本文介绍了ExpressJS Multer:将图像上传到服务器的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我是使用Node.js和Express.js的新手.
I'm newer with Node.js and Express.js.
我想先将图像上载到服务器(目录:uploads/spots)，然后(同步)上载MongoDB中的其余表单数据.
I want to upload first a image into the server (directory: uploads/spots), and then (synchronous) upload the rest of form data in MongoDB.
我正在使用REST(方法发布)
I'm using REST (Method Post)
并且我正在使用Multer将映像更新到服务器中，并且可以正常工作.
and I'm using Multer for updating the image into the server, and works.
app.use(multer(
{ dest: './public/uploads/spots',
onFileUploadStart: function (file) {
var imagePath = file.path;
gm(imagePath).resize(850, 850).quality(70).noProfile().write('public/uploads/spots/850x850/'+file.name, function (err) {
if (!err) {
gm(imagePath).resize(150, 150).quality(70).noProfile().write('public/uploads/spots/150x150/'+file.name, function (err) {
if (!err) {
}
else{
console.log('Error: '+err);
}
});
}
else{
console.log('Error: '+err);
}
});
}
}));正在工作，但是是异步的，并且在图像将被上传到服务器之前，将响应返回到前端.
Is working, but is asynchronous , and returns the response to frontend before that the image will be upload into the server.
我的问题是如何做到这一点但要同步，以及如何在上传图像后将响应返回到前端.
My question is how to do this but synchronous and how to return the response to the frontend after that the image was uploaded.
谢谢！
spots.server.routes.js
'use strict';
module.exports = function(app) {
var gm = require('gm');
var multer = require('multer');
var users = require('../controllers/users.server.controller.js');
var spots = require('../controllers/spots.server.controller.js');
//Upload image
app.use(multer(
{ dest: './public/uploads/spots',
onFileUploadStart: function (file) {
var imagePath = file.path;
gm(imagePath).resize(850, 850).quality(70).noProfile().write('public/uploads/spots/850x850/'+file.name, function (err) {
if (!err) {
gm(imagePath).resize(150, 150).quality(70).noProfile().write('public/uploads/spots/150x150/'+file.name, function (err) {
if (!err) {
}
else{
console.log('Error: '+err);
}
});
}
else{
console.log('Error: '+err);
}
});
}
}));
// Spots Routes
app.route('/spots')
.get(spots.list)
.post(users.requiresLogin, spots.create);
app.route('/spots/:spotId')
.get(spots.read)
.put(users.requiresLogin, spots.update)
.delete(users.requiresLogin, spots.hasAuthorization, spots.delete);
// Finish by binding the Spot middleware
app.param('spotId', spots.spotByID);
};spots.server.controller.js (创建方法)
'use strict';
/**
* Module dependencies.
*/
var mongoose = require('mongoose'),
errorHandler = require('./errors.server.controller.js'),
Spot = mongoose.model('Spot'),
_ = require('lodash'),
fs = require('fs');
/**
* Create a Spot
*/
exports.create = function(req, res) {
var spot = new Spot(JSON.parse(req.body.spot));
spot.user = req.user;
if(req.files.file)
spot.image=req.files.file.name;
else
spot.image='default.jpg';
spot.save(function(err) {
if (err) {
fs.unlinkSync('public/uploads/spots/'+spot.image);
fs.unlinkSync('public/uploads/spots/850x850/'+spot.image);
fs.unlinkSync('public/uploads/spots/150x150/'+spot.image);
return res.status(400).send({
message: errorHandler.getErrorMessage(err)
});
} else {
var socketio = req.app.get('socketio'); // tacke out socket instance from the app container
socketio.sockets.emit('spot.created.'+spot.municipality, {spot:spot, user:req.user});
socketio.sockets.emit('spot.created.'+spot.province, {spot:spot, user:req.user});
socketio.sockets.emit('spot.created.'+spot.community, {spot:spot, user:req.user});
socketio.sockets.emit('spot.created.'+spot.country, {spot:spot, user:req.user});
res.jsonp(spot);
}
});
};
/**
* Spot authorization middleware
*/
exports.hasAuthorization = function(req, res, next) {
if (req.spot.user.id !== req.user.id) {
return res.status(403).send('User is not authorized');
}
next();
};推荐答案
解决方案不是使用onFileUploadStart方法，而是在控制器中使用带有回调的函数.
The solution is not use onFileUploadStart method and use a function with callback in the controller.
路线
// Spots Routes
app.route('/spots')
.get(spots.list)
.post(users.requiresLogin,multer({ dest: './public/uploads/spots'}), spots.create);
控制器
exports.create = function(req, res) {
if (req.files.file)
exports.uploadImage(req.files.file,callback);
else
callback();
function callback(){
var spot = new Spot(JSON.parse(req.body.spot));
spot.user = req.user;
if (req.files.file)
spot.image = req.files.file.name;
else
spot.image = 'default.jpg';
spot.save(function (err) {
if (err) {
fs.unlink('public/uploads/spots/850x850/'+spot.image);
fs.unlink('public/uploads/spots/150x150/'+spot.image);
return res.status(400).send({
message: errorHandler.getErrorMessage(err)
});
} else {
var socketio = req.app.get('socketio'); // tacke out socket instance from the app container
socketio.sockets.emit('spot.created.' + spot.municipality, {spot: spot, user: req.user});
socketio.sockets.emit('spot.created.' + spot.province, {spot: spot, user: req.user});
socketio.sockets.emit('spot.created.' + spot.community, {spot: spot, user: req.user});
socketio.sockets.emit('spot.created.' + spot.country, {spot: spot, user: req.user});
req.spot = spot;
Feedback.subscribeSpot(req);
Notify.getLocalSubscriptors(spot.municipality,spot.province,spot.community,spot.country,function(subscriptions){
Notify.create(req,null,spot,null,null,null,subscriptions,'spots/'+spot._id,false,'SPOT_CREATED', function(){
res.jsonp(spot);
});
});
}
});
}
};
exports.uploadImage = function(file, fn){
var imagePath = file.path;
gm(imagePath).resize(850, 850).quality(70).noProfile().write('public/uploads/spots/850x850/'+file.name, function (err) {
if (!err) {
gm(imagePath).resize(150, 150).quality(70).noProfile().write('public/uploads/spots/150x150/'+file.name, function (err) {
if (!err) {
if(fn)fn();
}
else{
console.log('Error: '+err);
}
});
}
else{
console.log('Error: '+err);
}
});
};
这篇关于ExpressJS Multer:将图像上传到服务器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！