javascript - 使用 GridFS 下载文件

Question

我设法将文件上传到我的 mongoDB 数据库，如下所示：

uploadFile(file, uid) {
    var grid = require('gridfs-stream');
    var mongoose = require('mongoose');
    var fs = require('fs');

    mongoose.connect(config.db, {useNewUrlParser: true},).catch(e => console.log(e));
    var conn = mongoose.connection;
    grid.mongo = mongoose.mongo;
    const gfs = grid(conn.db);
    const writeStream = gfs.createWriteStream({
        filename: file.filename,
    });
    fs.createReadStream(file.path).pipe(writeStream);
    writeStream.on('close', file => {
        const {_id} = file;
        console.log(`${_id} written to the db`);
        return Account.findByIdAndUpdate(uid, {'employer.logo': _id}).then(r => console.log(r)).catch(e => console.log(e));
    });
}

所以这导致了这个：

{
    "_id": {
        "$oid": "5bc9d28270e5375dfbfe17fd"
    },
    "employer": {

        "logo": "5bd72702d5dfad7f0f9f8c08",
    },
}

它还创建了一个fs.files和fs.chunks文档

{
    "_id": {
        "$oid": "5bd72702d5dfad7f0f9f8c08"
    },
    "filename": "6d6104894af7d98779430a7457ce3e4e",
    "contentType": "binary/octet-stream",
    "length": 17283,
    "chunkSize": 261120,
    "uploadDate": {
        "$date": "2018-10-29T14:09:18.725Z"
    },
    "aliases": null,
    "metadata": null,
    "md5": "2e6afedd69510b1b526f1015c47065e2"
}

而这在fs.chunks

{
    "_id": {
        "$oid": "5bd72702d5dfad7f0f9f8c09"
    },
    "files_id": {
        "$oid": "5bd72702d5dfad7f0f9f8c08"
    },
    "n": 0,
    "data": "<Binary Data>"
}

所以我认为这里一切都很好。但现在我无法弄清楚如何阅读它。这就是我到目前为止所拥有的。

downloadFile: async id => {
    var fs = require('fs');
    fs.file.find(id).then(r => console.log(r)).catch(e => console.log(e));
}

我在互联网上看到过类似的东西，但现在找不到。知道这有什么问题吗？

标签： javascriptnode.jsmongodbmongoosegridfs