This seems like a straightforward google, but I can't seem to find the answer...
Can you pass in ES6 ES7 async functions to the Express router?
Example:
var express = require('express');
var app = express();
app.get('/', async function(req, res){
// some await stuff
res.send('hello world');
});
If not, can you point me in the right direction on how to handle this problem ES7 style? Or do I just have to use promises?
Thanks!
May be you didn't found results because async/await is an ES7 not ES6 feature, it is available in node >= 7.6.
Your code will work in node.
I have tested the following code
var express = require('express');
var app = express();
async function wait (ms) {
return new Promise((resolve, reject) => {
setTimeout(resolve, ms)
});
}
app.get('/', async function(req, res){
console.log('before wait', new Date());
await wait(5 * 1000);
console.log('after wait', new Date())
res.send('hello world');
});
app.listen(3000, err => console.log(err ? "Error listening" : "Listening"))
And voila
MacJamal:messialltimegoals dev$ node test.js
Listening undefined
before wait 2017-06-28T22:32:34.829Z
after wait 2017-06-28T22:32:39.852Z
^C
Basicaly you got it, you have to async a function in order to await on a promise inside its code.
This is not supported in node LTS v6, so may be use babel to transpile code.
Hope this helps.
Update
Since ExpressJs 5, async functions are supported, and throw errors as expected
Starting with Express 5, route handlers and middleware that return a Promise will call next(value) automatically when they reject or throw an error
source
In Express 4 or less, it sort of works, but not really
While it seems to work, it stops handling errors thrown inside the async function, and as a result, if an error is not handled, the server never responds and the client keeps waiting until it timeout.
The correct behavior should be to respond with a 500 status code.
Solutions
express-promise-router
const router = require('express-promise-router')();
// Use it like a normal router, it will handle async functions
express-asyncify
const asyncify = require('express-asyncify')
To fix routes set in the app object
Replace var app = express(); with
var app = asyncify(express());
To fix routes set in router objects
Replace var router = express.Router(); with
var router = asyncify(express.Router());
Note
You only need to apply the asyncify function in the objects where you set the routes directly
https://www.npmjs.com/package/express-asyncify
I think you can't do it directly because exceptions are not caught and the function won't return if one is thrown. This article explains how to create a wrapper function to make it work: http://thecodebarbarian.com/using-async-await-with-mocha-express-and-mongoose.html
I haven't tried it but was investigating this recently.
Use express-promise-router.
const express = require('express');
const Router = require('express-promise-router');
const router = new Router();
const mysql = require('mysql2');
const pool = mysql.createPool({
host: 'localhost',
user: 'myusername',
password: 'mypassword',
database: 'mydb',
waitForConnections: true,
connectionLimit: 10,
queueLimit: 0
}).promise();
router.get('/some_path', async function(req, res, next) {
const [rows, ] = await pool.execute(
'SELECT * ' +
'FROM mytable ',
[]
);
res.json(rows);
});
module.exports = router;
(The above is an example of using mysql2's promise interface with express-promise-router.)
Express 5 will automatically handle async errors for you
https://expressjs.com/en/guide/error-handling.html currently says it clearly:
Starting with Express 5, route handlers and middleware that return a Promise will call next(value) automatically when they reject or throw an error. For example:
app.get('/user/:id', async function (req, res, next) {
var user = await getUserById(req.params.id)
res.send(user)
})
If getUserById throws an error or rejects, next will be called with either the thrown error or the rejected value. If no rejected value is provided, next will be called with a default Error object provided by the Express router.
We can test that as follows:
const assert = require('assert')
const http = require('http')
const express = require('express')
const app = express()
app.get('/error', async (req, res) => {
throw 'my error'
})
const server = app.listen(3000, () => {
// Test it.
function test(path, method, status, body) {
const options = {
hostname: 'localhost',
port: server.address().port,
path: path,
method: method,
}
http.request(options, res => {
console.error(res.statusCode);
assert(res.statusCode === status);
}).end()
}
test('/error', 'GET', 500)
})
The terminal output on express#5.0.0-alpha.8 is the expected:
500
Error: my error
at /home/ciro/test/express5/main.js:10:9
at Layer.handle [as handle_request] (/home/ciro/test/node_modules/router/lib/layer.js:102:15)
at next (/home/ciro/test/node_modules/router/lib/route.js:144:13)
at Route.dispatch (/home/ciro/test/node_modules/router/lib/route.js:109:3)
at handle (/home/ciro/test/node_modules/router/index.js:515:11)
at Layer.handle [as handle_request] (/home/ciro/test/node_modules/router/lib/layer.js:102:15)
at /home/ciro/test/node_modules/router/index.js:291:22
at Function.process_params (/home/ciro/test/node_modules/router/index.js:349:12)
at next (/home/ciro/test/node_modules/router/index.js:285:10)
at Function.handle (/home/ciro/test/node_modules/router/index.js:184:3)
If you visit it on the browser, you will see an HTML page that says my error.
If you run the exact same code on express#4.17.1, you see on the terminal only:
UnhandledPromiseRejectionWarning: my error
but not the 500 nor my error. This is because the request just hangs forever. If you try to open it on the browser, you will see it hang more clearly.
TODO: how to make it show the stack trace as well instead of just my error? Getting the stack trace in a custom error handler in Express?
Express 4 solution
The simplest solution for Express 4 is to just wrap every single route in a try/catch as follows:
app.get('/error', async (req, res, next) => {
try {
throw new Error('my error'
res.send('never returned')
} catch(error) {
next(error);
}
})
which produces the same correct behavior as Express 5.
You can also factor this out further with some of the methods discussed at: express.js async router and error handling
Tested on Node.js v14.16.0.
To handle async requests in express routes use a try catch, which helps you to try for any errors in function and catch them. try{await stuff} catch{err}
An other less intrusive option is using express-async-errors
This will patch express to correctly handle async/await.
import express from 'express'
import 'express-async-errors'
Related
This question already has answers here:
Access current req object everywhere in Node.js Express
(2 answers)
Closed 8 months ago.
This post was edited and submitted for review 8 months ago and failed to reopen the post:
Original close reason(s) were not resolved
I have the following lines of code:
const express = require('express');
const app = express()
// ... defining the routes, app.get('/api/users', (req, res, next)=>{ }) ...etc
app.listen(3000, ()=> console.log('Listening on port 3000...'))
module.exports = app
I want to be able to read the request object outside an express middleware.
I have another file called mongoose_models.js, inside that file, I don't have the access to the express middleware arguments (req, res, next).
And the only option I have for reading the request body from that file is to import the app and somehow read the request Object.
NodeJs is event-driven, so there must be a way somehow to do so, for instance, inside the file mongoose_models.js I would have maybe something like this code:
// mongoose_models.js
// ... some code
const app = require('../app.js')
app.on('request', (req)=>{
// here I have the request
})
or maybe if express supports:
// mongoose_models.js
// ... some code
const { req } = require('express')
console.log(req.body) // ? maybe something like that ?
or maybe if express supports too:
// mongoose_models.js
// ... some code
const app = require('../app.js')
app.onRequest((req, res) => {
// here I have the access to the request object
})
Is there a way to reach the request object without having to be inside an express middleware in NodeJS?
edit:
Some of you asked me to provide the source code, unfortunately, I wanted to provide a stackblitz or code sandbox instance, but I didn't know how to set up the connections to the database.
Anyway, the following is the file structure of the sample project:
app.js file (full code):
const express = require('express')
const app = express()
const mongoose = require('mongoose')
const RoomModel = require('./mongoose_models')
app.use((req, res, next) => {
// this middleware is the "protect" middleware, it validates a JWT (JSON web token), decodes it, and then stores the user it finds to the req object:
// .... etc some code
// decode the JWT .. some code
// find the user in the DB const userDoc = await UserModel.findOne({ _id: decodedJWT.id )})
const userDoc = {
id: 'abc-123-edf-cds-123-321-qu5-eu4-dc9-182',
name: 'Murat',
// and some other fields ... etc
}
req.$loggedInUser = userDoc
})
app.get('/rooms', async(req, res, next) => {
const docs = await RoomModel.find({})
res.status(200).json({
message: 'here are all the rooms',
results: docs.length,
data: docs,
})
})
app.post('/rooms', async(req, res, next) => {
const doc = await RoomModel.create(req.body)
res.status(201).json({
message: 'the new room which got created:',
data: doc,
})
})
// connecting to the database:
mongoose.connect(
'mongodb+srv://USERNAME:PASSWORD#YOUR_CLUSTER.mongodb.net/?retryWrites=true&w=majority'
)
// starting the HTTP service:
app.listen(3000, () => console.log('app listening on port 3000...'))
mongoose_models.js file (full code):
const mongoose = require('mongoose')
const roomSchema = new mongoose.Schema({
name: String,
by: mongoose.Schema.ObjectId,
})
roomSchema.pre('save', function(next) {
// Here I want to make the by field be the req.$loggedInUser.id but I can't because I have no way to read the request object
const doc = this
// doc.by = req.$loggedInUser.id // < ----- 👈👈👈 HERE, I can't reach the req object
next()
})
const RoomModel = mongoose.model('Room', roomSchema, 'rooms')
module.exports = RoomModel
NodeJS is event driven, so there must be a way somehow to do so, for
instance, inside the file mongoose_models.js I would have maybe
something like this code:
// mongoose_models.js
// ... some code
const app = require('../app.js')
app.on('request', (req)=>{
// here I have the request
})
This approach is, essentially, middleware. So write is as middleware.
const myMiddleware = (req, res, next) => {
// here you have the request
next(); // go to next middleware
}
module.exports = myMiddleware
Attaching something to listen for requests is done with use (for non-method specific functions) and post, get, etc. There is no on method or onRequest method.
// mongoose_models.js
// ... some code
const { req } = require('express')
console.log(req.body) // ? maybe something like that ?
The request object doesn't exist until the client makes a request to the server.
You get a new request object each time a request is made.
The server might be handling multiple requests at the same time.
So no, you can't do anything like that.
Is there a way to reach the request object without having to be inside an express middleware in NodeJS?
No.
My Code:
const functions = require("firebase-functions");
const express = require("express");
const cors = require("cors");
const stripe = require("stripe")(
"sk_test"
);
const app = express();
app.use(cors({ origin: true }));
app.use(express.json());
app.post("/payments/create", async (request, response) => {
const total = request.query.total;
console.log("Payment Request Recieved for: ", total);
const paymentIntent = await stripe.paymentIntents.create({
amount: total,
currency: "usd",
});
response.status(201).send({
clientSecret: paymentIntent.client_secret,
});
});
exports.api = functions.https.onRequest(app);
The problem is in this line: Image of the source of issue
and the error message that comes up is:
Parsing error: Unexpected token =>
I have tried reinstalling everything but nothing seems to work
Would appreciate any help I can get
What version of Node are you using? It seems unlikely for a new server to use a version old enough that arrow functions aren't supported, but you should check by running node -v. Then check the compatibility chart.
If your version doesn't support arrow function and you cannot update, you can rewrite the function using function (request, response) { ... }, though I would expect you to then also have issues with the async/await pattern.
Related answer: https://stackoverflow.com/a/36843758/12474862
I'm trying to write a header of an MD5 hash token using crypto then return it back as a response. For some reason, it isn't actually running synchronously. I know JS is an asynchronous language, and that's really the only part I'm struggling with right now. Any help would be appreciated.
This is what I have so far:
const crypto = require('crypto');
const bodyParser = require('body-parser');
const formidable = require('formidable');
const async = require('async')
app.post('/pushurl/auth', (req, res) =>
var data = req.body.form1data1 + '§' + req.body.form1data2
async.waterfall([
function(callback) {
var token = crypto.createHash('md5').update(data).digest("hex");
callback(null, token);
},
function(token, callback) {
res.writeHead(301,
{Location: '/dashboard?token=' + token}
);
callback(null)
},
function(callback) {
res.end();
callback(null)
}
]);
}
});
Output:
Uncaught Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
<node_internals>/internal/errors.js:256
No debugger available, can not send 'variables'
Process exited with code 1
JavaScript is an asynchronous language, yes, but it can also do synchronous tasks very well. In your case, you don't need to do any async expect if you're dealing with promises.
If you write your code like in the example below it will just execute from top to bottom.
But the error (probably) occurred because you forgot to add an opening curly brace to your app.post callback, which results in the data var being immediately returned because of an implied return statement () => (implied), () => {} (explicit).
const crypto = require('crypto');
const bodyParser = require('body-parser');
const formidable = require('formidable');
app.post('/pushurl/auth', (req, res) => {
const data = req.body.form1data1 + '§' + req.body.form1data2;
const token = crypto.createHash('md5').update(data).digest("hex");
res.writeHead(301, {
Location: '/dashboard?token=' + token
});
res.end();
});
I am simply trying to work within my app.js or router file to handle possible missing router errors. (similar stackoverflow solutions have not worked for me)
my app.js or router files is thus (works fine as is; but am trying to handle missing router error properly):
'use strict'
var path = require('path');
var film = require('./healthymeals.js');
var express = require('express');
var router = express.Router();
var app = express();
module.exports = function(app) {
app.get('/allMeals', film.getAllMeals);
app.get('/meals/:id', film.getMealInfo);
app.get('/meals/:id/options',meal.getHealthyMealoptions);
app.get('*', function(req, res) {
res.send("Healthy meals");
});
I have installed npm's/express error handling package 'http-status-codes' .
And tried it's implementation:
var HttpStatus = require('http-status-codes');
response
.status(HttpStatus.OK)
.send('ok');
response
.status(HttpStatus.INTERNAL_SERVER_ERROR)
.send({
error: HttpStatus.getStatusText(HttpStatus.INTERNAL_SERVER_ERROR)
});
when the above is ran; I get a build error in terminal thrown on the 'response' word. I had no errors when installing relevant npm package.
ReferenceError: response is not defined
I have then tried a few suggestions I found on stackover, ie.
function getAllApps(request, response) {
appService.getApps(request.query.$expand).then(function (apps) {
response.status(200).send(apps);
})
.catch(function (err) {
console.error('Error occurred in Apps Api: ' + err);
response.status(500).send("" + err);
});
}
which is not effective and seems to just get ignored. any pointers appreciated (first time using this stack). cheers
Update, with the answer below from Jonas w - I was first getting time out error as follows:
Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
And then after increasing time out, I am getting below error:
TypeError: Cannot read property 'status' of undefined
For more context here is the test in which it is not passing with my attempts:
describe('error handling', function() {
it('handles missing routes', function(done) {
request
.get('/meals/brokenroute')
.expect(404)
.expect(function(res) {
ok('message' in res.body, '"message" key missing');
})
.end(done);
});
The best solution ive found yet ( using plain express only):
app.get('/allMeals', film.getAllMeals, END);
app.get('/meals/:id', film.getMealInfo, END);
app.get('/meals/:id/options',meal.getHealthyMealoptions,END);
function END(req,res){
res.end();
//note that this wont call next...
}
//all errors are handled below
app.get('*', function(req, res) {
res.status(404).end();
});
My Issue
I've coded a very simple CRUD API and I've started recently coding also some tests using chai and chai-http but I'm having an issue when running my tests with $ mocha.
When I run the tests I get the following error on the shell:
TypeError: app.address is not a function
My Code
Here is a sample of one of my tests (/tests/server-test.js):
var chai = require('chai');
var mongoose = require('mongoose');
var chaiHttp = require('chai-http');
var server = require('../server/app'); // my express app
var should = chai.should();
var testUtils = require('./test-utils');
chai.use(chaiHttp);
describe('API Tests', function() {
before(function() {
mongoose.createConnection('mongodb://localhost/bot-test', myOptionsObj);
});
beforeEach(function(done) {
// I do stuff like populating db
});
afterEach(function(done) {
// I do stuff like deleting populated db
});
after(function() {
mongoose.connection.close();
});
describe('Boxes', function() {
it.only('should list ALL boxes on /boxes GET', function(done) {
chai.request(server)
.get('/api/boxes')
.end(function(err, res){
res.should.have.status(200);
done();
});
});
// the rest of the tests would continue here...
});
});
And my express app files (/server/app.js):
var mongoose = require('mongoose');
var express = require('express');
var api = require('./routes/api.js');
var app = express();
mongoose.connect('mongodb://localhost/db-dev', myOptionsObj);
// application configuration
require('./config/express')(app);
// routing set up
app.use('/api', api);
var server = app.listen(3000, function () {
var host = server.address().address;
var port = server.address().port;
console.log('App listening at http://%s:%s', host, port);
});
and (/server/routes/api.js):
var express = require('express');
var boxController = require('../modules/box/controller');
var thingController = require('../modules/thing/controller');
var router = express.Router();
// API routing
router.get('/boxes', boxController.getAll);
// etc.
module.exports = router;
Extra notes
I've tried logging out the server variable in the /tests/server-test.js file before running the tests:
...
var server = require('../server/app'); // my express app
...
console.log('server: ', server);
...
and I the result of that is an empty object: server: {}.
You don't export anything in your app module. Try adding this to your app.js file:
module.exports = server
It's important to export the http.Server object returned by app.listen(3000) instead of just the function app, otherwise you will get TypeError: app.address is not a function.
Example:
index.js
const koa = require('koa');
const app = new koa();
module.exports = app.listen(3000);
index.spec.js
const request = require('supertest');
const app = require('./index.js');
describe('User Registration', () => {
const agent = request.agent(app);
it('should ...', () => {
This may also help, and satisfies #dman point of changing application code to fit a test.
make your request to the localhost and port as needed
chai.request('http://localhost:5000')
instead of
chai.request(server)
this fixed the same error message I had using Koa JS (v2) and ava js.
The answers above correctly address the issue: supertest wants an http.Server to work on. However, calling app.listen() to get a server will also start a listening server, this is bad practice and unnecessary.
You can get around by this by using http.createServer():
import * as http from 'http';
import * as supertest from 'supertest';
import * as test from 'tape';
import * as Koa from 'koa';
const app = new Koa();
# add some routes here
const apptest = supertest(http.createServer(app.callback()));
test('GET /healthcheck', (t) => {
apptest.get('/healthcheck')
.expect(200)
.expect(res => {
t.equal(res.text, 'Ok');
})
.end(t.end.bind(t));
});
Just in case, if someone uses Hapijs the issue still occurs, because it does not use Express.js, thus address() function does not exist.
TypeError: app.address is not a function
at serverAddress (node_modules/chai-http/lib/request.js:282:18)
The workaround to make it work
// this makes the server to start up
let server = require('../../server')
// pass this instead of server to avoid error
const API = 'http://localhost:3000'
describe('/GET token ', () => {
it('JWT token', (done) => {
chai.request(API)
.get('/api/token?....')
.end((err, res) => {
res.should.have.status(200)
res.body.should.be.a('object')
res.body.should.have.property('token')
done()
})
})
})
Export app at the end of the main API file like index.js.
module.exports = app;
We had the same issue when we run mocha using ts-node in our node + typescript serverless project.
Our tsconfig.json had "sourceMap": true . So generated, .js and .js.map files cause some funny transpiling issues (similar to this). When we run mocha runner using ts-node. So, I will set to sourceMap flag to false and deleted all .js and .js.map file in our src directory. Then the issue is gone.
If you have already generated files in your src folder, commands below would be really helpful.
find src -name ".js.map" -exec rm {} \;
find src -name ".js" -exec rm {} \;
I am using Jest and Supertest, but was receiving the same error. It was because my server takes time to setup (it is async to setup db, read config, etc). I needed to use Jest's beforeAll helper to allow the async setup to run. I also needed to refactor my server to separate listening, and instead use #Whyhankee's suggestion to create the test's server.
index.js
export async function createServer() {
//setup db, server,config, middleware
return express();
}
async function startServer(){
let app = await createServer();
await app.listen({ port: 4000 });
console.log("Server has started!");
}
if(process.env.NODE_ENV ==="dev") startServer();
test.ts
import {createServer as createMyAppServer} from '#index';
import { test, expect, beforeAll } from '#jest/globals'
const supertest = require("supertest");
import * as http from 'http';
let request :any;
beforeAll(async ()=>{
request = supertest(http.createServer(await createMyAppServer()));
})
test("fetch users", async (done: any) => {
request
.post("/graphql")
.send({
query: "{ getQueryFromGqlServer (id:1) { id} }",
})
.set("Accept", "application/json")
.expect("Content-Type", /json/)
.expect(200)
.end(function (err: any, res: any) {
if (err) return done(err);
expect(res.body).toBeInstanceOf(Object);
let serverErrors = JSON.parse(res.text)['errors'];
expect(serverErrors.length).toEqual(0);
expect(res.body.data.id).toEqual(1);
done();
});
});
Edit:
I also had errors when using data.foreach(async()=>..., should have use for(let x of... in my tests