Module: Philiprehberger::HeaderKit::Negotiation

Defined in:
lib/philiprehberger/header_kit/negotiation.rb

Overview

Content negotiation logic for matching Accept headers against available media types.

Class Method Summary collapse

Class Method Details

.negotiate(accept_header, available) ⇒ String?

Find the best matching media type from available types based on an Accept header.

Matching rules (RFC 7231):

  1. Exact type match

  2. Subtype wildcard (e.g., text/* matches text/html)

  3. Full wildcard (/) matches anything

Parameters:

  • accept_header (String) —

    the Accept header value

  • available (Array<String>) —

    list of available media types

Returns:

  • (String, nil) —

    the best matching type, or nil if no match



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# File 'lib/philiprehberger/header_kit/negotiation.rb', line 17

def self.negotiate(accept_header, available)
  return nil if available.nil? || available.empty?
  return available.first if accept_header.nil? || accept_header.strip.empty?

  accepted = Accept.parse(accept_header)
  return nil if accepted.empty?

  best_match = nil
  best_quality = -1.0
  best_specificity = -1

  accepted.each do |entry|
    available.each do |candidate|
      specificity = match_specificity(entry[:type], candidate)
      next unless specificity >= 0
      next unless entry[:quality] > best_quality ||
                  (entry[:quality] == best_quality && specificity > best_specificity)

      best_match = candidate
      best_quality = entry[:quality]
      best_specificity = specificity
    end
  end

  best_quality > 0.0 ? best_match : nil
end