refactor: migrate OC_EventSource to dependency injection

[kesselb]

• Resolves: #

Summary

Test: Increase the version number in version.php and visit Nextcloud.
The update should work as before.

Tip: Set a breakpoint in OC_EventSource.send and watch the request in your browser.

TODO

• ...

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[ChristophWurst]

Fine to be removed because deprecated but needs docs

[kesselb]

I overlooked that createEventSource always creates a new object.
Updated the service definition and set $shared = false for IEventSource.

Can't say if a new instance makes sense, but that was the old behavior.

[kesselb]

PR for docs: nextcloud/documentation#10479

[kesselb]

Example: Rello/audioplayer#586

[come-nc]

In this instance I find it clearer to use createEventSource, as it makes it clear this is not a singleton. What are the pros of DI for non-singletons?

[kesselb]

In this instance I find it clearer to use createEventSource, as it makes it clear this is not a singleton. What are the pros of DI for non-singletons?

I find that a valid point.
My motivation was to inject IRequest via DI and replace OC::$server->getRequest().

@ChristophWurst you deprecated it a while ago. Are you okay to keep createEventSource?

Should we also add createEventSource to https://github.com/nextcloud/server/blob/master/lib/public/Server.php so apps can use it without using a private api?

[icewind1991]

Might be worth adding an EventSourceFactory that can be injected. Same pattern as we use for http clients and others

[ChristophWurst]

Yes let's go with a injectable and mockable factory instead of a static function

[ChristophWurst]

Clean