Add an option to disable CORS proxy

Parchment automatically uses a proxy to download the story file if it detects that it’s not on the same domain. There are two cases where the proxy makes things worse rather than better:

1. The file is on a different domain, but the server sets the correct CORS headers so it works without the proxy. The file might be inaccessible to the proxy (localhost, internal network etc.)
2. The URL is a data URL (data:...)

I’ve been able to get around it with default_story: "data:text/javascript,processBase64Zcode('....'); // .js" which tricks Parchment into thinking that it’s a legacy .js file, but that’s a very hacky solution.

Arguably case 2 is a bug and it should detect data URLs, but for case 1 we’d need either that setting the proxy URL option to null would disable it altogether, or a separate setting that disables the proxy. Preferably with options auto-detection (current behavior), always enabled or always disabled. HugoJS has this setting:

// use a CORS proxy to load game files?
// "always" (or true), "never" (or false), or "auto".
// The "auto" option uses proxy only if the story URL points to another domain.
use_proxy: "auto"

[curiousdannii]

If you set

parchment_options = {auto_launch: 0}

Then Parchment won’t launch automatically. You can then call parchment.load() passing a Uint8Array and a format name:

parchment.load(data, 'glulx')

I think your concerns here have basically been handled by now, but if you have any more just make a new issue.

[juhana]

Thanks, that’ll certainly make things more straightforward!