I need help because I couldn't use a separate function to generate the token - it gives out a promise, not a value. I was told that a value can only be used inside a function.
For each request, I generate a new token in the first request and then pass that token into the second request.
I tried making a separate function to generate the token, but fetch returns a promise.
As a result, I made such a big function and it works.
Is there a way to make a separate function for the first request and pass the result to the second request?
The first token generation function is required frequently, while the second request is always different.
fetch('/api/token', {
method: 'POST',
headers: {
Accept: 'application/json',
'Content-Type': 'application/json',
},
body: JSON.stringify({ 'id': '5' }),
})
.then(response => response.json())
.then(result => {
fetch('/api/reviews', {
method: 'POST',
headers: {
Accept: 'application/json',
'Content-Type': 'application/json',
'Authorization': 'Bearer ' + result.token,
},
body: JSON.stringify({ 'limit': 10 }),
})
.then(response => response.json())
.then(result => {
this.setState({ data: result.data });
})
})
create a function that return promise
async function getToken() {
return await fetch('/api/token', {
method: 'POST',
headers: {
Accept: 'application/json',
'Content-Type': 'application/json',
},
body: JSON.stringify({ 'id': '5' }),
})
.then(response => response.json())
.then(result => {
return Promise.resolve(result.token);
}).catch(error => {
return Promise.reject(error);
})
}
async function getReview() {
const token = await getToken().then(token => {
return token
}).catch(error => {
//handle error
});
fetch('/api/reviews', {
method: 'POST',
headers: {
Accept: 'application/json',
'Content-Type': 'application/json',
'Authorization': 'Bearer ' + token,
},
body: JSON.stringify({ 'limit': 10 }),
})
.then(response => response.json())
.then(result => {
this.setState({ data: result.data });
})
}
i did not test this code but you get the idea
i will test and update my answer asap
Yes you can with async / await. It will allow you to lift the lexical scope of the API response from inside the .then "callback hell" and into the parent function scope.
Your separate function which fetches the token will return a promise, but then the requesting function will wait for the promise to execute and resolve before continuing.
async function fetchToken() {
const response = await fetch('/api/token', {
method: 'POST',
headers: {
Accept: 'application/json',
'Content-Type': 'application/json',
},
body: JSON.stringify({ 'id': '5' }),
})
return await response.json();
}
async function getReviews() {
const response = await fetch('/api/reviews', {
method: 'POST',
headers: {
Accept: 'application/json',
'Content-Type': 'application/json',
'Authorization': 'Bearer ' + result.token,
},
body: JSON.stringify({ 'limit': 10 }),
})
const result = await response.json();
this.setState({ data: result.data });
}
Additionally, if the token call does not need to be made every time the reviews call is made, then you can memoize the value, and use that memoized value.
const tokenMemo = useMemo(async () => await getToken(), []);
async function getReviews() {
const response = await fetch('/api/reviews', {
// ...
'Authorization': 'Bearer ' + tokenMemo,
// ...
}
I'm trying to POST a JSON object using fetch.
From what I can understand, I need to attach a stringified object to the body of the request, e.g.:
fetch("/echo/json/",
{
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json'
},
method: "POST",
body: JSON.stringify({a: 1, b: 2})
})
.then(function(res){ console.log(res) })
.catch(function(res){ console.log(res) })
When using jsfiddle's JSON echo I'd expect to see the object I've sent ({a: 1, b: 2}) back, but this does not happen - chrome devtools doesn't even show the JSON as part of the request, which means that it's not being sent.
With ES2017 async/await support, this is how to POST a JSON payload:
(async () => {
const rawResponse = await fetch('https://httpbin.org/post', {
method: 'POST',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json'
},
body: JSON.stringify({a: 1, b: 'Textual content'})
});
const content = await rawResponse.json();
console.log(content);
})();
Can't use ES2017? See #vp_art's answer using promises
The question however is asking for an issue caused by a long since fixed chrome bug.
Original answer follows.
chrome devtools doesn't even show the JSON as part of the request
This is the real issue here, and it's a bug with chrome devtools, fixed in Chrome 46.
That code works fine - it is POSTing the JSON correctly, it just cannot be seen.
I'd expect to see the object I've sent back
that's not working because that is not the correct format for JSfiddle's echo.
The correct code is:
var payload = {
a: 1,
b: 2
};
var data = new FormData();
data.append( "json", JSON.stringify( payload ) );
fetch("/echo/json/",
{
method: "POST",
body: data
})
.then(function(res){ return res.json(); })
.then(function(data){ alert( JSON.stringify( data ) ) })
For endpoints accepting JSON payloads, the original code is correct
I think your issue is jsfiddle can process form-urlencoded request only. But correct way to make json request is pass correct json as a body:
fetch('https://httpbin.org/post', {
method: 'POST',
headers: {
'Accept': 'application/json, text/plain, */*',
'Content-Type': 'application/json'
},
body: JSON.stringify({a: 7, str: 'Some string: &=&'})
}).then(res => res.json())
.then(res => console.log(res));
From search engines, I ended up on this topic for non-json posting data with fetch, so thought I would add this.
For non-json you don't have to use form data. You can simply set the Content-Type header to application/x-www-form-urlencoded and use a string:
fetch('url here', {
method: 'POST',
headers: {'Content-Type':'application/x-www-form-urlencoded'}, // this line is important, if this content-type is not set it wont work
body: 'foo=bar&blah=1'
});
An alternative way to build that body string, rather then typing it out as I did above, is to use libraries. For instance the stringify function from query-string or qs packages. So using this it would look like:
import queryString from 'query-string'; // import the queryString class
fetch('url here', {
method: 'POST',
headers: {'Content-Type':'application/x-www-form-urlencoded'}, // this line is important, if this content-type is not set it wont work
body: queryString.stringify({for:'bar', blah:1}) //use the stringify object of the queryString class
});
After spending some times, reverse engineering jsFiddle, trying to generate payload - there is an effect.
Please take eye (care) on line return response.json(); where response is not a response - it is promise.
var json = {
json: JSON.stringify({
a: 1,
b: 2
}),
delay: 3
};
fetch('/echo/json/', {
method: 'post',
headers: {
'Accept': 'application/json, text/plain, */*',
'Content-Type': 'application/json'
},
body: 'json=' + encodeURIComponent(JSON.stringify(json.json)) + '&delay=' + json.delay
})
.then(function (response) {
return response.json();
})
.then(function (result) {
alert(result);
})
.catch (function (error) {
console.log('Request failed', error);
});
jsFiddle: http://jsfiddle.net/egxt6cpz/46/ && Firefox > 39 && Chrome > 42
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()
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."
})
// 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()
I have created a thin wrapper around fetch() with many improvements if you are using a purely json REST API:
// Small library to improve on fetch() usage
const api = function(method, url, data, headers = {}){
return fetch(url, {
method: method.toUpperCase(),
body: JSON.stringify(data), // send it as stringified json
credentials: api.credentials, // to keep the session on the request
headers: Object.assign({}, api.headers, headers) // extend the headers
}).then(res => res.ok ? res.json() : Promise.reject(res));
};
// Defaults that can be globally overwritten
api.credentials = 'include';
api.headers = {
'csrf-token': window.csrf || '', // only if globally set, otherwise ignored
'Accept': 'application/json', // receive json
'Content-Type': 'application/json' // send json
};
// Convenient methods
['get', 'post', 'put', 'delete'].forEach(method => {
api[method] = api.bind(null, method);
});
To use it you have the variable api and 4 methods:
api.get('/todo').then(all => { /* ... */ });
And within an async function:
const all = await api.get('/todo');
// ...
Example with jQuery:
$('.like').on('click', async e => {
const id = 123; // Get it however it is better suited
await api.put(`/like/${id}`, { like: true });
// Whatever:
$(e.target).addClass('active dislike').removeClass('like');
});
Had the same issue - no body was sent from a client to a server.
Adding Content-Type header solved it for me:
var headers = new Headers();
headers.append('Accept', 'application/json'); // This one is enough for GET requests
headers.append('Content-Type', 'application/json'); // This one sends body
return fetch('/some/endpoint', {
method: 'POST',
mode: 'same-origin',
credentials: 'include',
redirect: 'follow',
headers: headers,
body: JSON.stringify({
name: 'John',
surname: 'Doe'
}),
}).then(resp => {
...
}).catch(err => {
...
})
This is related to Content-Type. As you might have noticed from other discussions and answers to this question some people were able to solve it by setting Content-Type: 'application/json'. Unfortunately in my case it didn't work, my POST request was still empty on the server side.
However, if you try with jQuery's $.post() and it's working, the reason is probably because of jQuery using Content-Type: 'x-www-form-urlencoded' instead of application/json.
data = Object.keys(data).map(key => encodeURIComponent(key) + '=' + encodeURIComponent(data[key])).join('&')
fetch('/api/', {
method: 'post',
credentials: "include",
body: data,
headers: {'Content-Type': 'application/x-www-form-urlencoded'}
})
The top answer doesn't work for PHP7, because it has wrong encoding, but I could figure the right encoding out with the other answers. This code also sends authentication cookies, which you probably want when dealing with e.g. PHP forums:
julia = function(juliacode) {
fetch('julia.php', {
method: "POST",
credentials: "include", // send cookies
headers: {
'Accept': 'application/json, text/plain, */*',
//'Content-Type': 'application/json'
"Content-Type": "application/x-www-form-urlencoded; charset=UTF-8" // otherwise $_POST is empty
},
body: "juliacode=" + encodeURIComponent(juliacode)
})
.then(function(response) {
return response.json(); // .text();
})
.then(function(myJson) {
console.log(myJson);
});
}
It might be useful to somebody:
I was having the issue that formdata was not being sent for my request
In my case it was a combination of following headers that were also causing the issue and the wrong Content-Type.
So I was sending these two headers with the request and it wasn't sending the formdata when I removed the headers that worked.
"X-Prototype-Version" : "1.6.1",
"X-Requested-With" : "XMLHttpRequest"
Also as other answers suggest that the Content-Type header needs to be correct.
For my request the correct Content-Type header was:
"Content-Type": "application/x-www-form-urlencoded; charset=UTF-8"
So bottom line if your formdata is not being attached to the Request then it could potentially be your headers. Try bringing your headers to a minimum and then try adding them one by one to see if your problem is resolved.
If your JSON payload contains arrays and nested objects, I would use URLSearchParams and jQuery's param() method.
fetch('/somewhere', {
method: 'POST',
body: new URLSearchParams($.param(payload))
})
To your server, this will look like a standard HTML <form> being POSTed.
You could do it even better with await/async.
The parameters of http request:
const _url = 'https://jsonplaceholder.typicode.com/posts';
let _body = JSON.stringify({
title: 'foo',
body: 'bar',
userId: 1,
});
const _headers = {
'Content-type': 'application/json; charset=UTF-8',
};
const _options = { method: 'POST', headers: _headers, body: _body };
With clean async/await syntax:
const response = await fetch(_url, _options);
if (response.status >= 200 && response.status <= 204) {
let data = await response.json();
console.log(data);
} else {
console.log(`something wrong, the server code: ${response.status}`);
}
With old fashion fetch().then().then():
fetch(_url, _options)
.then((res) => res.json())
.then((json) => console.log(json));
**//POST a request**
const createTodo = async (todo) => {
let options = {
method: "POST",
headers: {
"Content-Type":"application/json",
},
body: JSON.stringify(todo)
}
let p = await fetch("https://jsonplaceholder.typicode.com/posts", options);
let response = await p.json();
return response;
}
**//GET request**
const getTodo = async (id) => {
let response = await fetch('https://jsonplaceholder.typicode.com/posts/' + id);
let r = await response.json();
return r;
}
const mainFunc = async () => {
let todo = {
title: "milan7",
body: "dai7",
userID: 101
}
let todor = await createTodo(todo);
console.log(todor);
console.log(await getTodo(5));
}
mainFunc()
I think that, we don't need parse the JSON object into a string, if the remote server accepts json into they request, just run:
const request = await fetch ('/echo/json', {
headers: {
'Content-type': 'application/json'
},
method: 'POST',
body: { a: 1, b: 2 }
});
Such as the curl request
curl -v -X POST -H 'Content-Type: application/json' -d '#data.json' '/echo/json'
In case to the remote serve not accept a json file as the body, just send a dataForm:
const data = new FormData ();
data.append ('a', 1);
data.append ('b', 2);
const request = await fetch ('/echo/form', {
headers: {
'Content-type': 'application/x-www-form-urlencoded'
},
method: 'POST',
body: data
});
Such as the curl request
curl -v -X POST -H 'Content-type: application/x-www-form-urlencoded' -d '#data.txt' '/echo/form'
You only need to check if response is ok coz the call not returning anything.
var json = {
json: JSON.stringify({
a: 1,
b: 2
}),
delay: 3
};
fetch('/echo/json/', {
method: 'post',
headers: {
'Accept': 'application/json, text/plain, */*',
'Content-Type': 'application/json'
},
body: 'json=' + encodeURIComponent(JSON.stringify(json.json)) + '&delay=' + json.delay
})
.then((response) => {if(response.ok){alert("the call works ok")}})
.catch (function (error) {
console.log('Request failed', error);
});
// extend FormData for direct use of js objects
Object.defineProperties(FormData.prototype, {
load: {
value: function (d) {
for (var v in d) {
this.append(v, typeof d[v] === 'string' ? d[v] : JSON.stringify(d[v]));
}
}
}
})
var F = new FormData;
F.load({A:1,B:2});
fetch('url_target?C=3&D=blabla', {
method: "POST",
body: F
}).then( response_handler )
you can use fill-fetch, which is an extension of fetch. Simply, you can post data as below:
import { fill } from 'fill-fetch';
const fetcher = fill();
fetcher.config.timeout = 3000;
fetcher.config.maxConcurrence = 10;
fetcher.config.baseURL = 'http://www.github.com';
const res = await fetcher.post('/', { a: 1 }, {
headers: {
'bearer': '1234'
}
});
I want to retrieve the JSON response from the api call I am doing. Example, I want to retrieve something like this:
{"error":{},"success":true,"data":{"user":"tom","password":"123","skill":"beginner","year":2019,"month":"Mar","day":31,"playmorning":0,"playafternoon":1,"playevening":1}}
This is my API call using fetch in react. (yes I know sending password in URL is bad, it's for a school project)
fetch('/api/user/'+ user + '?password=' + password, {
method: 'GET',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json',
}}).then((res) => {
console.log(res); //I want to get the JSON stuff here
})
This is the API call I am calling.
app.get('/api/user/:user', function (req, res) {
// console.log(JSON.stringify(req));
// var user = req.body.user;
// var password = req.body.password;
var user = req.params.user;
var password = req.query.password;
console.log(user, password);
var result = { error: {} , success:false};
if(user==""){
result["error"]["user"]="user not supplied";
}
if(password==""){
result["error"]["password"]="password not supplied";
}
if(isEmptyObject(result["error"])){
let sql = 'SELECT * FROM user WHERE user=? and password=?;';
db.get(sql, [user, password], function (err, row){
if (err) {
res.status(500);
result["error"]["db"] = err.message;
} else if (row) {
res.status(200);
result.data = row;
result.success = true;
} else {
res.status(401);
result.success = false;
result["error"]["login"] = "login failed";
}
res.json(result);
});
} else {
res.status(400);
res.json(result);
}
});
When I do console.log(res) in the fetch call, this is what is printed:
Response {type: "basic", url: "http://localhost:3000/api/user/tim?password=123", redirected: false, status: 200, ok: true, …}body: (...)bodyUsed: falseheaders: Headers {}ok: trueredirected: falsestatus: 200statusText: "OK"type: "basic"url: "http://localhost:3000/api/user/tim?password=123"proto: Response
When I visit the website, the output is:
{"error":{},"success":true,"data":{"user":"tom","password":"123","skill":"beginner","year":2019,"month":"Mar","day":31,"playmorning":0,"playafternoon":1,"playevening":1}}
This is what I want.
In general, this is how you return the response body from the Promise.
fetch(`${baseUrl}/api/user/${user}?password=${password}`, {
method: 'GET',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json',
}})
.then(response => response.json())
.then(data=> {
console.log(data);
})
Try this way to parse the response:
fetch('/api/user/'+ user + '?password=' + password, {
method: 'GET',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json',
}}).then(async (res) => {
const raw = await res.text();
const parsed = raw ? JSON.parse(raw) : { success: res.ok };
console.log(parsed);
})
In this case you can also add some checks for response statuses (if you want, of course) along with parsing the result JSON.
for you to get the JSON body content from the response, you need to use json()
fetch('/api/user/'+ user + '?password=' + password, {
method: 'GET',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json',
}}).then((res) => {
const jsonData = res.json();
console.log(jsonData);
})
try this
fetch(${baseUrl}/api/user/${user}?password=${password},{
method:'GET',
headers: {
'Accept': 'application/json',
'Content-Type':
'application/json',
}}) .then(async(response ) => {
await response.json()
})
$ajax server response:
{"username":"","password":""}
fetch server response:
{"{\"username\":\"\",\"password\":\"\"}":""}
Why aren't they the same? I need the same server response. I'm using PHP+Apache
Here is my code:
import $ from 'jquery';
export function FetchData(type, data){
const serverUrl = 'http://localhost/oms/'+ type + ".php";
return new Promise((resolve, reject) => {
$.ajax({
type: 'POST',
url: serverUrl,
data //body : {username: "username", password:"password"}
})
.done(function(res) {
//console.log(res);
resolve (res);
})
.fail(function(jqXHR, exception){
//alert('server error()');
reject(jqXHR);
});
fetch(serverUrl,{
method: 'POST',
headers: {
Accept: '*/*',
'Content-Type': 'application/x-www-form-urlencoded',
//'Access-Control-Allow-Origin': '*',
//'Access-Control-Allow-Methods': 'POST,GET,OPTIONS,PUT,DELETE',
//'Access-Control-Allow-Headers': 'Content-Type,Accept',
},
body: JSON.stringify(data)
//body : {username: data.username, password: data.password}
})
.then((response) => response.json())
.then((responseJson) => {
resolve(responseJson);
})
.catch((error) => {
reject(error);
});
});
}
The responses are essentially the same just that response from fetch library returns a Stringified JSON.
You need to convert it into actual JS object.
const responseData = JSON.parse(response.json())
This occurs because you're sending the content type application/x-www-form-urlencoded with JSON data you need to change it to application/json like
export const FetchData = (type, data) => {
let serverUrl = 'http://localhost/oms/'+ type + ".php";
let data = {
username: data.username,
password: data.password
};
return new Promise((resolve, reject) => {
fetch(serverUrl, {
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Accept': 'application/json',
},
credentials: 'include',
body: JSON.stringify(data),
})
.then((response) => response.json())
.then((responseJson) => {
resolve(responseJson)
})
.catch((error) => {
reject(error)
})
})
};
I added credentials it's read-only property of the Request interface indicates whether the user agent should send cookies from the other domain in the case of cross-origin requests. This is similar to XHR’s withCredentials flag
If you want to use something smaller to jQuery you can use Axios It's XMLHttpRequests
If you get some CORS issues this will help you