从GridFS显示图像

Question

我正在尝试从GridFS读取图像。并得到以下错误。

var mongoose = require('mongoose');

exports.getLogo = function (req, res, next) {    


    var conn = mongoose.createConnection('localhost', 'database-name', 27017);

    conn.once('open', function () {

        var gs = new mongoose.GridStore(conn.db, 'img1.png', "w");

        gs.read(function (err, data) {

            res.setHeader('Content-Type', gs.contentType);
            res.setHeader('Content-Length', gs.length);
            res.setHeader('Content-Disposition', 'inline; filename="' + gs.filename + '"');

            res.end(data);

        });
    });

};

错误： -

D:\Projects\node_modules\mongoose\node_modules\mongodb\lib\mongodb\db.js:279
          throw err;
                ^
TypeError: undefined is not a function

如何解决此错误。

已编辑 -

TypeError: Cannot call method 'length' of undefined
    at Stream.GridStore.read

gridfs-stream输出： -

Answer 1

你真的需要仔细阅读这份文件。

var mongoose = require('mongoose');

exports.getLogo = function (req, res, next) {    


    var conn = mongoose.createConnection('localhost', 'database-name', 27017);

    conn.once('open', function () {

        var gs = new mongoose.mongo.GridStore(conn.db, /* the id */, 'img1.png', "r");
        gs.open(function(err, gs) {
            gs.read(gs.length, function (err, data) {

              res.setHeader('Content-Type', gs.contentType);
              res.setHeader('Content-Length', gs.length);
              // gs don't have a property filename, filename need to come from your req.
              res.setHeader('Content-Disposition', 'inline; filename="' + 'img1.png' + '"');

              res.end(data);

            });
        })



    });

};