问使用节点js在协作白板中上传和查看.ppt或.pdf文件

EN

var formidable = require('formidable'),
http = require('http'),
util = require('util'),
fs = require('fs');
http.createServer(function(req, res) {
    if (req.url == '/view' && req.method == 'GET') {
        fs.readFile('./temp.pdf', function(err, file) {
            res.writeHead(200, {"Content-Type" : "application/pdf" });
            res.write(file, "binary");
            res.end();
        });
        return;
    }
    if (req.url == '/upload' && req.method == 'POST') {
        // parse a file upload
        var form = new formidable.IncomingForm();
        form.parse(req, function(err, fields, files) {
            fs.rename(files.upload.path, './temp.pdf');
            res.writeHead(200, {'content-type': 'text/html'});
            res.write('Received upload: <a href="/view">View PDF</a>');
            res.end();
        });
        return;
    }
    // show a file upload form
    res.writeHead(200, {'content-type': 'text/html'});
    res.end(
        '<form action="/upload" enctype="multipart/form-data" method="post">'+
        '<input type="file" name="upload" multiple="multiple"><br>'+
        '<input type="submit" value="Upload">'+
        '</form>'
    );
}).listen(80);