Socket.io从1.0开始支持二进制流，有没有专门针对图像的完整例子 [英] Socket.io began to support binary stream from 1.0, is there a complete example especially for image

问题描述

我是 node.js 和 socket.io 的初学者.Socket.io从1.0开始支持二进制流，有没有完整的例子，特别是图片推送到客户端，在canvas上显示?谢谢

I'm a beginner on node.js and socket.io. Socket.io began to support binary stream from 1.0, is there a complete example especially for image push to client and show in canvas? thanks

推荐答案

解决方案有点复杂，但应该适用于 Chrome、Firefox 和 IE10+(不确定 Opera 和 Safari):

The solution is a bit complicated but should work in Chrome, Firefox, and IE10+ (not sure about Opera and Safari):

服务器端某处:

io.on('connection', function(socket){
    fs.readFile('/path/to/image.png', function(err, buffer){
        socket.emit('image', { buffer: buffer });
    });
});

以下是您在客户端上处理它的方式:

socket.on('image', function(data) {
    var uint8Arr = new Uint8Array(data.buffer);
    var binary = '';
    for (var i = 0; i < uint8Arr.length; i++) {
        binary += String.fromCharCode(uint8Arr[i]);
    }
    var base64String = window.btoa(binary);

    var img = new Image();
    img.onload = function() {
        var canvas = document.getElementById('yourCanvasId');
        var ctx = canvas.getContext('2d');
        var x = 0, y = 0;
        ctx.drawImage(this, x, y);
    }
    img.src = 'data:image/png;base64,' + base64String;
});

只需将 yourCanvasId 替换为您的画布 ID :)

Just replace yourCanvasId with your canvas id :)

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