I am trying to make a get route for this API:
https://api.nasa.gov/mars-photos/api/v1/rovers/opportunity/photos?sol=1000&api_key=92Ll6nGuQhfGjZnT2gxaUgiBhlCJ9K1zi2Fv5ONn
And although the syntax for the get route, the API still doesn't work in postman nor in client-side.
Here's the get route code:
app.get('/roverInfo/:rover_name', async (req, res) => {
const { rover_name } = req.params
try {
let images = await fetch(`https://api.nasa.gov/mars-photos/api/v1/rovers/${rover_name}/photos?sol=1000&api_key=${process.env.API_KEY}`).then((res) => res.json())
res.send({ images })
} catch (err) {
console.log('error:', err)
}
})
sandbox here
and here's the client-side request:
const showRovers = async (rovers) => {
try {
await fetch(`https://localhost:3000/roverInfo/:rover_name`)
.then((res) => {
return res.json()
})
.then((rovers) => updateStore(store, { rovers }), console.log(rovers))
} catch (error) {
console.log('errors:', error)
}
}
and here's the error I am getting:
Failed to load resource: net::ERR_SSL_PROTOCOL_ERROR
ADVISE: Don't mix await/async with .then, use either one
app.get("/roverInfo/:rover_name", async (req, res) => {
const { rover_name } = req.params;
try {
const res = await fetch(
`https://api.nasa.gov/mars-photos/api/v1/rovers/${rover_name}/photos?sol=1000&api_key=${process.env.API_KEY}`
) // removed .then
const images = await res.json(); // await response to json
res.send({ images });
} catch (err) {
console.log("error:", err);
}
});
02. should be http instead of https
03. need to pass rover name to param instead of using :rover_name
let getRovers = showRovers('opportunity');
const showRovers = async (roverName) => {
try {
console.log("roverName", roverName)
// use http here
await fetch(`http://localhost:3000/roverInfo/${roverName}`)
.then((res) => {
return res.json();
})
.then((rovers) => updateStore(store, { rovers }));
} catch (error) {
console.log("errors:", error);
}
};
Here's what I have going:
import 'whatwg-fetch';
function fetchVehicle(id) {
return dispatch => {
return dispatch({
type: 'FETCH_VEHICLE',
payload: fetch(`http://swapi.co/api/vehicles/${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}${encodeURI(textInput)}`)
.then(handleErrors)
.then((json) => {
output = json.contents.translated;
console.log(output);
outputDiv.innerHTML = "<p>" + output + "</p>";
})
.catch((error) => alert(error.statusText));
}
Another (shorter) version that resonates with most answers:
fetch(url)
.then(response => response.ok ? response.json() : Promise.reject(response))
.then(json => doStuff(json)) //all good
//next line is optional
.catch(response => handleError(response)) //handle error
I am using jumbo 4.1.1 template. I get the response, but this error occurs.
My code is below:
authAction.js:
...
export const userSignIn = (user) => {
// const {email, password} = user;
console.log(user)
axios.post(base_url +'login', user)
.then(response=> {
console.log(response.data)
return {
type: SIGNIN_USER,
payload: user
};
})
};
But when I run the project, I got the error TypeError: Cannot read property 'type' of undefined
I believe that is because you have not dispatched the action properly.
Are you using thunk?
If you are using Redux and making an async call, you should return dispatch.
const userSignup = (signupData) => {
return async (dispatch) => {
try {
let res = await axios.post(`${url}/user/`, { user: signupData });
dispatch({
type: "FETCH_CURRENT_USER_SUCCESS",
payload: res.data.user,
});
return true;
} catch (error) {
console.log(
"%c CATCH in userSignup ",
"background: red; color: #bada55",
error
);
}
};
};
Notice, that I am returning a function with dispatch as an argument in the second line. and then using that dispatch (4th line) that dispatches the action's type and payload.
Also I'm returning something from the function userSignUp, finally, so the invoker of the function userSignUp gets something in response.
If you don't understand anything above, please do let me know.
You could benefit from using async + await here.
For example:
export const userSignIn = async (user) => {
try {
// const {email, password} = user;
console.log(user);
const data = await axios.post(base_url +'login', user);
console.log(data);
return {
type: SIGNIN_USER,
payload: user,
};
} catch (error) {
console.log(error);
// return an error action...?
return {
type: ERROR,
payload: error,
};
}
};
I have this code that invokes a function and has a callback with error and data parameters:
app.get('/lights', (req,res) => {
hue.getLights(function(err, data){
if(err) res.status(401).send("An error occured: ", err.message);
res.send(data);
});
})
The function that it invokes is:
let getLights = function(callback){
fetch(`http://${gateway}/api/${username}/lights`, {
method: 'GET'
}).then((res) => {
if(res.ok){
return res.json();
}else{
throw new Error(res.message);
}
}).then((json) => {
lightsArray = []
for (var i in json){
lightsArray.push(`ID: ${i} Name: ${json[i]['name']}`);
}
return callback(lightsArray);
});
}
When I make an error occur, the error isn't caught, nor is any error displayed, the app crashes with the message: UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch().
Now I know I'm missing a lot, this is my first time using callbacks, let alone handling errors.
Could someone help me with making the error callback work, also show me some flaws in what I'm doing, as I know this won't catch every error that may happen, only errors caused by using the fetch function.
Thanks!
This is my other function (similar but uses a catch aswell, which I think I have done incorrectly too):
let getLightDetails = function (ID, callback) {
fetch(`http://${gateway}/api/${username}/lights/${ID}`, {
method: 'GET'
}).then((res) => {
if(res.ok){
return res.json();
}else{
throw new Error(res.message);
}
}).then((json) => {
return callback(json);
})
.catch((err) => {
console.log(err);
return callback(err.message);
});
}
Mixing callbacks and promises can make your code a bit messy. I would stick to promises:
app.get('/lights', (req, res) => {
return hue.getLights()
.then(data => {
res.send(data);
})
.catch(err => {
res.status(401).send("An error occured: ", err.message);
});
})
and hue.js
const fetch = require('node-fetch');
const gateway = "192.168.0.12";
const username = "username-A";
function fetchAPI(url, ...rest) {
return fetch(`http://${gateway}/api/${username}${url}`, ...rest);
}
function getLights() {
return fetchAPI(`/lights`)
.then(res => res.json())
.then(json => json.map((light, i) => `ID: ${i} Name: ${light.name}`));
}
function getLightDetails(id) {
return fetchAPI(`/lights/${id}`)
.then(res => res.json());
}
function getLightState(id) {
return fetchAPI(`/lights/${id}`)
.then(res => res.json())
.then(light => `Name: ${light.name} On: ${light.state.on}`);
}
function setLightState(id, state) {
return fetchAPI(`/lights/${id}/state`, {
method: 'PUT',
body: JSON.stringify({"on": state })
}).then(res => res.json());
}
module.exports = { getLights, getLightDetails, getLightState, setLightState };
I've been battling with an issue concerning Async/Await, I'm relatively new to Nodejs. I have a repository where I connect directly to my mongodb collection to retrieve some data it but when I connect my controller to this repository, I get a nulled response.
Please checkout my code below:-
SyncRepository.js
const mongoose = require('mongoose');
exports.ItemRepo = async (limit) => {
try {
await mongoose.connection.db.collection('items_1087342')
.find({}, {timeout: false}).limit(limit).toArray((err, results) => {
// results.forEach(e => {
// console.log(e.item_id);
// }); //This works well
return results;
});
} catch (e) {
throw Error('Error Loading Data:- ' + e.message);
}
};
SyncController.js
const syncRepo = require('../../../Repositories/Sync/SyncRepository');
exports.getItem = async (req, res) => {
try {
await syncRepo.ItemRepo(7)
.then(element => {
console.log(element);
return res.json(element); //This return null
});
// return await res.json(await syncRepo.ItemRepo(7));
} catch (e) {
return res.status(400).json({ status: 400, message: e.message });
}
};
You are mixing async/await and traditional Promise syntax. Try this :
SyncRepository.js
const mongoose = require('mongoose');
exports.ItemRepo = limit => {
return mongoose.connection.db.collection('items_1087342')
.find({}, {timeout: false})
.limit(limit)
.exec() // see #Enslev's explanation in the comments
};
SyncController.js
const syncRepo = require('../../../Repositories/Sync/SyncRepository');
exports.getItem = async (req, res) => {
try {
let element = await syncRepo.ItemRepo(7)
return res.json(element);
} catch (e) {
return res.status(400).json({ status: 400, message: e.message });
}
};