Add artifact and path hosting options to new server-less recipe hosting

[gnito-org]

Replacing flex-server by hosting recipes on GitHub is an awesome improvement.

As far as I can determine, custom flex endpoint overlays currently have to be hosted somewhere on a public web server (given the code in Download.php).

It would be really helpful if flex recipes could be hosted on the same hosting options available for Composer packages, specifically: public web server, artifact, and path.

That will cover recipes for private bundles that cannot be hosted on public web servers.

[nicolas-grekas]

Hello, I'm not sure what you mean exactly, but the good news is that now everything is open source and open to contributions. I'd be happy to review a more detailed proposal.

About storing in a local directory, the file:// protocol might allow it already. One thing that might be improved is resolution of links in the index.json: they have to be absolute currently, while it might help allowing them to be relative to said index.json.

PR welcome.

[gnito-org]

Where can one read about using the file:// protocol in flex?

[nicolas-grekas]

src/Downloader.php is the file that interacts with the API endpoint. That's the start. Then errors-n-trials might be the way to iterate. This reuses code found in composer so it might be worth following the rabbit down there. For now you could just give it a try and see where it blocks or if it works out of the box by configuring the extra.symfony.endpoint entry in your composer.json

[gnito-org]

Hosting private bundle recipes in a private GitHub repository works just fine, and it covers my use case.

[nicolas-grekas]

Relative URLs implemented in #872