Fix `content-type` header to `application/json`

[rubenferreira97]

Pull Request for Issue #43641.

Summary of Changes

JsonDocument in Joomla 4.4.5 wrongly sets text/plain to all browsers (tested on Edge, Firefox and Chrome). Browsers do not usually send application/json, instead they send */* with some lower priority.

Note: Joomla 5 already fixed this, so this change needs to be merged to Joomla 4 (maybe Joomla 4.4.6?).

Testing Instructions

Ping and API endpoint that extends JsonDocument. In my case I am returning a normal json response instead of a json:api.

Actual result BEFORE applying this Pull Request

Ping an API endpoint like localhost/api/index.php/v1/example: Content-Type: text/plain; charset=utf-8

Expected result AFTER applying this Pull Request

Ping an API endpoint like localhost/api/index.php/v1/example: Content-Type: application/json; charset=utf-8

Link to documentations

Please select:

• [ ] Documentation link for docs.joomla.org:

• [x] No documentation changes for docs.joomla.org needed

• [ ] Pull Request link for manual.joomla.org:

• [x] No documentation changes for manual.joomla.org needed

[laoneo]

Can you reference the pr which fixed this issue already in 5. The change here is a BC break, so not sure if the need to fix it weight's higher than the BC policy.

[rubenferreira97]

@laoneo The PR which fixed this issue was https://github.com/joomla/joomla-cms/pull/39397. IMO this is a bug that should be fixed since JsonDocument should always return application/json by default. Even the IE9 fix was a hacky workaround. Don't know about Joomla BC policy, but are people really expecting this and working around this behavior?

[laoneo]

Problem is that this behavior did exist now for a long time. Changing it in a patch release might cause unexpected issues in extensions using that class as it belongs to the public API. We will discuss it in maintainers group and report back.

[HLeithner]

Closing this PR, since 4.4 is in security mode only and it's fixed in 5.x