A flutter Client for ASP.NET Core SignalR

A Flutter SignalR Client for ASP.NET Core 3.1.
ASP.NET Core SignalR is an open-source library that simplifies adding real-time web functionality to apps. Real-time web functionality enables server-side code to push content to clients instantly.

The client is able to invoke server side hub functions (including streaming functions) and to receive method invocations issued by the server. It also supports the auto-reconnect feature.

The client supports the following transport protocols:

  • WebSocket
  • Service Side Events
  • Long Polling

The client supports the following hub protocols:

  • Json
  • ~~MessagePack~~ - Since I can't find a MessagePack library that support the current flutter version.

Examples

Getting Started

Add signalr_netcore to your pubspec.yaml dependencies:

...
dependencies:
  flutter:
    sdk: flutter

  signalr_netcore:
...

Usage

Let's demo some basic usages:

1. Create a hub connection:

// Import the library.
import 'package:signalr_netcore/signalr_client.dart';

// The location of the SignalR Server.
final serverUrl = "192.168.10.50:51001";
// Creates the connection by using the HubConnectionBuilder.
final hubConnection = HubConnectionBuilder().withUrl(serverUrl).build();
// When the connection is closed, print out a message to the console.
final hubConnection.onclose( (error) => print("Connection Closed"));

Logging is supported via the dart logging package:

// Import theses libraries.
import 'package:logging/logging.dart';
import 'package:signalr_netcore/signalr_client.dart';

// Configer the logging
Logger.root.level = Level.ALL;
// Writes the log messages to the console
Logger.root.onRecord.listen((LogRecord rec) {
  print('${rec.level.name}: ${rec.time}: ${rec.message}');
});

// If you want only to log out the message for the higer level hub protocol:
final hubProtLogger = Logger("SignalR - hub");
// If youn want to also to log out transport messages:
final transportProtLogger = Logger("SignalR - transport");

// The location of the SignalR Server.
final serverUrl = "192.168.10.50:51001";
final connectionOptions = HttpConnectionOptions
final httpOptions = new HttpConnectionOptions(logger: transportProtLogger);
//final httpOptions = new HttpConnectionOptions(logger: transportProtLogger, transport: HttpTransportType.WebSockets); // default transport type.
//final httpOptions = new HttpConnectionOptions(logger: transportProtLogger, transport: HttpTransportType.ServerSentEvents);
//final httpOptions = new HttpConnectionOptions(logger: transportProtLogger, transport: HttpTransportType.LongPolling);

// If you need to authorize the Hub connection than provide a an async callback function that returns 
// the token string (see AccessTokenFactory typdef) and assigned it to the accessTokenFactory parameter:
// final httpOptions = new HttpConnectionOptions( .... accessTokenFactory: () async => await getAccessToken() ); 

// Creates the connection by using the HubConnectionBuilder.
final hubConnection = HubConnectionBuilder().withUrl(serverUrl, options: httpOptions).configureLogging(hubProtLogger).build();
// When the connection is closed, print out a message to the console.
final hubConnection.onclose( (error) => print("Connection Closed"));

2. Connect to a Hub:

Calling following method starts handshaking and connects the client to SignalR server

await hubConnection.start();

3. Calling a Hub function:

Assuming there is this hub function:

public string MethodOneSimpleParameterSimpleReturnValue(string p1)
{
  Console.WriteLine($"'MethodOneSimpleParameterSimpleReturnValue' invoked. Parameter value: '{p1}");
  return p1;
}

The client can invoke the function by using:


  final result = await hubConnection.invoke("MethodOneSimpleParameterSimpleReturnValue", args: <Object>["ParameterValue"]);
  logger.log(LogLevel.Information, "Result: '$result");

4. Calling a client function:

Assuming the server calls a function "aClientProvidedFunction":

  await Clients.Caller.SendAsync("aClientProvidedFunction", null);

The Client provides the function like this:

  
  hubConnection.on("aClientProvidedFunction", _handleAClientProvidedFunction);

  // To unregister the function use:
  // a) to unregister a specific implementation:
  // hubConnection.off("aClientProvidedFunction", method: _handleServerInvokeMethodNoParametersNoReturnValue);
  // b) to unregister all implementations:
  // hubConnection.off("aClientProvidedFunction");
  ...
  void _handleAClientProvidedFunction(List<Object> parameters) {
    logger.log(LogLevel.Information, "Server invoked the method");
  }

A note about the parameter types

All function parameters and return values are serialized/deserialized into/from JSON by using the dart:convert package (json.endcode/json.decode). Make sure that you:

  • use only simple parameter types

or

  • use objects that implements toJson() since that method is used by the dart:convert package to serialize an object.

Flutter Json 101:

Use this package as a library

Depend on it

Run this command:

With Flutter:

 $ flutter pub add signalr_netcore

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

dependencies:
  signalr_netcore: ^1.2.2

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:signalr_netcore/abort_controller.dart';
import 'package:signalr_netcore/default_reconnect_policy.dart';
import 'package:signalr_netcore/errors.dart';
import 'package:signalr_netcore/handshake_protocol.dart';
import 'package:signalr_netcore/http_connection.dart';
import 'package:signalr_netcore/http_connection_options.dart';
import 'package:signalr_netcore/hub_connection.dart';
import 'package:signalr_netcore/hub_connection_builder.dart';
import 'package:signalr_netcore/iconnection.dart';
import 'package:signalr_netcore/ihub_protocol.dart';
import 'package:signalr_netcore/iretry_policy.dart';
import 'package:signalr_netcore/itransport.dart';
import 'package:signalr_netcore/json_hub_protocol.dart';
import 'package:signalr_netcore/long_polling_transport.dart';
import 'package:signalr_netcore/server_sent_events_transport.dart';
import 'package:signalr_netcore/signalr_client.dart';
import 'package:signalr_netcore/signalr_http_client.dart';
import 'package:signalr_netcore/text_message_format.dart';
import 'package:signalr_netcore/utils.dart';
import 'package:signalr_netcore/web_socket_transport.dart';
import 'package:signalr_netcore/web_supporting_http_client.dart'; 

example/lib/main.dart

import 'app.dart';
import 'package:flutter/material.dart';

const kChatServerUrl = "http://192.168.0.4:5000";

void main() {
  runApp(App());
} 

Download Details:

Author: sefidgaran

Source Code: https://github.com/sefidgaran/signalr_client

#flutter #SignalR 

What is GEEK

Buddha Community

A flutter Client for ASP.NET Core SignalR
Einar  Hintz

Einar Hintz

1602560783

jQuery Ajax CRUD in ASP.NET Core MVC with Modal Popup

In this article, we’ll discuss how to use jQuery Ajax for ASP.NET Core MVC CRUD Operations using Bootstrap Modal. With jQuery Ajax, we can make HTTP request to controller action methods without reloading the entire page, like a single page application.

To demonstrate CRUD operations – insert, update, delete and retrieve, the project will be dealing with details of a normal bank transaction. GitHub repository for this demo project : https://bit.ly/33KTJAu.

Sub-topics discussed :

  • Form design for insert and update operation.
  • Display forms in modal popup dialog.
  • Form post using jQuery Ajax.
  • Implement MVC CRUD operations with jQuery Ajax.
  • Loading spinner in .NET Core MVC.
  • Prevent direct access to MVC action method.

Create ASP.NET Core MVC Project

In Visual Studio 2019, Go to File > New > Project (Ctrl + Shift + N).

From new project window, Select Asp.Net Core Web Application_._

Image showing how to create ASP.NET Core Web API project in Visual Studio.

Once you provide the project name and location. Select Web Application(Model-View-Controller) and uncheck HTTPS Configuration. Above steps will create a brand new ASP.NET Core MVC project.

Showing project template selection for .NET Core MVC.

Setup a Database

Let’s create a database for this application using Entity Framework Core. For that we’ve to install corresponding NuGet Packages. Right click on project from solution explorer, select Manage NuGet Packages_,_ From browse tab, install following 3 packages.

Showing list of NuGet Packages for Entity Framework Core

Now let’s define DB model class file – /Models/TransactionModel.cs.

public class TransactionModel
{
    [Key]
    public int TransactionId { get; set; }

    [Column(TypeName ="nvarchar(12)")]
    [DisplayName("Account Number")]
    [Required(ErrorMessage ="This Field is required.")]
    [MaxLength(12,ErrorMessage ="Maximum 12 characters only")]
    public string AccountNumber { get; set; }

    [Column(TypeName ="nvarchar(100)")]
    [DisplayName("Beneficiary Name")]
    [Required(ErrorMessage = "This Field is required.")]
    public string BeneficiaryName { get; set; }

    [Column(TypeName ="nvarchar(100)")]
    [DisplayName("Bank Name")]
    [Required(ErrorMessage = "This Field is required.")]
    public string BankName { get; set; }

    [Column(TypeName ="nvarchar(11)")]
    [DisplayName("SWIFT Code")]
    [Required(ErrorMessage = "This Field is required.")]
    [MaxLength(11)]
    public string SWIFTCode { get; set; }

    [DisplayName("Amount")]
    [Required(ErrorMessage = "This Field is required.")]
    public int Amount { get; set; }

    [DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}")]
    public DateTime Date { get; set; }
}

C#Copy

Here we’ve defined model properties for the transaction with proper validation. Now let’s define  DbContextclass for EF Core.

#asp.net core article #asp.net core #add loading spinner in asp.net core #asp.net core crud without reloading #asp.net core jquery ajax form #asp.net core modal dialog #asp.net core mvc crud using jquery ajax #asp.net core mvc with jquery and ajax #asp.net core popup window #bootstrap modal popup in asp.net core mvc. bootstrap modal popup in asp.net core #delete and viewall in asp.net core #jquery ajax - insert #jquery ajax form post #modal popup dialog in asp.net core #no direct access action method #update #validation in modal popup

Einar  Hintz

Einar Hintz

1602564619

MVC User Registration & Login with ASP.NET Core Identity

User registration and authentication are mandatory in any application when you have little concern about privacy. Hence all most all application development starts with an authentication module. In this article, we will discuss the quickest way to use **ASP.NET Core Identity for User Login and Registration **in a new or existing MVC application.

Sub-topics discussed :

  • How to add ASP.NET Core Identity to MVC application.
  • Customize ASP.NET Core Identity.
  • Identity.UI Design Customization.
  • Next step.

Background

ASP.NET Core Identity is an API, which provides both user interface(UI) and functions for user authentication, registration, authorization, etc. Modules/ APIs like this will really be helpful and fasten the development process. It comes with ASP.NET Core Framework and used in many applications before. Which makes the API more dependable and trustworthy.

ASP.NET Core MVC with user authentication can easily be accomplished using Identity.UI. While creating the MVC project, you just need to select Authentication as Individual User Accounts.

Showing how to create an MVC application with ASP.NET Core Identity API

The rest will be handled by ASP.NET Core Identity UI. It already contains razor view pages and backend codes for an authentication system. But that’s not what we want in most of the cases. we want to customize ASP.NET Core Identity as per our requirement. That’s what we do here.

Create an ASP.NET Core MVC Project

First of all, I will create a brand new ASP.NET Core MVC application without any authentication selected. We could add ASP.NET Core Identity later into the project.

In Visual Studio 2019, Go to File > New > Project (Ctrl + Shift + N). From new project window, select ASP.NET Core Web Application.

Create an ASP.NET Core Web application

Once you provide the project name and location. A new window will be opened as follows, Select _Web Application(Model-View-Controller), _uncheck _HTTPS Configuration _and DO NOT select any authentication method. Above steps will create a brand new ASP.NET Core MVC project.

Select Model View Controller templet under .NET Core

#asp.net core article #asp.net core #add asp.net core identity to existing project #asp.net core identity in mvc #asp.net core mvc login and registration #login and logout in asp.net core

Jquery from validation || ASP NET Core client side validation

#Asp.net core #Asp.net core mvc #Core #Asp.net core tutorials #Asp.net core with entity framework

Authorization in asp.net core

#Asp.net core #Asp.net core mvc #Core #Asp.net core tutorials #Asp.net core with entity framework

AllowAnonymous in asp.net core

#Asp.net core #Asp.net core mvc #Core #Asp.net core tutorials #Asp.net core with entity framework