Sam  Son

Sam Son

1567220115

Fundamentals of Front End Django

While Django is useful for writing APIs, its main purpose is as a framework for creating full websites. Rendering HTML is one of Django's fundamental abilities, and it uses Jinja templates to make writing flexible, reusable webpages straightforward. This article will teach you how to make a basic website with Django; we will create a login-protected sales dashboard. This project will demonstrate essential techniques of web development with Django: writing views for HTML, authentication with forms, showing data from the DB, and including static assets.

This article will take an iterative approach to developing the webpage. You can start with Python 3 and Django 2.2 installed and follow along, or you can skip ahead and clone the final version from GitHub. If you're building along with me, start by running django-admin startproject dashboardcd dashboard to enter the directory then python manage.py startapp core will create the app. Make sure to add 'core.apps.CoreConfig' to INSTALLED_APPSin settings.py. From there, you will be able to follow along by modifying the individual files.

Whether you started by cloning the project or creating your own, make sure you run python manage.py migrate and python manage.py createsuperuserto finish setup. Run python manage.py runserver to start the Django site.

We'll start by writing a simple view for rendering HTML in a browser. Django supports function-based views and class-based views. In these examples we will use class-based views but that decision comes down to personal preference as both provide the same features with different syntax. Class-based views are most useful when you want to support multiple interactions with a single URL, for example, if you need to support several HTTP methods.

In this article, we're practicing Django, not HTML or CSS. Thus, we're going to use a fantastic open-source template from Start Bootstrap. The template will provide us with all of the HTML, CSS, and JS that we need for this exercise, allowing us to focus on the Django. If you are starting from scratch, download the template and copy the index.html and the login.html files into /core/templates. While we will leave a lot of the functionality in these templates as placeholders, they will help us write an interactive website.

After saving the template to "/core/templates/index.html," we can use the following view in "/core/views.py" to render the page.

from django.shortcuts import render
from django.views import View

class Index(View):
template = ‘index.html’

def get(self, request):
    return render(request, self.template)

Then, add the route to “/dashboard/urls.py” as follows:

from django.contrib import admin
from django.urls import path
from core import views

urlpatterns = [
path(‘admin/’, admin.site.urls),
path(‘’, views.Index.as_view(), name=‘index’)
]

With the view written, when we run the server and navigate to http://127.0.0.1:8000, we see the page.

Right now, the page doesn’t look very good. Fortunately, the template included a bunch of static assets (CSS, JavaScript, and other files) that we can include to improve the site. To do so, first make a folder “static” under “core,” then copy the folders “css,” “js,” and “vendor” into static. Finally, within the html page, you need to prepend “/static/” to the paths of the three CSS imports in the header and the nine JavaScript imports in the footer. Afterwards, the page looks much better.

Once we can properly see the contents of the page, it turns out that there is a lot of (fake) sensitive data here! Let’s restrict access by implementing a login page, which will serve as a great introduction to using forms within webpages in Django.

Start by copying the “login.html” template in to the same “core/templates/” folder as “index.html.” You will also want to make the same change as before to the two CSS imports and the three JavaScript sources. We’ll add a route and view to support this new page.

In urls.py:

path(‘login’, views.Login.as_view(), name=‘login’),

In views.py:

class Login(View):
template = ‘login.html’

def get(self, request):
    return render(request, self.template)

You’ll note that for the moment our login view is nearly identical to our index view. That will soon change to support the actual page. Let’s visit the login page at http://127.0.0.1/login/. Try to sign in using the superuser credentials that you created earlier.

While the page looks great, it doesn’t do anything yet. For that, we will need to use a form. Fortunately, Django provides a great default AuthenticationForm that accepts a username and password. We can add that to the view as follows:

from django.contrib.auth.forms import AuthenticationForm
from django.contrib.auth import login, authenticate

class Login(View):
template = ‘login.html’

def get(self, request):
    form = AuthenticationForm()
    return render(request, self.template, {'form': form})


def post(self, request):
    form = AuthenticationForm(request.POST)
    username = request.POST['username']
    password = request.POST['password']
    user = authenticate(request, username=username, password=password)
    if user is not None:
        login(request, user)
        return HttpResponseRedirect('/')
    else:
        return render(request, self.template, {'form': form})

This will also require some modifications to the HTML of the login page. Django supports Jinja templating out of the box. Jinja templating is an extension of HTML that allows you include data with a double bracket {{ data }} and expressions with similar syntax {% expression %}. We will use Jinja tags to incorporate the form into the HTML page.

<form method=“post” action=“/login/”>
{% csrf_token %}
<div class=“form-group”>
<div class=“form-label-group”>
{{ form.username }}
</div>
</div>
<div class=“form-group”>
<div class=“form-label-group”>
{{ form.password }}
</div>
</div>
<button class=“btn btn-primary btn-block” type=“submit”>Login</button>
</form>

We can add some css by including this script afterwards. Because Jinja elements are rendered into HTML server-side, we can rely on the element ids existing in the DOM by the time this script runs on the client.

<script>
document.getElementById(“id_username”).classList.add(“form-control”);
document.getElementById(“id_password”).classList.add(“form-control”);
document.getElementById(“id_username”).placeholder = “Username”;
document.getElementById(“id_password”).placeholder = “Password”;
document.getElementById(“id_username”).type = “text”;
document.getElementById(“id_password”).type = “password”;
document.getElementById(“id_username”).required = “required”;
document.getElementById(“id_password”).required = “required”;
document.getElementById(“id_username”).autofocus = “autofocus”;
</script>

After these changes, visiting the login page will allow us to sign in and view the main dashboard. However, eagle-eyed readers will notice that we have yet to implement any protections for the dashboard. Indeed, anyone could still visit the index and view all of the sensitive information there. Thus, we have to inherit another class in the Index view.

from django.contrib.auth.mixins import LoginRequiredMixin

class Index(LoginRequiredMixin, View):
template = ‘index.html’
login_url = ‘/login/’

def get(self, request):
    return render(request, self.template)

The LoginRequiredMixin class prevents anyone but authenticated users from accessing the pages that it protects. If someone tries to go to the index before signing in, it will conveniently redirect them to the login page to authenticate themselves.

We’ve used Jinja to incorporate a form; we can also use it to avoid repeated code. Right now, we only have two html pages, but a full implementation of this application would have dozens. Rather than copying and pasting common elements, we can inherit the header from a base template.

We’ll start by making a new file, “base.html,” in “core/templates.” This file will include common header information between the two pages.

<!DOCTYPE html>
<html lang=“en”>

<head>

<meta charset=“utf-8”>
<meta http-equiv=“X-UA-Compatible” content=“IE=edge”>
<meta name=“viewport” content=“width=device-width, initial-scale=1, shrink-to-fit=no”>
<meta name=“description” content=“”>
<meta name=“author” content=“”>

<title>{% block title %}{% endblock %}</title>

<!-- Custom fonts for this template–>
<link href=“/static/vendor/fontawesome-free/css/all.min.css” rel=“stylesheet” type=“text/css”>

<!-- Page level plugin CSS–>
<link href=“/static/vendor/datatables/dataTables.bootstrap4.css” rel=“stylesheet”>

{% block links %}
{% endblock %}

</head>

{% block body %}
{% endblock %}

</html>

Then, future pages can use the following syntax from the modified “index.html.”

{% extends “base.html” %}

{% block title %}Employee Dashboard{% endblock %}

{% block links %}
<!-- Custom styles for this template–>
<link href=“/static/css/sb-admin.css” rel=“stylesheet”>
{% endblock %}
{% block body %}
<!–html goes here–>
{% endblock %}

We have one more place to apply Jinja templating in the home page. Currently, all of the figures in the table are hard-coded into the HTML, requiring editing the webpage itself whenever the data changes. Instead, we can store that data in our database and pass it to the view. This will also save us nearly 500 lines of manual HTML with the current data.

First, we need a model to represent employees in the database. In “core/models.py”, we define an employee as follows.

from django.db import models

class Employee(models.Model):
name = models.CharField(max_length=150)
position = models.CharField(max_length=150)
office = models.CharField(max_length=150)
age = models.PositiveIntegerField()
start_date = models.DateField()
salary = models.PositiveIntegerField()

def __str__(self):
    return self.name

Make sure you register the model in “core/admin.py.”

from django.contrib import admin
from .models import Employee

class EmployeeAdmin(admin.ModelAdmin):
list_display = [f.name for f in Employee._meta.fields]

admin.site.register(Employee, EmployeeAdmin)

With the model written and registered, we can make and run migrations (quit the server, python manage.py makemigrationspython manage.py migratepython manage.py runserver). Navigate to /admin and click on the employees table. Click “Add Employee” in the upper right corner and enter whatever data you want in the form.

Do this a few more times until you have a small fake company. Then, return to our “views.py” and modify Index to pass the employee database into the HTML file as a QuerySet.

def get(self, request):
employees = Employee.objects.all()
return render(request, self.template, {‘employees’: employees})

Finally, delete the entire fake table in “index.html” and replace it with a for loop over the data we entered into the database.

<tbody>
{% for employee in employees %}
<tr>
<td>{{ employee.name }}</td>
<td>{{ employee.position }}</td>
<td>{{ employee.office }}</td>
<td>{{ employee.age }}</td>
<td>{{ employee.start_date }}</td>
<td>${{ employee.salary }}</td>
</tr>
{% endfor %}
</tbody>

Django creates the index by rendering from our database instead of simply returning the filler data. All of the search and ordering features still work exactly as they used to, the only difference is that the html is generated server-side from the database rather than hard-coded.

We have now seen several powerful patterns for creating web pages with Django and Jinja. Using templates and extensions allows us to reuse common code between pages. Forms allow us to securely collect and transmit user data (when the website is served over HTTPS). We can use server-side rendering to include data in the HTML and send it to the client. These fundamental patterns are the essential skills that will let you create a wide array of web pages in Django.

Thanks For Visiting, Keep Visiting. If you liked this post, share it with all of your programming buddies!

Further reading

☞ Complete Python Bootcamp: Go from zero to hero in Python 3

☞ Python and Django Full Stack Web Developer Bootcamp

☞ Python for Time Series Data Analysis

☞ Python Programming For Beginners From Scratch

☞ Beginner’s guide on Python: Learn python from scratch! (New)

☞ Python for Beginners: Complete Python Programming

☞ Django 2.1 & Python | The Ultimate Web Development Bootcamp

☞ Python eCommerce | Build a Django eCommerce Web Application

☞ Python Django Dev To Deployment


Originally published on mkdev.me

#python #django #web-development

What is GEEK

Buddha Community

Fundamentals of Front End Django
Hermann  Frami

Hermann Frami

1651383480

A Simple Wrapper Around Amplify AppSync Simulator

This serverless plugin is a wrapper for amplify-appsync-simulator made for testing AppSync APIs built with serverless-appsync-plugin.

Install

npm install serverless-appsync-simulator
# or
yarn add serverless-appsync-simulator

Usage

This plugin relies on your serverless yml file and on the serverless-offline plugin.

plugins:
  - serverless-dynamodb-local # only if you need dynamodb resolvers and you don't have an external dynamodb
  - serverless-appsync-simulator
  - serverless-offline

Note: Order is important serverless-appsync-simulator must go before serverless-offline

To start the simulator, run the following command:

sls offline start

You should see in the logs something like:

...
Serverless: AppSync endpoint: http://localhost:20002/graphql
Serverless: GraphiQl: http://localhost:20002
...

Configuration

Put options under custom.appsync-simulator in your serverless.yml file

| option | default | description | | ------------------------ | -------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------- | | apiKey | 0123456789 | When using API_KEY as authentication type, the key to authenticate to the endpoint. | | port | 20002 | AppSync operations port; if using multiple APIs, the value of this option will be used as a starting point, and each other API will have a port of lastPort + 10 (e.g. 20002, 20012, 20022, etc.) | | wsPort | 20003 | AppSync subscriptions port; if using multiple APIs, the value of this option will be used as a starting point, and each other API will have a port of lastPort + 10 (e.g. 20003, 20013, 20023, etc.) | | location | . (base directory) | Location of the lambda functions handlers. | | refMap | {} | A mapping of resource resolutions for the Ref function | | getAttMap | {} | A mapping of resource resolutions for the GetAtt function | | importValueMap | {} | A mapping of resource resolutions for the ImportValue function | | functions | {} | A mapping of external functions for providing invoke url for external fucntions | | dynamoDb.endpoint | http://localhost:8000 | Dynamodb endpoint. Specify it if you're not using serverless-dynamodb-local. Otherwise, port is taken from dynamodb-local conf | | dynamoDb.region | localhost | Dynamodb region. Specify it if you're connecting to a remote Dynamodb intance. | | dynamoDb.accessKeyId | DEFAULT_ACCESS_KEY | AWS Access Key ID to access DynamoDB | | dynamoDb.secretAccessKey | DEFAULT_SECRET | AWS Secret Key to access DynamoDB | | dynamoDb.sessionToken | DEFAULT_ACCESS_TOKEEN | AWS Session Token to access DynamoDB, only if you have temporary security credentials configured on AWS | | dynamoDb.* | | You can add every configuration accepted by DynamoDB SDK | | rds.dbName | | Name of the database | | rds.dbHost | | Database host | | rds.dbDialect | | Database dialect. Possible values (mysql | postgres) | | rds.dbUsername | | Database username | | rds.dbPassword | | Database password | | rds.dbPort | | Database port | | watch | - *.graphql
- *.vtl | Array of glob patterns to watch for hot-reloading. |

Example:

custom:
  appsync-simulator:
    location: '.webpack/service' # use webpack build directory
    dynamoDb:
      endpoint: 'http://my-custom-dynamo:8000'

Hot-reloading

By default, the simulator will hot-relad when changes to *.graphql or *.vtl files are detected. Changes to *.yml files are not supported (yet? - this is a Serverless Framework limitation). You will need to restart the simulator each time you change yml files.

Hot-reloading relies on watchman. Make sure it is installed on your system.

You can change the files being watched with the watch option, which is then passed to watchman as the match expression.

e.g.

custom:
  appsync-simulator:
    watch:
      - ["match", "handlers/**/*.vtl", "wholename"] # => array is interpreted as the literal match expression
      - "*.graphql"                                 # => string like this is equivalent to `["match", "*.graphql"]`

Or you can opt-out by leaving an empty array or set the option to false

Note: Functions should not require hot-reloading, unless you are using a transpiler or a bundler (such as webpack, babel or typescript), un which case you should delegate hot-reloading to that instead.

Resource CloudFormation functions resolution

This plugin supports some resources resolution from the Ref, Fn::GetAtt and Fn::ImportValue functions in your yaml file. It also supports some other Cfn functions such as Fn::Join, Fb::Sub, etc.

Note: Under the hood, this features relies on the cfn-resolver-lib package. For more info on supported cfn functions, refer to the documentation

Basic usage

You can reference resources in your functions' environment variables (that will be accessible from your lambda functions) or datasource definitions. The plugin will automatically resolve them for you.

provider:
  environment:
    BUCKET_NAME:
      Ref: MyBucket # resolves to `my-bucket-name`

resources:
  Resources:
    MyDbTable:
      Type: AWS::DynamoDB::Table
      Properties:
        TableName: myTable
      ...
    MyBucket:
      Type: AWS::S3::Bucket
      Properties:
        BucketName: my-bucket-name
    ...

# in your appsync config
dataSources:
  - type: AMAZON_DYNAMODB
    name: dynamosource
    config:
      tableName:
        Ref: MyDbTable # resolves to `myTable`

Override (or mock) values

Sometimes, some references cannot be resolved, as they come from an Output from Cloudformation; or you might want to use mocked values in your local environment.

In those cases, you can define (or override) those values using the refMap, getAttMap and importValueMap options.

  • refMap takes a mapping of resource name to value pairs
  • getAttMap takes a mapping of resource name to attribute/values pairs
  • importValueMap takes a mapping of import name to values pairs

Example:

custom:
  appsync-simulator:
    refMap:
      # Override `MyDbTable` resolution from the previous example.
      MyDbTable: 'mock-myTable'
    getAttMap:
      # define ElasticSearchInstance DomainName
      ElasticSearchInstance:
        DomainEndpoint: 'localhost:9200'
    importValueMap:
      other-service-api-url: 'https://other.api.url.com/graphql'

# in your appsync config
dataSources:
  - type: AMAZON_ELASTICSEARCH
    name: elasticsource
    config:
      # endpoint resolves as 'http://localhost:9200'
      endpoint:
        Fn::Join:
          - ''
          - - https://
            - Fn::GetAtt:
                - ElasticSearchInstance
                - DomainEndpoint

Key-value mock notation

In some special cases you will need to use key-value mock nottation. Good example can be case when you need to include serverless stage value (${self:provider.stage}) in the import name.

This notation can be used with all mocks - refMap, getAttMap and importValueMap

provider:
  environment:
    FINISH_ACTIVITY_FUNCTION_ARN:
      Fn::ImportValue: other-service-api-${self:provider.stage}-url

custom:
  serverless-appsync-simulator:
    importValueMap:
      - key: other-service-api-${self:provider.stage}-url
        value: 'https://other.api.url.com/graphql'

Limitations

This plugin only tries to resolve the following parts of the yml tree:

  • provider.environment
  • functions[*].environment
  • custom.appSync

If you have the need of resolving others, feel free to open an issue and explain your use case.

For now, the supported resources to be automatically resovled by Ref: are:

  • DynamoDb tables
  • S3 Buckets

Feel free to open a PR or an issue to extend them as well.

External functions

When a function is not defined withing the current serverless file you can still call it by providing an invoke url which should point to a REST method. Make sure you specify "get" or "post" for the method. Default is "get", but you probably want "post".

custom:
  appsync-simulator:
    functions:
      addUser:
        url: http://localhost:3016/2015-03-31/functions/addUser/invocations
        method: post
      addPost:
        url: https://jsonplaceholder.typicode.com/posts
        method: post

Supported Resolver types

This plugin supports resolvers implemented by amplify-appsync-simulator, as well as custom resolvers.

From Aws Amplify:

  • NONE
  • AWS_LAMBDA
  • AMAZON_DYNAMODB
  • PIPELINE

Implemented by this plugin

  • AMAZON_ELASTIC_SEARCH
  • HTTP
  • RELATIONAL_DATABASE

Relational Database

Sample VTL for a create mutation

#set( $cols = [] )
#set( $vals = [] )
#foreach( $entry in $ctx.args.input.keySet() )
  #set( $regex = "([a-z])([A-Z]+)")
  #set( $replacement = "$1_$2")
  #set( $toSnake = $entry.replaceAll($regex, $replacement).toLowerCase() )
  #set( $discard = $cols.add("$toSnake") )
  #if( $util.isBoolean($ctx.args.input[$entry]) )
      #if( $ctx.args.input[$entry] )
        #set( $discard = $vals.add("1") )
      #else
        #set( $discard = $vals.add("0") )
      #end
  #else
      #set( $discard = $vals.add("'$ctx.args.input[$entry]'") )
  #end
#end
#set( $valStr = $vals.toString().replace("[","(").replace("]",")") )
#set( $colStr = $cols.toString().replace("[","(").replace("]",")") )
#if ( $valStr.substring(0, 1) != '(' )
  #set( $valStr = "($valStr)" )
#end
#if ( $colStr.substring(0, 1) != '(' )
  #set( $colStr = "($colStr)" )
#end
{
  "version": "2018-05-29",
  "statements":   ["INSERT INTO <name-of-table> $colStr VALUES $valStr", "SELECT * FROM    <name-of-table> ORDER BY id DESC LIMIT 1"]
}

Sample VTL for an update mutation

#set( $update = "" )
#set( $equals = "=" )
#foreach( $entry in $ctx.args.input.keySet() )
  #set( $cur = $ctx.args.input[$entry] )
  #set( $regex = "([a-z])([A-Z]+)")
  #set( $replacement = "$1_$2")
  #set( $toSnake = $entry.replaceAll($regex, $replacement).toLowerCase() )
  #if( $util.isBoolean($cur) )
      #if( $cur )
        #set ( $cur = "1" )
      #else
        #set ( $cur = "0" )
      #end
  #end
  #if ( $util.isNullOrEmpty($update) )
      #set($update = "$toSnake$equals'$cur'" )
  #else
      #set($update = "$update,$toSnake$equals'$cur'" )
  #end
#end
{
  "version": "2018-05-29",
  "statements":   ["UPDATE <name-of-table> SET $update WHERE id=$ctx.args.input.id", "SELECT * FROM <name-of-table> WHERE id=$ctx.args.input.id"]
}

Sample resolver for delete mutation

{
  "version": "2018-05-29",
  "statements":   ["UPDATE <name-of-table> set deleted_at=NOW() WHERE id=$ctx.args.id", "SELECT * FROM <name-of-table> WHERE id=$ctx.args.id"]
}

Sample mutation response VTL with support for handling AWSDateTime

#set ( $index = -1)
#set ( $result = $util.parseJson($ctx.result) )
#set ( $meta = $result.sqlStatementResults[1].columnMetadata)
#foreach ($column in $meta)
    #set ($index = $index + 1)
    #if ( $column["typeName"] == "timestamptz" )
        #set ($time = $result["sqlStatementResults"][1]["records"][0][$index]["stringValue"] )
        #set ( $nowEpochMillis = $util.time.parseFormattedToEpochMilliSeconds("$time.substring(0,19)+0000", "yyyy-MM-dd HH:mm:ssZ") )
        #set ( $isoDateTime = $util.time.epochMilliSecondsToISO8601($nowEpochMillis) )
        $util.qr( $result["sqlStatementResults"][1]["records"][0][$index].put("stringValue", "$isoDateTime") )
    #end
#end
#set ( $res = $util.parseJson($util.rds.toJsonString($util.toJson($result)))[1][0] )
#set ( $response = {} )
#foreach($mapKey in $res.keySet())
    #set ( $s = $mapKey.split("_") )
    #set ( $camelCase="" )
    #set ( $isFirst=true )
    #foreach($entry in $s)
        #if ( $isFirst )
          #set ( $first = $entry.substring(0,1) )
        #else
          #set ( $first = $entry.substring(0,1).toUpperCase() )
        #end
        #set ( $isFirst=false )
        #set ( $stringLength = $entry.length() )
        #set ( $remaining = $entry.substring(1, $stringLength) )
        #set ( $camelCase = "$camelCase$first$remaining" )
    #end
    $util.qr( $response.put("$camelCase", $res[$mapKey]) )
#end
$utils.toJson($response)

Using Variable Map

Variable map support is limited and does not differentiate numbers and strings data types, please inject them directly if needed.

Will be escaped properly: null, true, and false values.

{
  "version": "2018-05-29",
  "statements":   [
    "UPDATE <name-of-table> set deleted_at=NOW() WHERE id=:ID",
    "SELECT * FROM <name-of-table> WHERE id=:ID and unix_timestamp > $ctx.args.newerThan"
  ],
  variableMap: {
    ":ID": $ctx.args.id,
##    ":TIMESTAMP": $ctx.args.newerThan -- This will be handled as a string!!!
  }
}

Requires

Author: Serverless-appsync
Source Code: https://github.com/serverless-appsync/serverless-appsync-simulator 
License: MIT License

#serverless #sync #graphql 

Generis: Versatile Go Code Generator

Generis

Versatile Go code generator.

Description

Generis is a lightweight code preprocessor adding the following features to the Go language :

  • Generics.
  • Free-form macros.
  • Conditional compilation.
  • HTML templating.
  • Allman style conversion.

Sample

package main;

// -- IMPORTS

import (
    "html"
    "io"
    "log"
    "net/http"
    "net/url"
    "strconv"
    );

// -- DEFINITIONS

#define DebugMode
#as true

// ~~

#define HttpPort
#as 8080

// ~~

#define WriteLine( {{text}} )
#as log.Println( {{text}} )

// ~~

#define local {{variable}} : {{type}};
#as var {{variable}} {{type}};

// ~~

#define DeclareStack( {{type}}, {{name}} )
#as
    // -- TYPES

    type {{name}}Stack struct
    {
        ElementArray []{{type}};
    }

    // -- INQUIRIES

    func ( stack * {{name}}Stack ) IsEmpty(
        ) bool
    {
        return len( stack.ElementArray ) == 0;
    }

    // -- OPERATIONS

    func ( stack * {{name}}Stack ) Push(
        element {{type}}
        )
    {
        stack.ElementArray = append( stack.ElementArray, element );
    }

    // ~~

    func ( stack * {{name}}Stack ) Pop(
        ) {{type}}
    {
        local
            element : {{type}};

        element = stack.ElementArray[ len( stack.ElementArray ) - 1 ];

        stack.ElementArray = stack.ElementArray[ : len( stack.ElementArray ) - 1 ];

        return element;
    }
#end

// ~~

#define DeclareStack( {{type}} )
#as DeclareStack( {{type}}, {{type:PascalCase}} )

// -- TYPES

DeclareStack( string )
DeclareStack( int32 )

// -- FUNCTIONS

func HandleRootPage(
    response_writer http.ResponseWriter,
    request * http.Request
    )
{
    local
        boolean : bool;
    local
        natural : uint;
    local
        integer : int;
    local
        real : float64;
    local
        escaped_html_text,
        escaped_url_text,
        text : string;
    local
        integer_stack : Int32Stack;

    boolean = true;
    natural = 10;
    integer = 20;
    real = 30.0;
    text = "text";
    escaped_url_text = "&escaped text?";
    escaped_html_text = "<escaped text/>";

    integer_stack.Push( 10 );
    integer_stack.Push( 20 );
    integer_stack.Push( 30 );

    #write response_writer
        <!DOCTYPE html>
        <html lang="en">
            <head>
                <meta charset="utf-8">
                <title><%= request.URL.Path %></title>
            </head>
            <body>
                <% if ( boolean ) { %>
                    <%= "URL : " + request.URL.Path %>
                    <br/>
                    <%@ natural %>
                    <%# integer %>
                    <%& real %>
                    <br/>
                    <%~ text %>
                    <%^ escaped_url_text %>
                    <%= escaped_html_text %>
                    <%= "<%% ignored %%>" %>
                    <%% ignored %%>
                <% } %>
                <br/>
                Stack :
                <br/>
                <% for !integer_stack.IsEmpty() { %>
                    <%# integer_stack.Pop() %>
                <% } %>
            </body>
        </html>
    #end
}

// ~~

func main()
{
    http.HandleFunc( "/", HandleRootPage );

    #if DebugMode
        WriteLine( "Listening on http://localhost:HttpPort" );
    #end

    log.Fatal(
        http.ListenAndServe( ":HttpPort", nil )
        );
}

Syntax

#define directive

Constants and generic code can be defined with the following syntax :

#define old code
#as new code

#define old code
#as
    new
    code
#end

#define
    old
    code
#as new code

#define
    old
    code
#as
    new
    code
#end

#define parameter

The #define directive can contain one or several parameters :

{{variable name}} : hierarchical code (with properly matching brackets and parentheses)
{{variable name#}} : statement code (hierarchical code without semicolon)
{{variable name$}} : plain code
{{variable name:boolean expression}} : conditional hierarchical code
{{variable name#:boolean expression}} : conditional statement code
{{variable name$:boolean expression}} : conditional plain code

They can have a boolean expression to require they match specific conditions :

HasText text
HasPrefix prefix
HasSuffix suffix
HasIdentifier text
false
true
!expression
expression && expression
expression || expression
( expression )

The #define directive must not start or end with a parameter.

#as parameter

The #as directive can use the value of the #define parameters :

{{variable name}}
{{variable name:filter function}}
{{variable name:filter function:filter function:...}}

Their value can be changed through one or several filter functions :

LowerCase
UpperCase
MinorCase
MajorCase
SnakeCase
PascalCase
CamelCase
RemoveComments
RemoveBlanks
PackStrings
PackIdentifiers
ReplacePrefix old_prefix new_prefix
ReplaceSuffix old_suffix new_suffix
ReplaceText old_text new_text
ReplaceIdentifier old_identifier new_identifier
AddPrefix prefix
AddSuffix suffix
RemovePrefix prefix
RemoveSuffix suffix
RemoveText text
RemoveIdentifier identifier

#if directive

Conditional code can be defined with the following syntax :

#if boolean expression
    #if boolean expression
        ...
    #else
        ...
    #end
#else
    #if boolean expression
        ...
    #else
        ...
    #end
#end

The boolean expression can use the following operators :

false
true
!expression
expression && expression
expression || expression
( expression )

#write directive

Templated HTML code can be sent to a stream writer using the following syntax :

#write writer expression
    <% code %>
    <%@ natural expression %>
    <%# integer expression %>
    <%& real expression %>
    <%~ text expression %>
    <%= escaped text expression %>
    <%! removed content %>
    <%% ignored tags %%>
#end

Limitations

  • There is no operator precedence in boolean expressions.
  • The --join option requires to end the statements with a semicolon.
  • The #writer directive is only available for the Go language.

Installation

Install the DMD 2 compiler (using the MinGW setup option on Windows).

Build the executable with the following command line :

dmd -m64 generis.d

Command line

generis [options]

Options

--prefix # : set the command prefix
--parse INPUT_FOLDER/ : parse the definitions of the Generis files in the input folder
--process INPUT_FOLDER/ OUTPUT_FOLDER/ : reads the Generis files in the input folder and writes the processed files in the output folder
--trim : trim the HTML templates
--join : join the split statements
--create : create the output folders if needed
--watch : watch the Generis files for modifications
--pause 500 : time to wait before checking the Generis files again
--tabulation 4 : set the tabulation space count
--extension .go : generate files with this extension

Examples

generis --process GS/ GO/

Reads the Generis files in the GS/ folder and writes Go files in the GO/ folder.

generis --process GS/ GO/ --create

Reads the Generis files in the GS/ folder and writes Go files in the GO/ folder, creating the output folders if needed.

generis --process GS/ GO/ --create --watch

Reads the Generis files in the GS/ folder and writes Go files in the GO/ folder, creating the output folders if needed and watching the Generis files for modifications.

generis --process GS/ GO/ --trim --join --create --watch

Reads the Generis files in the GS/ folder and writes Go files in the GO/ folder, trimming the HTML templates, joining the split statements, creating the output folders if needed and watching the Generis files for modifications.

Version

2.0

Author: Senselogic
Source Code: https://github.com/senselogic/GENERIS 
License: View license

#go #golang #code 

Aarna Davis

Aarna Davis

1625055931

Hire Front-end Developer | Dedicated Front-end Programmers In India

Hire top Indian front end developers for mobile-first, pixel perfect, SEO friendly and highly optimized front end development. We are a 16+ years experienced company offering frontend development services including HTML / CSS development, theme development & headless front end development utilising JS technologies such as Angular, React & Vue.

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Ahebwe  Oscar

Ahebwe Oscar

1620177818

Django admin full Customization step by step

Welcome to my blog , hey everyone in this article you learn how to customize the Django app and view in the article you will know how to register  and unregister  models from the admin view how to add filtering how to add a custom input field, and a button that triggers an action on all objects and even how to change the look of your app and page using the Django suit package let’s get started.

Database

Custom Titles of Django Admin

Exclude in Django Admin

Fields in Django Admin

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Front End Development Best Practices To Follow

This is image title
As someone from a non-tech background, you might not understand the complexities of front-end development. What we see on our mobile screens or PCs is a mere fragment of intricately woven code. But if you are looking forward to developing an application, you would have to dive in and know the scopes found in front-end development with the advent of new technologies, tools, and frameworks.

In this blog, we will help you understand the best practices of Front-end development and the burgeoning trends that would help you ensure the quality development of your digital products. Learn about the future of web development is here.

GUI Development Best Practices: UX And UI

Before you start the development work, it is essential to discuss the user experience and user interface of your product. The front-end of any software is the only thing that interacts with your users. Moreover, it is important that you make incredible contact with your users. It is not just about the smoothness; also about navigation; you have to make things as simple as possible for your users to interact with your product.

User Experience Vs. User Interface

Most people confuse user experience and user interface to be one and the same thing. But they cannot be more wrong. User experience and user interface work together; they are different components of your product’s front end? Here are a few things which they share and that differentiate them.

  1. User Experience
    Starting with UX, it is a term coined by Don Norman, and when he did that, he did not contextualize it to any kind of software product. It was used for multiple disciplines, including marketing, graphical & industrial design, interface, and engineering.
    This is image title
    In software development, it focuses on building user-centric processes that optimize the user interaction with the product. The best practices of delivering a great user experience include; researching customer behavior, understanding the context in which the audience takes action, and creating a systematic vision for the target audience to reach its goal.Use your newfound knowledge to develop an actual graphic design. It needs to be analytical and action-provoking. A good UX designer would always understand the way a user interacts with your product.

  2. User Interface
    User experience helps you define the user interface design. It would include the components that make up the entire experience of the product. Additionally, it includes toggle, background, fonts, animation, and other graphical elements.
    This is image title
    If the user experience is about how the user interacts with your products, the user interface is about giving them the channels to interact with your product. So, the best practices of creating a rewarding user interface are; following brand style guidelines, intuitive design, support for various screen sizes, and effective implementation.

Front-End Development Best Practices: Design To Development

Once you are done with the design part, it is time to dive into development. The process includes turning the graphical assets into a functioning product. There are various approaches that the software community uses, but the most rewarding one is object-driven design and development as it improves the user experience tenfold.

The object-driven approach allows you to design graphical assets that follow the same design and pattern. Also, it allows you to translate the components for faster delivery and a cohesive UX and UI experience across products and platforms.

The design to development process allows you to build interfaces that include layouts, colors, typography, spacing, and more. Front-end development teams are required to work according to the guidelines of the target platform, and they must focus on the UI and UX peculiarities of product development. It is likely that you may face some temporary technical challenges during development and implementation.

It is a trend to automate the front-end development of software with Zeplin or Avocode. The tools ensure access to the updated design, accurate specs and automatically generate the code snippet that allows faster delivery. Learn about the right process of web development here.

  1. Frontend CSS Frameworks
    Depending on the project specification, a software development company would suggest you the right toolsets. The most popular front-end CSS frameworks are Bootstrap, Foundation, Material Design; they are known for increasing the speed of development and come with ready-to-use components that make it easy to replace the manual code and comply with responsive web design standards.

Here is a list of popular front-end development technologies

  • React
  • Angular
  • Vue.JS
  • Knockout and Backbone

Continue Reading

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