使用mongoose，gridfs-stream和multer上传文件时出现MongoError [英] MongoError when uploading a file using mongoose, gridfs-stream and multer

问题描述

我正在使用 multer ， mongoose 与mongodb和我正在尝试上传文件并将其流式传输到gridfs.

I am running express 4 using multer, gridfs-stream and mongoose with mongodb and I am attempting to upload a file and stream it to gridfs.

执行此操作的快速路线定义为:

The express route that does this is defined as:

app.post('/uploadfile', function (req, res) {
    console.dir(req.files);

    // The mongodb instance created when the mongoose.connection is opened
    var db = mongoose.connection.db;

    // The native mongo driver which is used by mongoose
    var mongoDriver = mongoose.mongo;

    // Create a gridfs-stream
    var gfs = new Gridfs(db, mongoDriver);

    var file = req.files.myFile;

    var fileId = new ObjectId();

    console.log("Creating WriteStream");
    var writeStream = gfs.createWriteStream({
        _id: fileId,
        filename: file.originalname,
        mode: 'w',
        content_type: file.mimetype,
        metadata: {
            id: '123',
            number: '2',
            name: "Kenny Erasmuson"
        }
     });
     console.log("Created WriteStream");
     req.pipe(writeStream);
     console.log("Finished!");
});

Express应用程序运行后，将选择并上传一个文件(通过HTML multipart/form-data表单)，并且节点服务器的输出为:

Once the express app is running, a file is selected and uploaded (via an HTML multipart/form-data form), and the output from the node server is:

$ node server.js 
Listening on port 8001
{ myFile: 
    { fieldname: 'myFile',
    originalname: 'kenny-credit-rating.pdf',
    name: '1082e5071ede1002c4ae5be6123226d8.pdf',
    encoding: '7bit',
    mimetype: 'application/pdf',
    path: 'uploads/1082e5071ede1002c4ae5be6123226d8.pdf',
    extension: 'pdf',
    size: 110782,
    truncated: false,
    buffer: null } 
}
Creating WriteStream
Created WriteStream
Finished!
/Users/kenny/Dropbox/Dev/fileUploader/node_modules/mongoose/node_modules/mongodb/lib/mongodb/co nnection/base.js:246
    throw message;      
          ^
MongoError: The dollar ($) prefixed field '$conditionalHandlers' in '_id.$conditionalHandlers' is not valid for storage.
at Object.toError (/Users/kenny/Dropbox/Dev/fileUploader/node_modules/mongoose/node_modules/mongodb/lib/mongodb/utils.js:114:11)
at /Users/kenny/Dropbox/Dev/fileUploader/node_modules/mongoose/node_modules/mongodb/lib/mongodb/collection/core.js:569:27
at /Users/kenny/Dropbox/Dev/fileUploader/node_modules/mongoose/node_modules/mongodb/lib/mongodb/db.js:1157:7
at /Users/kenny/Dropbox/Dev/fileUploader/node_modules/mongoose/node_modules/mongodb/lib/mongodb/db.js:1890:9
at Server.Base._callHandler (/Users/kenny/Dropbox/Dev/fileUploader/node_modules/mongoose/node_modules/mongodb/lib/mongodb/connection/base.js:448:41)
at /Users/kenny/Dropbox/Dev/fileUploader/node_modules/mongoose/node_modules/mongodb/lib/mongodb/connection/server.js:481:18
at MongoReply.parseBody (/Users/kenny/Dropbox/Dev/fileUploader/node_modules/mongoose/node_modules/mongodb/lib/mongodb/responses/mongo_reply.js:68:5)
at null.<anonymous> (/Users/kenny/Dropbox/Dev/fileUploader/node_modules/mongoose/node_modules/mongodb/lib/mongodb/connection/server.js:439:20)
at emit (events.js:95:17)
at null.<anonymous> (/Users/kenny/Dropbox/Dev/fileUploader/node_modules/mongoose/node_modules/mongodb/lib/mongodb/connection/connection_pool.js:201:13)

是否有人知道导致错误的原因以及如何解决?

Has anyone any ideas what is causing the error and how to fix?

推荐答案

在我的代码中:

var fileId = new ObjectId();

console.log("Creating WriteStream");
var writeStream = gfs.createWriteStream({
    _id: fileId,
    filename: file.originalname,
    mode: 'w',
    content_type: file.mimetype,
    metadata: {
        id: '123',
        number: '2',
        name: "Kenny Erasmuson"
    }
 });

我正在将ObjectId而不是ObjectId的字符串表示形式分配给传递到gfs.createWriteStream的对象的_id属性.事实证明，这是导致我代码中出现MongoError的原因.

I am assigning an ObjectId rather than the string representation of an ObjectId to the _id property of the object passed into gfs.createWriteStream. It turns out this is causing the MongoError in my code.

在此处，用于更改导致问题的代码行为:

The fix, discovered here, is to change the line of code causing the issue to be:

_id: fileId.str,

这样做之后，我想到了文件没有放入fs.chunks mongodb集合的问题，尽管元数据确实出现在fs.files mongodb集合中. AddieD的答案此处开始解决这个问题:)

Having done that I then came to the issue of the file not being put into the fs.chunks mongodb collection although the metadata does end up in the fs.files mongodb collection. AddieD's answer here starts to address this :)

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