This question already has answers here:
No 'Access-Control-Allow-Origin' header is present on the requested resource—when trying to get data from a REST API
(26 answers)
Closed 2 years ago.
I am new to vueJS and version using is 2.0. I need to fetch some JSON data from url. Using javacsript fetch methods to get the data from URL. below is my code,
function getValue() {
const requestOptions = {
method: "GET",
header: {"Access-Control-Allow-Origin": "GET"}
};
fetch("http://api.plos.org/search?q=title:DNA", requestOptions)
.then(
(response) => {
console.log(response.json());
}
);
}
getValue();
I am getting CORS issue like,
Access to fetch at 'http://api.plos.org/search?q=title:DNA' from origin 'http://localhost:8080' 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.
I tried all the possibilities which available in stack-overflow. But no luck.
Any help would be much appreciated.
JSFiddle link - https://jsfiddle.net/m45hsekf/
Did you tried to set the mode to no-cors like the error suggests to you?
set the request's mode to 'no-cors' to fetch the resource with CORS
disabled.
I have tested it and it works:
const requestOptions = {
method: "GET",
mode: "no-cors"
};
So the request looks like this:
fetch("http://api.plos.org/search?q=title:DNA", {
mode: "no-cors"
})
.then(response => response.json())
.then(result => {
console.log(result);
});
CORS should be enabled at server level like node or java application.
Access-Control-Allow-Origin : "test-client.com" or use "*"(not recommended). Then allow this value at the server
Get is your http method not the origin value
To enable in node use this line
res. header("Access-Control-Allow-Origin", "*"); // again * is not a best practice. Please accept this as answer too
Refer to the url below for more info
https://dzone.com/articles/cors-in-node
when i have problems while i develop, i use crhome extension called CORS UNBLOCK, then i can test my api, and when i deploy to final server, always is in the same domain then i havent cors ploblem
Related
This question already has answers here:
Handle response - SyntaxError: Unexpected end of input when using mode: 'no-cors'
(5 answers)
Closed 4 years ago.
When trying to resolve a fetch promise with JS is set the mode to 'no-cors' based on this answer. However setting the mode to 'cors' results in having:
Access to fetch at
'{endpoint}'
from origin 'http://localhost:3000' 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.
So I wrote this in my function:
search() {
return fetch(`${baselink}${summonerEndpoint}${summoner}${apikey}`, {mode: 'no-cors'}).then(response => {
return response.json()
}).then(jsonResponse => {
console.log(jsonResponse);
if (!jsonResponse.info) {
return [];
}
return jsonResponse.info.items.map(info => ({
id: info.id,
accountId: info.accountId,
name: info.name,
profileIconId: info.profileIconId,
revisionDate: info.revisionDate,
summonerLevel: info.summonerLevel
}));
});
}
This results in following error Uncaught (in promise) SyntaxError: Unexpected end of input for return response.json(), but with no further message. What am I doing wrong?
If an opaque response serves your needs
It doesn't. You want to see the response. You can't see an opaque response (that is what opaque response means).
no-cors mode means that if the browser has to do anything that requires permission from CORS, it will fail silently instead of throwing an error.
So it is silently failing to get the response, then trying to parse that nothing as JSON (which throws a different error).
You need:
To not use no-cors mode
The server to grant permission using CORS
See this question for more information about CORS in general.
I tried to use this Cat Facts API like so:
const URL = "https://catfact.ninja/fact?limit=1" // In browser, this displays the JSON
fetch(URL).then(response=> {
console.log(response);
return response.json();
}
);
but I got
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://catfact.ninja/fact?limit=1. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing).
TypeError: NetworkError when attempting to fetch resource.
so after trying with
fetch(URL, {mode:'no-cors'})
.then(response=> {
console.log(response);
return response.json();
}
);
I now get
Response { type: "opaque", url: "", redirected: false, status: 0, ok: false, statusText: "", headers: Headers, body: null, bodyUsed: false }
SyntaxError: JSON.parse: unexpected end of data at line 1 column 1 of the JSON data
I understand from here that I won't be able to use this API as intended. But if so, what is the purpose of it and how is it intended to be used (this info does not account for the issue)?
An opaque response is one you cannot see the content of. They aren't useful in of themselves.
Setting mode: 'no-cors' is a declaration that you don't need to read the response (or do anything else that requires CORS permission).
For example, the JavaScript might be sending analytics data to be recorded by a server.
The benefit of no-cors mode is that it lets you send the data without getting exceptions reported in the JS console (which would (a) look bad if anyone opened it and (b) flood the console with junk that makes it hard to find real errors).
If you need to access the response, don't set mode: 'no-cors'. If it is a cross origin request then you will need to use some other technique to bypass the Same Origin Policy.
Aside: "Access-Control-Allow-Origin": "*" is a response header. Do not put it on a request. It will do nothing useful and might turn a simple request into a preflighted request.
Adding {mode: 'no-cors'} is not a catch-all for CORS errors. You might be better off using a CORS Proxy.
This question might also be of use to you.
Alternatively, and depending on your needs, using a different API could be the easiest solution. I was able to return a cat fact from "https://meowfacts.herokuapp.com/". See below.
const URL = "https://meowfacts.herokuapp.com/"
async function getCatFact() {
const response = await fetch(URL)
console.log(await response.json())
}
getCatFact()
This question already has answers here:
No 'Access-Control-Allow-Origin' header is present on the requested resource—when trying to get data from a REST API
(26 answers)
Closed 2 years ago.
I'm trying to make a GET request to the url "https://public-api.wordpress.com/wpcom/v2/work-with-us" with special header 'X-future' and value 'automattician'. However, I get the error that this header is not allowed in preflight response:
"Request header field x-future is not allowed by Access-Control-Allow-Headers in preflight response."
From searching around, it seems that this is a CORS issue and I have to add the header from the server side. However, I don't have access to the server.
Is this problem not solvable or am I missing something? Here's what I wrote in code pen to test:
let url = 'https://public-api.wordpress.com/wpcom/v2/work-with-us';
const options = {
method: 'GET', //default
headers: {'X-future': 'automattician'}
};
fetch(url, options)
.then(blob => blob.json())
.then(data => console.log(data));
You can get around these cors issues by running the fetch on your own server or serverless function.
Running this in a node script will work and allow you to pass the results back to your website.
const fetch = require("node-fetch");
function fetchServer() {
return fetch("https://public-api.wordpress.com/wpcom/v2/work-with-us", {
headers: { "X-future": "automattician" }
})
.then(res => res.json())
.then(res => res);
}
You can easily deploy this using a serverless function, sometimes called lambda in AWS but most cloud providers have something similar https://aws.amazon.com/lambda/
Im not an experienced with XML but trying to create a website and need to use some weather data from a norwegian weather services (yr.no) specific this url(https://www.yr.no/sted/Norge/Akershus/B%C3%A6rum/Kols%C3%A5s/varsel.xml)
I have tried using this code under, but having a problem having a problem.. where can i go from here?
fetch('https://www.yr.no/sted/Norge/Akershus/Bærum/Kolsås/varsel.xml', {
mode: 'no-cors'
})
.then(function(resp) {
return resp.text();
})
.then(function(data) {
let parser = new DOMParser(),
xmlDOc = parser.parseFromString(data, '/sted/Norge/Akershus/Bærum/Kolsås/varsel.xml'
);
console.log(xmlDOc);
});
mode: 'no-cors' means "I am not doing anything that needs CORS permission, don't ask for it".
resp.text(); requires CORS permission when dealing with cross-origin requests.
So don't say mode: 'no-cors'.
(If the URL does not come with CORS permission, then you'll need to look at changing that or using a proxy. Further reading: XMLHttpRequest cannot load XXX No 'Access-Control-Allow-Origin' header)
This question already has answers here:
No 'Access-Control-Allow-Origin' header is present on the requested resource—when trying to get data from a REST API
(26 answers)
Closed 3 years ago.
I'm trying to fetch data from a different origin to another server using Fetch API and I precise is from http to https
I can read the data from my browser but I don't know how to fetch them.
I already tried to set Access-Control-Allow-Origin to * but I still get this message :
I'm a little bit lost right know, Thank you for your support. 😁
const myHeaders = new Headers({
"Access-Control-Allow-Origin": "*",
"Content-Type": "application/json"
});
const fetchConfig = {
method: "GET",
headers: myHeaders,
mode: "cors",
cache: "no-cache"
};
function fetchData(url) {
fetch(url, fetchConfig)
.then(response => {
return response.json();
})
.then(data => {
console.log(data);
})
.catch(error => console.error(error));
}
fetchData("https://api.example.com/");
The Access-Control-Allow-Origin header needs to be set by the server you are retrieving the data from, in response to your request.
CORS Anywhere is a NodeJS proxy which adds CORS headers to the proxied request.
The URL to the proxy is literally taken from the path, validated and proxied. The protocol part of the proxied URI is optional, and defaults to "http". If port 443 is specified, the protocol defaults to "https".
This package does not put any restrictions on the http methods or headers, except for cookies. Requesting user credentials is disallowed. The app can be configured to require a header for proxying a request, for example, to avoid a direct visit from the browser.
You can simply add https://cors-anywhere.herokuapp.com/ at the beginning of your url.
Like this https://cors-anywhere.herokuapp.com/http://example.com/api/....
Check this link for more details: https://www.npmjs.com/package/cors-anywhere