I want to make a request to my server with fetch(), and have data returned to be used in the front end app.
here is my route:
app.get('/game-data', (req, res) => {
res.json({ data: "test-data" })
})
and here is my request:
button.addEventListener('click', () => {
fetch('/game-data', {
headers: {
'accept': 'application / json',
'Content-Type': 'application/json'
}
})
.then(response => {
console.log(response)
response.json()
})
.then(myJson => {
console.log(myJson)
})
})
I can see the response object in the first console log, but response.json(), or response.text() are returning undefined.
Please help me see what I am missing!
You need to return the value to use it in another .then
.then(response => {
console.log(response)
return response.json()
})
Related
I'm trying to doing a basic GET request from ReactJS app to a Node.js API, but I'm getting a response with status 304. I need get a 200 status to save the response of GET in a variable. (Im running Reactjs app in port 3000 and Nodejs API in port 3300)
Node API:
app.get('/serviciosextras', async (req, res) => {
let connection;
console.log(('Servicios Extras'));
try {
connection = await oracledb.getConnection({
user: 'portafolio',
password: '123',
connectString: "localhost:1521/orcl"
});
const result = await connection.execute(
`SELECT dep.id_departamento,
se.id_servicio,
se.precio_servicio
FROM departamento_servicio_detalle dsd
JOIN departamento DEP ON (dsd.id_departamento = dep.id_departamento)
JOIN servicio_extra SE ON (dsd.id_servicio = se.id_servicio)
ORDER BY 1 ASC`
)
const resultSet = result.rows;
let lista = [];
resultSet.map(obj => {
let serviciosSchema = {
'id_departamento': obj[0],
'id_servicio': obj[1],
'precio_servicio': obj[2]
}
lista.push(serviciosSchema);
});
console.log(lista);
res.json(lista);
connection.close();
} catch (err) {
console.error(err);
}
});
GET request from Reactjs
const getExtraServices = () => {
let endpoint = `${URL}serviciosextras`;
const requestOptions = {
method: "GET",
mode: 'no-cors'
// headers: {
// "Content-Type": "application/json",
// Accept: "application/json"
// },
};
console.log(endpoint);
fetch(endpoint, requestOptions)
.then((res, err) => {
console.log(res);
})
.then(result => {
console.log('fue aqui');
console.log(result);
})
.catch(err => {
console.log('ERROR');
console.log(err);
})
}
Im calling the method from this button:(onClick={getExtraServices()})
<Fab onClick={(e) => {
e.preventDefault();
getExtraServices();
}} variant="extended">
<NavigationIcon style={{marginRight: 'theme.spacing(1)'}} />
Navigate
</Fab>
so... I'm getting this:
Firefox Console when I clicked button to call getExtraServices() res is undefined
Network console of GET request I got a response but the status is 304, so I can't get this from code. :/
Console of Nodejs API this console.log if from console.log(lista) before send the res.json(lista)
Does someone know how can I fix this? I need get the response of the GET request to charge a list in ReactJS app, but I can't because the response has body:null.
Error 304 isn't the problem.
It looks like you are missing a statement to turn your response into JSON.
Here's an example from MDN:
fetch('https://example.com/profile', {
method: 'POST', // or 'PUT'
headers: {
'Content-Type': 'application/json',
},
body: JSON.stringify(data),
})
.then(response => response.json())
.then(data => {
console.log('Success:', data);
})
.catch((error) => {
console.error('Error:', error);
});
In particular:
.then(response => response.json())
In your code:
fetch(endpoint, requestOptions)
.then((res, err) => {
console.log(res); // logging res
// no data being returned here
})
.then(result => {
console.log('fue aqui');
console.log(result); // therefore result is undefined
})
.catch(err => {
console.log('ERROR');
console.log(err);
})
If I make a request on client side using the code below
public/foo.js
function bar() {
fetch('https://api.github.com/')
.then(response => response.json())
.then(data => {
console.log(data)
})
.catch(error => console.error(error))
}
how can I send the data variable to node backend?
/app.js
app.get("/", cors(), (request, response) => {
response.render('index.html');
})
It is my understanding that you are trying to fetch data from the URL that is not handled by your server-side on your client-side and send that data back to your own server-side.
On your server-side, create a new POST method:
app.post("/example", cors(), (request, response) => {
let body = request.body;
response.json(body);
})
On your client-side, send a new POST request:
function postExample(data) {
return fetch(`http://localhost:YOURPORT/example`, {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify(data)
});
}
Replace YOURPORT with your server's port. And make a call to the postExample:
function bar() {
fetch('https://api.github.com/')
.then(response => response.json())
.then(data => {
postExample(data).then(res => res.json())
.then(console.log(res));
})
.catch(error => console.error(error))
}
I want to display error message from my API, problem is that I can't reach that error if I check for response.ok, it returns Fetch error, not the one from API..
If I don't use if(response.ok)... it returns the error from API but it dispatches the success action.
Here is the example, login action:
export const signIn = data => dispatch => {
dispatch({
type: SIGN_IN
})
fetch(API_URL+'/login', {
method: 'POST',
headers: {
'content-type': 'application/json'
},
body: JSON.stringify(data),
})
.then( response => {
if (!response.ok) { throw response }
return response.json() //we only get here if there is no error
})
.then( json => {
dispatch({
type: SIGN_IN_SUCCESS, payload: json
}),
localStorage.setItem("token", 'Bearer '+json.token)
localStorage.setItem("user", JSON.stringify(json.user))
})
.catch( err => {
dispatch({
type: SIGN_IN_FAILED, payload: err
})
})
}
This is the code for action that dispatches the right message but as success action, not as failed one..
export const signIn = data => dispatch => {
dispatch({
type: SIGN_IN
})
fetch(API_URL+'/login', {
method: 'POST',
headers: {
'content-type': 'application/json'
},
body: JSON.stringify(data),
})
.then( response => response.json())
.then( json => {
dispatch({
type: SIGN_IN_SUCCESS, payload: json
}),
localStorage.setItem("token", 'Bearer '+json.token)
localStorage.setItem("user", JSON.stringify(json.user))
})
.catch( err => {
dispatch({
type: SIGN_IN_FAILED, payload: err
})
})
}
With the following solution one can handle JSON API error, Generic API error and Generic fetch error
fetch("api/v1/demo", {
method: "POST",
headers: {
"Content-Type": "application/json"
},
body: JSON.stringify({
"data": "demo"
})
})
.then(response => {
if (!response.ok) {
return Promise.reject(response);
}
return response.json();
})
.then(data => {
console.log("Success");
console.log(data);
})
.catch(error => {
if (typeof error.json === "function") {
error.json().then(jsonError => {
console.log("Json error from API");
console.log(jsonError);
}).catch(genericError => {
console.log("Generic error from API");
console.log(error.statusText);
});
} else {
console.log("Fetch error");
console.log(error);
}
});
according to This Article :
Per MDN, the fetch() API only rejects a promise when
“a network
error is encountered, although this usually means permissions issues
or similar.”
Basically fetch() will only reject a promise if the user
is offline, or some unlikely networking error occurs, such a DNS
lookup failure.
then, you can use this part of code to use non-network error handlings and make your code more readable
function handleErrors(response) {
if (!response.ok) throw new Error(response.status);
return response;
}
fetch("API URL")
// handle network err/success
.then(handleErrors)
// use response of network on fetch Promise resolve
.then(response => console.log("ok") )
// handle fetch Promise error
.catch(error => console.log(error) );
In order to extract API message from server in case of some error, you have to use the following idiom (which doesn't lie on the surface though), see link
fetch("http://localhost:8090/test/error", {
method: 'GET',
headers: {
'Accept': 'application/json'
}
})
.then(result => {
//Here body is not ready yet, throw promise
if (!result.ok) throw result;
return result.json();
})
.then(result => {
//Successful request processing
console.log(result);
}).catch(error => {
//Here is still promise
console.log(error);
error.json().then((body) => {
//Here is already the payload from API
console.log(body);
});
})
Verbose - yes!, but does exactly what is needed.
I have to set an header in api call. My POST API calls are working fine. But in my get api calls, header is not getting set.
return fetch('http://api-call.com', {
method: 'GET',
headers: {
Accept: 'application/json',
'Content-Type': 'application/json',
'custom-security':'XXXX',
'Purchase-Code':'XXXXXXX',
'Content-Type':'application/json',
'Cache-Control':'max-age=640000'
}
})
.then((response) => response.json())
.then((responseJson) => {
console.log(responseJson);
})
.catch((error) => {
console.error(error);
});
You should setup a Request object and pass your headers wrapped into a Headers object, like:
var request = new Request('http://api-call.com', {
method: 'GET',
headers: new Headers({
'Accept': 'application/json',
'custom-security':'XXXX',
'Purchase-Code':'XXXXXXX',
'Content-Type':'application/json',
'Cache-Control':'max-age=640000'
})
});
Then just invoke fetch with your request as parameter:
fetch(request)
.then((response) => response.json())
.then((responseJson) => {
console.log(responseJson);
})
.catch((error) => {
console.error(error);
});
Check reference
2021 answer: just in case you land here looking for how to make GET and POST Fetch api requests using async/await or promises as compared to axios.
I'm using jsonplaceholder fake API to demonstrate:
Fetch api GET request using async/await:
const asyncGetCall = async () => {
try {
const response = await fetch('https://jsonplaceholder.typicode.com/posts');
const data = await response.json();
// enter you logic when the fetch is successful
console.log(data);
} catch(error) {
// enter your logic for when there is an error (ex. error toast)
console.log(error)
}
}
asyncGetCall()
Fetch api POST request using async/await:
const asyncPostCall = async () => {
try {
const response = await fetch('https://jsonplaceholder.typicode.com/posts', {
method: 'POST',
headers: {
'Content-Type': 'application/json'
},
body: JSON.stringify({
// your expected POST request payload goes here
title: "My post title",
body: "My post content."
})
});
const data = await response.json();
// enter you logic when the fetch is successful
console.log(data);
} catch(error) {
// enter your logic for when there is an error (ex. error toast)
console.log(error)
}
}
asyncPostCall()
GET request using Promises:
fetch('https://jsonplaceholder.typicode.com/posts')
.then(res => res.json())
.then(data => {
// enter you logic when the fetch is successful
console.log(data)
})
.catch(error => {
// enter your logic for when there is an error (ex. error toast)
console.log(error)
})
POST request using Promises:
fetch('https://jsonplaceholder.typicode.com/posts', {
method: 'POST',
headers: {
'Content-Type': 'application/json',
},
body: JSON.stringify({
// your expected POST request payload goes here
title: "My post title",
body: "My post content."
})
})
.then(res => res.json())
.then(data => {
// enter you logic when the fetch is successful
console.log(data)
})
.catch(error => {
// enter your logic for when there is an error (ex. error toast)
console.log(error)
})
GET request using Axios:
const axiosGetCall = async () => {
try {
const { data } = await axios.get('https://jsonplaceholder.typicode.com/posts')
// enter you logic when the fetch is successful
console.log(`data: `, data)
} catch (error) {
// enter your logic for when there is an error (ex. error toast)
console.log(`error: `, error)
}
}
axiosGetCall()
Authenticated POST request using Axios:
const axiosPostCall = async () => {
try {
const { data } = await axios.post('https://jsonplaceholder.typicode.com/posts', {
// your expected POST request payload goes here
title: "My post title",
body: "My post content."
},{
headers: {
Authorization:
`Bearer ${token}`
}
})
// enter you logic when the fetch is successful
console.log(`data: `, data)
} catch (error) {
// enter your logic for when there is an error (ex. error toast)
console.log(`error: `, error)
}
}
axiosPostCall()
In my application, I have a simple fetch for retrieving a list of users which sends over an authentication token to an API
fetch("/users", {
method: "POST",
headers: {
Accept: "application/json",
"Content-Type": "application/json",
},
body: JSON.stringify({
token: this.props.getUser().token
})
})
.then(res => res.json())
.then(users => this.setState({ users }))
.catch(err => {
console.error(err);
});
However, the API may return a 401 error if the token is expired.
How do I handle it properly in the fetch so that the state is only set when the response is succesful?
A cleaner way to handle success/error of a fetch response would be to use the Response#ok readonly property
https://developer.mozilla.org/en-US/docs/Web/API/Response/ok
fetch('/users').then((response) => {
if (response.ok) {
return response.json();
}
throw response;
}).then((users) => {
this.setState({
users
});
}).catch((error) => {
// whatever
})
res inside callback function in your first .then function contains a key called status which holds the request status code.
const url = 'https://api.myjson.com/bins/s41un';
fetch(url).then((res) => {
console.log('status code:', res.status); // heres the response status code
if (res.status === 200) {
return res.json(); // request successful (status code 200)
}
return Promise.reject(new Error('token expired!')); // status code different than 200
}).then((response) => console.log(response));