Develop Reference

Post action API with object parameter within the URL

I've got an API where some of the parameters need to be given within the URL.
Example of how my api url looks like: https://www.server.com/api/actions/execute?auth_type=apikey&data={"Name": "name","Email" : "email"}
What my code looks like right now
register = async () => {
let data = {"Name":this.state.name, "Email":this.state.email}
data = JSON.stringify(data)
let URL = 'https://www.server.com/api/actions/execute?auth_type=apikey&data=';
fetch(URL, {
method: 'POST',
headers: new Headers({
'Content-Type': 'application/json'
}),
body: data
})
.then((response) => response.text())
.then((responseText) => {
alert(responseText);
})
.catch((error) => {
console.error(error);
});
}
The response I get on my device:
{"code":"succes","details":{"userMessage":["java.lang.Object#2e56000c"],"output_type":void","id:"20620000000018001"},"message":"function executed succesfully"}
This is alle working fine when I test it in postman but I can't get it to work within React-Native. I've tried stuff like 'Content-Type':'application/x-www-form-urlencoded' already.

First install the package axios from the url https://www.npmjs.com/package/react-native-axios
Then create two service for handling get and post request so that you can reuse them
GetService.js
import axios from 'axios';
let constant = {
baseurl:'https://www.sampleurl.com/'
};
let config = {
headers: {
'Content-Type': 'multipart/form-data',
'Accept': 'application/json'
}
};
export const GetService = (data,Path,jwtKey) => {
if(jwtKey != ''){
axios.defaults.headers.common['Authorization'] = 'Bearer '+jwtKey;
}
try{
return axios.get(
constant.baseUrl+'api/'+Path,
data,
config
);
}catch(error){
console.warn(error);
}
}
PostService.js
import axios from 'axios';
let constant = {
baseurl:'https://www.sampleurl.com/'
};
let config = {
headers: {
'Content-Type': 'multipart/form-data',
'Accept': 'application/json'
}
};
export const PostService = (data,Path,jwtKey) => {
if(jwtKey != ''){
axios.defaults.headers.common['Authorization'] = 'Bearer '+jwtKey;
}
try{
return axios.post(
constant.baseUrl+'api/'+Path,
data,
config
);
}catch(error){
console.warn(error);
}
}
Sample code for using get and post services is given below
import { PostService } from './PostService';
import { GetService } from './GetService';
let uploadData = new FormData();
uploadData.append('key1', this.state.value1);
uploadData.append('key2', this.state.value2);
//uploadData.append('uploads', { type: data.mime, uri: data.path, name: "samples" });
let jwtKey = ''; // Authentication key can be added here
PostService(uploadData, 'postUser.php', jwtKey).then((resp) => {
this.setState({ uploading: false });
// resp.data will contain json data from server
}).catch(err => {
// handle error here
});
GetService({}, 'getUser.php?uid='+uid, jwtKey).then((resp) => {
// resp.data will contain json data from server
}).catch(err => {
// handle error here
});

If you need to pass parameters via URL you should use GET, if you use POST then the parameters should be passed in the body

Service worker not getting body from request

So I have a service worker for fetch:
self.addEventListener('fetch', (event) => {
const requestProcessor = (idToken) => {
let req = event.request;
// For same origin https requests, append idToken to header.
if ((self.location.protocol === 'https:' ||
self.location.hostname === 'localhost') &&
idToken) {
// Clone headers as request headers are immutable.
const headers = new Headers();
for (let entry of req.headers.entries()) {
headers.append(entry[0], entry[1]);
}
// Add ID token to header.
headers.append('Authorization', self.location.origin === getOriginFromUrl(event.request.url) ? `Bearer ${idToken}` : idToken);
try {
req = new Request(req.url, {
method: req.method,
headers: headers,
mode: self.location.origin === getOriginFromUrl(event.request.url) ? 'same-origin' : req.mode,
credentials: req.credentials,
cache: req.cache,
redirect: req.redirect,
referrer: req.referrer,
body: req.body,
bodyUsed: req.bodyUsed,
context: req.context
});
} catch (e) {
console.error(e);
}
}
return fetch(req);
};
event.respondWith(getIdToken().then(requestProcessor));
});
It is being called in another file like so:
export const makePostRequest = (url = '', params = {}) => {
return fetch(url, {
method: 'POST',
body: JSON.stringify(params),
headers: {
'Content-type': 'application/json'
}
}).then((res) => res).catch((err) => console.log(err));
};
For some reason, the req.body is always undefined inside of the service worker. Furthermore, it looks like the fetch request happens twice. When I put a breakpoint and step through the code, I can see that nothing from the fetch is being picked up by the service worker. I don't understand.

Okay, so this isn't obvious. So after some research this solved my issue:
self.addEventListener('fetch', (event) => {
if (getOriginFromUrl(event.request.url) === 'https://app.example.com') {
const requestProcessor = (idToken) => {
let newRequest = null;
// For same origin https requests, append idToken to header.
if ((self.location.protocol === 'https:' || self.location.hostname === 'localhost') && idToken) {
try {
newRequest = new Request(event.request, {
headers: new Headers({
...event.request.Headers,
'Content-Type': 'application/json',
Authorization: 'Bearer ' + idToken,
})
})
} catch (e) {
console.log(e);
}
}
return fetch(newRequest);
};
/* Fetch the resource after checking for the ID token.
This can also be integrated with existing logic to serve cached files
in offline mode.*/
event.respondWith(getIdToken().then(requestProcessor, requestProcessor));
}
});
I also had to set the mode:
export const makePostRequest = (url = '', params = {}) => {
return fetch(url, {
method: 'POST',
mode: 'cors',
headers: {
'Content-type': 'application/json'
},
body: JSON.stringify(params)
}).then((res) => res).catch((err) => console.log(err));
};
There were two issues:
By default the header's mode was set to no-cors. According to a previous SO answer, I had to set the mode to cors to allow for non-basic headers which would also include body.
The other issue had to do with the headers being immutable. This had to be changed to copy properly.

The Request object will implement methods like .blob().
await req.blob()

Destructuring error, response from fetch()

I want to implement a Go style error-handling-first data fetch in a React component by destructuring the [responseError, response] objects returned from the fetch(). I'm running into this error:
Uncaught (in promise) TypeError: arr[Symbol.iterator] is not a function
Which is being triggered by the destructuring syntax.
The fetch works fine when I set it up without destructuring i.e
const res = await fetch(APIurl) .
What I want to do:
let requestBody = {
query: `
query {
users {
email
}
}
`
}
const [resError, res] = await fetch(APIurl, {
method: 'POST',
body: JSON.stringify(requestBody),
headers: {
'Content-Type': 'application/json',
Authorization: 'Bearer ' + context.token
}
})
if (resError || !res) {
console.log('Request failed', resError)
return
}
const [parseError, json] = await res.json()
if (parseError || !json) {
console.log('Request failed', parseError)
return
}
const userData = json.data.users
setUsers(userData)
}
What works currently:
let requestBody = {
query: `
query {
users {
email
}
}
`
}
const res = await fetch(APIurl, {
method: 'POST',
body: JSON.stringify(requestBody),
headers: {
'Content-Type': 'application/json',
Authorization: 'Bearer ' + context.token
}
})
if (res.status !== 200 && res.status !== 201) {
throw new Error('Fetch failed')
}
const json = await res.json()
const userData = json.data.users
setUsers(userData)
}
I expect the output to be the same, but the destructuring is triggering the error mentioned above. I am trying to replicate the pattern mentioned in this article: https://www.dalejefferson.com/articles/2016-01-25-error-first-pattern-for-es7-async-await/

You need to write your own middleware that handles your Responses.
const validate = (req) => {
// do some magic
return [err, res];
};
const request = fetch('/api/url');
const [err, res] = validate(request);

HTTP headers not getting sent with fetch()

I'm trying to configure the backend API on my app and here's the code to send a request:
static async xhr(endpoint, args, method) {
const url = `${API_SERVER}${endpoint}`;
let formBody = [];
for (let property in args) {
let encodedKey = encodeURIComponent(property);
let encodedValue = encodeURIComponent(args[property]);
formBody.push(encodedKey + "=" + encodedValue);
}
formBody = formBody.join("&");
let options = Object.assign({ method: method }, args ? { body: formBody } : null );
try {
let headers = {
'Accept': 'application/json',
'Content-Type': 'application/x-www-form-urlencoded',
};
accessToken = 'bdi8HD8js91jdoach7234h';
if(accessToken != null)
headers['Authorization'] = accessToken;
options.headers = headers;
return fetch(url, options).then( resp => {
console.log(resp);
let json = resp.json();
if(resp.status >= 200 && resp.status < 300) {
if (resp.ok) {
return json
}
} else {
return {};
}
return json.then(err => {throw err});
});
} catch (error) {
return null;
}
}
Note: I debugged and found that the headers are correctly getting added to the options variable, but for some reason, the server isn't receiving the Authorization header.
I used Postman to send the exact same request with the exact same headers and I'm getting the correct response via it. I have no idea what's wrong, except it would only be so if the headers aren't getting sent in the first place.
Can someone please tell me what am I doing wrong? Thanks!

The headers option has to be an instance of Headers. You can transform your current headers object to a Headers instance by passing it to its constructor like this:
const headers = new Headers({
'Accept': 'application/json',
'Content-Type': 'application/x-www-form-urlencoded',
});
Note that I also replaced let with const since that variable is not going to be reassigned.
To change a header or add a new header to that Headers instance, you can use the set method. Instead of headers['Authorization'] = accessToken you'd do ...
headers.set('Authorization', accessToken)

localstorage.getitem('key') sometimes returns null - in a react app

this is a very weird problem! I'm trying to build a login form which sets a JWT token in localstorage. Other forms then use that token to post requests. I can see the token in my console.log just fine, but sometimes (like 3 out of 5 times), when I am setting localstorage.getitem('idToken'), it shows as null. This behavior most noticeably happens when I remove the console.log(idToken) from my loginUser() function (code in actions.js file - given below). What am I doing wrong? my app is built using React/Redux.
action.js
export function loginUser(creds) {
const data = querystring.stringify({_username: creds.username, _password: creds.password});
let config = {
method: 'POST',
headers: { 'Content-Type':'application/x-www-form-urlencoded' },
body: data
};
return dispatch => {
// We dispatch requestLogin to kickoff the call to the API
dispatch(requestLogin(creds));
return fetch(BASE_URL+'login_check', config)
.then(response =>
response.json().then(user => ({ user, response }))
).then(({ user, response }) => {
if (!response.ok) {
// If there was a problem, we want to
// dispatch the error condition
dispatch(loginError(user.message));
return Promise.reject(user)
} else {
localStorage.setItem('idToken', user.token);
let token = localStorage.getItem('idToken')
console.log(token);
// if I remove this log, my token is returned as null during post.
dispatch(receiveLogin(user));
}
}).catch(err => console.log("Error: ", err))
}
}
here's my POST request:
import axios from 'axios';
import {BASE_URL} from './middleware/api';
import {reset} from 'redux-form';
let token = localStorage.getItem('idToken');
const AuthStr = 'Bearer '.concat(token);
let headers ={
headers: { 'Content-Type':'application/json','Authorization' : AuthStr }
};
export default (async function showResults(values, dispatch) {
console.log(AuthStr);
axios.post(BASE_URL + 'human/new', values, headers)
.then(function (response) {
console.log(response);
alert("Your submit was successful");
//dispatch(reset('wizard'));
}).catch(function (error) {
console.log(error.response);
alert(error.response.statusText);
});
});
This GET request works everytime, BTW:
getHouses = (e) => {
let token = localStorage.getItem('idToken') || null;
const AuthStr = 'Bearer '.concat(token);
axios.get(BASE_URL + 'household/list', { headers: { Authorization: AuthStr } }).then((response) =>
{
let myData = response.data;
let list = [];
let key =[];
for (let i = 0; i < myData._embedded.length; i++) {
let embedded = myData._embedded[i];
list.push(embedded.friendlyName);
key.push(embedded.id);
}
this.setState({data: list, key: key});
})
.catch((error) => {
console.log('error' + error);
});
}
I'm at my wit's end! Please help!

The localStorage.setItem() is a asynchronous task, and sometimes you run let token = localStorage.getItem('idToken') just after the setItem will fail, so you get a null, so please put the getItem operation some later, have a try, it will be different :
setTimeout(function() {
let token = localStorage.getItem('idToken');
dispatch(receiveLogin(user));
}, 50);

Move your token logic (i.e. localStorage.getItem('idToken');) inside the exported function and it should work
export default (async function showResults(values, dispatch) {
let token = localStorage.getItem('idToken');
const AuthStr = 'Bearer '.concat(token);
let headers ={
headers: { 'Content-Type':'application/json','Authorization' : AuthStr
}
};
axios.post(BASE_URL + 'human/new', values, headers)...

There can't be a case where you set a key value in localstorage and then it returns you null, immediately in the next line.
localStorage.setItem('idToken', user.token);
let token = localStorage.getItem('idToken');
This will only happen if your user.token value is null.
Maybe the case here is your thennable function not returning value to your next then like this:
....
.then(response =>
// return response to your next then function
// this will be passed to next then function as params
return response.json();
).then(({ user, response }) => {
....

Make a function whose return the value or a default value
const [hideTyC, setHideTyC] = useState(false);
const loadTyCFlag = (): any => {
if (
localStorage.getItem("tyc") !== null ||
localStorage.getItem("tyc") !== undefined
) {
return localStorage.getItem("tyc") || false;
}
};
useIonViewDidEnter(() => {
hideTabBar();
setHideTyC(loadTyCFlag());
});