%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2001-2009. All Rights Reserved.
%%
%% 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 online 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.
%%
%% %CopyrightEnd%
%%
%%
-module(mod_responsecontrol).
-export([do/1]).
-include("httpd.hrl").
do(Info) ->
?DEBUG("do -> response_control",[]),
case proplists:get_value(status, Info#mod.data) of
%% A status code has been generated!
{_StatusCode, _PhraseArgs, _Reason} ->
{proceed, Info#mod.data};
%% No status code has been generated!
undefined ->
case proplists:get_value(response, Info#mod.data) 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 proplists:get_value("range", Info#mod.parsed_header) of
undefined->
undefined;
_Range ->
case proplists:get_value("if-range", Info#mod.parsed_header) 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(proplists:get_value(HeaderField,
Info#mod.parsed_header)) 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(proplists:get_value(HeaderField,
Info#mod.parsed_header)) 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}}.
