1 files changed, 416 insertions, 0 deletions
diff --git a/src/couch_inets/mod_range.erl b/src/couch_inets/mod_range.erl
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+++ b/src/couch_inets/mod_range.erl
@@ -0,0 +1,416 @@
+%% ``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_range).
+-export([do/1]).
+-include("httpd.hrl").
+
+%% do
+
+do(Info) ->
+    ?DEBUG("do -> entry",[]),
+    case Info#mod.method of
+	"GET" ->
+	    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 httpd_util:key1search(Info#mod.parsed_header,
+						       "range") of
+				undefined ->
+				    %Not a range response
+				    {proceed,Info#mod.data};
+				Range ->
+				    %%Control that there weren't a
+				    %%if-range field that stopped The
+				    %%range request in favor for the
+				    %%whole file
+				    case httpd_util:key1search(Info#mod.data,
+							       if_range) of
+					send_file ->
+					    {proceed,Info#mod.data};
+					_undefined ->
+					    do_get_range(Info,Range)
+				    end
+			    end; 			
+			%% A response has been generated or sent!
+			_Response ->
+			    {proceed, Info#mod.data}
+		    end
+	    end;
+	%% Not a GET method!
+	_ ->
+	    {proceed,Info#mod.data}
+    end.
+
+do_get_range(Info,Ranges) ->
+    ?DEBUG("do_get_range -> Request URI: ~p",[Info#mod.request_uri]), 
+     Path = mod_alias:path(Info#mod.data, Info#mod.config_db, 
+			  Info#mod.request_uri),
+    {FileInfo, LastModified} = get_modification_date(Path),
+    send_range_response(Path, Info, Ranges, FileInfo, LastModified).
+
+
+send_range_response(Path, Info, Ranges, FileInfo, LastModified)->
+    case parse_ranges(Ranges) of
+	error->
+	    ?ERROR("send_range_response-> Unparsable range request",[]),
+	    {proceed,Info#mod.data};
+	{multipart,RangeList}->
+	    send_multi_range_response(Path, Info, RangeList);
+	{Start,Stop}->
+	    send_range_response(Path, Info, Start, Stop, FileInfo, 
+				LastModified)
+    end.
+%%More than one range specified
+%%Send a multipart reponse to the user
+%
+%%An example of an multipart range response
+
+% HTTP/1.1 206 Partial Content
+% Date:Wed 15 Nov 1995 04:08:23 GMT
+% Last-modified:Wed 14 Nov 1995 04:08:23 GMT 
+% Content-type: multipart/byteranges; boundary="SeparatorString" 
+%
+% --"SeparatorString"
+% Content-Type: application/pdf
+% Content-Range: bytes 500-600/1010
+% .... The data..... 101 bytes
+%
+% --"SeparatorString"
+% Content-Type: application/pdf
+% Content-Range: bytes 700-1009/1010
+% .... The data.....
+
+
+
+send_multi_range_response(Path,Info,RangeList)->
+    case file:open(Path, [raw,binary]) of
+	{ok, FileDescriptor} ->
+	    file:close(FileDescriptor),
+	    ?DEBUG("send_multi_range_response -> FileDescriptor: ~p",
+		   [FileDescriptor]),
+	    Suffix = httpd_util:suffix(Path),
+	    PartMimeType = httpd_util:lookup_mime_default(Info#mod.config_db,
+							  Suffix,"text/plain"),
+	    {FileInfo,  LastModified} = get_modification_date(Path),
+	    case valid_ranges(RangeList,Path,FileInfo) of
+		{ValidRanges,true}->
+		    ?DEBUG("send_multi_range_response ->Ranges are valid:",[]),
+		    %Apache breaks the standard by sending the size
+		    %field in the Header.
+		    Header = 
+			[{code,206},
+			 {content_type, "multipart/byteranges;boundary" 
+			  "=RangeBoundarySeparator"}, 
+			 {etag, httpd_util:create_etag(FileInfo)} | 
+			 LastModified],
+		    ?DEBUG("send_multi_range_response -> Valid Ranges: ~p",
+			   [RagneList]),
+		    Body = {fun send_multiranges/4,
+			    [ValidRanges, Info, PartMimeType, Path]},
+		    {proceed,[{response,
+			       {response, Header, Body}} | Info#mod.data]};
+		_ ->
+		    {proceed, [{status, {416, "Range not valid",
+					 bad_range_boundaries }}]}
+	    end;
+	{error, _Reason} ->
+	    ?ERROR("do_get -> failed open file: ~p",[_Reason]),
+	    {proceed,Info#mod.data}
+    end.
+
+send_multiranges(ValidRanges,Info,PartMimeType,Path)->    
+    ?DEBUG("send_multiranges -> Start sending the ranges",[]),
+    case file:open(Path, [raw,binary]) of
+	{ok,FileDescriptor} ->
+	    lists:foreach(fun(Range)->
+				  send_multipart_start(Range,
+						       Info,
+						       PartMimeType,
+						       FileDescriptor)
+			  end,ValidRanges),
+	    file:close(FileDescriptor),
+	    %%Sends an end of the multipart
+	    httpd_socket:deliver(Info#mod.socket_type,Info#mod.socket,
+				 "\r\n--RangeBoundarySeparator--"),
+	    sent;
+	_ ->
+	    close
+    end.
+   
+send_multipart_start({{Start,End},{StartByte,EndByte,Size}},Info,
+		     PartMimeType,FileDescriptor)when StartByte<Size->
+    PartHeader=["\r\n--RangeBoundarySeparator\r\n","Content-type: ",
+		PartMimeType,"\r\n",
+                "Content-Range:bytes=",integer_to_list(StartByte),"-",
+		integer_to_list(EndByte),"/",
+		integer_to_list(Size),"\r\n\r\n"],
+    send_part_start(Info#mod.socket_type, Info#mod.socket, PartHeader,
+		    FileDescriptor, Start, End);
+
+
+send_multipart_start({{Start,End},{StartByte,EndByte,Size}}, Info,
+		     PartMimeType, FileDescriptor)->
+    PartHeader=["\r\n--RangeBoundarySeparator\r\n","Content-type: ",
+		PartMimeType,"\r\n",
+                "Content-Range:bytes=",integer_to_list(Size-(StartByte-Size)),
+		"-",integer_to_list(EndByte),"/",
+		integer_to_list(Size),"\r\n\r\n"],
+    send_part_start(Info#mod.socket_type, Info#mod.socket, PartHeader,
+		    FileDescriptor, Start, End).
+
+send_part_start(SocketType, Socket, PartHeader, FileDescriptor, Start, End)->
+    case httpd_socket:deliver(SocketType, Socket, PartHeader) of
+	ok ->
+	    send_part_start(SocketType,Socket,FileDescriptor,Start,End);
+	_ ->
+	    close
+    end.    
+
+send_range_response(Path, Info, Start, Stop, FileInfo, LastModified)->
+    case file:open(Path, [raw,binary]) of
+	{ok, FileDescriptor} ->
+	    file:close(FileDescriptor),
+	    ?DEBUG("send_range_response -> FileDescriptor: ~p",
+		   [FileDescriptor]),
+	    Suffix = httpd_util:suffix(Path),
+	    MimeType = httpd_util:lookup_mime_default(Info#mod.config_db,
+						      Suffix,"text/plain"),
+	    Size = get_range_size(Start,Stop,FileInfo),
+	    case valid_range(Start,Stop,FileInfo) of
+		{true,StartByte,EndByte,TotByte}->
+		    Head =[{code,206},{content_type, MimeType}, 
+			   {etag, httpd_util:create_etag(FileInfo)},
+			   {content_range,["bytes=",
+					   integer_to_list(StartByte),"-",
+					   integer_to_list(EndByte),"/",
+					   integer_to_list(TotByte)]},
+			   {content_length, Size} | LastModified],
+		    BodyFunc = fun send_range_body/5,
+		    Arg = [Info#mod.socket_type, 
+			  Info#mod.socket, Path, Start, Stop], 
+		    {proceed,[{response,{response ,Head,  {BodyFunc,Arg}}}|
+			      Info#mod.data]};
+		{false,Reason} ->
+		    {proceed, [{status, {416, Reason, bad_range_boundaries }}]}
+	    end;
+	{error, _Reason} ->
+	    ?ERROR("send_range_response -> failed open file: ~p",[_Reason]),
+	    {proceed,Info#mod.data}
+    end.
+
+
+send_range_body(SocketType,Socket,Path,Start,End) ->
+    ?DEBUG("mod_range -> send_range_body",[]),
+    case file:open(Path, [raw,binary]) of
+	{ok,FileDescriptor} ->
+	    send_part_start(SocketType,Socket,FileDescriptor,Start,End),
+	    file:close(FileDescriptor);
+	_ ->
+	    close
+    end.
+
+send_part_start(SocketType,Socket,FileDescriptor,Start,End) ->
+    case Start of
+	from_end ->
+	    file:position(FileDescriptor,{eof,End}),
+	    send_body(SocketType,Socket,FileDescriptor);
+	from_start ->
+	    file:position(FileDescriptor,{bof,End}),
+	    send_body(SocketType,Socket,FileDescriptor);
+	Byte when integer(Byte) ->
+	    file:position(FileDescriptor,{bof,Start}),
+	    send_part(SocketType,Socket,FileDescriptor,End)
+    end,
+    sent.
+
+
+%%This function could replace send_body by calling it with Start=0 end
+%%=FileSize But i gues it would be stupid when we look at performance
+send_part(SocketType,Socket,FileDescriptor,End)->
+    case file:position(FileDescriptor,{cur,0}) of
+	{ok,NewPos} ->
+	   if 
+	       NewPos > End ->
+		   ok;
+	       true ->
+		   Size = get_file_chunk_size(NewPos,End,?FILE_CHUNK_SIZE),
+		   case file:read(FileDescriptor,Size) of
+		       eof ->
+			   ok;
+		       {error, _Reason} ->
+			   ok;
+		       {ok,Binary} ->
+			   case httpd_socket:deliver(SocketType,Socket,
+						     Binary) of
+			       socket_closed ->
+				   ?LOG("send_range of body -> socket "   
+					"closed while sending",[]),
+				   socket_close;
+			       _ ->
+				   send_part(SocketType,Socket,
+					     FileDescriptor,End)
+			   end
+		   end
+	   end;
+	_->
+	    ok
+    end.
+
+%% validate that the range is in the limits of the file
+valid_ranges(RangeList, _Path, FileInfo)->
+    lists:mapfoldl(fun({Start,End},Acc)->
+			case Acc of 
+			    true ->
+				case valid_range(Start,End,FileInfo) of
+				    {true,StartB,EndB,Size}->
+					{{{Start,End},
+					  {StartB,EndB,Size}},true};
+				    _ ->
+					false
+				end;
+			    _ ->
+				{false,false}
+			end
+		   end,true,RangeList).
+				 
+			      
+
+valid_range(from_end,End,FileInfo)->
+    Size=FileInfo#file_info.size,
+    if
+	End < Size ->
+	    {true,(Size+End),Size-1,Size};
+	true ->
+	    false
+    end;
+valid_range(from_start,End,FileInfo)->
+  Size=FileInfo#file_info.size,
+    if
+	End < Size ->
+	    {true,End,Size-1,Size};
+	true ->
+	    false
+    end;
+
+valid_range(Start,End,FileInfo)when Start=<End->
+    case FileInfo#file_info.size of
+	FileSize when Start< FileSize ->
+	    case FileInfo#file_info.size of
+		Size when End<Size ->
+		    {true,Start,End,FileInfo#file_info.size};
+		Size ->
+		    {true,Start,Size-1,Size}
+	    end;
+	_->
+	    {false,"The size of the range is negative"}
+    end;
+		      
+valid_range(_Start,_End,_FileInfo)->
+    {false,"Range starts out of file boundaries"}.
+%% Find the modification date of the file
+get_modification_date(Path)->
+    case file:read_file_info(Path) of
+	{ok, FileInfo0} ->
+	    case (catch httpd_util:rfc1123_date(FileInfo0#file_info.mtime)) of
+		Date when is_list(Date) ->
+		    {FileInfo0, [{last_modified, Date}]};
+		_ ->
+		    {FileInfo0, []}
+	    end;
+	_ ->
+	    {#file_info{}, []}
+    end.
+
+%Calculate the size of the chunk to read
+	
+get_file_chunk_size(Position, End, DefaultChunkSize) 
+  when (Position+DefaultChunkSize) =< End->
+    DefaultChunkSize;
+get_file_chunk_size(Position, End, _DefaultChunkSize)->
+    (End-Position) +1.
+
+
+
+%Get the size of the range to send. Remember that
+%A range is from startbyte up to endbyte which means that
+%the nuber of byte in a range is (StartByte-EndByte)+1
+
+get_range_size(from_end, Stop, _FileInfo)->
+    integer_to_list(-1*Stop);
+
+get_range_size(from_start, StartByte, FileInfo) ->
+    integer_to_list((((FileInfo#file_info.size)-StartByte)));
+
+get_range_size(StartByte, EndByte, _FileInfo) ->
+    integer_to_list((EndByte-StartByte)+1).
+
+parse_ranges("\bytes\=" ++ Ranges)->
+    parse_ranges("bytes\=" ++ Ranges);
+parse_ranges("bytes\=" ++ Ranges)->
+    case string:tokens(Ranges,", ") of
+       [Range] ->
+	   parse_range(Range);
+       [Range1|SplittedRanges]->
+	   {multipart,lists:map(fun parse_range/1,[Range1|SplittedRanges])}
+    end;
+%Bad unit
+parse_ranges(Ranges)->
+    io:format("Bad Ranges : ~p",[Ranges]),
+    error.
+%Parse the range  specification from the request to {Start,End}
+%Start=End : Numreric string | []
+
+parse_range(Range)->
+    format_range(split_range(Range,[],[])).
+format_range({[],BytesFromEnd})->
+    {from_end,-1*(list_to_integer(BytesFromEnd))};
+format_range({StartByte,[]})->    
+    {from_start,list_to_integer(StartByte)};
+format_range({StartByte,EndByte})->        
+    {list_to_integer(StartByte),list_to_integer(EndByte)}.
+%Last case return the splitted range
+split_range([],Current,Other)->
+    {lists:reverse(Other),lists:reverse(Current)};
+
+split_range([$-|Rest],Current,Other)->
+    split_range(Rest,Other,Current);
+
+split_range([N|Rest],Current,End) ->
+    split_range(Rest,[N|Current],End).
+
+send_body(SocketType,Socket,FileDescriptor) ->
+    case file:read(FileDescriptor,?FILE_CHUNK_SIZE) of
+	{ok,Binary} ->
+	    ?DEBUG("send_body -> send another chunk: ~p",[size(Binary)]),
+	    case httpd_socket:deliver(SocketType,Socket,Binary) of
+		socket_closed ->
+		    ?LOG("send_body -> socket closed while sending",[]),
+		    socket_close;
+		_ ->
+		    send_body(SocketType,Socket,FileDescriptor)
+	    end;
+	eof ->
+	    ?DEBUG("send_body -> done with this file",[]),
+	    eof
+    end.