REFACTOR: Introduce RouteMatcher class

This consolidates logic used to match routes in ApiKey, UserApiKey and DefaultCurrentUserProvider. This reduces duplicated logic, and will allow UserApiKeysScope to easily re-use the parameter matching logic from ApiKeyScope

lib/route_matcher.rb

@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+class RouteMatcher
+  attr_reader :actions, :params, :methods, :aliases, :formats, :allowed_param_values
+
+  def initialize(actions: nil, params: nil, methods: nil, formats: nil, aliases: nil, allowed_param_values: nil)
+    @actions = Array(actions) if actions
+    @params = Array(params) if params
+    @methods = Array(methods) if methods
+    @formats = Array(formats) if formats
+    @aliases = aliases
+    @allowed_param_values = allowed_param_values
+  end
+
+  # Return an identical route matcher, with the allowed_param_values replaced
+  def with_allowed_param_values(new_allowed_param_values)
+    RouteMatcher.new(
+      actions: actions,
+      params: params,
+      methods: methods,
+      formats: formats,
+      aliases: aliases,
+      allowed_param_values: new_allowed_param_values
+    )
+  end
+
+  def match?(env:)
+    request = ActionDispatch::Request.new(env)
+
+    action_allowed?(request) &&
+      params_allowed?(request) &&
+      method_allowed?(request) &&
+      format_allowed?(request)
+  end
+
+  private
+
+  def action_allowed?(request)
+    return true if actions.nil? # actions are unrestricted
+    path_params = request.path_parameters
+
+    # message_bus is not a rails route, special handling
+    return true if actions.include?("message_bus") && request.fullpath =~ /^\/message-bus\/.*\/poll/
+
+    actions.include? "#{path_params[:controller]}##{path_params[:action]}"
+  end
+
+  def params_allowed?(request)
+    return true if params.nil? || allowed_param_values.blank? # params are unrestricted
+
+    requested_params = request.parameters
+
+    params.all? do |param|
+      param_alias = aliases&.[](param)
+      allowed_values = [allowed_param_values[param.to_s]].flatten
+
+      value = requested_params[param.to_s]
+      alias_value = requested_params[param_alias.to_s]
+
+      return false if value.present? && alias_value.present?
+
+      value = value || alias_value
+      value = extract_category_id(value) if param_alias == :category_slug_path_with_id
+
+      allowed_values.blank? || allowed_values.include?(value)
+    end
+  end
+
+  def extract_category_id(category_slug_with_id)
+    parts = category_slug_with_id.split('/')
+    !parts.empty? && parts.last =~ /\A\d+\Z/ ? parts.pop : nil
+  end
+
+  def method_allowed?(request)
+    return true if methods.nil?
+    request_method = request.request_method&.downcase&.to_sym
+    methods.include?(request_method)
+  end
+
+  def format_allowed?(request)
+    return true if formats.nil?
+    request_format = request.formats&.first&.symbol
+    formats.include?(request_format)
+  end
+end