流文件到S3的“错误:流意外结束”

Question

更新：

我相信这可能是因为我使用的是express提供的body解析器。这会扰乱多方试图解析的流吗？

我的解决方案是基于这个答案的。

我想做的事情：流--一个从客户机浏览器直接到S3的文件，由我的NodeJS服务器充当代理(出于安全目的)。我不希望该文件触及服务器的文件系统以避免这个瓶颈。

我得到了以下错误：

events.js:72
        throw er; // Unhandled 'error' event
              ^
Error: stream ended unexpectedly
    at Form.<anonymous> (/Users/kentcdodds/Developer/bucketstreams/node_modules/multiparty/index.js:619:24)
    at Form.EventEmitter.emit (events.js:117:20)
    at finishMaybe (/Users/kentcdodds/Developer/bucketstreams/node_modules/multiparty/node_modules/readable-stream/lib/_stream_writable.js:443:14)
    at endWritable (/Users/kentcdodds/Developer/bucketstreams/node_modules/multiparty/node_modules/readable-stream/lib/_stream_writable.js:452:3)
    at Form.Writable.end (/Users/kentcdodds/Developer/bucketstreams/node_modules/multiparty/node_modules/readable-stream/lib/_stream_writable.js:419:5)
    at onend (_stream_readable.js:457:10)
    at process._tickCallback (node.js:415:13)

我看过代码，似乎不太明白是什么导致了这个问题。我使用角文件上传，因为我在前端使用角。以下是请求的内容：

Request URL:http://local.bucketstreams.com:3000/upload/image
Request Headers CAUTION: Provisional headers are shown.
Accept:application/json, text/plain, */*
Cache-Control:no-cache
Content-Type:multipart/form-data; boundary=----WebKitFormBoundaryNKuH2H9IUB7kvmea
Origin:http://local.bucketstreams.com:3000
Pragma:no-cache
Referer:http://local.bucketstreams.com:3000/getting-started
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/32.0.1700.107 Safari/537.36
Request Payload
------WebKitFormBoundaryNKuH2H9IUB7kvmea
Content-Disposition: form-data; name="type"

profile
------WebKitFormBoundaryNKuH2H9IUB7kvmea
Content-Disposition: form-data; name="user"

pie
------WebKitFormBoundaryNKuH2H9IUB7kvmea
Content-Disposition: form-data; name="file0"; filename="Screen Shot 2014-02-18 at 10.54.06 PM.png"
Content-Type: image/png


------WebKitFormBoundaryNKuH2H9IUB7kvmea--

下面是我的代码：

var ErrorController = require('../controller/ErrorController');
var AuthenticationController = require('../controller/AuthenticationController');
var logger = require('winston');

var http = require('http');
var util = require('util');
var multiparty = require('multiparty');
var knox = require('knox');
var Batch = require('batch');

var s3Client = knox.createClient({
  secure: false,
  key: process.env.S3_KEY,
  secret: process.env.S3_SECRET,
  bucket: process.env.S3_BUCKET_IMAGES
});

var Writable = require('readable-stream').Writable;
util.inherits(ByteCounter, Writable);
function ByteCounter(options) {
  Writable.call(this, options);
  this.bytes = 0;
}

ByteCounter.prototype._write = function(chunk, encoding, cb) {
  this.bytes += chunk.length;
  cb();
};

var supportedTypes = {
  profile: true,
  post: true
};

module.exports = function(app) {
  app.post('/upload/image', AuthenticationController.checkAuthenticated, function(req, res) {
    var type = req.body.type;
    var userId = req.user._id;
    if (!supportedTypes[type]) {
      return ErrorController.sendErrorJson(res, 401, 'Unsupported image upload type: ' + type);
    }

    var headers = {
      'x-amz-acl': 'public-read'
    };
    var form = new multiparty.Form();
    var batch = new Batch();
    batch.push(function(cb) {
      form.on('field', function(name, value) {
        if (name === 'path') {
          var destPath = value;
          if (destPath[0] !== '/') destPath = '/' + destPath;
          cb(null, destPath);
        }
      });
    });

    batch.push(function(cb) {
      form.on('part', function(part) {
        if (! part.filename) return;
        cb(null, part);
      });
    });

    batch.end(function(err, results) {
      if (err) throw err;
      form.removeListener('close', onEnd);
      var destPath = '/' + userId + results[0];
      var part = results[1];

      var counter = new ByteCounter();
      part.pipe(counter); // need this until knox upgrades to streams2
      headers['Content-Length'] = part.byteCount;
      s3Client.putStream(part, destPath, headers, function(err, s3Response) {
        if (err) throw err;
        res.statusCode = s3Response.statusCode;
        s3Response.pipe(res);
        console.log('https://s3.amazonaws.com/' + process.env.S3_BUCKET_IMAGES + destPath);
      });
      part.on('end', function() {
        console.log('part end');
        console.log('size', counter.bytes);
      });
    });

    form.on('close', function(error) {
      logger.error(error);
      return ErrorController.sendErrorJson(res, 500, 'There was a problem uploading the file.');
    });
    form.parse(req);
  });
};

看起来，正在爆炸的部分是multiparty，我已经研究了一些代码，但没有效果。我不确定我是否提出了错误的请求，或者我的服务器代码有什么问题。我不认为这与我的S3桶有任何关系，但我想也可能是这样。

不管怎样，任何小费都是欢迎的。

Answer 1

解决方案的关键是不要使用(显然不推荐的) bodyParser()。我不知道它能做什么，但是它破坏了multiparty使用的表单的各个部分。因此，如果您遇到了与我相同的问题，而不是使用bodyParser()，请使用您需要的内容(例如)：

app.use(express.urlencoded());
app.use(express.json());

然后，对于你的多部分内容，只需使用多方来解析自己的身体。“多党制”一书的作者就这一主题给出了更多信息。

Answer 2

在节点-多方源上有一个S3示例。

https://github.com/andrewrk/node-multiparty/tree/master/examples

var http = require('http'),
    util = require('util'),
    multiparty = require('../'),
    knox = require('knox'),
    Batch = require('batch'),
    PORT = process.env.PORT || 27372

var s3Client = knox.createClient({
    secure: false,
    key: process.env.S3_KEY,
    secret: process.env.S3_SECRET,
    bucket: process.env.S3_BUCKET,
});

var server = http.createServer(function(req, res) {
    if (req.url === '/') {
        res.writeHead(200, {
            'content-type': 'text/html'
        });
        res.end(
            '<form action="/upload" enctype="multipart/form-data" method="post">' +
            '<input type="text" name="path"><br>' +
            '<input type="file" name="upload"><br>' +
            '<input type="submit" value="Upload">' +
            '</form>'
        );
    } else if (req.url === '/upload') {
        var headers = {
            'x-amz-acl': 'public-read',
        };
        var form = new multiparty.Form();
        var batch = new Batch();
        batch.push(function(cb) {
            form.on('field', function(name, value) {
                if (name === 'path') {
                    var destPath = value;
                    if (destPath[0] !== '/') destPath = '/' + destPath;
                    cb(null, destPath);
                }
            });
        });
        batch.push(function(cb) {
            form.on('part', function(part) {
                if (!part.filename) return;
                cb(null, part);
            });
        });
        batch.end(function(err, results) {
            if (err) throw err;
            form.removeListener('close', onEnd);
            var destPath = results[0],
                part = results[1];

            headers['Content-Length'] = part.byteCount;
            s3Client.putStream(part, destPath, headers, function(err, s3Response) {
                if (err) throw err;
                res.statusCode = s3Response.statusCode;
                s3Response.pipe(res);
                console.log("https://s3.amazonaws.com/" + process.env.S3_BUCKET + destPath);
            });
        });
        form.on('close', onEnd);
        form.parse(req);

    } else {
        res.writeHead(404, {
            'content-type': 'text/plain'
        });
        res.end('404');
    }

    function onEnd() {
        throw new Error("no uploaded file");
    }
});
server.listen(PORT, function() {
    console.info('listening on http://0.0.0.0:' + PORT + '/');
});