为什么我不能写第二个文件到gridfs没有刷新模板视图在MEAN应用程序

Question

我在向gridfs写入第二个音频文件时遇到了问题。我使用ng-file-upload选择一个文件，将文件/二进制数据传递给gridfs，并将其写入数据库。第一个文件工作得很好，但是，除非我首先加载不同的视图，然后回到我的音频视图/模板页面，我每次都得到这个错误:

TypeError: path must be a string
    at TypeError (native)
    at Object.fs.open (fs.js:540:11)
    at ReadStream.open (fs.js:1673:6)
    at new ReadStream (fs.js:1660:10)
    at Object.fs.createReadStream (fs.js:1608:10)
    at NativeConnection.<anonymous> (Z:techFilezwebAppMyPiCloudroutesIOwriteFile.js:42:29)
    at NativeConnection.g (events.js:260:16)
    at emitNone (events.js:67:13)
    at NativeConnection.emit (events.js:166:7)
    at open (Z:techFilezwebAppMyPiCloudnode_modulesmongooselibconnection.js:518:11)
    at NativeConnection.Connection.onOpen (Z:techFilezwebAppMyPiCloudnode_modulesmongooselibconnection.js:527:5)
    at Z:techFilezwebAppMyPiCloudnode_modulesmongooselibconnection.js:487:11
    at Z:techFilezwebAppMyPiCloudnode_modulesmongooselibdriversnode-mongodb-nativeconnection.js:71:5
    at Z:techFilezwebAppMyPiCloudnode_modulesmongoosenode_modulesmongodblibdb.js:232:5
    at connectHandler (Z:techFilezwebAppMyPiCloudnode_modulesmongoosenode_modulesmongodblibserver.js:333:7)
    at g (events.js:260:16)
Z:techFilezwebAppMyPiCloudnode_modulesmongoosenode_modulesmongodblibserver.js:336
      process.nextTick(function() { throw err; })
                                    ^
TypeError: path must be a string
    at TypeError (native)
    at Object.fs.open (fs.js:540:11)
    at ReadStream.open (fs.js:1673:6)
    at new ReadStream (fs.js:1660:10)
    at Object.fs.createReadStream (fs.js:1608:10)
    at NativeConnection.<anonymous> (Z:techFilezwebAppMyPiCloudroutesIOwriteFile.js:42:29)
    at NativeConnection.g (events.js:260:16)
    at emitNone (events.js:67:13)
    at NativeConnection.emit (events.js:166:7)
    at open (Z:techFilezwebAppMyPiCloudnode_modulesmongooselibconnection.js:518:11)
    at NativeConnection.Connection.onOpen (Z:techFilezwebAppMyPiCloudnode_modulesmongooselibconnection.js:527:5)
    at Z:techFilezwebAppMyPiCloudnode_modulesmongooselibconnection.js:487:11
    at Z:techFilezwebAppMyPiCloudnode_modulesmongooselibdriversnode-mongodb-nativeconnection.js:71:5
    at Z:techFilezwebAppMyPiCloudnode_modulesmongoosenode_modulesmongodblibdb.js:232:5
    at connectHandler (Z:techFilezwebAppMyPiCloudnode_modulesmongoosenode_modulesmongodblibserver.js:333:7)
    at g (events.js:260:16)
 [nodemon] app crashed - waiting for file changes before starting...

我做了几件事:我确保使用fs.unlink(myFile)从文件系统中删除，并在每次成功写入文件后关闭与mongoose的连接。我用了一个变量var myFile =文件。路径(这是ng-file-upload的文件路径)-在成功写入后，我尝试将myFile设置为null，但无济于事。

它工作时，我切换视图或刷新页面，但因为我要单页应用程序的东西，我想避免这种.....

下面是我在服务器端的代码:

/**
 * Created by foolishklown on 8/27/2016.
 */
var mongoose = require('mongoose'),
    path = require('path'),
    Grid = require('gridfs-stream'),
    fs = require('fs'),
    User = require('../../models/user');
module.exports = function(file, userId, fileType, res) {
    var fileId;
    //console.log('called the write file for gridfs'.green);
    //console.log('file is: ', file);
    var conn = mongoose.createConnection('mongodb://localhost/media', (error) => {
        if(error) {
            console.error('Error connecting to mongod media instance'.red);
            process.exit(1);
        } else {
            console.info('Connected successfully to mongod media instance in the write file!'.blue);
        }
    });
    // The following line is designating a file to grab/read, and save into mongo
    //  in our case it will be something from ng-file-upload that the user wants to upload
    var myFile = file.path;
    // Connect gridFs and mongo
    Grid.mongo = mongoose.mongo;
    conn.once('open', function () {
        console.log('connection open, ready for I/O!');
        var gfs = Grid(conn.db);
        // This write stream is how well write to mongo
        var writeStream = gfs.createWriteStream({
            // Name the file the way you want it stored in mongo
            filename: file.originalFilename,
            type: fileType
        });
        // Create a read stream, so that we can read its data, and then with that well use the
        //  write stream to write to the DB via piping the writestream
        var readStream = fs.createReadStream(myFile)
            .on('end', () => {
                writeToUserDb(userId, fileType, readStream.id);
                res.status(200).send({id: readStream.id, type: fileType, user: userId});
            })
            .on('error', () => {
                res.status(500).send('error in writing with gridfs');
            })
            .pipe(writeStream);
        //fs.createReadStream(myFile).pipe(writeStream);
        writeStream.on('close', function (file) {
            console.log(file.filename + 'written to DB');
            /**
            setTimeout(1000, () => {
                fs.unlink(myFile);
            });
             */
            fs.unlink(myFile);
            myFile = null;
            conn.close();
        });
    });
    function writeToUserDb(uid, type, fileId) {
        var userConn = mongoose.createConnection('mongodb://localhost/mean-auth', (error) => {
            if(error) {
                console.error('Error connecting to the mean-auth instance'.red);
                process.exit(1);
            } else {
                console.info('Connected to the mean-auth instance!'.blue);
                console.info('Attempting to find user: ' + uid + ', filetype: ' + type + ', streamID: ' + fileId + '!'.green);
                User.findById(uid, (err, doc) => {
                    if(err) {
                        console.error('Error finding user with id: ', uid);
                        process.exit(1);
                    } else {
                        console.log('original doc: ', doc);
                        doc.addMedia(type, fileId);
                        doc.save();
                        console.log('new doc: ', doc);
                    }
                })
            }
        });
        userConn.close();
    }
};

Answer 1

唉，这根本不是后端问题，这是ng-file上传的角度问题.......

我的html:

<div class="row">
    <div class="col-lg-10">
        <h1>MyPi Audio</h1>
    </div>
    <div class="col-lg-2">
        <form name="form">
            <input type="file" id="file1" name="file" ng-files="getTheFiles($files)"
                   ng-keep="false"
                   accept="'audio/*'">
            <input type="button" class="btn btn-default" ng-click="uploadFiles('/dashboard/uploadAudio', 'audio', myCont.currentUser)" value="Upload">
        </form>
    </div>
</div>
<div class="row">
  <div ng-repeat="audio in myCont.media.audio" style="width:100%;background-color:#999999;border:1px solid deeppink;">
      <img ng-src="{{audio.url}}" />
      <span>{{audio.name}}</span>
  </div>
</div>

在控制器内部，建筑表单数据没有重置......旧代码:

var formdata = new FormData();
    $scope.getTheFiles = function ($files) {        
            angular.forEach($files, function (value, key) {
                //console.log('key: ' + key + ', val: ' + $files[key]);
                formdata.append(key, value);
            });
        }
    };

从服务器发回响应后，我简单地调用$scope.getTheFiles(null)，并在重置表单数据的函数中添加空条件检查

var formdata = new FormData();
    $scope.getTheFiles = function ($files) {
        if($files == null) {
            formdata = new FormData();
        } else {
            angular.forEach($files, function (value, key) {
                //console.log('key: ' + key + ', val: ' + $files[key]);
                formdata.append(key, value);
            });
        }
    };

我回答了我的问题，以防将来有人有同样的问题