Add HTTP status helper class

[schlessera]

This PR adds a utility class to deal with HTTP status codes and messages and then changes existing code in Http exceptions and the TransportMock to make use of this utility class.

Pull Request Type

• I have checked there is no other PR open for the same change.

This is a:

• Bug fix
• New feature
• Documentation improvement
• Code quality improvement

Context

PR #582 added a new TransportRedirectMock which was based on TransportMock. While doing so, it needed to duplicate the long list of status code messages already included in TransportMock. To make this process easier and simplify maintenance, we decided to extract knowledge about HTTP status codes and texts into a separate utility class instead, making both transport mock classes simpler in the process.

Detailed Description

The new helper class HttpStatus contains two methods:

• get_text($code) retrieves a status text from a status code
• is_valid_code($code) returns a boolean on whether a given code is a valid (known) status code

Note: This will need a follow-up PR to complete the list of HTTP status codes and texts, as the current codebase is outdated and does not contain all official HTTP status codes yet.

The helper class also contains constants that can be directly referenced, like so:

$not_found_status_message = '404 ' . HttpStatus::TEXT_404;

The PR updates all Http exceptions to make use of this to de-duplicate the status text strings.

Quality assurance

• This change does NOT contain a breaking change (fix or feature that would cause existing functionality to change).
• I have commented my code, particularly in hard-to-understand areas.
• I have added unit tests to accompany this PR.
• The (new/existing) tests cover this PR 100%.
• I have (manually) tested this code to the best of my abilities.
• My code follows the style guidelines of this project.

Documentation

For new features:

• I have added a code example showing how to use this feature to the examples directory.
• I have added documentation about this feature to the docs directory.
  If the documentation is in a new markdown file, I have added a link to this new file to the Docs folder README.md file.

[jrfnl]

Reviewed. Left a few notes. Nothing major.

[jrfnl]

Looking good, left a few notes inline. Nothing major.

[jrfnl]

Thanks for all your work on this @schlessera ! LGTM.

I've added two small commits still with some very minor nitpicks (mostly CS).

Do you want to clean up the branch before merge ? Or shall I merge it as is ?

[jrfnl]

P.S.: build failures are due to GH having trouble. We'll probably best restart them once GH has recovered.

[jrfnl]

Yippia-a-yeah! Ready for merge once the build finishes.