Etags: add strong and weak matchers

.mailmap

@@ -1 +1,2 @@
-Dan Olson <[email protected]>
+Dan Olson <[email protected]>
+Thomas Morgan <[email protected]>

lib/protocol/http/header/etags.rb

@@ -2,21 +2,42 @@
 
 # Released under the MIT License.
 # Copyright, 2020-2023, by Samuel Williams.
+# Copyright, 2023, by Thomas Morgan.
 
 require_relative 'split'
 
 module Protocol
 	module HTTP
 		module Header
-			# This implementation is not strictly correct according to the RFC-specified format.
 			class ETags < Split
 				def wildcard?
 					self.include?('*')
 				end
 
+				# This implementation is not strictly correct according to the RFC-specified format.
 				def match?(etag)
 					wildcard? || self.include?(etag)
 				end
+
+				# Useful with If-Match
+				def strong_match?(etag)
+					wildcard? || (!weak_tag?(etag) && self.include?(etag))
+				end
+
+				# Useful with If-None-Match
+				def weak_match?(etag)
+					wildcard? || self.include?(etag) || self.include?(opposite_tag(etag))
+				end
+
+				private
+
+				def opposite_tag(etag)
+					weak_tag?(etag) ? etag[2..-1] : "W/#{etag}"
+				end
+
+				def weak_tag?(tag)
+					tag&.start_with? 'W/'
+				end
 			end
 		end
 	end

license.md

@@ -8,6 +8,7 @@ Copyright, 2020-2023, by Bruno Sutic.
 Copyright, 2022, by Herrick Fang.  
 Copyright, 2022, by Dan Olson.  
 Copyright, 2023, by Genki Takiuchi.  
+Copyright, 2023, by Thomas Morgan.  
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

test/protocol/http/header/etags.rb

@@ -2,6 +2,7 @@
 
 # Released under the MIT License.
 # Copyright, 2020-2023, by Samuel Williams.
+# Copyright, 2023, by Thomas Morgan.
 
 require 'protocol/http/header/etags'
 
@@ -14,21 +15,43 @@
 		end
 
 		it "matches anything" do
-			expect(header).to be(:match?, "anything")
+			expect(header).to be(:match?, '"anything"')
 		end
 	end
 
-	with "abcd" do
+	with '"abcd"' do
 		it "is not a wildcard" do
 			expect(header).not.to be(:wildcard?)
 		end
 
 		it "matches itself" do
-			expect(header).to be(:match?, "abcd")
+			expect(header).to be(:match?, '"abcd"')
+		end
+
+		it "strongly matches only another strong etag" do
+			expect(header).to be(:strong_match?, '"abcd"')
+			expect(header).not.to be(:strong_match?, 'W/"abcd"')
+		end
+
+		it "weakly matches both weak and strong etags" do
+			expect(header).to be(:weak_match?, '"abcd"')
+			expect(header).to be(:weak_match?, 'W/"abcd"')
 		end
 
 		it "does not match anything else" do
-			expect(header).not.to be(:match?, "anything else")
+			expect(header).not.to be(:match?, '"anything else"')
+		end
+	end
+
+	with 'W/"abcd"' do
+		it "never strongly matches" do
+			expect(header).not.to be(:strong_match?, '"abcd"')
+			expect(header).not.to be(:strong_match?, 'W/"abcd"')
+		end
+
+		it "weakly matches both weak and strong etags" do
+			expect(header).to be(:weak_match?, '"abcd"')
+			expect(header).to be(:weak_match?, 'W/"abcd"')
 		end
 	end
 end