Question

它解释了很多东西。但是问题是我已经有一个用Express创建的项目，因此我的连接是在app.js中完成的，如下所示：

// mongodb connection
var mongoose = require('mongoose');
var config = require('./globals/config');
mongoose.connect(config.db, {useNewUrlParser: true},).catch(e => console.log(e));

var db = mongoose.connection;
db.once('open', () => {
    console.log('Connected to mongodb. Go to http://localhost:3000 to open app');
});

现在，我想使用gridFS，在另一个文件中将文件上传到我的数据库中，我尝试这样做：

var grid = require('gridfs-stream');
var mongoose = require('mongoose');
var fs = require('fs');
uploadFile(file) {
    var config = require('./config');
    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', function (file) {
        console.log(`${file.filename} written to the db`);
    });
}

但这没有意义，因为我要重新打开2个连接。我看了mongoose-gridfs，但它也显示以“ app.js”的形式使用它，没有跨文件的处理方式。如何在不打开2个连接并使用2个不同的js文件的情况下使用gridfs？

Answer 1

创建一个单独的模块，假设mygridfs.js并将函数放在module.exports中。将mongoose设置为此函数的参数：

var grid = require('gridfs-stream');
var fs = require('fs');
exports.uploadFile = function(file, mongoose) {
    grid.mongo = mongoose.mongo;
    const gfs = grid(mongoose.connection.db);
    const writeStream = gfs.createWriteStream({
        filename: file.filename,
    });
    fs.createReadStream(file.path).pipe(writeStream);
    writeStream.on('close', function (file) {
        console.log(`${file.filename} written to the db`);
    });
}

在主app.js文件中，仅需要以下模块：

var mygridfs= require("mygridfs");
mygridfs.uploadFile(file, mongoose);

难以理解gridfs和连接

1 个答案: