make sure to use json for federation post and get

[mrow4a]

Description

After update of guzzle , it was no longer possible to request format of response to be json when adding in query parameter. Because default OCSController method assigns xml https://github.com/owncloud/core/blob/v10.12.0/lib/public/AppFramework/OCSController.php#L143-L146 , it was returning XML, but apps/federation/lib/Controller/OCSAuthAPIController.php expects JSON.

Now exchange is correctly performed, and servers are marked "green"

WARNING: the patch/fix needs to be applied on all federated severs that are not yet "paired" and have the issue with guzzle library. Otherwise pairing will not work.

Remarks:

• the initial pairing still leaves systems in "yellow" boxes state, but what is important is that both servers correctly exchanged "shared secret and have entries properly updated. To speed up the process, after adding trusted servers in UI force background jobs for "GetSharedSecret" and/or "RequestSharedSecret"

occ background:queue:execute --force --accept-warning 19
occ background:queue:execute --force --accept-warning 20 

• to make the instances green, run below commands

occ dav:sync-system-addressbook
occ federation:sync-addressbook

Related Issue

• Fixes https://github.com/owncloud/enterprise/issues/5676

Types of changes

• Bugfix

Checklist:

• Code changes
• Unit tests added
• Acceptance tests added
• Documentation ticket (not needed)
• Changelog item, see TEMPLATE

[update-docs]

Thanks for opening this pull request! The maintainers of this repository would appreciate it if you would create a changelog item based on your changes.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

100.0% Coverage
66.7% Duplication

[jvillafanez]

WARNING: the patch/fix needs to be applied on all federated severs that are not yet "paired" and have the issue with guzzle library. Otherwise pairing will not work.

If this depends on the guzzle version, the affected OC versions should be 10.11.x and 10.12.x . It should be irrelevant for earlier versions.
I mean, if your 10.12.x versions wants to pair with a 10.8.x version, the patch should be applied only in the 10.12.x version.