node.js 错误 ReferenceError: ObjectID 未定义
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error ReferenceError: ObjectID is not defined
提问by Anup
I want to upload image with GridJS. I am using https://www.npmjs.org/package/gridfs-streamfor this. It gives me errorReferenceError: ObjectID is not defined.
我想用 GridJS 上传图片。我为此使用https://www.npmjs.org/package/gridfs-stream。它给了我errorReferenceError: ObjectID is not defined。
I am beginner to this, so have no idea whats going.
我是初学者，所以不知道发生了什么。
How to solve this error?
如何解决这个错误？
var Grid = require('gridfs-stream');
var conn = mongoose.createConnection('localhost', 'Test', 27017);
var gfs = Grid(conn.db, mongoose);
var fileId = new ObjectID(uniqId);
var fileType = req.header('X-File-Type');
var fileName = req.header('X-File-Name');
var uniqId = req.param('uniqId', '112211112111');
console.log('upload start');
// streaming to gridfs
var writestream = gfs.createWriteStream(fileId, [{ "content_type": fileType, "metadata": { "fileName": fileName, "uploaded_at": (new Date()).toString() } }]);
fs.createReadStream('/some/path').pipe(writestream);
// streaming from gridfs
var readstream = gfs.createReadStream(fileId, [{ "content_type": fileType, "metadata": { "fileName": fileName, "uploaded_at": (new Date()).toString() } }]);
//error handling, e.g. file does not exist
readstream.on('error', function (err) {
console.log('An error occurred!', err);
throw err;
});
readstream.pipe(response);
console.log('upload done');
回答by Illegal Argument
Not directly a solution but a small typo wasted 10 minutes of my time:
不是直接的解决方案，而是一个小错误浪费了我 10 分钟的时间：
var ObjectId = require('mongodb').ObjectID;
I declared a variable ObjectId with small dbut when using the variable, I tried ObjectIDwith capital D.
我用小d声明了一个变量 ObjectId ，但是在使用该变量时，我尝试用大写D 表示ObjectID。
回答by Paul Mougel
ObjectIDis not a global variable, it is defined by mongoose (see the documentation):
ObjectID不是全局变量，它是由 mongoose 定义的（参见文档）：
var fileId = mongoose.Types.ObjectId();
