restructured CONNEG library

fixed various issue in .ecf files

library/protocol/CONNEG/src/variants.e

@@ -0,0 +1,76 @@
+note
+	description: "Summary description for {VARIANTS}. Utility class to support Server Side Content Negotiation "
+	author: ""
+	date: "$Date$"
+	revision: "$Revision$"
+	description: "[
+		Reference : http://www.w3.org/Protocols/rfc2616/rfc2616-sec12.html#sec12.1
+		Server-driven Negotiation :	If the selection of the best representation for a response is made by an algorithm located at the server,
+		it is called server-driven negotiation. Selection is based on the available representations of the response (the dimensions over which it can vary; e.g. language, content-coding, etc.)
+		and the contents of particular header fields in the request message or on other information pertaining to the request (such as the network address of the client).
+		Server-driven negotiation is advantageous when the algorithm for selecting from among the available representations is difficult to describe to the user agent,
+		or when the server desires to send its "best guess" to the client along with the first response (hoping to avoid the round-trip delay of a subsequent request if the "best guess" is good enough for the user).
+		In order to improve the server's guess, the user agent MAY include request header fields (Accept, Accept-Language, Accept-Encoding, etc.) which describe its preferences for such a response.
+]"
+class
+	VARIANTS
+
+inherit
+	SHARED_CONNEG
+	REFACTORING_HELPER
+feature -- Media Type Negotiation
+
+	media_type_preference ( mime_types_supported : LIST[STRING]; header : STRING) : STRING
+			-- mime_types_supported represent media types supported by the server.
+			-- header represent the Accept header, ie, the client preferences.
+			-- Return which media type to use for representaion in a response, if the server support
+			-- one media type, or empty in other case.
+			-- Reference : http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.1
+		do
+			Result := mime.best_match (mime_types_supported, header)
+		end
+
+
+feature -- Encoding Negotiation
+
+	charset_preference (server_charset_supported : LIST[STRING]; header: STRING) : STRING
+			-- server_charset_supported represent a list of charset supported by the server.
+			-- header represent the Accept-Charset header, ie, the client preferences.
+			-- Return which Charset to use in a response, if the server support
+			-- one Charset, or empty in other case.
+			-- Reference: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.2
+		do
+			Result := common.best_match (server_charset_supported, header)
+		end
+
+
+feature -- Compression Negotiation
+
+	encoding_preference (server_encoding_supported : LIST[STRING]; header: STRING) : STRING
+			-- server_encoding_supported represent a list of encoding supported by the server.
+			-- header represent the Accept-Encoding header, ie, the client preferences.
+			-- Return which Encoding to use in a response, if the server support
+			-- one Encoding, or empty in other case.
+			-- Representation: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3
+		do
+			Result := common.best_match (server_encoding_supported, header)
+		end
+
+feature -- Language Negotiation
+
+	language_preference (server_language_supported : LIST[STRING]; header: STRING) : STRING
+			-- server_language_supported represent a list of languages supported by the server.
+			-- header represent the Accept-Language header, ie, the client preferences.
+			-- Return which Language to use in a response, if the server support
+			-- one Language, or empty in other case.
+			-- Reference: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4
+		do
+			Result := language.best_match (server_language_supported, header)
+		end
+
+note
+	copyright: "2011-2011, Javier Velilla, Jocelyn Fiat and others"
+	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
+end
+
+