node.js – 从MongoDB / NodeJs / GridFS堆栈中的GridFS下载文件的问题

我正在研究NodeJs API,我选择使用GridFS来存储和下载文件.我有两个API用于此事：上传和下载.当我使用Postman调用它们时,两种API都能正常工作;但是我在使用浏览器下载文件时遇到问题.浏览器似乎看到了200个HTTP代码,并期望文件在内容仍在流式传输时立即出现.因此,它抱怨图像或PDF等有错误或格式无效.唯一可用的文件类型是MP3,浏览器启动MP3播放插件播放音乐.

var Grid = require('gridfs-stream');
Grid.mongo = mongoose.mongo;
var gfs = new Grid(mongoose.connection.db);
//.... some code in here
exports.download = function(req, res) {
    gfs.files.find({ "_id": mongoose.Types.ObjectId(req.params.id) }).toArray(function (err, files) {
            if(files.length===0){
            return res.status(400).send({
                message: 'File not found'
            });
            }



        var readstream = gfs.createReadStream({
              filename: files[0].filename
        });

        readstream.pipe(res);
    });
};

我使用Fiddler捕获请求和响应：

这是请求：

GET http://localhost:9000/api/file/download/5586fd1a04de649c4eff2223?access_token=bluhbluhbluhbluhbluh HTTP/1.1
Host: localhost:9000
Connection: keep-alive
Cache-Control: max-age=0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.124 Safari/537.36
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8,fa;q=0.6
Cookie: _ga=xxxxxxxxxxxxx; wp-settings-1=editor%3Dhtml%26align%3Dleft%26unfold%3D1%26mfold%3Do%26hidetb%3D1; wp-settings-time-1=1434314682; session_id=xxxxxxxxxxxxxxxxx; connect.sid=xxxxxxxxxx; token=xxxxxxxxxx

这是回应：

HTTP/1.1 200 OK
X-Powered-By: Express
content-length: 2412930
Date: Mon, 22 Jun 2015 16:45:04 GMT
Connection: keep-alive

%PDF-1.4
%    
< The rest of  PDF content comes in here >

任何想法如何解决这个问题？

听起来问题是MIME类型.添加node-mime模块并尝试以下操作：

//Get Readstream code here
var mimetype = mime.lookup(files[0].filename);

res.setHeader('Content-disposition', 'attachment; filename=' + files[0].filename);
res.setHeader('Content-type', mimetype);

readstream.pipe(res);

您还可以将mimetype设置为application / pdf,以便首先使用PDF文件对其进行测试.