Using Edge.js, call C #. Net in JavaScript

Edge.js enables developers to invoke C # interfaces in JavaScript to improve application extensibility. Here's how to call the C # interface to get the picture data and send it to the Web client through the WebSocket server built by node. js.

Reference: How to useedge.js to Empower WebSocket Solutions in JavaScript

Pass. NET interface gets the picture back to JavaScript

Let's take a look at the simple use of JavaScript to load local images:

var fs = require (' FS '); Fs.readfile (' Capture.jpg ', function (err, data) {Console.log (data.length);//image data});

To use Edge.js, use the following command to install:

NPM Install Edge

Create C # file NativeImageLoader.cs:

#r   "System.Drawing.dll" using system.threading.tasks;using system.drawing; public  Class startup{    public async task<object> invoke (object  Input)     {           byte[]  Imagebuffer;        image image = image.fromfile (" Capture.jpg ");        using  (System.io.memorystream stream  = new system.io.memorystream ())         {             image. Save (stream, system.drawing.imaging.imageformat.jpeg);             imagebuffer = stream. GetBuffer ();        }          return imagebuffer;    }} 

By default, the system DLLs loaded by the Edge are only mscorlib.dll and System.dll, so they need to be added manually by #r "System.Drawing.dll" .

Now you can get the image on the JavaScript layer:

var nativeimageloader = Edge.func (Require (' path '). Join (__dirname, ' NativeImageLoader.cs '); Nativeimageloader (' Load            ', function (error, result) {if (error) throw error; Result is the loaded image});

Create a WebSocket solution using node. js

First install the WebSocket package:

NPM Install WS

A few lines of code take care of the server's image data sending:

var websocketserver = require (' ws '). Server, WSS = new Websocketserver ({port:8080}), Wss.on (' Connection ', function (WS) {ws.on (' message ', functio        N (message) {Console.log (' Received:%s ', message);            Nativeimageloader (' Load ', function (error, result) {if (error) throw error; Ws.send (result);    Send the captured image}); });});

Run Server:

Node Server.js

To receive data in the client:

Var ws = new websocket ("ws://127.0.0.1:8080/");      ws.binarytype  =  "Arraybuffer";  ws.onopen = function ()  {        alert ("opened");        ws.send ("I ' M dynamsoft");     };     ws.onmessage = function  (EVT)  {          var bytes = new uint8array (Evt.data);     var data =  "";    var len =  bytes.bytelength;    for  (var i = 0; i < len; + +i)  {        data += string.fromcharcode (Bytes[i]);     }    var img = document.getelementbyid ("image");     img.src =  "Data:image/png;base64, "+window.btoa (data);    };     ws.onclose =  function ()  {       alert ("Closed");    };      ws.onerror = function (ERR)  {        alert ("error: "  + err);    };

Open client.htm to see the data received:

Source

Https://github.com/DynamsoftRD/WebSocket-in-JavaScript

git clone https://github.com/DynamsoftRD/WebSocket-in-JavaScript.git

Using Edge.js, call C #. Net in JavaScript