This question already has answers here:
CORS error even after setting Access-Control-Allow-Origin or other Access-Control-Allow-* headers on client side
(2 answers)
Closed 1 year ago.
I'm trying to get data from an end-point using VueJS and axios, but I keep getting the following CORS error on this code.
axios
.get(url, {
headers: {
"Access-Control-Allow-Origin": "*",
},
})
.then((response) => {
this.data = response.data;
});
Access to XMLHttpRequest at [url] from origin 'http://localhost:8081' 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.
I've looked at multiple answers but the only solutions I'm seeing are using a Chrome extension or changing the server's configuration, which I do not have access to. Is there any way to solve this exclusively through the front-end?
You could use a CORS proxy, like CORS anywhere:
axios
.get("https://cors-anywhere.herokuapp.com/" + url)
.then((response) => {
this.data = response.data;
});
However, this is not a good solution for production, as it relies on an external service to handle your requests, which could lead to issues later down the line.
This question already has answers here:
How does the 'Access-Control-Allow-Origin' header work?
(19 answers)
Closed 3 years ago.
I'm making an app in angular 7 that connects to API that I wrote in python. I want to send a text in POST request and API does some nlp stuff and returns the result. API is using RestPlus and is hosted on GCP App Engine. So in angular I have this code:
posts: any;
readonly ROOT_URL = 'XXX';
const httpOptions = {
headers: new HttpHeaders({
'Access-Control-Allow-Origin': '*',
'Content-Type': 'application/json',
'X-API-KEY': 'X',
})
};
const data: any = {
"article": this.text
};
this.posts = this.http.post(this.ROOT_URL, data, httpOptions);
this.text is a value I get from form and I've already checked if it's valid. X-API-KEY is a token I set in API.
In console I get:
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at XXX. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing)
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at XXX. (Reason: CORS request did not succeed).
I tried sending a post request to postb.in to test it and got the same errors. And postb.in shows that it only received OPTION requests.
Cross origin request means that you are trying to make an API call to a server which is not your origin (this server is not rendering the front-end/client-end).
Example: If http://localhost/dummy-app delivers the front-end and you are trying to make an API call from this front-end to http://localhost:3000/dummy-api, it will result in a CORS issue.
Resolutions:
Render the front-end from the server where the API end point exists. This is only a technical solution and may not be a good architecture or not even possible at times.
Allow CORS in server. (Not highly recommended)
Use a middleware server to render your front end. This server can have an API endpoint through which you can pass the request to desired API. CORS issue appears to be a blocking by the browser and appears only when an external API is called from front-end. You can call an API in the middleware server which then further calls the external API.
Recommended : Use your web server to do the job. For example, create a new route in Nginx which proxy passes your request to the API.
location /api{
proxy_pass http://localhost:3000
}
In this method http://localhost/dummy-app can call the API as http://localhost/api/dummy-api.
I've been trying to create a react web app for a few days now for my internship and I've encountered a CORS error. I am using the latest version of reactJS, and placing this in the create-react-app, and below is the code for fetching:
componentDidMount() {
fetch('--------------------------------------------',{
method: "GET",
headers: {
"access-control-allow-origin" : "*",
"Content-type": "application/json; charset=UTF-8"
}})
.then(results => results.json())
.then(info => {
const results = info.data.map(x => {
return {
id: x.id,
slug: x.slug,
name: x.name,
address_1: x.address_1,
address_2: x.address_2,
city: x.city,
state: x.state,
postal_code: x.postal_code,
country_code: x.country_code,
phone_number: x.phone_number,
}
})
this.setState({warehouses: results, lastPage: info.last_page});
})
.then(console.log(this.state.warehouses))
}
I'm sorry that I can't post the url for the API due to company rules, however, it is confirmed that there are no CORS setting in the API backend.
However, I encounter the following errors when run on mozilla
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at ------------------. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing).
and
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at ---------------------------------------------. (Reason: CORS request did not succeed).
If run on chrome it gives the following error
Failed to load resource: the server responded with a status of 405 (Method Not Allowed)
and
Failed to load --------------------------------------------------------: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:3000' is therefore not allowed access. The response had HTTP status code 405. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
and
Uncaught (in promise) TypeError: Failed to fetch
Another thing is that I am able to open the url in my browsers with no problems or whatsoever.
Please help and thanks!
Additional Information
The reason I added the CORS setting is because it gives a CORS error, so removing it does not really solve the issue.
Next I tried to perform proxy setting, however, it now gives
Unhandled Rejection (SyntaxError): Unexpected token < in JSON at position 0
According to the internet this is caused becasue the response is not a JSON. However when I checked the API it gives this
api img
which means that return type should be a JSON right?
Additional Info
checking the respond will yield this
{"status":200,"total":1,"per_page":3,"current_page":1,"last_page":1,"next_page_url":null,"prev_page_url":null,"from":1,"to":3,"data":[{"id":1,"slug":"america","name":"america","address_1":"USA Court","address_2":"USA","city":"USA","state":"USA","postal_code":"94545","country_code":"US","phone_number":"10000001","created_by":null,"updated_by":null,"created_at":"2017-11-10 11:30:50+00","updated_at":"2018-06-28 07:27:55+00"}]}
The CORS settings need to be setup in the API to allow access from your React app domain. No CORS settings, no AJAX from different domains. It's simple as that. You can either add CORS settings to your company API (this is unlikely to happen) or you can work around like described below:
The CORS is solely a mechanism of client browser to protect users from malicious AJAX. So one way to work around this is proxying your AJAX request from your React app to its own web server. As Vincent suggests, the create-react-app provides an easy way to do this: in your package.json file, simply chuck "proxy": "http://your-company-api-domain". For more details, please see this link
Then in your react app you can using relative URL like this: fetch('/api/endpoints'). Notice that the relative URL has to match with your company API. This will send a request to your server, then the server will forward the request to your company API and return the response back to your app. Since the request is handled in the server-to-server way not browser-to-server so the CORS check won't happen. Therefore, you can get rid of all unnecessary CORS headers in your request.
This is what I did using vite
Package.json file add:
"proxy": "http://api_website_where_the_request_is_comming/",
App component or whatever component you making the call do this
let endpoint = /api/your_endpoint/;
fetch(endpoint).then(function (response) {
return response.json()
})
.then(function (jsonData){
console.log('Banner log', jsonData);
})
In your backend, make sure that the app is use cors.
Run this to install cors
npm install cors --save
Import cors in the app using
const cors = require('cors');
app.use(cors()) // if name of your backend is app
This question already has answers here:
XMLHttpRequest cannot load XXX No 'Access-Control-Allow-Origin' header
(11 answers)
Closed 3 years ago.
I've found simple tutorial how to make cross domain json call here
And it works perfectly fine, so i decided to use this example, just change url from:
var url = "http://api.myjson.com/bins/23xvb";
to
var url = "http://dl.sniper.pl/test.json"
Unfortunately changing it returns such an error (in chrome):
XMLHttpRequest cannot load http://dl.sniper.pl/test.json. Response to
preflight request doesn't pass access control check: No
'Access-Control-Allow-Origin' header is present on the requested
resource. Origin 'null' is therefore not allowed access.
Googling that error didnt provide any answers to find a solution so here's the question:
Why i get such an error and how to solve it?
The http://dl.sniper.pl/ server must be configured to send the Access-Control-Allow-Origin response header in responses to requests for http://dl.sniper.pl/test.json.
But because that server isn’t sending the Access-Control-Allow-Origin response header, your browser is refusing to allow your frontend JavaScript code to access that response.
So you either nust configure the http://dl.sniper.pl/ server to send Access-Control-Allow-Origin or else you can make the request through a CORS proxy.
There’s an open CORS proxy you can make you request through by changing your code to this:
var url = "https://cors-anywhere.herokuapp.com/http://dl.sniper.pl/test.json"
That sends the request through the open CORS proxy https://cors-anywhere.herokuapp.com which adds the Access-Control-Allow-Origin response header to it and then passes that back to your requesting frontend code as the response.
That response with the Access-Control-Allow-Origin response header is what the browser sees, so the browser allows your frontend JavaScript code to actually access the response.
You can also easily set up your own CORS proxy using https://github.com/Rob--W/cors-anywhere/
See https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS for an explanation of how browsers behave when you send cross-origin requests frontend JavaScript code using XHR or the Fetch API or AJAX methods from JavaScript libraries—and for details about what response headers must be received in order for browsers to allow frontend code to access the responses.
you should configure you server todo this in your htaccess
u need something like this
<RequireAll>
Require all granted
</RequireAll>
This question already has answers here:
Origin is not allowed by Access-Control-Allow-Origin
(18 answers)
Closed 6 years ago.
I am using webpack angular2 starter kit (https://github.com/AngularClass/angular2-webpack-starter) for my application and now i have an issue.
I try to make get call
getSomeData(): Observable<any> {
let url = here is my api URL;
let headers = new Headers({ 'Content-Type': 'application/json; charset=utf-8', "Access-Control-Allow-Origin": "*", 'dataType': 'json', });
let options = new RequestOptions({ headers: headers });
return this._http.get(url, options).map(res => res.json());
}
And I have next error
XMLHttpRequest cannot load (my URL) Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:3000' is therefore not allowed access. The response had HTTP status code 405.
This Api (It using firebird) returns XML by default, maybe this cause a problem.
How to make that always came JSON?
How to fix this problem with CORS?
This issue is at the server side. The latter must return a Access-Control-Allow-Origin header in the response of the HTTP call.
Most of time, there are tools you can plug into your server application to do this for you. The server knows that CORS headers must be returned when the client sends a Origin header (automatically added by the browser).
See this article for more details about CORS:
http://restlet.com/blog/2015/12/15/understanding-and-using-cors/