如何在Node.js / Express中发布大量JSON数据（而非文件）

Question

So I am doing an ajax(jquery) post that uploads quite a big amount of json data. When posting a large data, the data is generally broken into chunks. So we have to listen for post data requests and construct a full buffer of the upload data. Something like this:

    req.on('data', function(chunk) {
        console.log("upload on data "+ chunk.length);
        chunks.push(chunk);
        total+= chunk.length;
    });
    req.on('error', function(e) {
            console.log('Got Error ' + e.message);
    });
    req.on('end', function() {
        var buf = new Buffer(total)
            cur = 0;
        for (var i = 0, l = chunks.length; i < l; i++) {
            chunks[i].copy(buf, cur, 0);
            cur += chunks[i].length;
        }

        var level = 1;
        var path = "level"+level+".json";
        writeToFile(buf,path);
        res.send("Update successfull as level "+level);
    });

This seems to be working if I am uploading a file with form:

function display_form(req, res) {
    res.sendHeader(200, {"Content-Type": "text/html"});
    res.write(
        '<form action="/upload" method="post" enctype="multipart/form-data">'+
        '<input type="file" name="upload-file">'+
        '<input type="submit" value="Upload">'+
        '</form>'
    );
    res.close();
}

But I need to upload json data (which is dynamic). I am doing this in this way:

           $.ajax({
                type: "POST",
                url: "/upload",
                data: {"data": JSON.stringify(gamePack)},
                success: cb,
            });

Then there seems to be no callback to req 'data' or 'end'. So how are uploading files different from posting data?

Answer 1

This seems to have solved my problem:

$.ajax({
        type: "POST",
        dataType: 'json',
        url: "/upload",
        contentType:"application/jsonrequest",
        data: JSON.stringify(gamePack),
        success: cb,
});

Answer 2

POST 'ing data via an XMLHttpRequest (which is what jQuery uses from within) isn't streaming. The whole item will be posted to the server and then the handler will fire, with the content already loaded (in req.body ). If you want this to be sent chunked, then you will have to implement this yourself. For instance, by using the HTML5 FileSystem API to read files, chunk them yourself, and use a websocket to write the chunked data to the server. I have done something like this in socketio-upload , so you might want to look into that.