217 lines
8.0 KiB
Plaintext
217 lines
8.0 KiB
Plaintext
note
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description: "Summary description for {CONNEG_SERVER_SIDE}. Utility class to support Server Side Content Negotiation "
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author: ""
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date: "$Date$"
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revision: "$Revision$"
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description: "[
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Reference : http://www.w3.org/Protocols/rfc2616/rfc2616-sec12.html#sec12.1
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Server-driven Negotiation : If the selection of the best representation for a response is made by an algorithm located at the server,
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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.)
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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).
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Server-driven negotiation is advantageous when the algorithm for selecting from among the available representations is difficult to describe to the user agent,
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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).
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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.
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]"
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class
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CONNEG_SERVER_SIDE
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inherit
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SHARED_CONNEG
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REFACTORING_HELPER
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create
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make
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feature -- Initialization
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make ( a_mime: STRING; a_language : STRING; a_charset :STRING; an_encoding: STRING)
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do
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set_mime_default (a_mime)
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set_language_default (a_language)
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set_charset_default (a_charset)
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set_encoding_defautl (an_encoding)
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end
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feature -- Server Side Defaults Formats
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mime_default : STRING
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set_mime_default ( a_mime: STRING)
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-- set the mime_default with `a_mime'
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do
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mime_default := a_mime
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ensure
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set_mime_default: a_mime ~ mime_default
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end
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language_default : STRING
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set_language_default (a_language : STRING)
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-- set the language_default with `a_language'
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do
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language_default := a_language
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ensure
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set_language : a_language ~ language_default
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end
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charset_default : STRING
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set_charset_default (a_charset : STRING)
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-- set the charset_default with `a_charset'
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do
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charset_default := a_charset
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ensure
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set_charset : a_charset ~ charset_default
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end
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encoding_default : STRING
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set_encoding_defautl (an_encoding : STRING)
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do
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encoding_default := an_encoding
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ensure
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set_encoding : an_encoding ~ encoding_default
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end
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feature -- Media Type Negotiation
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media_type_preference ( mime_types_supported : LIST[STRING]; header: detachable READABLE_STRING_8) : MEDIA_TYPE_VARIANT_RESULTS
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-- mime_types_supported represent media types supported by the server.
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-- header represent the Accept header, ie, the client preferences.
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-- Return which media type to use for representaion in a response, if the server support
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-- one media type, or empty in other case.
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-- Reference : http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.1
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local
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mime_match: STRING
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do
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create Result
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if header = Void or else header.is_empty then
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-- the request has no Accept header, ie the header is empty, in this case we use the default format
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Result.set_acceptable (TRUE)
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Result.set_media_type (mime_default)
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else
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-- select the best match, server support, client preferences
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mime_match := mime.best_match (mime_types_supported, header)
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if mime_match.is_empty then
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-- The server does not support any of the media types prefered by the client
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Result.set_acceptable (False)
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Result.set_supported_variants (mime_types_supported)
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else
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-- Set the best match
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Result.set_media_type(mime_match)
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Result.set_acceptable (True)
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Result.set_variant_header
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end
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end
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end
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feature -- Encoding Negotiation
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charset_preference (server_charset_supported : LIST[STRING]; header: detachable READABLE_STRING_8) : CHARACTER_ENCODING_VARIANT_RESULTS
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-- server_charset_supported represent a list of charset supported by the server.
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-- header represent the Accept-Charset header, ie, the client preferences.
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-- Return which Charset to use in a response, if the server support
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-- one Charset, or empty in other case.
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-- Reference: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.2
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local
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charset_match : STRING
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do
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create Result
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if header = Void or else header.is_empty then
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-- the request has no Accept-Charset header, ie the header is empty, in this case use default charset encoding
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-- (UTF-8)
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Result.set_acceptable (TRUE)
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Result.set_character_type (charset_default)
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else
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-- select the best match, server support, client preferences
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charset_match := common.best_match (server_charset_supported, header)
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if charset_match.is_empty then
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-- The server does not support any of the compression types prefered by the client
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Result.set_acceptable (False)
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Result.set_supported_variants (server_charset_supported)
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else
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-- Set the best match
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Result.set_character_type(charset_match)
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Result.set_acceptable (True)
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Result.set_variant_header
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end
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end
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end
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feature -- Compression Negotiation
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encoding_preference (server_encoding_supported : LIST[STRING]; header: detachable READABLE_STRING_8) : COMPRESSION_VARIANT_RESULTS
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-- server_encoding_supported represent a list of encoding supported by the server.
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-- header represent the Accept-Encoding header, ie, the client preferences.
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-- Return which Encoding to use in a response, if the server support
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-- one Encoding, or empty in other case.
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-- Representation: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3
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local
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compression_match : STRING
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do
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create Result
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if header = Void or else header.is_empty then
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-- the request has no Accept-Encoding header, ie the header is empty, in this case do not compress representations
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Result.set_acceptable (TRUE)
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Result.set_compression_type (encoding_default)
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else
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-- select the best match, server support, client preferences
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compression_match := common.best_match (server_encoding_supported, header)
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if compression_match.is_empty then
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-- The server does not support any of the compression types prefered by the client
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Result.set_acceptable (False)
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Result.set_supported_variants (server_encoding_supported)
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else
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-- Set the best match
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Result.set_compression_type(compression_match)
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Result.set_acceptable (True)
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Result.set_variant_header
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end
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end
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end
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feature -- Language Negotiation
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language_preference (server_language_supported : LIST[STRING]; header: detachable READABLE_STRING_8) : LANGUAGE_VARIANT_RESULTS
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-- server_language_supported represent a list of languages supported by the server.
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-- header represent the Accept-Language header, ie, the client preferences.
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-- Return which Language to use in a response, if the server support
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-- one Language, or empty in other case.
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-- Reference: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4
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local
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language_match: STRING
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do
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create Result
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if header = Void or else header.is_empty then
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-- the request has no Accept header, ie the header is empty, in this case we use the default format
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Result.set_acceptable (TRUE)
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Result.set_language_type (language_default)
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else
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-- select the best match, server support, client preferences
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language_match := language.best_match (server_language_supported, header)
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if language_match.is_empty then
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-- The server does not support any of the media types prefered by the client
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Result.set_acceptable (False)
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Result.set_supported_variants (server_language_supported)
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else
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-- Set the best match
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Result.set_language_type(language_match)
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Result.set_acceptable (True)
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Result.set_variant_header
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end
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end
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end
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feature -- Apache Conneg Algorithm
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note
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copyright: "2011-2011, Javier Velilla, Jocelyn Fiat and others"
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license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
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end
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