Disable CORS error for localhost

[louwers]

When trying to add a source with http, you always see this message:

Error: CORS policy won't allow fetching resources served over http from https, use a https:// domain

However this is even the case for http://localhost, even though CORS does not apply to localhost (I never had any problems at least). This error should not be shown when the host is localhost.

[oobayly]

I had assumed that this was a blocking error, and not just a simple message, so I never bothered clicking the "Load from URL" button and ended up running my own docker image 🤦
It was only when I looked at fixing this that I though to try to load a http: URL.

A simple fix would be to test the hostname of the url too:

const getUrlParams = (url: string) => {
    let protocol: string | undefined;
    let isLocal = false;

    try {
        const urlObj = new URL(url);
        
        protocol = urlObj.protocol;
        isLocal = /^(localhost|\[::1\]|127(.[0-9]{1,3}){3})/i.test(urlObj.hostname);
    } catch (err) {
    }

    return {protocol, isLocal};
}

const {protocol, isLocal} = getUrlParams(url);

...

  else if (
    protocol &&
    protocol === "http:" &&
    window.location.protocol === "https:" &&
    !isLocal
  ) {

[HarelM]

Feel free to submit a PR, I'll be happy to review it.

[roblabs]

The Vite server supports configuration of CORS. That is when you start development with npm run start, one can get past CORS issues on localhost. I am not sure if it catches @louwers original case of: a) run Maputnik on localhost:8888, and b) serve a styles from localhost:3001. I just haven't tried that case.

See:

• Style Development for unpublished, or private or local styles #954
• And the changes to the Vite config that configures CORS.