GridFS/multeR语言 无法读取未定义的属性"文件名"

Question

我不是一个伟大的网络开发专家(至少目前，希望如此(，所以我的问题可能有点傻。

这是我的问题：我一直在研究Node.Js，并试图创建一个数据库，在那里我可以上传图片，然后检索它们，并通过.ejs文件在浏览器上显示它们。

不幸的是，在app.js文件中，我可以对images数组进行console.log，并检查至少一个文件的filename，同时在.ejs-doc上循环执行以下操作：

`<% for(var i = 0; i <= images.length; i++){ %>
<img src="<%= images[i].filename %>">
<% } %>`

我得到了这个问题标题所示的错误。

有人知道我做错了什么吗？我相信我在GridFS或multer上设置了一些错误，但我不能100%确定。

提前感谢将要回复的人。

在这里，你可以找到我目前在app.js文件中使用的代码：

var express                         = require('express'),
mongoose                        = require('mongoose'),
bodyParser                      = require('body-parser'),
methodOverride                  = require('method-override'),
expressSanitizer                = require('express-sanitizer'),
path                            = require('path'),
crypto                          = require('crypto'),
multer                          = require('multer'),
GridFsStorage                   = require('multer-gridfs-storage'),
Grid                            = require('gridfs-stream'),
app                             = express();
//connect to the MongoDB database
mongoose.connect("mongodb+srv://***:*****@cluster-***-***-q5eof.mongodb.net/*****?retryWrites=true&w=majority", 
{ useNewUrlParser: true,
useUnifiedTopology: true,
useFindAndModify: false,
useCreateIndex: true});
//connect to the MongoDB database
var mongoURI = "mongodb+srv://***:*****@cluster-***-***-q5eof.mongodb.net/*****?retryWrites=true&w=majority";
var conn = mongoose.createConnection(mongoURI)
//parseing incoming request bodies in a middleware before the handlers, available under the req.body property
app.use(bodyParser.urlencoded({extended: true}));
//setting the engine to read directly the ejs files without specifying their extentions on the routes
app.set('view engine', 'ejs');
//serving images, CSS files, and JavaScript files in a directory named public:
app.use(express.static('public'));
//setting method-override to be used via '_method' text before specifying the type of method used in a form
app.use(methodOverride('_method'));
//execute express-sanitizer
app.use(expressSanitizer());
let gfs
conn.once('open', () => {
gfs = Grid(conn.db, mongoose.mongo)
gfs.collection('uploads')
console.log('GRID CONNECTION SUCCESSFUL')
})
//Landing page
app.get('/', function(req, res){
gfs.files.find().toArray(function(err, images){
if(err){
console.log(err)
} else {
images.map(function(image){
image.isImage = true;
});
}
res.render('landing', {images: images});
console.log(images[0].filename);
});
});
//Create storage engine
var storage = new GridFsStorage({
url: mongoURI,
file: (req, file) => {
return new Promise((resolve, reject) => {
crypto.randomBytes(16, (err, buf) => {
if (err) {
return reject(err);
}
const filename = buf.toString('hex') + path.extname(file.originalname);
const fileInfo = {
filename: filename,
bucketName: 'uploads'
};
resolve(fileInfo);
});
});
}
});
const upload = multer({ storage });
//Upload page
app.get('/upload', function(req, res){
res.render('upload');
});
//Sending form from upload page
app.post('/upload', upload.array('file'), function(req, res){
res.json({file: req.files});
});
app.listen('3000', function(err){
if(err){
console.log(err)
} else{
console.log("APP CONNECTED")
}
});

Answer 1

这将适用于您，示例代码

const multer = require('multer');   //FOR FILE UPLOAD
let storage = multer.diskStorage({ //multers disk storage settings
destination: function (req, file, cb) {
cb(null, './public');
},
filename: function (req, file, cb) {
let datetimestamp = Date.now();
cb(null, file.originalname);
}
});
let upload = multer({ //multer settings
storage: storage
}).single('file');

let uploadfile = (req, res, next) => {
let path = '';
upload(req, res, function (err) {
if (err) {
return res.status(422).send("an Error occured");
}
let path = req.file.path;
req.file = path;
next();
});
}