将POST请求中的数据流存储在GridFS，Express，mongoDB，node.js中

Question

我试图弄清楚如何可以将图像直接发布到GridFS而不先将其作为临时文件存储在服务器上的任何位置。

我正在使用Postman（chrome ext。）发布文件，并且使用以下方法设法将此帖子存储为文件：

req.pipe(fs.createWriteStream('./test.png'));

当从服务器上的文件创建readStream时，我也能够从readStream直接存储到GridFS。（请参见代码）

我有以下文件，saveFromReq.js它们侦听POST并基本上将其传递给savePic.js。

saveFromReq.js：

var express = require('express');
var app = express();
var savePic = require('./savePic');
var fs = require('fs');
var GridStore = require('mongodb').GridStore;
var pic = './square.png';
var picID;



//When the following

 //var pic = fs.createReadStream('./square.png', {autoClose: true});

//is not commented out, and 'req' is replaced with 'pic' in the savePic function,
//the file square.png is stored correctly to GridFS

app.post('/picture', function(req, res){

    savePic(req, function(id){});
    res.writeHead(200, {'Content-Type': 'text' });
    res.end("Sucsess!\n");

});

app.listen(process.env.PORT || 3413);

savePic.js：

var savePic = function(req, callback){


var Db = require('mongodb').Db,
    MongoClient = require('mongodb').MongoClient,
    Server = require('mongodb').Server,
    ReplSetServers = require('mongodb').ReplSetServers,
    ObjectID = require('mongodb').ObjectID,
    Binary = require('mongodb').Binary,
    GridStore = require('mongodb').GridStore,
    Grid = require('mongodb').Grid,
    Code = require('mongodb').Code,
    BSON = require('mongodb').pure().BSON,
    assert = require('assert');
    fs = require('fs');

    //When the following

      //req.pipe(fs.createWriteStream('./test.png'));

    //is not commented out, the correct image is stored to test.png, and 
    //the sequence after req.on("data"... starts
    //(That sequence does not start at all when this is commented out..)

var fileId = new ObjectID();
var db = new Db('testDB', new Server('localhost', 27017));
// Establish connection to db
db.open(function(err, db) {


  var gridStore = new GridStore(db, 'test', 'w');

  //open 
  gridStore.open(function(err, gridStore) {
    console.log("opened");


    req.on("data", function (data) {
        console.log("data recieved");
            gridStore.write(data, function (err, gridStore) {
                if (err) {
                    console.log("error writing file");
                }
            });
        });
     req.on("end", function () {
            gridStore.close(function (err, gridStore) {
                if (!err) {
                    console.log("The file has been stored to database.");
                    db.close();
                }
            });
        });
           req.pipe(gridStore);


      });




});
callback(fileId);
};
module.exports = savePic;

任何帮助将不胜感激！

Answer 1

gridfs-stream 使事情变得很简单：

// `gfs` is a gridfs-stream instance
app.post('/picture', function(req, res) {
  req.pipe(gfs.createWriteStream({
    filename: 'test'
  }));
  res.send("Success!");
});