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MIG libray for .Net/Mono

MIG is a .Net library providing an integrated solution for developing networked applications and real time web applications.

How it works

We have two main actors in MIG: Gateway and Interface.

A Gateway is the medium used for receiving API commands from the client and for transmitting responses and events back to it.

An Interface is where all API commands are defined and related actions take place.

So, when writing an application based on MIG, the developer will just focus on the API coding.

Once the API commands are implemented, the application is ready to communicate with its clients through the desired Gateway medium. This can be a raw TCP socket server (TcpSocketGateway), an HTTP server (WebServiceGateway), a WebSocket server (WebSocketGateway), a MQTT server (MqttServiceGateway) or even ALL of them at the same time, so to have a multi-protocol support for the application.

Example code:

var migService = new MigService();

// Add Web Server gateway
var webServiceGw = migService.AddGateway(Gateways.WebServiceGateway);

// Add Web Socket gateway
var webSocketGw = migService.AddGateway(Gateways.WebSocketGateway);

// Define an API handler for myapp/demo/greet command
migService.RegisterApi("myapp/demo/greet", (request)=>{
    // we registered an handler for
    // myapp/demo/greet/<option_0>[/<option_1>/../<option_n>]
    var name = request.Command.GetOption(0);
    // raise an event in the form
    // <domain>, <source>, <description>, <property>, <value>
    migService.RaiseEvent("myapp", "demo", "Reply to greet", "Greet.User", name);
    // return the response (objects are automatically serialized to JSON)
    return new ResponseStatus(Status.Ok);
});

// OR we can define a generic API handler for any request starting with myapp/....
migService.RegisterApi("myapp", (request)=>{
    // we registered an handler for
    // myapp/<module_address>/<command>/<option_0>[/<option_1>/../<option_n>]

    var cmd = request.Command;
    switch(cmd.Address)
    {
    case "demo":
        // myapp/demo/....
        switch (cmd.Command)
        {
        case "greet":
            // myapp/demo/greet/....
            // ....
            break;
        case "ping":
            // myapp/demo/ping/....
            // ...
            break;
        }
        break;
    case "configure":
        // myapp/configure/....
        // ...
        break;
    }

    // return the response (objects are automatically serialized to JSON)
    return new ResponseStatus(Status.Ok);
});

In the above example we defined an handler for the API command myapp/demo/greet. This command can be issued from the web browser by either using a standard HTTP call

// HTTP service API commands have to be issued using the /api/ prefix
$.get('http://localhost/api/myapp/demo/greet/Foo+Bar', function(res) { ... });

or by using the websocket client connection

wsclient.send('myapp/demo/greet/Foo Bar');

Gateways

Each gateway can be configured by using the SetOption method.

WebServiceGateway

Features

Option List

Example

var web = migService.AddGateway(Gateways.WebServiceGateway);
// HTML files folder 
web.SetOption(WebServiceGatewayOptions.HomePath, "html");
// base URL for html files
web.SetOption(WebServiceGatewayOptions.BaseUrl, "/pages/"); 
// listen on any address
web.SetOption(WebServiceGatewayOptions.Host, "*"); 
// TCP port
web.SetOption(WebServiceGatewayOptions.Port, "8080");
// enable authentication
web.SetOption(WebServiceGatewayOptions.Authentication, "Digest"); 
// disable file caching
web.SetOption(WebServiceGatewayOptions.EnableFileCaching, "False"); 
// disable CORS
web.SetOption(WebServiceGatewayOptions.CorsAllowOrigin, ""); 
// add a url alias (`path/to/myfile.jpg` will serve `real/path/file.jpg`)
web.SetOption(WebServiceGatewayOptions.UrlAliasPrefix, "path/to/myfile.jpg:real/path/file.jpg");
// add web-app folder (used for deploying SPA and PWA such as Angular2 apps)
// all requested files non found in `app/` will be redirected to `app/index.html`
web.SetOption(WebServiceGatewayOptions.UrlAliasPrefix, "app/*:app/index.html");

User authentication with Digest or Basic methods

string authReam = "My App Realm";
web.SetOption(WebServiceGatewayOptions.Authentication, WebAuthenticationSchema.Digest);
web.SetOption(WebServiceGatewayOptions.AuthenticationRealm, authRealm);
web.UserAuthenticationHandler += (sender, eventArgs) =>
{
    // lookup 'eventArgs.Username' in your database
    var user = GetUser(eventArgs.Username);
    if (user != null)
    {
        // WebServiceGateway requires password to be encrypted using the `Digest.CreatePassword(..)` method.
        // This applies both to 'Digest' and 'Basic' authentication methods.
        // So if 'user.Password' is stored in clear (not recommended) it must be encrypted
        string encryptedPassword = Digest.CreatePassword(user.Username, authRealm, user.Password);
        // if 'user.Password' is already encrypted the previous line can be removed
        return new User(user.Username, authRealm, encryptedPassword);
    }
    return null;
};

WebSocketGateway

Options

Example

var ws = migService.AddGateway(Gateways.WebSocketGateway);
ws.SetOption(WebSocketGatewayOptions.Port, "8181");

Authentication using Token

When Authentication option is set to Token, the websocket service will require the client to connect by providing an authentication token in the url query-string as the at parameter.

The authorization token is obtained by calling the following method

double expireSeconds = 5; // 5 seconds validity
var token = ws.GetAuthorizationToken(expireSeconds);
// ...

When the client is a browser, then GetAuthorizationToken can be exposed implementing a custom API method as shown in the included example application (Test.WebService).

The following snippet from the example application shows how to request and use the token in JavaScript:

var webSocket;
fetch('/api/myapp/demo/token').then(function(response) {
    return response.json();
}).then(function(data) {
    var token = data.ResponseValue;
    webSocket = new WebSocket("ws://localhost:8181/events?at="+token);
    // ...
}).catch(function() {
    // ...
});

User authentication with Digest or Basic methods

This is similar as seen for WebServiceGateway the only difference is that the password is not encrypted.

TcpSocketGateway

Options

MqttServiceGateway

A MIG Gateway for supporting the MQTT protocol will be integrated in future releases. In the meantime a simple MQTT broker implementation is available as a MIG Interface from this repository.

Interfaces

While in the earlier examples we used the RegisterApi method to dynamically add new API commands, these can also be added by using Interface plugins. Interface plugins are library modules (dll) that can be dinamically loaded into MIG. See MIG.HomeAutomation project source code for an example about how to create a MIG Interface plugin.

Code for loading an Interface plugin:

// Load the "HomeAutomation.ZWave" Interface from the "MIG.HomeAutomation.dll" library file
var zwave = migService.AddInterface("HomeAutomation.ZWave", "MIG.HomeAutomation.dll");
// configure the serial port
zwave.SetOption("Port", "/dev/ttyUSB0");

The example above is used to load the HomeAutomation.ZWave Interface plugin into MIG. This will add a set of new API commands for controlling Z-Wave Home Automation hardware. For a list of currently available Interfaces and API, see the MIG API documentation page.

Suggested syntax for API commands

The following is the suggested syntax for a MIG API command:

<api_domain>/<module_address>/<command>[/<option_0>/.../<option_n>]

Where <api_domain> is used to address a specific API domain, <module_address> the target module of the API <command> and <option_0>...<option_n> are optional parameters that the <command> may require.

So in the previous example where we used the RegisterApi methods, we have:

<api_domain> ::= "myapp"
<module_address> ::= "demo"
<command> ::= "greet"
<option_0> ::= "Foo+Bar"

NuGet Package

MIG is available as a NuGet package.

Run Install-Package MIG in the Package Manager Console or search for “MIG” in your IDE’s package management console.

Related Projects

License

MIG is open source software, licensed under the terms of Apache license 2.0. See the LICENSE file for details.