I have seen dozens of questions on SO and different blogs talking about this with "answers" -- all to no avail.
I have a React.js app on my local machine (Ubuntu 16.04). Locally, I try to test it by running npm start
and it opens up the browser to http://localhost:3000.
On one page, I am trying to access my PHP api which is on my shared hosting server.
Chrome and Firefox both say that it fails due to server not having Access-Control-Allow-Orgin
.
Exact Message:
Failed to load http://---/api/v1/categories: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost.com:3000' is therefore not allowed access. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
localhost.com/:1 Uncaught (in promise) TypeError: Failed to fetch
However, upon my php server entry point I do have:
header("Access-Control-Allow-Orgin: *");
header("Access-Control-Allow-Methods: *");
Here is where I make my api call in my react app:
componentDidMount() {
var options = {
method: 'get',
headers: {
"Access-Control-Request-Headers": "*",
"Access-Control-Request-Method": "*"
},
}
// I have since removed the headers from the options as advised in the comments
fetch('http://---/api/v1/categories', options)
.then(results => {
return results.json();
}).then(data => {
let categories = data.map((category) => {
return(
// edited out
)
})
this.setState({categories: categories});
})
}
}
I have tried this on both Chrome and Firefox; I have also tried to alias my server away from localhost. I have tried the no-cors
approach, which does get me access -- but breaks everything of course. I have tried with and without passing headers along with my fetch
request.
UPDATE:
I did get it to work by installing this Chrome plugin. I feel this is a workaround and would like to know if there is a coding answer here.
Use the proxy setting in Create React App Now when you make an API request to https://localhost:3000/api/facts Create React App will proxy the API request to https://cat-fact.herokuapp.com/facts and the CORS error will be resolved.
To get rid of a CORS error, you can download a browser extension like CORS Unblock ↗. The extension appends Access-Control-Allow-Origin: * to every HTTP response when it is enabled. It can also add custom Access-Control-Allow-Origin and Access-Control-Allow-Methods headers to the responses.
Having given the concept that CORS does not provide any additional security when talking about API access, this means that that allowing a particular domain like localhost does not make your API less secure.
To allow any site to make CORS requests without using the * wildcard (for example, to enable credentials), your server must read the value of the request's Origin header and use that value to set Access-Control-Allow-Origin , and must also set a Vary: Origin header to indicate that some headers are being set ...
I'm an idiot.
Origin
was misspelled as Orgin
.
This typo has existed in my project for almost three years. This was the first time I needed to use cross-domain access.
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