I'm in a situation where I have to use a catch block to execute some code but I don't want to consider it an error.
Basically, I want to update/create a user based on whether the user is already registered or not respectively. The admin sdk let me create a user, and if the user already exists it throws an error. So if I'm in the catch block I know that the user already exists and I want to update it.
function addClient(client) {
return new Promise((resolve, reject) => {
admin.auth().createUser({
uid: client.id,
email: client.email,
emailVerified: true,
password: client.password,
}).then(record => {
resolve(record);
return null;
}).catch(
// the user already exist, I update it
admin.auth().updateUser(client.id, {
email: client.email
}).then(record => {
resolve(record);
return null;
}).catch(
err => {
reject(err);
}
)
);
});
}
The problem is that when I call the function with an existing user, it is updated correctly but the HTTP response is an internal server error (I guess because it enters the catch block and it considers this as an error). The same is if I send a new user: it is created correctly but the HTTP response code is a 500.
There is a way to avoid this behaviour?
This is the main function that calls the previous one for each user received and it's responsible for sending the HTTP response:
exports.addClients = functions.https.onRequest((req, res) => {
// fetch recevied list from payload
var receivedClients = req.body.clients;
var promises = [];
receivedClients.forEach(client => {
promises.push(addClient(client));
})
Promise.all(promises)
.then(() => {
res.sendStatus(200);
return null;
})
.catch(err => {
res.status(500).send(err);
});
});
I guess that what I want to achieve is to have all the promises resolving.
You need to pass a callback to .catch, not a promise. Also avoid the Promise constructor antipattern!
function addClient(client) {
return admin.auth().createUser({
uid: client.id,
email: client.email,
emailVerified: true,
password: client.password,
}).catch(err => {
// ^^^^^^^^
// if (err.code != "UserExists") throw err;
return admin.auth().updateUser(client.id, {
email: client.email
})
});
}
Related
I hope you can help me. I am developing a functionality that reads a series of data (data is taked from csv file) and checks if it has to put it in a list or not. The problem comes when I start to check the data (through promises) since it gives me an error telling me that the rejected promise has not been captured. You will need to use the following:
// -npm install email-existence
const emailExistence = require("email-existence");
The code:
function checkEmailExistencePromise(element) {
return new Promise((resolve, reject) => {
emailExistence.check(element.email, (error, response) => {
if (error) {
reject(error);
return;
}
// If the person has false email the promise will be save (as object) with "Exists" attribute in false.
if (!response) {
resolve({
name: element.name,
phone: element.phone,
email: element.email,
document: element.document,
weight: element.weight,
tags: element.tags,
exists: false,
});
return;
}
// If the person has valid email the promise will be save (as object) with "Exists" attribute in true.
resolve({
name: element.name,
phone: element.phone,
email: element.email,
document: element.document,
weight: element.weight,
tags: element.tags,
exists: true,
});
});
}).catch(() => {
throw console.error();
});
}
// I call the function that will write the CSV file with valid email records.
checkEmails();
// This function collects the promises of the "checkEmailExistencePromise" function and dumps them into an array.
async function checkEmails() {
const promises = sinRepetidos.map((element) =>
checkEmailExistencePromise(element)
);
const values = await Promise.all(promises);
// Here we go through the promises (which are also objects) and those with the true attribute I put them in a new array that will be printed later.
values.forEach((element) => {
if (element.exists === true) {
checked.push(element);
}
});
Because checkEmailExistencePromise() can throw an error (both through the reject() and the throw call), you need to wrap your
const values = await Promise.all(promises);
call in checkEmails() in a try..catch as well, like so
let values = null;
try {
values = await Promise.all(promises)
} catch (e) {
console.error(e)
}
// do something with values, if it's not null
Edit
As you most likely don't want checkEmailExistencePromise to throw an error, you can replace it with this:
function checkEmailExistencePromise(element) {
// NOTE: we're making is so that this promise never rejects - if there's
// an error in there, we'll assume that the email isn't valid
return new Promise(resolve => {
emailExistence.check(element.email, (error, response) => {
let exists = false;
if (error) {
// we can log the error, to make sure we're not doing anything wrong
// that needs to be fixed - some errors can be legit, though
console.error(error);
}
// NOTE: we should probably actually check the response
if(response) {
exists = true;
}
resolve({
name: element.name,
phone: element.phone,
email: element.email,
document: element.document,
weight: element.weight,
tags: element.tags,
exists
})
});
})
}
We take any error to mean that the email isn't valid.
Also, if element only contains those 6 properties (name, phone, email...), then you can simplify the resolve further with something like this:
resolve(Object.assign({},element,{exists}))
This will make a shallow clone of the object and add the exists property to it
I have an express route for handling password resets, and with that i have a route, where i first find the user, and have some error handling with that, but now i want aditional error handling inside a nested function, and I'm not sure what pattern to use
function triggerPasswordResetEmailSend(req, res, next) {
var email = req.body.email;
if (!email) return res.status(422).json({error: "Please provide an email."});
UserRepositoryClass.findUserByEmail(email).then(user =>{
if(!user) return res.status(422).json({message: "User not found"})
sendPasswordReset(user);
return res.status(200).json({user: user});
}).catch(err =>{
return res.status(500).json({error: err})
});
}
Inside this function i do some initial error handling. The issue now is that the sendPasswordReset function can also throw errors, but there are not caught by the .catch() function, so I'm looking for something to handle this function.
I have tried passing the req and res objects into the function, but that does not seem like a good solution. I could do some try catch or maybe return a promise. But i want to ensure, that i follow the same pattern and best practises as i have already tried to do.
Here is the code snippet from my mail function:
module.exports = (user) => {
const userResetToken = generatePasswordToken();
UserRepositoryClass.setPasswordResetToken(user.id, userResetToken);
const passwordResetUrl = PASSWORD_RESET_URL(user._id, userResetToken);
return sendMail(options(user.email, passwordResetUrl));
}
You can use promise instead of function.
module.exports.sendPasswordReset = user = new Promise((resolve, reject) => {
const userResetToken = generatePasswordToken();
UserRepositoryClass.setPasswordResetToken(user.id, userResetToken);
const passwordResetUrl = PASSWORD_RESET_URL(user._id, userResetToken);
sendMail(options(user.email, passwordResetUrl))
.then(response => {
resolve(response, null); // we can get result as (data,error) here error is null
})
.catch(err => {
reject(null, err); // here response is null
});
});
You can use sendPasswordReset Promise like this:
sendPasswordReset(user).then((res, err) => {
// here you can get your res as well as err
if (err) throw new Error("Error while sending an email");
console.log("response", res);
});
I'm using a Firebase function that detects when a Stripe Token is added to a user collection, which then creates a Stripe User and creates a Subscription for that user.
The problem I'm having is that the below code has an error in it, and whilst I need to figure out what that error is, the Promise Chain doesn't seem to catch the actual error.
All that logs out is Function execution took 4375 ms, finished with status: 'connection error'
Does anyone know why this is happening. The only way I can get it to log catch the error is to nest the Promises.
exports.createStripeUser = functions.firestore
// A Stripe Token is created in a user, therefore they have agreed to pay
// Create a User in Stripe, and then attach the subscription to the Stripe customer
.document('users/{userId}/stripe/{stripeCollectionId}')
.onCreate((snap, context) => {
const stripeToken = snap.data().stripeToken;
let customer;
return admin.auth().getUser(`${context.params.userId}`)
.then(userObj => {
const user = userObj.toJSON();
return stripe.customers.create({
email: user.email,
source: stripeToken
})
})
.then(cust => {
customer = cust;
return db.collection('users').doc(context.params.userId).collection('plan').doc(context.params.userId).get()
})
.then(plan => {
return stripe.subscriptions.create({
customer: customer.id,
items: [{plan: plan.data().plan}]
})
})
.catch(e => {
console.log("ERRR", e)
throw new functions.https.HttpsError('unknown', e.message, e);
})
})
Wrap your block in a
try {
}
catch (e) {
// e holds the nested error message
}
block and pick up the error there.
Code snippet below is using sails waterline ORM to make DB queries and sending response. However, the execution flow is weird, The code outside of map function is running before the map function has finished executing. 'I am outside of map' is being printed in the console before 'I am inside of map'. I think it can be solved this using Promise or async / await. I have tried using Promise.all() below, but it doesn't work, the response is always an empty array. I would be grateful if you could give an example on how to solve this kind of issues.
allMembers: (req, res) => {
const projectId = req.params.id;
ProjectMembers.find({projectId: projectId}).exec( (err, members) => {
if(err) res.serverError("bad request!");
if(members.length === 0) res.notFound({message: "No members are found for this project!"});
let membersInfo = [];
let promise = Promise.all(members.map(m => {
User.findOne({id: m.userId}).exec( (err, user) => {
if(err) membersInfo.push({name: null, userId: null, email:null,rate:null, error: 'Internal error!'})
else if(!user) membersInfo.push({name: null, userId: null, email:null,rate:null, error: 'No user found'})
else membersInfo.push({name: user.name, userId: user.id, rate: m.rate, error: null})
console.log("i am inside of map");
})
}));
console.log("I am outsie of map")
promise.then( (resolve) => {return res.ok({members: membersInfo})});
}
I was about to tell you "don't use queries in .map", but on looking, I think your code is quite close to working. The argument of Promise.all has to be an array of promises. Each User.findOne is indeed a promise - the stumbling block is that once you use .exec it no longer returns a promise.
I think the answer is to do your processing inside the .then instead of right inside the .map:
ProjectMembers.find({projectId: projectId}).exec( (err, members) => {
if(err) return res.serverError("bad request!");
if(members.length === 0) return res.notFound({message: "No members are found for this project!"});
let promise = Promise.all(members.map(m => User.findOne({id: m.userId})));
promise.then( (values) => {
// values is the array of user objects returned from the array of queries
let membersInfo = values.map((user) => {
if (!user) {
return {name: null, userId: null, email:null,rate:null, error: 'No user found'};
} else {
return {name: user.name, userId: user.id, rate: m.rate, error: null};
}
});
return res.ok({members: membersInfo});
}, (err) => {
return res.serverError("Error finding users");
});
The promise only has a single fail callback, so you lose the ability to individually catch and handle querying errors (though you can still individually handle not-found results).
In a backend API I have a login route which should perform the following sequence of actions:
Given an username and password, try to authenticate the user against an Active Directory. If authentication has failed reply with status 401. If success, continue.
Look for an user with the given username in the database. If not found reply with status 403, otherwise continue.
Find if the user document has some details like email, display name, etc (in case this is not the first time logging in). If yes reply with the user object, otherwise continue.
Get user details from the Active Directory and update the user object in the database. Reply with the updated object.
Code:
router.post('/login', (req, res, next) => {
// capture credentials
const username = req.body.username;
const password = req.body.password;
let user = null;
// authenticate
ad.authenticate(username, password)
.then((success) => {
if (!success) {
res.status(401).send(); // authentication failed
next();
}
return User.findOne({ username }).exec();
})
.then((found) => {
if (!found) {
res.status(403).send(); // unauthorized, no account in DB
next();
}
user = found;
if (user.displayName) {
res.status(201).json(user); // all good, return user details
next();
}
// fetch user details from the AD
return ad.getUserDetails(username, password);
})
.then((details) => {
// update user object with the response details and save
// ...
return user.save();
})
.then((update) => {
res.status(201).json(update); // all good, return user object
next();
})
.catch(err => next(err));
});
Now I had this running with callbacks but it was really nested. So I wanted to give Bluebird promises a try, but I have two problems:
Looks chaotic, any better way to chain the calls and handle responses?
Whenever I call next() to stop the request after replying, the execution continues to the other .then(). Although the client receives the correct response, in the server log I find that the execution have continued. For example, if there is no account in DB for a given user, the client receives the 403 response but in the server log I see an exception failed to read property displayName of null, because there was no user and it should have stopped in the next() after res.status(403).send();.
Best use if/else to make clear what branches will execute and which won't:
ad.authenticate(username, password).then((success) => {
if (!success) {
res.status(401).send(); // authentication failed
} else {
return User.findOne({ username }).exec().then(user => {
if (!user) {
res.status(403).send(); // unauthorized, no account in DB
} else if (user.displayName) {
res.status(201).json(user); // all good, return user details
} else {
// fetch user details from the AD
return ad.getUserDetails(username, password).then(details => {
// update user object with the response details and save
// ...
return user.save();
}).then(update => {
res.status(201).json(update); // all good, return user object
});
}
});
}
}).then(() => next(), err => next(err));
The nesting of then calls is quite necessary for conditional evaluation, you cannot chain them linearly and "break out" in the middle (other than by throwing exceptions, which is really ugly).
If you don't like all those then callbacks, you can use async/await syntax (possibly with a transpiler - or use Bluebird's Promise.coroutine to emulate it with generator syntax). Your whole code then becomes
router.post('/login', async (req, res, next) => {
try {
// authenticate
const success = await ad.authenticate(req.body.username, req.body.password);
if (!success) {
res.status(401).send(); // authentication failed
} else {
const user = await User.findOne({ username }).exec();
if (!user) {
res.status(403).send(); // unauthorized, no account in DB
} else if (user.displayName) {
res.status(201).json(user); // all good, return user details
} else {
// fetch user details from the AD
const details = await ad.getUserDetails(username, password);
// update user object with the response details and save
// ...
const update = await user.save();
res.status(201).json(update); // all good, return user object
}
}
next(); // let's hope this doesn't throw
} catch(err) {
next(err);
}
});
To answer your second point, you have to reject your promise after calling next() (or at least return something, otherwise the line after will be executed). Something like
next();
return Promise.reject()
and change your catch so it works if you do not have an error
.catch(err => {
if (err)
next(err)
});
To your second question first: there is no way to break/stop a promise chain, unless your callback throw err like
doAsync()
.then(()=>{
throw 'sth wrong'
})
.then(()=>{
// code here never runs
})
You can simply try below demos to verify the second callback still runs.
doAsync()
.then(()=>{
res.end('end')
})
.then(()=>{
// code here always runs
})
doAsync()
.then(()=>{
return;
})
.then(()=>{
// code here always runs
})
To your first question: to use the second parameter in then(), which means reject. And each time split the logic to two parts.
var p = new Promise(function(resolve, reject) {
return
ad.auth(username, password).then(()={
// check if 401 needed. If needed, return reject
if (dont needed 401 in your logic)
resolve(username)
else
reject({ msg: 'authentication has failed', status: 401 })
})
});
p
.then( (username)=>{
// this only runs when the previous resolves
return User.findOne({ username }).exec()
}, (data)=>{
// in fact in your case you dont even have to have the reject callback
return data
} )
.then( (found)=>{
return
new Promise(function(resolve, reject) {
if (found && /*your logic to determine it's not 403*/)
resolve(user)
else
reject({ msg: 'unauthorized, no account in DB', status: 403 })
})
} )
.then( (found)=>{
return
new Promise(function(resolve, reject) {
if (found && /*your logic to determine it's not 403*/)
resolve(user)
else
reject({ msg: 'unauthorized, no account in DB', status: 403 })
})
} )
.then( (user)=>{
return
new Promise(function(resolve, reject) {
if (/*your logic to determine it has the full info*/)
resolve(user)
else
return ad.getUserDetails(username, password)
})
} )
.then( (user)=>{
// all is good, do the good logic
}, (data)=>{
// something wrong, so here you can handle all the reject in one place
res.send(data)
} )