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+%% ``The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved via the world wide web at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% The Initial Developer of the Original Code is Ericsson Utvecklings AB.
+%% Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
+%% AB. All Rights Reserved.''
+%%
+%% $Id$
+%%
+
+-module(mod_responsecontrol).
+-export([do/1]).
+
+-include("httpd.hrl").
+
+do(Info) ->
+ ?DEBUG("do -> response_control",[]),
+ case httpd_util:key1search(Info#mod.data,status) of
+ %% A status code has been generated!
+ {_StatusCode, _PhraseArgs, _Reason} ->
+ {proceed, Info#mod.data};
+ %% No status code has been generated!
+ undefined ->
+ case httpd_util:key1search(Info#mod.data, response) of
+ %% No response has been generated!
+ undefined ->
+ case do_responsecontrol(Info) of
+ continue ->
+ {proceed, Info#mod.data};
+ Response ->
+ {proceed,[Response | Info#mod.data]}
+ end;
+ %% A response has been generated or sent!
+ _Response ->
+ {proceed, Info#mod.data}
+ end
+ end.
+
+%%----------------------------------------------------------------------
+%%Control that the request header did not contians any limitations
+%%wheather a response shall be createed or not
+%%----------------------------------------------------------------------
+do_responsecontrol(Info) ->
+ ?DEBUG("do_response_control -> Request URI: ~p",[Info#mod.request_uri]),
+ Path = mod_alias:path(Info#mod.data, Info#mod.config_db,
+ Info#mod.request_uri),
+ case file:read_file_info(Path) of
+ {ok, FileInfo} ->
+ control(Path, Info, FileInfo);
+ _ ->
+ %% The requested asset is not a plain file and then it must
+ %% be generated everytime its requested
+ continue
+ end.
+
+%%----------------------------------------------------------------------
+%%Control the If-Match, If-None-Match, and If-Modified-Since
+%%----------------------------------------------------------------------
+
+
+%% If a client sends more then one of the if-XXXX fields in a request
+%% The standard says it does not specify the behaviuor so I specified it :-)
+%% The priority between the fields is
+%% 1.If-modified
+%% 2.If-Unmodified
+%% 3.If-Match
+%% 4.If-Nomatch
+
+%% This means if more than one of the fields are in the request the
+%% field with highest priority will be used
+
+%%If the request is a range request the If-Range field will be the winner.
+
+control(Path, Info, FileInfo) ->
+ case control_range(Path, Info, FileInfo) of
+ undefined ->
+ case control_Etag(Path, Info, FileInfo) of
+ undefined ->
+ case control_modification(Path, Info, FileInfo) of
+ continue ->
+ continue;
+ ReturnValue ->
+ send_return_value(ReturnValue, FileInfo)
+ end;
+ continue ->
+ continue;
+ ReturnValue ->
+ send_return_value(ReturnValue, FileInfo)
+ end;
+ Response->
+ Response
+ end.
+
+%%----------------------------------------------------------------------
+%%If there are both a range and an if-range field control if
+%%----------------------------------------------------------------------
+control_range(Path,Info,FileInfo) ->
+ case httpd_util:key1search(Info#mod.parsed_header, "range") of
+ undefined->
+ undefined;
+ _Range ->
+ case httpd_util:key1search(Info#mod.parsed_header,"if-range") of
+ undefined ->
+ undefined;
+ EtagOrDate ->
+ control_if_range(Path,Info,FileInfo,EtagOrDate)
+ end
+ end.
+
+control_if_range(_Path, Info, FileInfo, EtagOrDate) ->
+ case httpd_util:convert_request_date(strip_date(EtagOrDate)) of
+ bad_date ->
+ FileEtag=httpd_util:create_etag(FileInfo),
+ case FileEtag of
+ EtagOrDate ->
+ continue;
+ _ ->
+ {if_range,send_file}
+ end;
+ _ErlDate ->
+ %%We got the date in the request if it is
+ case control_modification_data(Info, FileInfo#file_info.mtime,
+ "if-range") of
+ modified ->
+ {if_range,send_file};
+ _UnmodifiedOrUndefined->
+ continue
+ end
+ end.
+
+%%----------------------------------------------------------------------
+%%Controls the values of the If-Match and I-None-Mtch
+%%----------------------------------------------------------------------
+control_Etag(Path, Info, FileInfo)->
+ FileEtag = httpd_util:create_etag(FileInfo),
+ %%Control if the E-Tag for the resource matches one of the Etags in
+ %%the -if-match header field
+ case control_match(Info, FileInfo, "if-match", FileEtag) of
+ nomatch ->
+ %%None of the Etags in the if-match field matched the current
+ %%Etag for the resource return a 304
+ {412, Info, Path};
+ match ->
+ continue;
+ undefined ->
+ case control_match(Info, FileInfo, "if-none-match", FileEtag) of
+ nomatch ->
+ continue;
+ match ->
+ case Info#mod.method of
+ "GET" ->
+ {304, Info, Path};
+ "HEAD" ->
+ {304, Info, Path};
+ _OtherrequestMethod ->
+ {412, Info, Path}
+ end;
+ undefined ->
+ undefined
+ end
+ end.
+
+%%----------------------------------------------------------------------
+%%Control if there are any Etags for HeaderField in the request if so
+%%Control if they match the Etag for the requested file
+%%----------------------------------------------------------------------
+control_match(Info, _FileInfo, HeaderField, FileEtag)->
+ case split_etags(httpd_util:key1search(Info#mod.parsed_header,
+ HeaderField)) of
+ undefined->
+ undefined;
+ Etags->
+ %%Control that the match any star not is availible
+ case lists:member("*",Etags) of
+ true->
+ match;
+ false->
+ compare_etags(FileEtag, Etags)
+ end
+ end.
+
+%%----------------------------------------------------------------------
+%%Split the etags from the request
+%%----------------------------------------------------------------------
+split_etags(undefined)->
+ undefined;
+split_etags(Tags) ->
+ string:tokens(Tags,", ").
+
+%%----------------------------------------------------------------------
+%%Control if the etag for the file is in the list
+%%----------------------------------------------------------------------
+compare_etags(Tag,Etags) ->
+ case lists:member(Tag,Etags) of
+ true ->
+ match;
+ _ ->
+ nomatch
+ end.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% %%
+%%Control if the file is modificated %%
+%% %%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+%%----------------------------------------------------------------------
+%%Control the If-Modified-Since and If-Not-Modified-Since header fields
+%%----------------------------------------------------------------------
+control_modification(Path,Info,FileInfo)->
+ ?DEBUG("control_modification() -> entry",[]),
+ case control_modification_data(Info,
+ FileInfo#file_info.mtime,
+ "if-modified-since") of
+ modified->
+ continue;
+ unmodified->
+ {304, Info, Path};
+ undefined ->
+ case control_modification_data(Info,
+ FileInfo#file_info.mtime,
+ "if-unmodified-since") of
+ modified ->
+ {412, Info, Path};
+ _ContinueUndefined ->
+ continue
+ end
+ end.
+
+%%----------------------------------------------------------------------
+%%Controls the date from the http-request if-modified-since and
+%%if-not-modified-since against the modification data of the
+%%File
+%%----------------------------------------------------------------------
+%%Info is the record about the request
+%%ModificationTime is the time the file was edited last
+%%Header Field is the name of the field to control
+
+control_modification_data(Info, ModificationTime, HeaderField)->
+ case strip_date(httpd_util:key1search(Info#mod.parsed_header,
+ HeaderField)) of
+ undefined->
+ undefined;
+ LastModified0 ->
+ LastModified = calendar:universal_time_to_local_time(
+ httpd_util:convert_request_date(LastModified0)),
+ ?DEBUG("control_modification_data() -> "
+ "~n Request-Field: ~s"
+ "~n FileLastModified: ~p"
+ "~n FieldValue: ~p",
+ [HeaderField, ModificationTime, LastModified]),
+ FileTime =
+ calendar:datetime_to_gregorian_seconds(ModificationTime),
+ FieldTime = calendar:datetime_to_gregorian_seconds(LastModified),
+ if
+ FileTime =< FieldTime ->
+ ?DEBUG("File unmodified~n", []), unmodified;
+ FileTime >= FieldTime ->
+ ?DEBUG("File modified~n", []), modified
+ end
+ end.
+
+%% IE4 & NS4 sends an extra '; length=xxxx' string at the end of the If-Modified-Since
+%% header, we detect this and ignore it (the RFCs does not mention this).
+strip_date(undefined) ->
+ undefined;
+strip_date([]) ->
+ [];
+strip_date([$;,$ | _]) ->
+ [];
+strip_date([C | Rest]) ->
+ [C | strip_date(Rest)].
+
+send_return_value({412,_,_}, _FileInfo)->
+ {status,{412,none,"Precondition Failed"}};
+
+send_return_value({304,Info,Path}, FileInfo)->
+ Suffix = httpd_util:suffix(Path),
+ MimeType = httpd_util:lookup_mime_default(Info#mod.config_db,Suffix,
+ "text/plain"),
+ LastModified =
+ case (catch httpd_util:rfc1123_date(FileInfo#file_info.mtime)) of
+ Date when is_list(Date) ->
+ [{last_modified, Date}];
+ _ -> %% This will rarly happen, but could happen
+ %% if a computer is wrongly configured.
+ []
+ end,
+
+ Header = [{code,304},
+ {etag, httpd_util:create_etag(FileInfo)},
+ {content_length,"0"}, {mime_type, MimeType} | LastModified],
+ {response, {response, Header, nobody}}.
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-09 00:33:53 +0000