I have this action to fetch the details of a specific location url stored in Firebase.
The original code (Version 1) worked no problem, whereby I dispatch authGetToken(), the code recognises the token (string) stored in redux, then uses it to to fetch the stored data.
Version 1
return dispatch => {
dispatch(authGetToken())
.then(token => {
return fetch("https://myProject/location.json?auth=" + token);
})
.catch(() => {
alert("No valid token found!");
})
.then(res => {
if (res.ok) {
return res.json();
} else {
throw(new Error());
}
})
};
But now that I modified the url requirements to include the user UID as part of the url, it does not work. I know there must be a flaw in my logic but I can't see it.
What I was hoping to write is that once I dispatch authGetToken(), the token dispatches authGetUserUID then uses both strings (userUID and token) to fetch the data.
Version 2
return dispatch => {
dispatch(authGetToken())
.then(token => {
dispatch(authGetuserUID())
return fetch("https://myProject/location/"+ userUID + ".json?auth=" + token);
})
.catch(() => {
alert("No valid token found!");
})
.then(res => {
if (res.ok) {
return res.json();
} else {
throw(new Error());
}
})
};
Would appreciate you guys pointing out the obvious to me >< as I my noob eyes can't see it. Thanks in advance.
I think it might have something to do with userUID, it doesn't seem to be initialised anywhere. Maybe try something like this:
return dispatch => {
dispatch(authGetToken()).then(token => {
dispatch(authGetuserUID()).then(userUID=>{
return fetch("https://myProject/location/"+ userUID + ".json?auth=" + token);
})
})
.catch(() => {
alert("No valid token found!");
})
.then(res => {
if (res.ok) {
return res.json();
} else {
throw(new Error());
}
})
};
Related
Here's what I have going:
import 'whatwg-fetch';
function fetchVehicle(id) {
return dispatch => {
return dispatch({
type: 'FETCH_VEHICLE',
payload: fetch(`http://swapi.co/api/vehicles/${id}/`)
.then(status)
.then(res => res.json())
.catch(error => {
throw(error);
})
});
};
}
function status(res) {
if (!res.ok) {
return Promise.reject()
}
return res;
}
EDIT: The promise doesn't get rejected, that's what I'm trying to figure out.
I'm using this fetch polyfill in Redux with redux-promise-middleware.
Fetch promises only reject with a TypeError when a network error occurs. Since 4xx and 5xx responses aren't network errors, there's nothing to catch. You'll need to throw an error yourself to use Promise#catch.
A fetch Response conveniently supplies an ok , which tells you whether the request succeeded. Something like this should do the trick:
fetch(url).then((response) => {
if (response.ok) {
return response.json();
}
throw new Error('Something went wrong');
})
.then((responseJson) => {
// Do something with the response
})
.catch((error) => {
console.log(error)
});
The following login with username and password example shows how to:
Check response.ok
reject if not OK, instead of throw an error
Further process any error hints from server, e.g. validation issues
login() {
const url = "https://example.com/api/users/login";
const headers = {
Accept: "application/json",
"Content-Type": "application/json",
};
fetch(url, {
method: "POST",
headers,
body: JSON.stringify({
email: this.username,
password: this.password,
}),
})
.then((response) => {
// 1. check response.ok
if (response.ok) {
return response.json();
}
return Promise.reject(response); // 2. reject instead of throw
})
.then((json) => {
// all good, token is ready
this.store.commit("token", json.access_token);
})
.catch((response) => {
console.log(response.status, response.statusText);
// 3. get error messages, if any
response.json().then((json: any) => {
console.log(json);
})
});
},
Thanks for the help everyone, rejecting the promise in .catch() solved my issue:
export function fetchVehicle(id) {
return dispatch => {
return dispatch({
type: 'FETCH_VEHICLE',
payload: fetch(`http://swapi.co/api/vehicles/${id}/`)
.then(status)
.then(res => res.json())
.catch(error => {
return Promise.reject()
})
});
};
}
function status(res) {
if (!res.ok) {
throw new Error(res.statusText);
}
return res;
}
For me,
fny answers really got it all. since fetch is not throwing error, we need to throw/handle the error ourselves.
Posting my solution with async/await. I think it's more strait forward and readable
Solution 1: Not throwing an error, handle the error ourselves
async _fetch(request) {
const fetchResult = await fetch(request); //Making the req
const result = await fetchResult.json(); // parsing the response
if (fetchResult.ok) {
return result; // return success object
}
const responseError = {
type: 'Error',
message: result.message || 'Something went wrong',
data: result.data || '',
code: result.code || '',
};
const error = new Error();
error.info = responseError;
return (error);
}
Here if we getting an error, we are building an error object, plain JS object and returning it, the con is that we need to handle it outside.
How to use:
const userSaved = await apiCall(data); // calling fetch
if (userSaved instanceof Error) {
debug.log('Failed saving user', userSaved); // handle error
return;
}
debug.log('Success saving user', userSaved); // handle success
Solution 2: Throwing an error, using try/catch
async _fetch(request) {
const fetchResult = await fetch(request);
const result = await fetchResult.json();
if (fetchResult.ok) {
return result;
}
const responseError = {
type: 'Error',
message: result.message || 'Something went wrong',
data: result.data || '',
code: result.code || '',
};
let error = new Error();
error = { ...error, ...responseError };
throw (error);
}
Here we are throwing and error that we created, since Error ctor approve only string, Im creating the plain Error js object, and the use will be:
try {
const userSaved = await apiCall(data); // calling fetch
debug.log('Success saving user', userSaved); // handle success
} catch (e) {
debug.log('Failed saving user', userSaved); // handle error
}
Solution 3: Using customer error
async _fetch(request) {
const fetchResult = await fetch(request);
const result = await fetchResult.json();
if (fetchResult.ok) {
return result;
}
throw new ClassError(result.message, result.data, result.code);
}
And:
class ClassError extends Error {
constructor(message = 'Something went wrong', data = '', code = '') {
super();
this.message = message;
this.data = data;
this.code = code;
}
}
Hope it helped.
2021 TypeScript Answer
What I do is write a fetch wrapper that takes a generic and if the response is ok it will auto .json() and type assert the result, otherwise the wrapper throws the response
export const fetcher = async <T>(input: RequestInfo, init?: RequestInit) => {
const response = await fetch(input, init);
if (!response.ok) {
throw response;
}
return response.json() as Promise<T>;
};
and then I'll catch errors and check if they are an instanceof Response. That way TypeScript knows that error has Response properties such as status statusText body headers etc. and I can apply a custom message for each 4xx 5xx status code.
try {
return await fetcher<LoginResponse>("http://localhost:8080/login", {
method: "POST",
headers: {
Accept: "application/json",
"Content-Type": "application/json",
},
body: JSON.stringify({ email: "user#example.com", password: "passw0rd" }),
});
} catch (error) {
if (error instanceof Response) {
switch (error.status) {
case 401:
throw new Error("Invalid login credentials");
/* ... */
default:
throw new Error(`Unknown server error occured: ${error.statusText}`);
}
}
throw new Error(`Something went wrong: ${error.message || error}`);
}
and if something like a network error occurs it can be caught outside of the instanceof Response check with a more generic message i.e.
throw new Error(`Something went wrong: ${error.message || error}`);
The answer by #fny (the accepted answer) didn't work for me. The throw new Error() wasn't getting picked up by the .catch. My solution was to wrap the fetch with a function that builds a new promise:
function my_fetch(url, args) {
return new Promise((resolve, reject) => {
fetch(url, args)
.then((response) => {
response.text().then((body) => {
if (response.ok) {
resolve(body)
} else {
reject(body)
}
})
})
.catch((error) => { reject(error) })
})
}
Now every error and non-ok return will be picked up by the .catch method:
my_fetch(url, args)
.then((response) => {
// Do something with the response
})
.catch((error) => {
// Do something with the error
})
function handleErrors(response) {
if (!response.ok) {
throw Error(response.statusText);
}
return response;
}
fetch("https://example.com/api/users")
.then(handleErrors)
.then(response => console.log("ok") )
.catch(error => console.log(error) );
I wasn't satisfied with any of the suggested solutions, so I played a bit with Fetch API to find a way to handle both success responses and error responses.
Plan was to get {status: XXX, message: 'a message'} format as a result in both cases.
Note: Success response can contain an empty body. In that case we fallback and use Response.status and Response.statusText to populate resulting response object.
fetch(url)
.then(handleResponse)
.then((responseJson) => {
// Do something with the response
})
.catch((error) => {
console.log(error)
});
export const handleResponse = (res) => {
if (!res.ok) {
return res
.text()
.then(result => JSON.parse(result))
.then(result => Promise.reject({ status: result.status, message: result.message }));
}
return res
.json()
.then(result => Promise.resolve(result))
.catch(() => Promise.resolve({ status: res.status, message: res.statusText }));
};
I just checked the status of the response object:
$promise.then( function successCallback(response) {
console.log(response);
if (response.status === 200) { ... }
});
Hope this helps for me throw Error is not working
function handleErrors(response) {
if (!response.ok) {
return new Promise((resolve, reject) => {
setTimeout(() => {
reject({
status: response.status,
statusText: response.statusText,
});
}, 0);
});
}
return response.json();
}
function clickHandler(event) {
const textInput = input.value;
let output;
fetch(`${URL}${encodeURI(textInput)}`)
.then(handleErrors)
.then((json) => {
output = json.contents.translated;
console.log(output);
outputDiv.innerHTML = "<p>" + output + "</p>";
})
.catch((error) => alert(error.statusText));
}
Another (shorter) version that resonates with most answers:
fetch(url)
.then(response => response.ok ? response.json() : Promise.reject(response))
.then(json => doStuff(json)) //all good
//next line is optional
.catch(response => handleError(response)) //handle error
For some reason this code fail to sign up on firebase,
app.post('/signup', (req, res) => {
const newUser = {
email: req.body.email,
password: req.body.password,
confirmPassword: req.body.confirmPassword,
handle: req.body.handle
}
let token, userId;
db.doc(`/users/${newUser.handle}`).get().then(doc => {
if (doc.exists) {
return res.status(400).json({ handle: 'this handle already exists' })
} else {
return firebase.auth().createUserWithEmailAndPassword(newUser.email, newUser.password)
}
})
.then(data => {
userId = data.user.uid;
return data.user.getIdToken();
})
.then(idToken => {
token = idToken;
const userCredentials = {
handle: newUser.handle,
email: newUser.email,
createdAt: new date().toISOString(),
userId
}
return db.doc(`/users/${newUser.handle}`).set(userCredentials)
})
.then(() => {
return res.status(201).json({ token });
})
.catch(err => {
if (err.code === "auth/email-already-in-use") {
return res.status(400).json({ email: 'Email is alrready in use' })
} else {
return res.status(500).json({ general: 'something went wrong, please try again' })
}
})
});
I always get { general: 'something went wrong, please try again' } , i am using postman to mimic the request to firebase,
This code works perfectly:
firebase.auth().createUserWithEmailAndPassword(newUser.email, newUser.password)
.then(data => {
return data.user.getIdToken();
})
.then(token => {
return res.status(201).json({token})
})
.catch(err => {
console.error(err);
return res.status(500).json({error: 'something went wrongly'})
})
The first trial is from a tutorial i am following in Youtube and sadly it doesn't work
On the backend, you can use Firebase Admin SDK to get details about any user but it does not have any ability to login on behalf of user.
My use case is fairly simple, i want to create a new user (username,email,password) but first check that the username/email doesn't exist already.
After checking, i use bcrypt to hash the password and create/store the user in my database
Here is the code i'm actually using, it works but i think it's a little too complicated so i'm wondering if there is anything i can do to make it a bit more readable/optimized
ipcMain.on('register', (e, newUser) => {
userRepo.findByUsername(newUser.username).then(
(user) => {
if (user)
e.sender.send('register-failed', "Username already exists!");
else {
userRepo.findByEmail(newUser.email).then(
(user) => {
if (user)
e.sender.send('register-failed', "Email already exists!");
else {
bcrypt.hash(newUser.password, saltRounds).then(
(hasedPassword) => {
newUser.password = hasedPassword;
userRepo.create(newUser).then(
(user) => {
e.sender.send('register-success', user.get({plain:true}));
},
(error) => {
e.sender.send('register-failed', "Unexpected Error");
}
)
}
)
}
}
)
}
},
(error) => { e.sender.send('register-failed', "Unexpected Error"); }
).catch(error => e.sender.send('register-failed', "Unexpected Error"));
});
userRepo module :
const db = require('../db.js');
const findByUsername = function (username) {
return db.models.User.findOne({
where: {
username: username
}
});
}
const findByEmail = function (email) {
return db.models.User.findOne({
where: {
email: email
}
});
}
const create = function (newUser) {
return db.models.User.create({
username: newUser.username,
email: newUser.email,
password: newUser.password
});
}
module.exports = { findByUsername, findByEmail, create }
Thanks for the help.
EDIT:
Here's a much more readable code (that may be optimized more, but i find it readable enough)
ipcMain.on('register', (e, newUser) => {
Promise.all([userRepo.isUsernameAvailable(newUser.username), userRepo.isEmailAvailable(newUser.email)])
.then(creation => {
bcrypt.hash(newUser.password, saltRounds).then(
(hashedPassword) => {
newUser.password = hashedPassword;
userRepo.create(newUser).then(
(user) => {
e.sender.send('register-success', user.get({ plain: true }));
}
).catch(error => e.sender.send('register-failed', "Unexpected internal error!"))
}
).catch(error => e.sender.send('register-failed', "Unexpected internal error!"));
}) // User already exists
.catch((exists) => e.sender.send('register-failed', exists))
})
Using the two functions to check availability of username and email
async function isUsernameAvailable(username){
const user = await findByUsername(username);
if(!user)
return Promise.resolve(`Username : "${username}" is available`)
return Promise.reject(`Username : "${username}" is already taken !`)
}
async function isEmailAvailable(email){
const user = await findByEmail(email);
if(!user)
return Promise.resolve(`Email : "${email}" is available`)
return Promise.reject(`Email : "${email}" is already taken !`)
}
You are first checking whether username exists and then checking whether email exists. However, both of them can be checked asynchronously using Promise.all.
If anyone of the username or email already exists then you can return an error message.
You have used a promise chain however code looks much cleaner and easy to read if you implement the same code using async-await.
Please refer the below blog for how to implement Promise.all using async-await.
https://www.taniarascia.com/promise-all-with-async-await/
I am trying to return a promise from dispatch so that I can do something like this in my react component
this.props.dispatch(requestLogin(data))
.then((res) => {
Navigate.toHome()
}).catch((err) => {
this.showErrorMessage()
})
currently I wrapped my fetch to reuse the common things i pass on the server API and to put some logs for debugging. I did it like this:
export const query = (path, opts) => {
// common config and boilerplates here
// e.g add device id to every api request
return fetch(opts.url, reqOpts)
.then((response) => {
console.log('response received')
if (response.ok) {
return response.json()
} else
console.log('response not ok')})
.then((respData) => {
if (respData.status === true) {
console.log('response success')
return respData
} else {
const errObj = respData
errObj.server = true
throw errObj
}
}).catch((err) => {
console.log('error catched')
if (err.server) {
throw err
}
throw { status: false, errors: { error_code: 'ERR_FATAL', error_msg: 'Something went wrong.' }, err }
})
then my action creator is like this:
export function requestLogin (data) {
return function (dispatch) {
const opts = {
method: 'POST',
body: data,
}
return query(Paths.OP_USR_LOGIN, opts)
.then((data) => {
data.TYPE = APP_LOGIN
dispatch(resultData)
},
(data2) => {
// the thrown error actually returns here
// this returned value goes to the .then of the dispatch
return data2
},
).catch((err) => {
// this is not executed
return err
})
}
}
whats happening is
this.props.dispatch(requestLogin(data))
.then((res) => {
// the error actually goes here
Navigate.toHome()
}
(err) => {
// not here
}).catch((err) => {
// or here
this.showErrorMessage()
})
First, it's important to understand that the second argument you give then(onFulfilled, onRejected), which is onRejected, is another syntax to catch, so because it's written before your catch in the action creator, you get to there when the query function throws an error. that is why the catch block isn't executed. (read about promise's then).
after you catch your error in onRejected, it returns a promise, which is not an error anymore(the promise's state is fulfilled and not rejected).
if you want the promise to get to the catch block, you should change your action creator:
return query(Paths.OP_USR_LOGIN, opts)
.then((data) => {
data.TYPE = APP_LOGIN
dispatch(resultData)
},
(data2) => {
// the thrown error actually returns here
// this returned value goes to the .then of the dispatch
return new Promise((resolve,reject) => {
reject(data2)
}
})
that will return a promise, which is rejected, so it will be caught by the catch block.
also, you can change the
return new Promise((resolve,reject) => {
reject(data2)
}
with
throw 'error'
or
Promise.reject(data2)
let me know if you need any further explanation.
When you doing:
query(Paths.OP_USR_LOGIN, opts)
.then((data) => {
data.TYPE = APP_LOGIN
dispatch(resultData)
},
(data2) => {
// the thrown error actually returns here
// this returned value goes to the .then of the dispatch
return data2
})
.catch((err) => {
// this is not executed
return err
})
It's actually, you do catch the error of query function already, then you return data2. It means you want to return a Promise success (resolve) with data2. The same thing happen with catch.
To fix it, you just need to remove the (data2) => {} and the catch block.
query(Paths.OP_USR_LOGIN, opts)
.then((data) => {
data.TYPE = APP_LOGIN
dispatch(resultData)
})
The second way, in case you still want to do something with the error before, you need to return Promise.reject:
query(Paths.OP_USR_LOGIN, opts)
.then((data) => {
data.TYPE = APP_LOGIN
dispatch(resultData)
})
.catch((err) => {
// you can do something with error, and still return a promise.reject here
console.log('I found an error here', err)
return Promise.reject(err)
})
I'm very bad when it comes to thinking of a title question, sorry for that.
My Problem:
I'm unit testing my async redux actions like it's suggested in the docs. I mock the API calls with nock and check for the dispatched actions with redux-mock-store. It works great so far, but I have one test that fails even though it clearly does work. The dispatched action neither does show up in the array returned by store.getActions() nor is the state changed in store.getState(). I'm sure that it does happen because I can see it when I test manually and observe it with Redux Dev Tools.
The only thing that is different in this action dispatch is that it is called in a promise in a catch of another promise. (I know that sounds confusing, just look at the code!)
What my code looks like:
The action:
export const login = (email, password) => {
return dispatch => {
dispatch(requestSession());
return httpPost(sessionUrl, {
session: {
email,
password
}
})
.then(data => {
dispatch(setUser(data.user));
dispatch(push('/admin'));
})
.catch(error => {
error.response.json()
.then(data => {
dispatch(setError(data.error))
})
});
};
}
This httpPost method is just a wrapper around fetch that throws if the status code is not in the 200-299 range and already parses the json to an object if it doesn't fail. I can add it here if it seems relevant, but I don't want to make this longer then it already is.
The action that doesn't show up is dispatch(setError(data.error)).
The test:
it('should create a SET_SESSION_ERROR action', () => {
nock(/example\.com/)
.post(sessionPath, {
session: {
email: fakeUser.email,
password: ''
}
})
.reply(422, {
error: "Invalid email or password"
})
const store = mockStore({
session: {
isFetching: false,
user: null,
error: null
}
});
return store.dispatch(actions.login(
fakeUser.email,
""))
.then(() => {
expect(store.getActions()).toInclude({
type: 'SET_SESSION_ERROR',
error: 'Invalid email or password'
})
})
});
Thanks for even reading.
Edit:
The setErroraction:
const setError = (error) => ({
type: 'SET_SESSION_ERROR',
error,
});
The httpPostmethod:
export const httpPost = (url, data) => (
fetch(url, {
method: 'POST',
headers: createHeaders(),
body: JSON.stringify(data),
})
.then(checkStatus)
.then(response => response.json())
);
const checkStatus = (response) => {
if (response.status >= 200 && response.status < 300) {
return response;
}
const error = new Error(response.statusText);
error.response = response;
throw error;
};
Because of you are using nested async function in catch method - you need to return the promise:
.catch(error => {
return error.response.json()
.then(data => {
dispatch(setError(data.error))
})
});
Otherwise, dispatch will be called after your assertion.
See primitive examples:
https://jsfiddle.net/d5fynntw/ - Without returning
https://jsfiddle.net/9b1z73xs/ - With returning