Named capturing matchers

[netthier]

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• I have discussed this feature request with the community.

Describe the background of your feature request

Authorizing based on path components is currently a bit hacky.
If I have an API like /file/<uuid>/delete I need to both match the <uuid> part exactly and then again retrieve it inside of the authorizer by extracting it out of .Request.URL.Path. This kind of double matching is in my opinion error-prone, and retrieving path segments from the full path via regular expressions or numeric indexing is not very readable, especially if the template is defined separately from the rule.

Describe your idea

I propose an additional kind of matcher, which would always be named and equivalent to the <*> glob (though to be useful #1037 needs to be implemented in some capacity).
This matcher would be trivially convertable to regexp, where named capturing shouldn't be an issue (unlike with the current glob library).
Compare

rules:
  - id: rule:1
    match:
      url: http://hosty.mchostface/files/<*>/delete
    forward_to:
      host: server:8080
    methods:
      - ALL
    execute:
      - authorizer: openfga_check # remote authorizer 
        config:
          # Note: I originally wanted to do this with values, but apparently they cannot template? They should be able to :v
          payload: |
            {
              "user": {{ .Subject.ID | quote }},
              "relation": "can_delete",
              "object": "file:{{ index (splitList "/" .Request.URL.Path) 2 }}"
            }

and

rules:
  - id: rule:1
    match:
      url: http://hosty.mchostface/files/<:uuid>/delete
    forward_to:
      host: server:8080
    methods:
      - ALL
    execute:
      - authorizer: openfga_check # remote authorizer 
        config:
          payload: |
            {
              "user": {{ .Subject.ID | quote }},
              "relation": "can_delete",
              "object": "file:{{ .Request.URL.Captures.uuid }}"
            }

Are there any workarounds or alternatives?

See the first example above

Version

dev (cda0a84)

Additional Context

Originally suggested on Discord here: https://discord.com/channels/1100447190796742698/1174322443859538000/1174322443859538000