Node.js文件上传（Express 4，MongoDB，GridFS，GridFS-Stream） [英] Node.js File Upload (Express 4, MongoDB, GridFS, GridFS-Stream)
问题描述
我正在尝试在node.js应用程序中设置文件API。我的目标是能够将文件流直接写入gridfs，而无需最初将文件存储到磁盘。好像我的创建代码正在运行。我能够将文件上传保存到gridfs。问题是正在读取文件。当我尝试通过Web浏览器窗口下载保存的文件时，我看到文件内容包含如下内容：
I am trying to setup a file API in my node.js application. My goal is to be able to write the file stream directly to gridfs, without needing to store the file to disk initially. It seems like my create code is working. I am able to save a file upload to gridfs. The problem is reading the file. When I try to download a saved file via a web browser window, I see that the file contents are wrapped with something like the following:
------WebKitFormBoundarye38W9pfG1wiA100l
Content-Disposition: form-data; name="file"; filename="myfile.txt"
Content-Type: text/javascript
***File contents here***
------WebKitFormBoundarye38W9pfG1wiA100l--
所以我的问题是我需要做些什么来从文件流中去除边界信息在将其保存到gridfs之前？这是我正在使用的代码：
So my question is what do I need to do to strip the boundary information from the file stream before saving it to gridfs? Here's the code i'm working with:
'use strict';
var mongoose = require('mongoose');
var _ = require('lodash');
var Grid = require('gridfs-stream');
Grid.mongo = mongoose.mongo;
var gfs = new Grid(mongoose.connection.db);
// I think this works. I see the file record in fs.files
exports.create = function(req, res) {
var fileId = new mongoose.Types.ObjectId();
var writeStream = gfs.createWriteStream({
_id: fileId,
filename: req.query.name,
mode: 'w',
content_type: req.query.type,
metadata: {
uploadedBy: req.user._id,
}
});
writeStream.on('finish', function() {
return res.status(200).send({
message: fileId.toString()
});
});
req.pipe(writeStream);
};
// File data is returned, but it's wrapped with
// WebKitFormBoundary and has headers.
exports.read = function(req, res) {
gfs.findOne({ _id: req.params.id }, function (err, file) {
if (err) return res.status(400).send(err);
// With this commented out, my browser will prompt
// me to download the raw file where I can see the
// webkit boundary and request headers
//res.writeHead(200, { 'Content-Type': file.contentType });
var readstream = gfs.createReadStream({
_id: req.params.id
// I also tried this way:
//_id: file._id
});
readstream.pipe(res);
});
};
顺便说一句，我目前没有在这些路线上使用任何中间件，但我愿意做所以。我只是不希望文件在发送到gridfs之前到达磁盘。
By the way, i'm not currently using any middleware for these routes, but am open to doing so. I just didn't want the file to hit the disk prior to being sent to gridfs.
编辑：
Per @fardjad，我为多部分添加了 node-multiparty 模块/ form-data解析，它有点工作。但是当我下载上传的文件并与原始文件（作为文本）进行比较时，编码有很多差异，下载的文件将无法打开。这是我最近的尝试。
Per @fardjad, I added the node-multiparty module for multipart/form-data parsing and it kind of worked. But when I download an uploaded file and compare with an original (as text), there are lots of differences in the encoding, and the downloaded file won't open. Here's my latest attempt.
'use strict';
var mongoose = require('mongoose');
var _ = require('lodash');
var multiparty = require('multiparty');
var Grid = require('gridfs-stream');
Grid.mongo = mongoose.mongo;
var gfs = new Grid(mongoose.connection.db);
exports.create = function(req, res) {
var form = new multiparty.Form();
var fileId = new mongoose.Types.ObjectId();
form.on('error', function(err) {
console.log('Error parsing form: ' + err.stack);
});
form.on('part', function(part) {
if (part.filename) {
var writeStream = gfs.createWriteStream({
_id: fileId,
filename: part.filename,
mode: 'w',
content_type: part.headers['content-type'],
metadata: {
uploadedBy: req.user._id,
}
})
part.pipe(writeStream);
}
});
// Close emitted after form parsed
form.on('close', function() {
return res.status(200).send({
message: fileId.toString()
});
});
// Parse req
form.parse(req);
};
exports.read = function(req, res) {
gfs.findOne({ _id: req.params.id }, function (err, file) {
if (err) return res.status(400).send(err);
res.writeHead(200, { 'Content-Type': file.contentType });
var readstream = gfs.createReadStream({
_id: req.params.id
});
readstream.pipe(res);
});
};
最终编辑：
这是我从其他开发人员复制并修改的简单实现。这对我有用:(我还在试图弄清楚为什么它在我的原始快递应用程序中不起作用。似乎有些干扰）
Here's a simple implementation that I copied from another developer and modified. This is working for me: (I'm still trying to figure out why it won't work in my original express app. Something seems to be interfering)
https://gist.github.com/pos1tron/094ac862c9d116096572
var Busboy = require('busboy'); // 0.2.9
var express = require('express'); // 4.12.3
var mongo = require('mongodb'); // 2.0.31
var Grid = require('gridfs-stream'); // 1.1.1"
var app = express();
var server = app.listen(9002);
var db = new mongo.Db('test', new mongo.Server('127.0.0.1', 27017));
var gfs;
db.open(function(err, db) {
if (err) throw err;
gfs = Grid(db, mongo);
});
app.post('/file', function(req, res) {
var busboy = new Busboy({ headers : req.headers });
var fileId = new mongo.ObjectId();
busboy.on('file', function(fieldname, file, filename, encoding, mimetype) {
console.log('got file', filename, mimetype, encoding);
var writeStream = gfs.createWriteStream({
_id: fileId,
filename: filename,
mode: 'w',
content_type: mimetype,
});
file.pipe(writeStream);
}).on('finish', function() {
// show a link to the uploaded file
res.writeHead(200, {'content-type': 'text/html'});
res.end('<a href="/file/' + fileId.toString() + '">download file</a>');
});
req.pipe(busboy);
});
app.get('/', function(req, res) {
// show a file upload form
res.writeHead(200, {'content-type': 'text/html'});
res.end(
'<form action="/file" enctype="multipart/form-data" method="post">'+
'<input type="file" name="file"><br>'+
'<input type="submit" value="Upload">'+
'</form>'
);
});
app.get('/file/:id', function(req, res) {
gfs.findOne({ _id: req.params.id }, function (err, file) {
if (err) return res.status(400).send(err);
if (!file) return res.status(404).send('');
res.set('Content-Type', file.contentType);
res.set('Content-Disposition', 'attachment; filename="' + file.filename + '"');
var readstream = gfs.createReadStream({
_id: file._id
});
readstream.on("error", function(err) {
console.log("Got error while processing stream " + err.message);
res.end();
});
readstream.pipe(res);
});
});
推荐答案
查看我对你在
See my comment on the issue you created on github. I had the same problem but I managed to debug the issue. I narrowed it down to where i was confident that the problem was a piece of express middleware modified the request. I disabled my middleware one by one until i found the unlikely culprit: connect-livereload
我注释掉app.use（require（'connect-livereload'）（）） ;问题就消失了。
我相信它是将livereload脚本注入响应（二进制图像文件）。
I commented out app.use(require('connect-livereload')()); and the problem went away. I believe it was injecting the livereload script into the response (a binary image file).
这篇关于Node.js文件上传（Express 4，MongoDB，GridFS，GridFS-Stream）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
