Learning how to do testing with Express with using Mocha, Chai, Chai-HTTP plugin, and MongoDB with Mongoose. I have a test to purposely detect if MongoDB will send back an error from trying to find a document using a faulty _id value (too short).
I noticed that part of my code is repeating around my other Express routes, and want to reuse it for other routes so I exported it from another module, but now I get this:
Uncaught Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
Not sure why I am getting this error. If I have the same code, as the exported function, inside the route code it works fine, but exported it just complains.
Here is the code:
test/route/example.test.js Snippit
it('Bad request with a too short ID string (12 characters minimum)', () => {
// /api/v1/example is the endpoint
// /blah is the param
chai.request(app).get('/api/v1/example/blah').end((err, res) => {
// Insert all the nice assert stuff. :)
});
});
route/example.js Snippit
// Packages
const router = require('express').Router();
// Models (Mongoose Schemas)
const Example = require('../models/example.model');
// Helpers
const { foundMongoError } = require('../helpers/routes');
// -----Snipped-----
router.route('/:exampleId').get((req, res) => {
// Retrieve the exampleId parameter.
const exampleId = req.params.exampleId;
Example.findById(exampleId, (mongoError, mongoResponse) => {
foundMongoError(mongoError, res); // Having an issue
// If I have the same code that makes up foundMongoError inside here, no issues,
// but it will no longer be DRY.
// Check if any responses from MongoDB
if(mongoResponse) {
res.status(200).json(mongoResponse);
} else {
return res.status(404).json({
errorCode: 404,
errorCodeMessage: 'Not Found',
errorMessage: `Unable to find example with id: ${exampleId}.`
});
}
});
});
helpers/routes.js
const foundMongoError = (mongoError, res) => {
if(mongoError) {
return res.status(400).json({
errorCode: 400,
errorCodeMessage: 'Bad Request',
errorMessage: mongoError.message
});
}
};
module.exports = {
foundMongoError
};
That just means you send and response res twice back. The first time you send it back at here:
if(mongoError) {
return res.status(400).json({
errorCode: 400,
errorCodeMessage: 'Bad Request',
errorMessage: mongoError.message
});
}
You sended an response back but the function still continue its work, that means the function moves on till here then:
if(mongoResponse) {
res.status(200).json(mongoResponse);
} else {
return res.status(404).json({
errorCode: 404,
errorCodeMessage: 'Not Found',
errorMessage: `Unable to find example with id: ${exampleId}.`
});
}
Here happens the second response, and here you get the error.
I would rewrite the code like this:
Instead of returning the response, you return an true that means there is an error, otherwise false :
const foundMongoError = (mongoError, res) => {
if(mongoError) {
res.status(400).json({
errorCode: 400,
errorCodeMessage: 'Bad Request',
errorMessage: mongoError.message
});
return true;
}
return false;
};
module.exports = {
foundMongoError
};
Then you can write it like this:
if(foundMongoError(mongoError, res)) return;
The return will stop the function to execute the rest of the code
Related
I have created middleware to validate fields in body, here is how it looks like:
Front-end route:
router.post('/s-i', async (req, res) => {
try {
const { data } = await api.post('/sign-in', req.body)
res.cookie("_rt", data._rt, { httpOnly: true, secure: false })
delete data._rt
return res.json(data)
} catch (e) {
// Here is error
return res.status(e.response.status).json(e.response.data)
}
});
Route (back-end):
router.post('/sign-in', v(['email', 'password', 'twoFa', 'phone']), wrapAsync(userController.signIn));
Middleware:
exports.v = fields => {
return (req, res, next) => {
fields.forEach(field => {
if (req.body[field]) {
const result = require(`./validators/${field}`)(req.body[field])
if (!result)
return res.status(400).json({ message: 'bad-request', status: 400 })
}
})
next()
}
}
In the place where comment is placed I can see this error, actually, everything works find, and if there is wrong field in body front will receive 400 status code, but in back-end terminal I still have this error and can't get why.
The problem is I still keep getting this ERR_HTTP_HEADERS_SENT error. I know the reason of this problem - for example - if you are trying do res.send({}) twice, but I don't really see the reason of problem in this case.
The return res.status(400)... statement returns only from the inner function fields.forEach(field => {...}), but you must return from the middleware function, otherwise the next() will invoke subsequent middlewares after the .json output, leading to the observed error.
You can achieve this by replacing fields.forEach(field => {...}) with
for (var field of fields) {
if (req.body[field]) {
const result = require(`./validators/${field}`)(req.body[field])
if (!result)
return res.status(400).json({ message: 'bad-request', status: 400 })
}
}
I made a controller on nestjs as below.
#Post()
public async addConfig(#Res() res, #Body() createConfigDto: CreateConfigDto) {
let config = null;
try {
config = await this.configService.create(createConfigDto);
} catch (err) {
return res.status(HttpStatus.INTERNAL_SERVER_ERROR).json({
status: 500,
message: 'Error: Config not created!',
});
}
if (!config) {
return res.status(HttpStatus.NOT_FOUND).json({
status: 404,
message: 'Not Found',
});
}
return res.status(HttpStatus.OK).json({
message: 'Config has been created successfully',
config,
});
}
And there is a service in other file.
public async create(createConfigDto: CreateConfigDto): Promise<IConfig> {
do something 1
do something 2
do something 3
return result;
}
If an internal server error occurs among "do somehting 1,2 or 3" when I request to this api, it will gives me response 500.
But I want to know in which line the error happend.
Therefore I made catch line function.
const getStackTrace = () => {
const obj = {};
Error.captureStackTrace(obj, getStackTrace);
return obj.stack;
};
And I wrap the code with this function, like this
public async create(createConfigDto: CreateConfigDto): Promise<IConfig> {
try{
do something 1
}catch(error){
console.log(error)
getTrace()
}
try{
do something 2
}catch(error){
console.log(error)
getTrace()
}
try{
do something 3
}catch(error){
console.log(error)
getTrace()
}
return result;
}
But the problem is the service code will grow a lot with this trace function.
I want to know whether there is more efficient way avoiding duplicate code using nestJs for this case.
I think interceptor or execption filter help this.
But I don't know how to code for this case , since I 'm about to start using nestjs.
Thank you for reading my question.
I'm trying to create unit tests for my auth middleware in an Express app.
The middleware is as simple as this:
const jwt = require('jsonwebtoken');
const auth = (req, res, next) => {
const tokenHeader = req.headers.auth;
if (!tokenHeader) {
return res.status(401).send({ error: 'No token provided.' });
}
try {
const decoded = jwt.verify(tokenHeader, process.env.JWT_SECRET);
if (decoded.id !== req.params.userId) {
return res.status(403).json({ error: 'Token belongs to another user.' });
}
return next();
} catch (err) {
return res.status(401).json({ error: 'Invalid token.' });
}
}
module.exports = auth;
And this is my test, where I want to ensure that if the token is ok everything will go smoothly and the middleware just calls next():
it('should call next when everything is ok', async () => {
req.headers.auth = 'rgfh4hs6hfh54sg46';
jest.mock('jsonwebtoken/verify', () => {
return jest.fn(() => ({ id: 'rgfh4hs6hfh54sg46' }));
});
await auth(req, res, next);
expect(next).toBeCalled();
});
But instead of returning the object with and id field as desired, the mock always returns undefined. I have tried returning the object instead of jest.fn() but it didn't work too.
I know there are some similar threads here on stack overflow but unfortunately none of the solutions proposed worked for me.
If more context is needed, here is my full test suite. Thanks in advance.
One way to solve this is to mock the jsonwebtoken module and then use mockReturnValue on the method to be mocked. Consider this example:
const jwt = require('jsonwebtoken');
jest.mock('jsonwebtoken');
jwt.verify.mockReturnValue({ id: 'rgfh4hs6hfh54sg46' });
it('should correctly mock jwt.verify', () => {
expect(jwt.verify("some","token")).toStrictEqual({ id: 'rgfh4hs6hfh54sg46' })
});
Am try to implement and learn async await functions in my login example, but I don't know if is the best, elegant and clean code. I have doubs meanly in catch errors, and if I need implement in a best way the const and functional programing. Can share your opinions?
app.post('/', async (req, res) => {
try {
const { email } = req.body.email; // destructuring
const usuarioEncontrado = await Usuario.findOne({email: email});
// Validate user exist
if (!usuarioEncontrado) { // when not exist return null
throw res.status(404).json({error: 'El usuario no existe'});
}
// validate user pass
if (!bcrypt.compareSync(req.body.password, usuarioEncontrado.password)) {
throw res.status(404).json({error: 'No match'});
}
const token = jwt.sign( // generate token
{
usuario: usuarioEncontrado
},
SEED,
{
expiresIn: (60 * 60)
}
);
res.status(200).json({ // send response
token: token,
usuario: usuarioEncontrado
});
} catch (e) { // send error
res.status(404).json(e);
}
}
THANKS
Your code shows a couple problems:
You're attempting to send double responses. First you do throw res.status(404).json(...). Then, you catch that exception and do res.status(404).json(e) again. That's not right. If you're going to send the response, then just return, don't throw. Or, just throw the exception without sending a response and send the actual error response from the catch handler.
Also, throw res.status(404).json({error: 'No match'}); sends the response and then throws whatever .json() returns which is probably not what you want. That won't be an error object of any kind.
I prefer to centralize the places I send an error response to one place in the request handler. That keeps you from ever attempting to send multiple responses and just makes the flow of the request handler easier to understand (in my opinion).
To do that, I just throw a custom error that may have a custom message/status associated with it and then catch all possible errors in one place. Here's one way to do that. The myError class can be used everywhere in your project, not specific to just one route. The idea is that often when you throw, you know in that context what you want the status and message to be so you set that in the custom Error object and can then use that info in the catch. The catch then has to determine whether it has your custom error or just a regular error. First, I have a reusable Error subclass that lets me throw, not only a message, but also a status value.
// reusable error class that contains a status in addition to the message
class MyError extends Error {
// this static method saves having to compare if it's a custom error object or not
// every time we use this
static sendError(res, e, status = 500) {
if (e instanceof MyError) {
e.sendError(res);
} else {
res.sendStatus(status);
}
}
constructor(msg, status = 500) {
// allow calling with or without new
if (!(this instanceof MyError)) {
return new MyError(msg, status);
}
super(msg);
this.status = status;
}
sendError(res) {
res.status(this.status).send(this.message);
}
}
And, then here's how you use that in your code and centralize the sending of the error status.
app.post('/', async (req, res) => {
try {
const { email } = req.body.email; // destructuring
const usuarioEncontrado = await Usuario.findOne({email: email});
// Validate user exist
if (!usuarioEncontrado) { // when not exist return null
throw MyError('El usuario no existe', 404);
}
// validate user pass
if (!bcrypt.compareSync(req.body.password, usuarioEncontrado.password)) {
throw MyError('No Match', 404);
}
const token = jwt.sign( // generate token
{
usuario: usuarioEncontrado
},
SEED,
{
expiresIn: (60 * 60)
}
);
res.status(200).json({ // send response
token: token,
usuario: usuarioEncontrado
});
} catch (e) { // log and send error response
// e may be either MyError or some other system generated Error
console.log(e);
MyError.sendError(res, e);
}
}
When I request data on client(vue.js) with axios,
I got a error code in server side, 'GET/ 304 --'
But I don't know why this happened
and how to approach this problem or how to fix that.
If I delete codes about 'axios' on client side,
That error doesn't show up.
Please can someone help me.
the code below:
Client side
created() {
axios
.get("http://localhost:4000/")
.then(
result => (
(this.greeting = result.data.greeting),
(this.greeting2 = result.data.greeting2)
)
);
}
Server side
export const getHome = async (req, res) => {
let user;
if (req.headers.authorization !== undefined) {
try {
user = auth.verify(req.headers.authorization);
user = await models.User.findOne({
where: { id: user.id }
});
} catch (err) {
console.log(err);
}
} else {
user = null;
}
const name = user ? user.name : 'Please LOGIN';
res.json({ greeting: `Welcome to Chat N Chill`, greeting2: name });
};
auth.verify code on server side
verify(token) {
return jwt.verify(token.replace(/^Bearer\s/, ''), SECRET_KEY);
}
Express will automatically set the status code to 304 for requests that are fresh:
https://github.com/expressjs/express/blob/e1b45ebd050b6f06aa38cda5aaf0c21708b0c71e/lib/response.js#L206
The property fresh is defined here:
https://github.com/expressjs/express/blob/e1b45ebd050b6f06aa38cda5aaf0c21708b0c71e/lib/request.js#L467
It is documented here:
https://expressjs.com/en/4x/api.html#req.fresh
It should be nothing to worry about, it just means that the content of the response hasn't changed relative to what the browser already has in its cache.