly used for silk screen and thermal pads)
# Ground planes and silk screen or larger copper rectangles or circles are filled line-by-line using this resolution.
use constant FILL_WIDTH => .01; #fill at most 0.01 inch at a time
# The max number of characters to read into memory
use constant MAX_BYTES => 10 * M; #bumped up to 10 MB, use const
use constant DUP_DRILL1 => TRUE; #FALSE; #kludge: ViewPlot doesn't load drill files that are too small so duplicate first tool
my $runtime = time(); #Time::HiRes::gettimeofday(); #measure my execution time
print STDERR "Loaded config settings from '${\(__FILE__)}'.\n";
1; #last value must be truthful to indicate successful load
#############################################################################################
#junk/experiment:
#use Package::Constants;
#use Exporter qw(import); #https://perldoc.perl.org/Exporter.html
#my $caller = "pdf2gerb::";
#sub cfg
#{
# my $proto = shift;
# my $class = ref($proto) || $proto;
# my $settings =
# {
# $WANT_DEBUG => 990, #10; #level of debug wanted; higher == more, lower == less, 0 == none
# };
# bless($settings, $class);
# return $settings;
#}
#use constant HELLO => "hi there2"; #"main::HELLO" => "hi there";
#use constant GOODBYE => 14; #"main::GOODBYE" => 12;
#print STDERR "read cfg file\n";
#our @EXPORT_OK = Package::Constants->list(__PACKAGE__); #https://www.perlmonks.org/?node_id=1072691; NOTE: "_OK" skips short/common names
#print STDERR scalar(@EXPORT_OK) . " consts exported:\n";
#foreach(@EXPORT_OK) { print STDERR "$_\n"; }
#my $val = main::thing("xyz");
#print STDERR "caller gave me $val\n";
#foreach my $arg (@ARGV) { print STDERR "arg $arg\n"; }Download Details:
Author: swannman
Source Code: https://github.com/swannman/pdf2gerb
License: GPL-3.0 license
1604402893
Build and Deploy a Spring Boot App on Kubernetes | spring Boot Docker Kubernetes
#spring #spring-framework #spring-boot #docker #devops #kubernetes