Fannie  Zemlak

Fannie Zemlak

1595935080

Implementing a Robust Portable Cron-Like Scheduler via Couchbase Eventing (Part 1)

This is the first of a multi-part series to leverage the Couchbase Eventing Service to run multiple scheduled tasks at specific recurring intervals in a cron like fashion completely inside the database without requiring additional infrastructure via a single general-purpose Eventing Function. In this installment, we will focus on running fixed user routines, JavaScript functions defined inside an Eventing Function. Later in subsequent articles we will extend the cron like Eventing Function to schedule and execute database driven dynamic N1QL statements and then finally in we will explore scheduling database driven dynamic JavaScript functions.

Background

The Couchbase Eventing Service provides a framework for writing your own routines, simple JavaScript functions, to process document changes. This service provides all the needed infrastructure to create scalable and robust cloud-based functions allowing you to focus on developing pure business logic to interact in near real-time to changes in your data. Your functions are able to access the Couchbase data service (KV), the Couchbase query service (N1QL), and REST endpoints external to the Couchbase system. Eventing Life Cycle 6.5 I/OThe JSON data model in Couchbase came from JavaScript, thus it is only natural that the Eventing Service exposes the ability to write JavaScript code to analyze and manipulate JSON documents on any type of change events including Inserts, Updates, Merges, and Deletes (together referred to as mutations). Eventing Functions typically allow you to deploy and execute custom code fragments to that react to thousands and even millions of mutations per seconds in your documents. Several typical use cases are documented for developing high velocity at-scale Eventing Functions that respond to mutations of Couchbase documents. Eventing Life Cycle 6.5 This article will focus instead on a very low velocity use case of the Eventing Service building a reliable “in database” distributed crontab, allowing you to execute JavaScript functions that interact with Couchbase services on a regular periodic schedule.

Scheduling Business Logic to Run at a Specified Date or Time

Cron, named after “Chronos,” the Greek word for time is one of the most useful utilities in a Linux system. In Linux the cron utility is driven by a crontab (cron table) file, a configuration file that specifies shell commands to run periodically on a given schedule. One drawback in running cron is that it is not designed to be a distributed service; it runs on single box, as such it presents a single point of failure. If the system is offline for several hours all scheduled tasks are missed.

Yes, there are some distributed cron implementations such as Google’s Cloud Service, AWS’ Scheduled Tasks, and Azure Functions / Time Triggers. But each cloud vendors offerings have their own idioms are not directly portable. In addition, the methodology of configuration and control needs to be secured, for example if you control a distributed cron system via a REST API over HTTP/S you need to account for this in your security plan.

Using the Couchbase Itself to Run Periodic Commands

With a minor amount of code and planning you can leverage Couchbase’s Eventing service to provide flexible cron like functionality for your scheduled database operations or maintenance. Building the scheduler into the database allows you to achieve the following benefits:

  • Portability across Cloud providers, if you rehost your Couchbase cluster your scheduler is not impacted.
  • Supportability, if you utilize Couchbase you have single vendor to provided support and other services.
  • Distributed, no single point of failure and all Couchbase services support distributed replicas.
  • Guaranteed execution, your task gets executed even after recovery from a node failure.

Couchbase Scheduling, Timers the Secret Sauce

Timers are Couchbase Eventing Service constructs by which developers can specify a routine (business logic) to be triggered at a future time. We will use this functionality to implement a pure Couchbase configurable crontab system that allows you the ability to trigger repetitive tasks as part of your workflows whether you need to execute a simple N1QL query or build a complex rules engine. In all of the subsequent designs we will limit our cron implementations to a resolution of 15 seconds or greater.

We have this limitation because although timers scale to the millions and are guaranteed to fire and execute, they are not wall-clock accurate currently have a bounded steady state delay of less than 14 seconds [1]. Of course, if you need a tighter schedule, i.e. less than 15 seconds, then you should merely process the mutation itself in Eventing logic without the use of a timer construct to schedule a call back in the future. As of this writing the current Couchbase release is version 6.5.1 which two limitations that we must work around when making a robust cron system.

  1. In the 5.5.x, 6.0.x and 6.5.x releases a function that is invoked by a timer callback cannot reliably create a fresh timer (a user space work around can be done via a second cooperative Function).
  2. In the 6.5.x releases creating timers in the future (as in one hour+) in an otherwise idle system can result in a growing number of metadata bucket operations which can eventually block mutations for a given Eventing function (in 6.5.X a user space work around can be accomplished via a second cooperative Function). The severity is governed by:
  • The number of vBuckets holding an active timer. Therefore if there are only a few timers in the future the issue may not be noticeable or materialize. This is the case with just a few cron schedules but for completeness in case you add date functionality I put in a fix for this issue for the code supplied in this article.
  • Whether an Eventing timer has fired recently on a vBucket (which clears the issue for the given vBucket on a per function basis). Therefore systems with lots of near term timer activity will not experience this issue even if timers are scheduled far into the future.

Fortunately in version 6.6.0 both of the above issues or restrictions are lifted and a scheduler can be made in a single simple unified Eventing Function. Eventing cron update

Prerequisites

In this article we will be using the latest GA version, i.e. Couchbase version 6.5.1 (you may need to make some changes to the Eventing Functions described for earlier Couchbase versions). The example in this article will run against the travel-sample data set which is delivered with the Couchbase server.

PRO TIPFor Advanced users onlyif you are familiar with Couchbase Eventing and also our CLI / REST tools you can skip the bulk of this blog and download a ZIP file to quickly setup and run the scheduler system presented below. Right-click on the following link and choose Save Link As to download the file  cron_impl_2func_CLI.zipmove it to an Eventing node, extract the ZIP file, and refer to the extracted README.txt file.

However, if you are not familiar with Couchbase or the Eventing service please walk through GET STARTED and one Eventing example specifically refer to the following:

  • Setup a working Couchbase 6.5.1 server as per the directions in Start Here!

  • Make sure you can run a N1QL query against the travel-sample data set as per the directions in Run Your First N1QL Query.

  • Understand how to deploy a basic Eventing function as per the directions in the Document Archival example that also uses the travel-sample data set.

  • Make sure you have the travel-sample bucket in the Buckets view of the UI.

  • Make sure you a bucket called metadata in the Buckets view of the UI it should have the minimum size of 200MB.

  • In the Buckets view of the UI create a bucket called crondata with the minimum size of 200MB. For detailed steps on how to create buckets, see Create a Bucket.

  • Set allow_interbucket_recursion to true in order to allow two (2) Eventing functions to alter the same KV document [2].

  • Java

  • 1

curl -X POST -u "$CB_USERNAME:$CB_PASSWORD" 'http://localhost:8091/_p/event/api/v1/config' -d '{ "allow_interbucket_recursion":true }'

#database #tutorial #big data #couchbase #reactive programming #eventing #cron #scheduled tasks

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Buddha Community

Implementing a Robust Portable Cron-Like Scheduler via Couchbase Eventing (Part 1)
Fannie  Zemlak

Fannie Zemlak

1595935080

Implementing a Robust Portable Cron-Like Scheduler via Couchbase Eventing (Part 1)

This is the first of a multi-part series to leverage the Couchbase Eventing Service to run multiple scheduled tasks at specific recurring intervals in a cron like fashion completely inside the database without requiring additional infrastructure via a single general-purpose Eventing Function. In this installment, we will focus on running fixed user routines, JavaScript functions defined inside an Eventing Function. Later in subsequent articles we will extend the cron like Eventing Function to schedule and execute database driven dynamic N1QL statements and then finally in we will explore scheduling database driven dynamic JavaScript functions.

Background

The Couchbase Eventing Service provides a framework for writing your own routines, simple JavaScript functions, to process document changes. This service provides all the needed infrastructure to create scalable and robust cloud-based functions allowing you to focus on developing pure business logic to interact in near real-time to changes in your data. Your functions are able to access the Couchbase data service (KV), the Couchbase query service (N1QL), and REST endpoints external to the Couchbase system. Eventing Life Cycle 6.5 I/OThe JSON data model in Couchbase came from JavaScript, thus it is only natural that the Eventing Service exposes the ability to write JavaScript code to analyze and manipulate JSON documents on any type of change events including Inserts, Updates, Merges, and Deletes (together referred to as mutations). Eventing Functions typically allow you to deploy and execute custom code fragments to that react to thousands and even millions of mutations per seconds in your documents. Several typical use cases are documented for developing high velocity at-scale Eventing Functions that respond to mutations of Couchbase documents. Eventing Life Cycle 6.5 This article will focus instead on a very low velocity use case of the Eventing Service building a reliable “in database” distributed crontab, allowing you to execute JavaScript functions that interact with Couchbase services on a regular periodic schedule.

Scheduling Business Logic to Run at a Specified Date or Time

Cron, named after “Chronos,” the Greek word for time is one of the most useful utilities in a Linux system. In Linux the cron utility is driven by a crontab (cron table) file, a configuration file that specifies shell commands to run periodically on a given schedule. One drawback in running cron is that it is not designed to be a distributed service; it runs on single box, as such it presents a single point of failure. If the system is offline for several hours all scheduled tasks are missed.

Yes, there are some distributed cron implementations such as Google’s Cloud Service, AWS’ Scheduled Tasks, and Azure Functions / Time Triggers. But each cloud vendors offerings have their own idioms are not directly portable. In addition, the methodology of configuration and control needs to be secured, for example if you control a distributed cron system via a REST API over HTTP/S you need to account for this in your security plan.

Using the Couchbase Itself to Run Periodic Commands

With a minor amount of code and planning you can leverage Couchbase’s Eventing service to provide flexible cron like functionality for your scheduled database operations or maintenance. Building the scheduler into the database allows you to achieve the following benefits:

  • Portability across Cloud providers, if you rehost your Couchbase cluster your scheduler is not impacted.
  • Supportability, if you utilize Couchbase you have single vendor to provided support and other services.
  • Distributed, no single point of failure and all Couchbase services support distributed replicas.
  • Guaranteed execution, your task gets executed even after recovery from a node failure.

Couchbase Scheduling, Timers the Secret Sauce

Timers are Couchbase Eventing Service constructs by which developers can specify a routine (business logic) to be triggered at a future time. We will use this functionality to implement a pure Couchbase configurable crontab system that allows you the ability to trigger repetitive tasks as part of your workflows whether you need to execute a simple N1QL query or build a complex rules engine. In all of the subsequent designs we will limit our cron implementations to a resolution of 15 seconds or greater.

We have this limitation because although timers scale to the millions and are guaranteed to fire and execute, they are not wall-clock accurate currently have a bounded steady state delay of less than 14 seconds [1]. Of course, if you need a tighter schedule, i.e. less than 15 seconds, then you should merely process the mutation itself in Eventing logic without the use of a timer construct to schedule a call back in the future. As of this writing the current Couchbase release is version 6.5.1 which two limitations that we must work around when making a robust cron system.

  1. In the 5.5.x, 6.0.x and 6.5.x releases a function that is invoked by a timer callback cannot reliably create a fresh timer (a user space work around can be done via a second cooperative Function).
  2. In the 6.5.x releases creating timers in the future (as in one hour+) in an otherwise idle system can result in a growing number of metadata bucket operations which can eventually block mutations for a given Eventing function (in 6.5.X a user space work around can be accomplished via a second cooperative Function). The severity is governed by:
  • The number of vBuckets holding an active timer. Therefore if there are only a few timers in the future the issue may not be noticeable or materialize. This is the case with just a few cron schedules but for completeness in case you add date functionality I put in a fix for this issue for the code supplied in this article.
  • Whether an Eventing timer has fired recently on a vBucket (which clears the issue for the given vBucket on a per function basis). Therefore systems with lots of near term timer activity will not experience this issue even if timers are scheduled far into the future.

Fortunately in version 6.6.0 both of the above issues or restrictions are lifted and a scheduler can be made in a single simple unified Eventing Function. Eventing cron update

Prerequisites

In this article we will be using the latest GA version, i.e. Couchbase version 6.5.1 (you may need to make some changes to the Eventing Functions described for earlier Couchbase versions). The example in this article will run against the travel-sample data set which is delivered with the Couchbase server.

PRO TIPFor Advanced users onlyif you are familiar with Couchbase Eventing and also our CLI / REST tools you can skip the bulk of this blog and download a ZIP file to quickly setup and run the scheduler system presented below. Right-click on the following link and choose Save Link As to download the file  cron_impl_2func_CLI.zipmove it to an Eventing node, extract the ZIP file, and refer to the extracted README.txt file.

However, if you are not familiar with Couchbase or the Eventing service please walk through GET STARTED and one Eventing example specifically refer to the following:

  • Setup a working Couchbase 6.5.1 server as per the directions in Start Here!

  • Make sure you can run a N1QL query against the travel-sample data set as per the directions in Run Your First N1QL Query.

  • Understand how to deploy a basic Eventing function as per the directions in the Document Archival example that also uses the travel-sample data set.

  • Make sure you have the travel-sample bucket in the Buckets view of the UI.

  • Make sure you a bucket called metadata in the Buckets view of the UI it should have the minimum size of 200MB.

  • In the Buckets view of the UI create a bucket called crondata with the minimum size of 200MB. For detailed steps on how to create buckets, see Create a Bucket.

  • Set allow_interbucket_recursion to true in order to allow two (2) Eventing functions to alter the same KV document [2].

  • Java

  • 1

curl -X POST -u "$CB_USERNAME:$CB_PASSWORD" 'http://localhost:8091/_p/event/api/v1/config' -d '{ "allow_interbucket_recursion":true }'

#database #tutorial #big data #couchbase #reactive programming #eventing #cron #scheduled tasks

A Wrapper for Sembast and SQFlite to Enable Easy

FHIR_DB

This is really just a wrapper around Sembast_SQFLite - so all of the heavy lifting was done by Alex Tekartik. I highly recommend that if you have any questions about working with this package that you take a look at Sembast. He's also just a super nice guy, and even answered a question for me when I was deciding which sembast version to use. As usual, ResoCoder also has a good tutorial.

I have an interest in low-resource settings and thus a specific reason to be able to store data offline. To encourage this use, there are a number of other packages I have created based around the data format FHIR. FHIR® is the registered trademark of HL7 and is used with the permission of HL7. Use of the FHIR trademark does not constitute endorsement of this product by HL7.

Using the Db

So, while not absolutely necessary, I highly recommend that you use some sort of interface class. This adds the benefit of more easily handling errors, plus if you change to a different database in the future, you don't have to change the rest of your app, just the interface.

I've used something like this in my projects:

class IFhirDb {
  IFhirDb();
  final ResourceDao resourceDao = ResourceDao();

  Future<Either<DbFailure, Resource>> save(Resource resource) async {
    Resource resultResource;
    try {
      resultResource = await resourceDao.save(resource);
    } catch (error) {
      return left(DbFailure.unableToSave(error: error.toString()));
    }
    return right(resultResource);
  }

  Future<Either<DbFailure, List<Resource>>> returnListOfSingleResourceType(
      String resourceType) async {
    List<Resource> resultList;
    try {
      resultList =
          await resourceDao.getAllSortedById(resourceType: resourceType);
    } catch (error) {
      return left(DbFailure.unableToObtainList(error: error.toString()));
    }
    return right(resultList);
  }

  Future<Either<DbFailure, List<Resource>>> searchFunction(
      String resourceType, String searchString, String reference) async {
    List<Resource> resultList;
    try {
      resultList =
          await resourceDao.searchFor(resourceType, searchString, reference);
    } catch (error) {
      return left(DbFailure.unableToObtainList(error: error.toString()));
    }
    return right(resultList);
  }
}

I like this because in case there's an i/o error or something, it won't crash your app. Then, you can call this interface in your app like the following:

final patient = Patient(
    resourceType: 'Patient',
    name: [HumanName(text: 'New Patient Name')],
    birthDate: Date(DateTime.now()),
);

final saveResult = await IFhirDb().save(patient);

This will save your newly created patient to the locally embedded database.

IMPORTANT: this database will expect that all previously created resources have an id. When you save a resource, it will check to see if that resource type has already been stored. (Each resource type is saved in it's own store in the database). It will then check if there is an ID. If there's no ID, it will create a new one for that resource (along with metadata on version number and creation time). It will save it, and return the resource. If it already has an ID, it will copy the the old version of the resource into a _history store. It will then update the metadata of the new resource and save that version into the appropriate store for that resource. If, for instance, we have a previously created patient:

{
    "resourceType": "Patient",
    "id": "fhirfli-294057507-6811107",
    "meta": {
        "versionId": "1",
        "lastUpdated": "2020-10-16T19:41:28.054369Z"
    },
    "name": [
        {
            "given": ["New"],
            "family": "Patient"
        }
    ],
    "birthDate": "2020-10-16"
}

And we update the last name to 'Provider'. The above version of the patient will be kept in _history, while in the 'Patient' store in the db, we will have the updated version:

{
    "resourceType": "Patient",
    "id": "fhirfli-294057507-6811107",
    "meta": {
        "versionId": "2",
        "lastUpdated": "2020-10-16T19:45:07.316698Z"
    },
    "name": [
        {
            "given": ["New"],
            "family": "Provider"
        }
    ],
    "birthDate": "2020-10-16"
}

This way we can keep track of all previous version of all resources (which is obviously important in medicine).

For most of the interactions (saving, deleting, etc), they work the way you'd expect. The only difference is search. Because Sembast is NoSQL, we can search on any of the fields in a resource. If in our interface class, we have the following function:

  Future<Either<DbFailure, List<Resource>>> searchFunction(
      String resourceType, String searchString, String reference) async {
    List<Resource> resultList;
    try {
      resultList =
          await resourceDao.searchFor(resourceType, searchString, reference);
    } catch (error) {
      return left(DbFailure.unableToObtainList(error: error.toString()));
    }
    return right(resultList);
  }

You can search for all immunizations of a certain patient:

searchFunction(
        'Immunization', 'patient.reference', 'Patient/$patientId');

This function will search through all entries in the 'Immunization' store. It will look at all 'patient.reference' fields, and return any that match 'Patient/$patientId'.

The last thing I'll mention is that this is a password protected db, using AES-256 encryption (although it can also use Salsa20). Anytime you use the db, you have the option of using a password for encryption/decryption. Remember, if you setup the database using encryption, you will only be able to access it using that same password. When you're ready to change the password, you will need to call the update password function. If we again assume we created a change password method in our interface, it might look something like this:

class IFhirDb {
  IFhirDb();
  final ResourceDao resourceDao = ResourceDao();
  ...
    Future<Either<DbFailure, Unit>> updatePassword(String oldPassword, String newPassword) async {
    try {
      await resourceDao.updatePw(oldPassword, newPassword);
    } catch (error) {
      return left(DbFailure.unableToUpdatePassword(error: error.toString()));
    }
    return right(Unit);
  }

You don't have to use a password, and in that case, it will save the db file as plain text. If you want to add a password later, it will encrypt it at that time.

General Store

After using this for a while in an app, I've realized that it needs to be able to store data apart from just FHIR resources, at least on occasion. For this, I've added a second class for all versions of the database called GeneralDao. This is similar to the ResourceDao, but fewer options. So, in order to save something, it would look like this:

await GeneralDao().save('password', {'new':'map'});
await GeneralDao().save('password', {'new':'map'}, 'key');

The difference between these two options is that the first one will generate a key for the map being stored, while the second will store the map using the key provided. Both will return the key after successfully storing the map.

Other functions available include:

// deletes everything in the general store
await GeneralDao().deleteAllGeneral('password'); 

// delete specific entry
await GeneralDao().delete('password','key'); 

// returns map with that key
await GeneralDao().find('password', 'key'); 

FHIR® is a registered trademark of Health Level Seven International (HL7) and its use does not constitute an endorsement of products by HL7®

Use this package as a library

Depend on it

Run this command:

With Flutter:

 $ flutter pub add fhir_db

This will add a line like this to your package's pubspec.yaml (and run an implicit flutter pub get):

dependencies:
  fhir_db: ^0.4.3

Alternatively, your editor might support or flutter pub get. Check the docs for your editor to learn more.

Import it

Now in your Dart code, you can use:

import 'package:fhir_db/dstu2.dart';
import 'package:fhir_db/dstu2/fhir_db.dart';
import 'package:fhir_db/dstu2/general_dao.dart';
import 'package:fhir_db/dstu2/resource_dao.dart';
import 'package:fhir_db/encrypt/aes.dart';
import 'package:fhir_db/encrypt/salsa.dart';
import 'package:fhir_db/r4.dart';
import 'package:fhir_db/r4/fhir_db.dart';
import 'package:fhir_db/r4/general_dao.dart';
import 'package:fhir_db/r4/resource_dao.dart';
import 'package:fhir_db/r5.dart';
import 'package:fhir_db/r5/fhir_db.dart';
import 'package:fhir_db/r5/general_dao.dart';
import 'package:fhir_db/r5/resource_dao.dart';
import 'package:fhir_db/stu3.dart';
import 'package:fhir_db/stu3/fhir_db.dart';
import 'package:fhir_db/stu3/general_dao.dart';
import 'package:fhir_db/stu3/resource_dao.dart'; 

example/lib/main.dart

import 'package:fhir/r4.dart';
import 'package:fhir_db/r4.dart';
import 'package:flutter/material.dart';
import 'package:test/test.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();

  final resourceDao = ResourceDao();

  // await resourceDao.updatePw('newPw', null);
  await resourceDao.deleteAllResources(null);

  group('Playing with passwords', () {
    test('Playing with Passwords', () async {
      final patient = Patient(id: Id('1'));

      final saved = await resourceDao.save(null, patient);

      await resourceDao.updatePw(null, 'newPw');
      final search1 = await resourceDao.find('newPw',
          resourceType: R4ResourceType.Patient, id: Id('1'));
      expect(saved, search1[0]);

      await resourceDao.updatePw('newPw', 'newerPw');
      final search2 = await resourceDao.find('newerPw',
          resourceType: R4ResourceType.Patient, id: Id('1'));
      expect(saved, search2[0]);

      await resourceDao.updatePw('newerPw', null);
      final search3 = await resourceDao.find(null,
          resourceType: R4ResourceType.Patient, id: Id('1'));
      expect(saved, search3[0]);

      await resourceDao.deleteAllResources(null);
    });
  });

  final id = Id('12345');
  group('Saving Things:', () {
    test('Save Patient', () async {
      final humanName = HumanName(family: 'Atreides', given: ['Duke']);
      final patient = Patient(id: id, name: [humanName]);
      final saved = await resourceDao.save(null, patient);

      expect(saved.id, id);

      expect((saved as Patient).name?[0], humanName);
    });

    test('Save Organization', () async {
      final organization = Organization(id: id, name: 'FhirFli');
      final saved = await resourceDao.save(null, organization);

      expect(saved.id, id);

      expect((saved as Organization).name, 'FhirFli');
    });

    test('Save Observation1', () async {
      final observation1 = Observation(
        id: Id('obs1'),
        code: CodeableConcept(text: 'Observation #1'),
        effectiveDateTime: FhirDateTime(DateTime(1981, 09, 18)),
      );
      final saved = await resourceDao.save(null, observation1);

      expect(saved.id, Id('obs1'));

      expect((saved as Observation).code.text, 'Observation #1');
    });

    test('Save Observation1 Again', () async {
      final observation1 = Observation(
          id: Id('obs1'),
          code: CodeableConcept(text: 'Observation #1 - Updated'));
      final saved = await resourceDao.save(null, observation1);

      expect(saved.id, Id('obs1'));

      expect((saved as Observation).code.text, 'Observation #1 - Updated');

      expect(saved.meta?.versionId, Id('2'));
    });

    test('Save Observation2', () async {
      final observation2 = Observation(
        id: Id('obs2'),
        code: CodeableConcept(text: 'Observation #2'),
        effectiveDateTime: FhirDateTime(DateTime(1981, 09, 18)),
      );
      final saved = await resourceDao.save(null, observation2);

      expect(saved.id, Id('obs2'));

      expect((saved as Observation).code.text, 'Observation #2');
    });

    test('Save Observation3', () async {
      final observation3 = Observation(
        id: Id('obs3'),
        code: CodeableConcept(text: 'Observation #3'),
        effectiveDateTime: FhirDateTime(DateTime(1981, 09, 18)),
      );
      final saved = await resourceDao.save(null, observation3);

      expect(saved.id, Id('obs3'));

      expect((saved as Observation).code.text, 'Observation #3');
    });
  });

  group('Finding Things:', () {
    test('Find 1st Patient', () async {
      final search = await resourceDao.find(null,
          resourceType: R4ResourceType.Patient, id: id);
      final humanName = HumanName(family: 'Atreides', given: ['Duke']);

      expect(search.length, 1);

      expect((search[0] as Patient).name?[0], humanName);
    });

    test('Find 3rd Observation', () async {
      final search = await resourceDao.find(null,
          resourceType: R4ResourceType.Observation, id: Id('obs3'));

      expect(search.length, 1);

      expect(search[0].id, Id('obs3'));

      expect((search[0] as Observation).code.text, 'Observation #3');
    });

    test('Find All Observations', () async {
      final search = await resourceDao.getResourceType(
        null,
        resourceTypes: [R4ResourceType.Observation],
      );

      expect(search.length, 3);

      final idList = [];
      for (final obs in search) {
        idList.add(obs.id.toString());
      }

      expect(idList.contains('obs1'), true);

      expect(idList.contains('obs2'), true);

      expect(idList.contains('obs3'), true);
    });

    test('Find All (non-historical) Resources', () async {
      final search = await resourceDao.getAll(null);

      expect(search.length, 5);
      final patList = search.toList();
      final orgList = search.toList();
      final obsList = search.toList();
      patList.retainWhere(
          (resource) => resource.resourceType == R4ResourceType.Patient);
      orgList.retainWhere(
          (resource) => resource.resourceType == R4ResourceType.Organization);
      obsList.retainWhere(
          (resource) => resource.resourceType == R4ResourceType.Observation);

      expect(patList.length, 1);

      expect(orgList.length, 1);

      expect(obsList.length, 3);
    });
  });

  group('Deleting Things:', () {
    test('Delete 2nd Observation', () async {
      await resourceDao.delete(
          null, null, R4ResourceType.Observation, Id('obs2'), null, null);

      final search = await resourceDao.getResourceType(
        null,
        resourceTypes: [R4ResourceType.Observation],
      );

      expect(search.length, 2);

      final idList = [];
      for (final obs in search) {
        idList.add(obs.id.toString());
      }

      expect(idList.contains('obs1'), true);

      expect(idList.contains('obs2'), false);

      expect(idList.contains('obs3'), true);
    });

    test('Delete All Observations', () async {
      await resourceDao.deleteSingleType(null,
          resourceType: R4ResourceType.Observation);

      final search = await resourceDao.getAll(null);

      expect(search.length, 2);

      final patList = search.toList();
      final orgList = search.toList();
      patList.retainWhere(
          (resource) => resource.resourceType == R4ResourceType.Patient);
      orgList.retainWhere(
          (resource) => resource.resourceType == R4ResourceType.Organization);

      expect(patList.length, 1);

      expect(patList.length, 1);
    });

    test('Delete All Resources', () async {
      await resourceDao.deleteAllResources(null);

      final search = await resourceDao.getAll(null);

      expect(search.length, 0);
    });
  });

  group('Password - Saving Things:', () {
    test('Save Patient', () async {
      await resourceDao.updatePw(null, 'newPw');
      final humanName = HumanName(family: 'Atreides', given: ['Duke']);
      final patient = Patient(id: id, name: [humanName]);
      final saved = await resourceDao.save('newPw', patient);

      expect(saved.id, id);

      expect((saved as Patient).name?[0], humanName);
    });

    test('Save Organization', () async {
      final organization = Organization(id: id, name: 'FhirFli');
      final saved = await resourceDao.save('newPw', organization);

      expect(saved.id, id);

      expect((saved as Organization).name, 'FhirFli');
    });

    test('Save Observation1', () async {
      final observation1 = Observation(
        id: Id('obs1'),
        code: CodeableConcept(text: 'Observation #1'),
        effectiveDateTime: FhirDateTime(DateTime(1981, 09, 18)),
      );
      final saved = await resourceDao.save('newPw', observation1);

      expect(saved.id, Id('obs1'));

      expect((saved as Observation).code.text, 'Observation #1');
    });

    test('Save Observation1 Again', () async {
      final observation1 = Observation(
          id: Id('obs1'),
          code: CodeableConcept(text: 'Observation #1 - Updated'));
      final saved = await resourceDao.save('newPw', observation1);

      expect(saved.id, Id('obs1'));

      expect((saved as Observation).code.text, 'Observation #1 - Updated');

      expect(saved.meta?.versionId, Id('2'));
    });

    test('Save Observation2', () async {
      final observation2 = Observation(
        id: Id('obs2'),
        code: CodeableConcept(text: 'Observation #2'),
        effectiveDateTime: FhirDateTime(DateTime(1981, 09, 18)),
      );
      final saved = await resourceDao.save('newPw', observation2);

      expect(saved.id, Id('obs2'));

      expect((saved as Observation).code.text, 'Observation #2');
    });

    test('Save Observation3', () async {
      final observation3 = Observation(
        id: Id('obs3'),
        code: CodeableConcept(text: 'Observation #3'),
        effectiveDateTime: FhirDateTime(DateTime(1981, 09, 18)),
      );
      final saved = await resourceDao.save('newPw', observation3);

      expect(saved.id, Id('obs3'));

      expect((saved as Observation).code.text, 'Observation #3');
    });
  });

  group('Password - Finding Things:', () {
    test('Find 1st Patient', () async {
      final search = await resourceDao.find('newPw',
          resourceType: R4ResourceType.Patient, id: id);
      final humanName = HumanName(family: 'Atreides', given: ['Duke']);

      expect(search.length, 1);

      expect((search[0] as Patient).name?[0], humanName);
    });

    test('Find 3rd Observation', () async {
      final search = await resourceDao.find('newPw',
          resourceType: R4ResourceType.Observation, id: Id('obs3'));

      expect(search.length, 1);

      expect(search[0].id, Id('obs3'));

      expect((search[0] as Observation).code.text, 'Observation #3');
    });

    test('Find All Observations', () async {
      final search = await resourceDao.getResourceType(
        'newPw',
        resourceTypes: [R4ResourceType.Observation],
      );

      expect(search.length, 3);

      final idList = [];
      for (final obs in search) {
        idList.add(obs.id.toString());
      }

      expect(idList.contains('obs1'), true);

      expect(idList.contains('obs2'), true);

      expect(idList.contains('obs3'), true);
    });

    test('Find All (non-historical) Resources', () async {
      final search = await resourceDao.getAll('newPw');

      expect(search.length, 5);
      final patList = search.toList();
      final orgList = search.toList();
      final obsList = search.toList();
      patList.retainWhere(
          (resource) => resource.resourceType == R4ResourceType.Patient);
      orgList.retainWhere(
          (resource) => resource.resourceType == R4ResourceType.Organization);
      obsList.retainWhere(
          (resource) => resource.resourceType == R4ResourceType.Observation);

      expect(patList.length, 1);

      expect(orgList.length, 1);

      expect(obsList.length, 3);
    });
  });

  group('Password - Deleting Things:', () {
    test('Delete 2nd Observation', () async {
      await resourceDao.delete(
          'newPw', null, R4ResourceType.Observation, Id('obs2'), null, null);

      final search = await resourceDao.getResourceType(
        'newPw',
        resourceTypes: [R4ResourceType.Observation],
      );

      expect(search.length, 2);

      final idList = [];
      for (final obs in search) {
        idList.add(obs.id.toString());
      }

      expect(idList.contains('obs1'), true);

      expect(idList.contains('obs2'), false);

      expect(idList.contains('obs3'), true);
    });

    test('Delete All Observations', () async {
      await resourceDao.deleteSingleType('newPw',
          resourceType: R4ResourceType.Observation);

      final search = await resourceDao.getAll('newPw');

      expect(search.length, 2);

      final patList = search.toList();
      final orgList = search.toList();
      patList.retainWhere(
          (resource) => resource.resourceType == R4ResourceType.Patient);
      orgList.retainWhere(
          (resource) => resource.resourceType == R4ResourceType.Organization);

      expect(patList.length, 1);

      expect(patList.length, 1);
    });

    test('Delete All Resources', () async {
      await resourceDao.deleteAllResources('newPw');

      final search = await resourceDao.getAll('newPw');

      expect(search.length, 0);

      await resourceDao.updatePw('newPw', null);
    });
  });
} 

Download Details:

Author: MayJuun

Source Code: https://github.com/MayJuun/fhir/tree/main/fhir_db

#sqflite  #dart  #flutter 

Best Review

1629825646

Design Beast Review & OTO Link

Design Beast Review & OTOs + $20k Bonuses

CHECK BONUSES & GRAB IT AT: https://bit.ly/3yhtcqi

Welcome to my Design Beast Review A Very warm welcome to my DesignBeast Review Here You Will Find Honest Opinion About The Design Beast Whether It is A Right Fit For You or not also I Have Covered All Working processes of DesignBeast, Live Video Demo, features Pros & Cons & All Design Beast OTO details.

Govind Rana Here Stay Till the End Of This Review I Have included $20k Bonuses At the end Of DesignBeast Review

DesignBeast Review – World finest graphic designing & animation software that will come into existence in some days. If you are searching for DesignBeast Review then this is the right platform to get in-depth information and the truth for Design Beast Review. An AI-based designing software that enables the 3D designing technology to you.

I am pretty much excited to share my point of view about the design beast. and this is because I want to meet you to the high technology graphics software.

This software is going to launch on 26 Aug. 2021 by the very famous vendor Paul Ponna and this time he is launching is 2 years of efforts on this amazing app. So do believe me without any doubt, here I only share the actual facts for Designbeast Review.

At this time the limited information is available on the web so I have included the creator of DesignBeast, Paul Ponna’s previous launches, what is DesignBeast, features & benefits, examples, who will best fit for this app, pros & cons, included with a huge bonuses.

Discount will be rolling out from 26th August

(fingers crossed till its launch because it is the launch beyond expectations)

Design Beast Review – Overview

  • Creator: Paul Ponna
  • Product Name: DesignBeast
  • Launch Date – 2021-Aug-24
  • Launch Timing – 11:00 EDT
  • Pricing – $67
  • Official Website – Visit
  • Money-Back Guarantee- Information Not Available
  • Category – Graphic Designing
  • Training – Yes, Available
  • Bonuses – Techevoke Special Bonuses Available

About Paul Ponna the vendor & Creator of DesignBeast

Paul Ponna is an entrepreneur and a digital geek in the internet marketing niche. His previous launches were hit the market products and were evergreen. No comparison of his products because he knows what is a need in today’s market and how online marketers will get benefited from online technologies.

So let’s have a look at Paul Ponna’s previous hits in the saas industry.

  1. DoodleMaker – This is the doodle video maker and the popular software on JVZoo that is the biggest launch in the history of internet marketing software. With a doodle maker, you can create studio-quality doodle videos with this application.
  2. VideoCreator – A readymade video editing app that is more authentic than existing video editing software. No more templates creation is required and no extra efforts to make and you can make exciting effects with videocreator.
  3. There is more software that has been launched by Paul Ponna…
  • DoodleMaker
  • Avatar Builder
  • VideoCreator
  • DesignBeast (available on 26th Aug)

Paul Ponna is a tech entrepreneur and he was started his journey from his 18 and with a website and hosting spending only $20. And he is a millionaire and frequently launches products that are really amazing and useful.

So not further delays let come to the designbeast review and let’s talk about what will be this software and how can you get benefited from this.

What is Design Beast?

Design beast is a software that comes with 6 world-class designing technology, and with those 6 modules, you can fulfill your graphics needs in just 1 price tag.

DesignBeast is a software that is responsible for multipurpose designs and better technology including these below-mentioned modules.

  1. Design Automation App #1– All in One Design and Mockup Engine
  2. Design Automation App #1– 3D Live Motion Photos
  3. Design Automation App #1– Magic Object Remover
  4. Design Automation App #1– 1-Click Background Removal
  5. Design Automation App #1– Slick Image Editor
  6. Design Automation App #1– AI Logo Creator

This is app bundle is fully loaded with advanced graphics features that are essential for making high-quality posts, infographics, motion pictures, 3D banners, and more.

Here are all modules explanations of DesignBeast

So this is clear this app has various technologies that are responsible for advanced editing and professional graphical designs. So here is the module’s explanation.

  1. All in One Design and mockup Engine

This is a designs library, not an ordinary image or premade design library. All elements are customizable and you can create any of your imagination with this design and mockup engine.

7000+ ready-to-use customizable designs and mockups are available in this module. Just head over to the DesignBeast software and you will get the professional DFY designs and mockups for your graphics need.

There are for all social apps, means available in various sizes.

2. 3D Live Motion Photos

Now you can convert a still, boring photo to a live, 3D effect photo with the A.I. technology of DesignBeast. With this effect, you can engage with your audience in a more effective manner.

And you all know that a moving object with a visual effect is 10x more engaging than an ordinary graphical image. with this technology, you can grab the attention of your customers and get more clicks on your sales platform.

3. Magic Object Removal Tool

Most of the time we need to remove some object or any person from any of the selected images and this module will give you access to select the required object or person and the remove that thing is just one click.

The feature Paul Ponna offers in his software is rarely available on any other software. With only one click the magic happens and the object will be removed.

4. 1-Click Background Removal

Because the software has technology that is based on AI and Machine Learning. So it auto-detects the edges and objects in your photos and automatically erases the background from any photo.

You don’t need to make extra effects just select the 1 click background removal option and click on the image background and it will vanish within seconds.

5. Slick Image Editor

This has the multi-feature of basic editing for any photo. Just like edit, crop, short, effects, blur, and more. You don’t need to go for different apps to perform different tasks every time.

You can convert any still normal photo to a high-class visual and ready-to-use, ready-to-print photo with this module.

6. Artificial Intelligence Logo Creator

An AI logo creator, not just a free tool that is available in the online market but it is quite effective and useful for you to generate any kind of logo. You can now bulk-create 50 logo variations for any brand in 3 easy steps.

All designs are fully customizable, also a single object is customizable with this app.

How DesignBeast will fire in the saas market?

In this section of DesignBeast Review, I am sharing its popularity, hype, and the vendor name-fame with you, so that you can evaluate its worth.

Just because you need a better, time-saving, authentic, graphic designing and animation software that will fulfill your professional graphics need for online marketing.

Because paul Ponna is a tech entrepreneur and he knows what is write to tab the market and what should be the next useful tool for every marketer.

DesignBeast is now going to be a popular one from the software list of its vendor. No matter what competitors of DesignBeast will say about this software. But as a consumer and a digital marketer, I am pretty much excited for its official launch.

DesignBeast Features & Benefits

If you want to create designs for Social media, websites, e-commerce sites, local businesses, promos, and advertising then focus on the features & benefits of DesignBeast Review, so that you can evaluate its actual strength.

 A.I. & Machine Learning Technology

This is the platform that suggests automatically the designs, objects, effects & more things that are based on your needs and the design frame you choose.

Automate design tasks with machine learning and artificial intelligence to leapfrog your competition and maximize revenues.

 6 Apps in the Price of One

There is no comparison of this app in the online market because the bundle of 6 apps and those apps are highly authentic useful in today’s competitive marketing world.

You can replace multiple graphics apps from one that is DesignBeast and you need to replace it if you want to save your money and time.

 Multilingual

This app is available in multi-languages, and with this feature, it doesn’t matter from where you are in this world.

It enables you to sell your service towards the globe and also give you the access to create graphical content in your local language.

 Commercial and resell rights available

Commercial licensing brings you to another stage of selling your services to clients. Now you can freely sell all generated content to your clients in the market. Also charge extra fees according to your skills and set your service on commercial platforms.

 Copywrite free assets and resources

Assets that are really expensive and everyone even I needs to purchase from the online market and those services are very expensive for all of us. But now all are available at one place that is design beast, you will get premium royalty-free images, icons, backgrounds & animations.

 Save Time and money

You can build world-class designs in minutes and all designs are professional, in starting you need to learn some lessons and practice to perform with DesignBeast membersarea.

 Dynamic Visual Effects

The effects offered by this software is so amazing and fully customizable so that I have given the term dynamic. All things are editable and ready to use.

Is there are any skills required to work with DesignBeast?

Designbeast is a DFY editable templates advanced graphic design software that will suggest to you the designs from its A.I. and machine learning technology. So I am sure you don’t need any advanced skills to use DesignBeast.

But to be honest, you need to work on these soft skills.

  1. Knowledge of using basic online apps.
  2. The mindset to Selecting the best
  3. Knowledge of colors
  4. Knowledge of graphics
  5. Understanding of designs
  6. Branding

And there are most soft skills required.

Design Beast Review – Who will be fit for this software?

So now in this series, it’s time to share the industry people who are best fit for this software that is Designbeast. And after lots of research and analysis, I decided to include these professionals in the DesignBeast audience. I am happy to share my point views in this DesignBeast Review.

  • Graphic Designers
  • Digital Marketers
  • Bloggers.
  • Vloggers
  • Youtubers
  • Media Agency
  • Advertising agency
  • Local Businesses
  • Ecommerce Players

DesignBeast Review – Pros & Cons

I have shared the sure short pros and cons for this revolutionary software. But there are some cons also available. After reviewing the product, as a marketer, I also realized this has lots of pros and some cons available in the market.

Pros

  • 6 modules in 1 app
  • 3d photo creation technology with AI and machine learning
  • Background and object removal technology.
  • Designs library over 7000
  • Kindly support team.
  • Trustable vendor
  • 30 Days money back gaurantee.
  • And more…

Cons

  • Some modules are more useful than 1 or 2 other modules.
  • You cannot download the software to your computer or on a desktop.
  • No more cons I have found for this software.

Design Beast OTOs/Upgrades

Here are the details of its upgrade, so that you can utilize all its advanced features. In this DesignBeast Review, I have mentioned the name and price of OTOs, and the rest of the details will be available soon.

Front End: DesignBeast Commercial

Price – $47 Onetime

  • Six Designs App For Price of One
  • Mockup Designer App
  • AI Logo Maker App
  • 1-Click Background Removal App
  • Live Motion Photos App
  • Multi-Purpose Image Editor App
  • Magic Object Removal App
  • 7000+ Ready-to-Use Templates
  • Millions of Royalty-Free Images
  • Copyright-Free Vectors & Icons
  • Hundreds of Fonts
  • Multi-Lingual Support
  • Step-by-Step Video Training
  • Commercial License
  • Sell The Designs For Profit
  • Facebook Group Access
  • Skype Mentorship Group Access
  • 8 Week Training Webinars

OTO#1: DesignBeast Elite

Price – $49 Onetime

Get access to additional features worth thousands. 10X your results, sales and profits and get ahead of the competition and other DesignBeast customers. 

  • Unlock 2,000 additional ready-to-use templates
  • Get 80 new templates added to your account each month for 1 year. (no monthly or yearly fees.)
  • Thousands of Premium Text Effects and Animations
  • Millions of Premium Royalty Free Design Assets, Icons and vectors.
  • Millions of Copyright-Free Image
  • Priority Future Software Updates

OTO#2: DesignBeast Agency

Price – $67

Sell videos for $300 to $500 each with the done-for-you agency package included. This upgrade makes it easy for everyone to find clients and sell their designs for top dollar. 

  • 5 sub accounts
  • Done-For-You Agency Marketing Bundle
  • Done-For-You Legal Client Contracts
  • Done-For-You Agency Website
  • Done-For-You Agency Sales Video

OTO#3: DesignBeast 4 in 1 Ultra.

Price – $39 OneTime

Customers get access to FOUR additional apps as part of this upgrade. 

  • Pixel Perfect
  • Instantly turn any image, even a low quality image, into ultra HD, high quality photo that can be blown up to any size – even billboard size – without any pixelation or distortion.
  • Animated Ads Builder 

Create animated ads in all languages, shapes and sizes using hundreds of ready to use design templates. Use animated ads to promote your products, create ads for clients or sell animated designs on freelancer websites like fiverr, upwork and freelancer to maximize profits. 

  • Video Resizer

With this powerful technology you can resize any video into multiple video sizes perfectly sized for all social platforms. Turn a single video into multiple dimensions and sizes within minutes and share the video onto different platforms to drive more traffic and sales!

  • Video Survey Pro

With this powerful app you can instantly collect:

* Video Testimonials

* Live video feedback from clients about your work

* Add video surveys on your websites to collect valuable information

* Have your team record video feedback about any project 

Streamline your workflows without any confusion or relying on old and outdated methods like email and text.  

OTO#4: DesignBeast Unlimited

Price $67 OneTime

With the DesignBeast basic license, you can create unlimited designs forever with one limit of 600 credits per month on each of the six apps included. 

The limits reset each month so you can continue creating amazing designs, graphics and animations forever without any monthly fees. 

This limit is put in place to prevent abuse and ensure all our customers are getting the best value for years to come at an unbeatable price.

As part of this special unlimited upgrade, you can remove all the monthly limits and restrictions for all the cutting-edge apps and technologies included. 

Design Beast Review Conclusion

From my take, this will be a good and useful tool for you if you belong to these above-mentioned professional categories. No matter you have advanced skills or not because everything will be DFY and ready to use. And the best thing is that you can customize and edit each and every pre-made effect, design, and more thing. According to my opinion, graphics designing software is ned for every marketer and business person, but everyone cannot go for photoshop, AI, and Coral, so for making it easy and useful there will be a choice in your hand that is DesignBeast.

CHECK BONUSES & GRAB IT AT: https://bit.ly/3yhtcqi

SOURCE: https://bit.ly/3Dch4KV

Cron Job Scheduling In Laravel

Today I will show you Cron Job Scheduling In Laravel, many time we require to run some piece of code specific interval time period in laravel and we need to run manually every time but command scheduler through we can run and create cron job in laravel.

So, here i will teach you how to create cron job in laravel, and how to create custom command in laravel.

Cron Job Scheduling In Laravel

https://websolutionstuff.com/post/cron-job-scheduling-in-laravel

#cron job scheduling in laravel #laravel #scheduling #scheduler #cron #how to create cron job in laravel

Carmen  Grimes

Carmen Grimes

1595494844

How to start an electric scooter facility/fleet in a university campus/IT park

Are you leading an organization that has a large campus, e.g., a large university? You are probably thinking of introducing an electric scooter/bicycle fleet on the campus, and why wouldn’t you?

Introducing micro-mobility in your campus with the help of such a fleet would help the people on the campus significantly. People would save money since they don’t need to use a car for a short distance. Your campus will see a drastic reduction in congestion, moreover, its carbon footprint will reduce.

Micro-mobility is relatively new though and you would need help. You would need to select an appropriate fleet of vehicles. The people on your campus would need to find electric scooters or electric bikes for commuting, and you need to provide a solution for this.

To be more specific, you need a short-term electric bike rental app. With such an app, you will be able to easily offer micro-mobility to the people on the campus. We at Devathon have built Autorent exactly for this.

What does Autorent do and how can it help you? How does it enable you to introduce micro-mobility on your campus? We explain these in this article, however, we will touch upon a few basics first.

Micro-mobility: What it is

micro-mobility

You are probably thinking about micro-mobility relatively recently, aren’t you? A few relevant insights about it could help you to better appreciate its importance.

Micro-mobility is a new trend in transportation, and it uses vehicles that are considerably smaller than cars. Electric scooters (e-scooters) and electric bikes (e-bikes) are the most popular forms of micro-mobility, however, there are also e-unicycles and e-skateboards.

You might have already seen e-scooters, which are kick scooters that come with a motor. Thanks to its motor, an e-scooter can achieve a speed of up to 20 km/h. On the other hand, e-bikes are popular in China and Japan, and they come with a motor, and you can reach a speed of 40 km/h.

You obviously can’t use these vehicles for very long commutes, however, what if you need to travel a short distance? Even if you have a reasonable public transport facility in the city, it might not cover the route you need to take. Take the example of a large university campus. Such a campus is often at a considerable distance from the central business district of the city where it’s located. While public transport facilities may serve the central business district, they wouldn’t serve this large campus. Currently, many people drive their cars even for short distances.

As you know, that brings its own set of challenges. Vehicular traffic adds significantly to pollution, moreover, finding a parking spot can be hard in crowded urban districts.

Well, you can reduce your carbon footprint if you use an electric car. However, electric cars are still new, and many countries are still building the necessary infrastructure for them. Your large campus might not have the necessary infrastructure for them either. Presently, electric cars don’t represent a viable option in most geographies.

As a result, you need to buy and maintain a car even if your commute is short. In addition to dealing with parking problems, you need to spend significantly on your car.

All of these factors have combined to make people sit up and think seriously about cars. Many people are now seriously considering whether a car is really the best option even if they have to commute only a short distance.

This is where micro-mobility enters the picture. When you commute a short distance regularly, e-scooters or e-bikes are viable options. You limit your carbon footprints and you cut costs!

Businesses have seen this shift in thinking, and e-scooter companies like Lime and Bird have entered this field in a big way. They let you rent e-scooters by the minute. On the other hand, start-ups like Jump and Lyft have entered the e-bike market.

Think of your campus now! The people there might need to travel short distances within the campus, and e-scooters can really help them.

How micro-mobility can benefit you

benefits-micromobility

What advantages can you get from micro-mobility? Let’s take a deeper look into this question.

Micro-mobility can offer several advantages to the people on your campus, e.g.:

  • Affordability: Shared e-scooters are cheaper than other mass transportation options. Remember that the people on your campus will use them on a shared basis, and they will pay for their short commutes only. Well, depending on your operating model, you might even let them use shared e-scooters or e-bikes for free!
  • Convenience: Users don’t need to worry about finding parking spots for shared e-scooters since these are small. They can easily travel from point A to point B on your campus with the help of these e-scooters.
  • Environmentally sustainable: Shared e-scooters reduce the carbon footprint, moreover, they decongest the roads. Statistics from the pilot programs in cities like Portland and Denver showimpressive gains around this key aspect.
  • Safety: This one’s obvious, isn’t it? When people on your campus use small e-scooters or e-bikes instead of cars, the problem of overspeeding will disappear. you will see fewer accidents.

#android app #autorent #ios app #mobile app development #app like bird #app like bounce #app like lime #autorent #bird scooter business model #bird scooter rental #bird scooter rental cost #bird scooter rental price #clone app like bird #clone app like bounce #clone app like lime #electric rental scooters #electric scooter company #electric scooter rental business #how do you start a moped #how to start a moped #how to start a scooter rental business #how to start an electric company #how to start electric scooterrental business #lime scooter business model #scooter franchise #scooter rental business #scooter rental business for sale #scooter rental business insurance #scooters franchise cost #white label app like bird #white label app like bounce #white label app like lime