I am using axios for making a post request with data to an endpoint:
This works:
import axios from 'axios';
axios.post('https://example.com/v1/login', {
name: 'myuser',
password: 'mypassword',
});
But this doesn't
import axios from 'axios';
export const apiBase = axios.create({
baseURL: "https://example.com/v1/",
withCredentials: true,
headers: {
'Content-Type': 'application/json;charset=UTF-8',
},
});
apiBase.post('login', {
name: 'myuser',
password: 'mypassword',
});
Which logs:
Access to XMLHttpRequest at 'https://example.com/v1/login'
from origin 'http://example.com' has been blocked by CORS policy:
Response to preflight request doesn't pass access control check: The
value of the 'Access-Control-Allow-Origin' header in the response must
not be the wildcard '*' when the request's credentials mode is
'include'. The credentials mode of requests initiated by the
XMLHttpRequest is controlled by the withCredentials attribute.
And actually, no header 'Content-Type' is added to this request.
Does anyone know what is wrong here?
EDIT: modified following comments
import axios from 'axios';
export const apiBase = axios.create({
baseURL: "https://example.com/v1/",
withCredentials: true,
headers: {
'Content-Type': 'application/json;charset=UTF-8',
},
});
apiBase.defaults.headers['Content-Type'] = 'pplication/json;charset=UTF-8';
apiBase.defaults.headers['Access-Control-Allow-Origin'] = 'http://example.com';
apiBase.defaults.headers['Host'] = 'example.com';
apiBase.defaults.headers['Referer'] = 'example.com';
apiBase.defaults.headers['Accept-Encoding'] = 'gzip, deflate, br';
apiBase.post('login', {
name: 'myuser',
password: 'mypassword',
});
Which still returns
Access to XMLHttpRequest at 'https://example.com/v1/login'
from origin 'http://example.com' has been blocked by CORS policy: Response
to preflight request doesn't pass access control check: The value of the
'Access-Control-Allow-Origin' header in the response must not be the
wildcard '*' when the request's credentials mode is 'include'. The
credentials mode of requests initiated by the XMLHttpRequest is controlled
by the withCredentials attribute.
Setting credentials or setting the content-type to JSON will trigger a preflight request.
The requirements for a response to a preflight are stricter than for a non-preflighted request.
One of them is, as the error message says, that you can't use the wildcard. You have to specify the origin explicitly. You aren't doing that.
And actually, no header 'Content-Type' is added to this request.
Naturally. The preflight didn't get permission to set it, so the request is never made.
Axios, for whatever reason, doesn’t allow you to send data in a POST request in the form of a JSON object when withCredentials is set to true. You’ll need to stringify your data before passing it along.
Check your code :
-----> apiBase.defaults.headers['Content-Type'] = 'pplication/json;charset=UTF-8';
apiBase.defaults.headers['Content-Type'] = 'application/json;charset=UTF-8';
Related
My frontend and backend services are in different origins, hence problem with CORS. But in my backend (python fastAPI) I have already added allow all origins:
api.add_middleware(
CORSMiddleware,
allow_origin_regex=".*",
allow_credentials=True,
allow_methods=["*"],
allow_headers=["*"],
)
This is how my frontend is making the call
fetch('https://someurl.com/call', {
method: 'POST',
headers:{
'Content-Type': 'application/x-www-form-urlencoded',
'Signature': btoa('0000')
},
body: new URLSearchParams({
})
}).then(res => {
return res.json()
})
Error that I am getting:
Access to fetch at 'https://someurl.com/call' from origin 'https://frontend.com' has been blocked by CORS policy: Request header field signature is not allowed by Access-Control-Allow-Headers in preflight response.
Is there something I am missing? Is my custom header 'Signature': btoa('0000') the problem?
I am trying to debug, this is what I am getting from the browser console
I want to GET JSON from the endpoint https://api.brawlstars.com/v1/brawlers.
(https://api.brawlstars.com/v1/brawlers?Authorization="Bearer%20[My API Key]")
Here's my Code:
let url = 'https://api.brawlstars.com/v1/brawlers'
fetch(url, {
method: "GET",
headers: {
"Authorization": "Bearer **USER'S API KEY GOES HERE**"
}
}).then((response) => {
let json = response.json();
console.log(json);
}).catch((err) => {
console.error(err)
});
This is the output (error):
Access to fetch at 'https://api.brawlstars.com/v1/brawlers' from origin 'http://127.0.0.1:8887' has been
blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If
an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS
disabled.
sketch.js:3 GET https://api.brawlstars.com/v1/brawlers net::ERR_FAILED
127.0.0.1/:1 Uncaught (in promise) TypeError: Failed to fetch
What am I missing?
In your header, you need to enable CORS like CBroe said :
headers.append('Access-Control-Allow-Origin', 'http://127.0.0.1:8887');
headers.append('Access-Control-Allow-Credentials', 'true');
Edit :
The server (that the POST request is sent to) needs to include the Access-Control-Allow-Headers header (etc) in its response. Putting them in your request from the client has no effect.
This is because it is up to the server to specify that it accepts cross-origin requests (and that it permits the Content-Type request header, and so on) – the client cannot decide for itself that a given server should allow CORS.
I'm consuming an API using fetch but i'm getting CORS error.
I tried multiples headers, but I'm not understading what's the problem.
I'm not the owner of the API, so I couldn't change it, but checking the response it's returning access-control-allow-origin.
Following is my request method:
export const execPOST = (url, body) => {
return fetch(url, {
method: "POST",
headers: {
"Access-Control-Allow-Origin": "*",
"Content-Type": "application/json"
},
body: JSON.stringify(body)
});
};
The response is:
Request URL: http://api
Request Method: OPTIONS
Status Code: 405 Method Not Allowed
Remote Address: ip
Referrer Policy: no-referrer-when-downgrade
Response Headers:
Access-Control-Allow-Origin: *
Isn't this response above enough to allow my request?
console error:
OPTIONS http://api net::ERR_ABORTED 405 (Method Not Allowed)
Access to fetch at 'http://api' from origin 'http://localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: It does not have HTTP ok status.
I got this working (meanwhile I develop) using "https://cors-anywhere.herokuapp.com/", but I don't think that I should use this for production enviroment.
I found a lot of material about this problem, but nothing that worked besides implements a backend to make the request or use something else as a proxy to make the request and so on...
Update code as given below (use 'mode' with the value 'no-cors' ):
For more details follow the link => https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch
export const execPOST = (url: string, body: any) => {
return fetch(url, {
mode: 'no-cors',
method: 'POST',
headers: {
'Content-Type': 'application/json'
},
body: JSON.stringify(body)
});
};
CORS headers are set by the API to protect users from malicious code making requests to sites on their behalf.
This means that you cannot enable or disable it from the client side as the Access-Control-Allow-Origin header is a server side only header.
If you don't have access to the API to change the headers then you won't be able to use the API from the client side.
In production you would have to create your own API that will handle the requests to the API you are trying to contact.
I have to implement an angular application with CURD operations. API is already hosted IN AWS, Which is working fine with Postman.
But my angular application getting
Access to XMLHttpRequest at 'https://acp56df5alc.execute-api.us-east-1.amazonaws.com/ams/getmember' from origin 'http://localhost:4200' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.
My code is like below,
http_GET(actionUrl: string): Observable<any> {
const httpOptions = {
headers: new HttpHeaders({
'Content-Type': 'application/json',
'Access-Control-Allow-Origin': '*',
'Access-Control-Allow-Credentials': 'true',
'Access-Control-Allow-Headers': 'Content-Type',
'Access-Control-Allow-Methods': 'GET,PUT,POST,DELETE',
'key': 'x-api-key',
'value': 'NNctr6Tjrw9794gFXf3fi6zWBZ78j6Gv3UCb3y0x',
})
};
return this.http.get<any>(this.baseUrl + actionUrl, httpOptions).pipe(
(response => {
return response;
}));
}
I have tried hard to solve this.But need some help
I had the same cors issue and tried all the suggested ways of setting Access-Control-Allow-Origin * without success.
Later I found two issues:
The data format I sent via POST request was not properly formatted.
The server could not handle empty parameters received from the post request.
Original request:
return this.http.post(API_URL + 'customer/login',
{email: email, password: password},{ headers: headers}
)
Worked after i wrapped the post data using JSON.stringify()
return this.http.post(API_URL + 'customer/login',
JSON.stringify({email: email, password: password}),{ headers: headers}
)
All/Most of these headers need to be defined on the server-side (whatever hosts the API on AWS)... not client side.
headers: new HttpHeaders({
'Content-Type': 'application/json',
'Access-Control-Allow-Origin': '*',
'Access-Control-Allow-Credentials': 'true',
'Access-Control-Allow-Headers': 'Content-Type',
'Access-Control-Allow-Methods': 'GET,PUT,POST,DELETE',
'key': 'x-api-key',
'value': 'NNctr6Tjrw9794gFXf3fi6zWBZ78j6Gv3UCb3y0x',
...
The most likely reason that postman works is that it directly sends a GET request. what you are sending is a complex request which is called 'pre-flight' and which causes an 'OPTIONS' request to be sent before the actual GET. this is not allowed by the remote side.
That's a common CORS problem that (if you're using asp .net core on backend) can be solved enabling CORS following this thread
I'm building a SignUp form and have the following API call to POST the form:
const request = new Request('http://localhost:4300/auth/', {
method: 'POST',
headers: new Headers({
'Accept' : 'application/json',
'Content-Type' : 'application/json',
}),
body: JSON.stringify({ user: data })
});
fetch(request).then(response => {
console.log(response);
const auth = response.headers.get('Authorization');
console.log(auth)
});
The problem is response.headers.get('Authorization') is returning as null. Even though if I look at Chrome's Network XHR request I see the Response Headers being sent by the API server.
Why is React not providing me with response.headers via the request above?
Thanks
The value of the Access-Control-Expose-Headers response header for the response from http://localhost:4300/auth/ must include "Authorization" if you want your requesting frontend JavaScript code to be allowed to access the Authorization response header value.
If the response includes no value for the Access-Control-Expose-Headers header, the only response headers browsers will let you access from client-side JavaScript in your web app are Cache-Control,
Content-Language,
Content-Type,
Expires,
Last-Modified
and
Pragma.
See https://fetch.spec.whatwg.org/#cors-safelisted-response-header-name for the spec.