Read file with node.js, mongoose, gridfs-stream

Question

I am using mongoose and gridfs-stream to store and read files from mongodb. I am following the example here: https://github.com/aheckmann/gridfs-stream Writing files into db is working fine but I faced a problem to read files. What the mongodb looks (show collections) ``` fs.chunks fs.files ``` What the file index looks (db.fs.files.find()) ``` { "_id" : ObjectId("5140392659851df70b000001"), "filename" : "cover", "contentType" : "binary/octet-stream", "length" : 85734, "chunkSize" : 262144, "uploadDate" : ISODate("2013-03-13T08:30:30.299Z"), "aliases" : null, "metadata" : null, "md5" : "4476b26067daa0677978ba501308a35d" } ``` Then I use this code to get file named "cover" ``` ... var gfs = Grid(mongoose.connection.db, mongoose.mongo) var readstream = gfs.createReadStream('cover') ``` An error occured: ``` Error: cover does not exist at self.collection.self.fileId (/mypath/node_modules/mongoose/node_modules/mongodb/lib/mongodb/gridfs/gridstore.js:198:26) at Cursor.nextObject (/mypath/n…

Accepted Answer

The example code on GitHub was a little bit misleading; I initially received the same error message you did. In my case, it was due to the fact that I was attempting to read the file before the write stream had finished. I resolved this by doing the read inside the event handler for `"close"`:

```
var fs = require("fs"),
    mongo = require("mongodb"),
    Grid = require("gridfs-stream"),
    gridfs,
    writeStream,
    readStream,
    buffer = "";

mongo.MongoClient.connect("mongodb://localhost/gridfs_test", function (err, db) {
    "use strict";
    gridfs = Grid(db, mongo);

// write file
    writeStream = gridfs.createWriteStream({ filename: "test.txt" });
    fs.createReadStream("test.txt").pipe(writeStream);

// after the write is finished
    writeStream.on("close", function () {
        // read file, buffering data as we go
        readStream = gridfs.createReadStream({ filename: "test.txt" });

readStream.on("data", function (chunk) {
            buffer += chunk;
        });

// dump contents to console when complete
        readStream.on("end", function () {
            console.log("contents of file:

", buffer);
        });
    });
});
```

Read file with node.js, mongoose, gridfs-stream

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