[BUG][PHP] Accept headers are discarding content types in favour of application/json

Created by: Pittiplatsch

Bug Report Checklist

Have you provided a full/minimal spec to reproduce the issue?
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Have you tested with the latest master to confirm the issue still exists?
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Description

What's the point of removing all Accept headers not matching sth. like application/json? ->see HeaderSelector::selectAcceptHeader()

By truncating all but the json content types the endpoint specified in the YAML below isn't reachable: The sunny case (aka HTTP 200) only delivers application/octet-stream -> if requested with Accept: application/json it fails with 406 Not acceptable according to RFC 2616.

I assume to understand the intention of HeaderSelector::selectAcceptHeader(): prioritize application/json as the PHP client only can interpret / deserialize JSON responses. However, there are services which may respond with non-JSON, especially with a plain file which the client can handle as well.

openapi-generator version

4.3.1
5.0.0
6.0.1

OpenAPI declaration file content or url

https://gist.github.com/Pittiplatsch/d345dcdd40027e2ef31fc71213626373

Generation Details

No special configuration needed.

Steps to reproduce

Just generate PHP client according to documentation.

Related issues/PRs

#4684 #5163 (closed)

Suggest a fix

Maybe some kind of prioritizing via quality values might help? This of course requires the server to interpret them correctly.