nodejs利用gridfs存文档到mongo中

最近开发一个web是用nodejs开发的,有个上传文档的功能
mongo链接端
首先npm install下载需要的模块
mongo中fs.files中有字段filesname,metadata,利用metadata作为文档的分类

var mongoose = require('mongoose');var conn = mongoose.createConnection('mongodb://127.0.0.1:27017/NodeJS');var fs = require('fs');var Grid = require('gridfs-stream');Grid.mongo = mongoose.mongo;var gfs = Grid(conn.db);var path = require('path');var util = require('util');var urlencode = require('urlencode');var mongooseSchema = new mongoose.Schema({    filename: String,    metadata: String,    aliases: String}, {collection: "fs.files", versionKey: ""});var getFile = conn.model('getFile', mongooseSchema);var fileUpload = {};//根据metadata列出存mongo里的filenamefileUpload.findAllFiles = function (httpId, callback) {    getFile.find({metadata: httpId}, {"filename": '1'}, function (err, docs) {        if (err) {            callback(err);        } else {            callback(null, docs);        }    })};//将文档存到mongo中fileUpload.loadToMongo = function (name,httpId,callback) {    var writestream = gfs.createWriteStream({        filename: name,        metadata:httpId    });    fs.createReadStream(files).pipe(writestream);    writestream.on('close', function (file) {    });};//通过filename从mongo中将文档下载到磁盘中fileUpload.readFile = function (dir, name, callback) {    var fs_write_stream = fs.createWriteStream("documents/" + dir + "/" + name);    var readstream = gfs.createReadStream({        filename: name    });    readstream.pipe(fs_write_stream);    fs_write_stream.on('close', function () {        callback(null);    });};