Add new GET /api/config/_properties endpoint

[DL6ER]

What does this implement/fix?

Add new GET /api/config/_properties endpoint listing read-only config items. It may be extended to more things later. See #2348

Related issue or feature (if applicable): N/A

Pull request in docs with documentation (if applicable): N/A

---

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[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[github-actions]

Conflicts have been resolved.

[DL6ER]

Rebased on latest development

[Copilot]

Copilot wasn't able to review any files in this pull request.

Files not reviewed (6)

• src/api/api.c: Language not supported
• src/api/api.h: Language not supported
• src/api/config.c: Language not supported
• src/api/docs/content/specs/config.yaml: Language not supported
• src/api/docs/content/specs/main.yaml: Language not supported
• test/test_suite.bats: Language not supported

[yubiuser]

Should users be able to query specific properties directly? Like pihole api config/_properties/read_only ?

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Maybe I don't understand misc.readOnly but I would have expected all configuration elements to be returned when misc.readOnly=true

nanopi@nanopi:~$ pihole api config/_properties
API Authentication: Not needed

Requesting: GET https://127.0.0.1:443/api/config/_properties

Status: 200
Data:
{
  "config": {
    "read_only": [
      {
        "key": "misc.readOnly",
        "reason": "read_only",
        "description": "Variable can only be set in pihole.toml, not via API"
      }
    ]
  },
  "took": 0.00019168853759765625
}
API Logout: Success (no valid session)
nanopi@nanopi:~$ pihole-FTL --config misc.readOnly
true

[DL6ER]

Should users be able to query specific properties directly? Like pihole api config/_properties/read_only ?

I don't think so. It'd mean adding a lot of code for a feature that is unlikely to be used interactively. This is only meant for the external scripts to have such information available, see #2348 (comment) for the motivation behind this PR.

Maybe I don't understand misc.readOnly but I would have expected all configuration elements to be returned when misc.readOnly=true.

Yes, this makes sense. I will change this.

Changes added in e5c0ee1

[yubiuser]

Is this case still needed after you added the case for misc.readOnly. Because I think FLAG_READ_ONLY is only set once misc.readOnly is true.

[DL6ER]

This is a special flag that a dedicated feature on its own. Only misc.readOnly has this flag. It prevents the CLI and/or the API from being able to set this option (and effective lock out itself). It is there to "protect" users. You can set this only by manually editing pihole.toml.