%% ``Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions 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: mod_responsecontrol.erl,v 1.1 2008/12/17 09:53:35 mikpe Exp $
%%
-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=httpd_util:convert_request_date(LastModified0),
?DEBUG("control_modification_data() -> "
"~n Request-Field: ~s"
"~n FileLastModified: ~p"
"~n FieldValue: ~p",
[HeaderField,ModificationTime,LastModified]),
case LastModified of
bad_date ->
undefined;
_ ->
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
end.
%%----------------------------------------------------------------------
%%Compare to dates on the form {{YYYY,MM,DD},{HH,MIN,SS}}
%%If the first date is the biggest returns biggest1 (read biggestFirst)
%%If the first date is smaller
% compare_date(Date,bad_date)->
% bad_date;
% compare_date({D1,T1},{D2,T2})->
% case compare_date1(D1,D2) of
% equal ->
% compare_date1(T1,T2);
% GTorLT->
% GTorLT
% end.
% compare_date1({T1,T2,T3},{T12,T22,T32}) when T1>T12 ->
% bigger1;
% compare_date1({T1,T2,T3},{T1,T22,T32}) when T2>T22 ->
% bigger1;
% compare_date1({T1,T2,T3},{T1,T2,T32}) when T3>T32 ->
% bigger1;
% compare_date1({T1,T2,T3},{T1,T2,T3})->
% equal;
% compare_date1(_D1,_D2)->
% smaller1.
%% 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([$;,$ |Rest]) ->
[];
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"),
Header = [{code,304},
{etag,httpd_util:create_etag(FileInfo)},
{content_length,0},
{last_modified,httpd_util:rfc1123_date(FileInfo#file_info.mtime)}],
{response,{response,Header,nobody}}.
