Register custom browser protocols for .pdez and .pdex files

[SableRaf]

Since Processing 4.0, you can bundle sketches as double-clickable .pdez files and Libraries/Modes/Tools as .pdex files for easy sharing and installation. (see Processing #73, Processing #3987, and the release notes for 4.0 beta1)

A great next step would be to allow .pdez and .pdex files to be opened in the PDE directly from a url in a web browser. This would enable easier sharing of sketches on the forum, better UX for multi-tab examples on the website, and open the possibility for online Processing sketch galleries.

This would require the user to register the protocol on their system (which I imagine could be done from the PDE ?) For example, this page describes the steps needed to register a custom browser protocol on Window, macOS and Linux. There is also a W3C documentation page about custom scheme and content handlers.

[SableRaf]

On a side note, we may need to warn people to only run code when they trust the author (similar to VSCode's restricted mode)

[benfry]

That should be in place because the file extension mapping should be happening. Is that not working?

For the second point, can you open a separate issue? Or perhaps even before that, have you tried it to see what it says now? I realize it's not making a stink about the security implications, but it should already be prompting whether you meant to open it or not.

[SableRaf]

It works as intended if you download the file then open it.

I was talking about opening the file directly by clicking a link in the form processing4://my-website.com/sketch220924.pdez in the browser. This requires an extra step of registering the URI scheme at the OS level. If Processing already does that I couldn't find it in core.

[SableRaf]

I did some more research.

On macOS at least, the first step is adding the protocol name and scheme to the info.plist file. For example:

<key>CFBundleURLTypes</key>
<array>
	<dict>
		<key>CFBundleURLName</key>
		<string>Processing 4</string>
		<key>CFBundleURLSchemes</key>
		<array>
			<string>processing4</string>
		</array>
	</dict>
</array>

Then there needs to be a handler for these URLs in the PDE code using setOpenURIHandler from what I understand (which is admittedly very little).

References:

• Handle custom URL schemes in an OS X Java application
• Access parameters from custom URI scheme in Java application on OS X

[benfry]

You can just use http:// or https:// URLs, no need to do a special protocol handler.

[SableRaf]

I made a quick test to show the current behavior: https://sableraf.github.io/testURIscheme/

http:// or https:// links trigger the browser to download the file (tested on Windows 10 and macOS 12.5.1)

Note: I also included a placeholder link with a processingOrg:// custom protocol for future testing.

[benfry]

Implemented for macOS and Windows for 4.2; uses pde:// and can point to a local file or an https url online. More to come…

[SableRaf]

Thanks @benfry this is amazing! Shoutout to @opyh for initially suggesting the idea in a conversation we had back in August.