rewrite replicator using OTP behaviours

- only one instance of given source->target runs at a time
- supervisor restarts replications that terminate abnormally
- pull repl. streams attachments directly to disk
- improved memory utilization
- temporarily rollback parallel async doc GETs during pull rep.
- replication updates show up in Futon Status window


git-svn-id: https://svn.apache.org/repos/asf/couchdb/trunk@751305 13f79535-47bb-0310-9956-ffa450edef68

8 files changed, 810 insertions, 449 deletions

diff --git a/src/couchdb/Makefile.am b/src/couchdb/Makefile.am
index 51e4878c..8bea5290 100644
--- a/src/couchdb/Makefile.am
+++ b/src/couchdb/Makefile.am
@@ -64,6 +64,7 @@ source_files = \
     couch_query_servers.erl \
     couch_ref_counter.erl \
     couch_rep.erl \
+    couch_rep_sup.erl \
     couch_server.erl \
     couch_server_sup.erl \
     couch_stats_aggregator.erl \
@@ -104,6 +105,7 @@ compiled_files = \
     couch_query_servers.beam \
     couch_ref_counter.beam \
     couch_rep.beam \
+    couch_rep_sup.beam \
     couch_server.beam \
     couch_server_sup.beam \
     couch_stats_aggregator.beam \
@@ -139,6 +141,7 @@ compiled_files = \
 #     couch_log.html \
 #     couch_query_servers.html \
 #     couch_rep.html \
+#     couch_rep_sup.html \
 #     couch_server.html \
 #     couch_server_sup.html \
 #     couch_stream.html \
diff --git a/src/couchdb/couch_doc.erl b/src/couchdb/couch_doc.erl
index 1eb1575a..9860ac0c 100644
--- a/src/couchdb/couch_doc.erl
+++ b/src/couchdb/couch_doc.erl
@@ -51,7 +51,13 @@ to_json_revs_info(Meta) ->
 
 to_json_attachment_stubs(Attachments) ->
     BinProps = lists:map(
-        fun({Name, {Type, BinValue}}) ->
+        fun({Name, {Type, {_RcvFun, Length}}}) ->
+            {Name, {[
+                {<<"stub">>, true},
+                {<<"content_type">>, Type},
+                {<<"length">>, Length}
+            ]}};
+        ({Name, {Type, BinValue}}) ->
             {Name, {[
                 {<<"stub">>, true},
                 {<<"content_type">>, Type},
@@ -66,7 +72,13 @@ to_json_attachment_stubs(Attachments) ->
 
 to_json_attachments(Attachments) ->
     BinProps = lists:map(
-        fun({Name, {Type, BinValue}}) ->
+        fun({Name, {Type, {RcvFun, Length}}}) ->
+            Data = read_streamed_attachment(RcvFun, Length, _Acc = []),
+            {Name, {[
+                {<<"content_type">>, Type},
+                {<<"data">>, couch_util:encodeBase64(Data)}
+            ]}};
+        ({Name, {Type, BinValue}}) ->
             {Name, {[
                 {<<"content_type">>, Type},
                 {<<"data">>, couch_util:encodeBase64(bin_to_binary(BinValue))}
@@ -100,7 +112,9 @@ from_json_obj({Props}) ->
     Bins = lists:flatmap(fun({Name, {BinProps}}) ->
         case proplists:get_value(<<"stub">>, BinProps) of
         true ->
-            [{Name, stub}];
+            Type = proplists:get_value(<<"content_type">>, BinProps),
+            Length = proplists:get_value(<<"length">>, BinProps),
+            [{Name, {stub, Type, Length}}];
         _ ->
             Value = proplists:get_value(<<"data">>, BinProps),
             Type = proplists:get_value(<<"content_type">>, BinProps,
@@ -225,7 +239,7 @@ has_stubs(#doc{attachments=Bins}) ->
     has_stubs(Bins);
 has_stubs([]) ->
     false;
-has_stubs([{_Name, stub}|_]) ->
+has_stubs([{_Name, {stub, _, _}}|_]) ->
     true;
 has_stubs([_Bin|Rest]) ->
     has_stubs(Rest).
@@ -233,9 +247,15 @@ has_stubs([_Bin|Rest]) ->
 merge_stubs(#doc{attachments=MemBins}=StubsDoc, #doc{attachments=DiskBins}) ->
     BinDict = dict:from_list(DiskBins),
     MergedBins = lists:map(
-        fun({Name, stub}) ->
+        fun({Name, {stub, _, _}}) ->
             {Name, dict:fetch(Name, BinDict)};
         ({Name, Value}) ->
             {Name, Value}
         end, MemBins),
     StubsDoc#doc{attachments= MergedBins}.
+
+read_streamed_attachment(_RcvFun, 0, Acc) ->
+    list_to_binary(lists:reverse(Acc));
+read_streamed_attachment(RcvFun, LenLeft, Acc) ->
+    Bin = RcvFun(),
+    read_streamed_attachment(RcvFun, LenLeft - size(Bin), [Bin|Acc]).
diff --git a/src/couchdb/couch_rep.erl b/src/couchdb/couch_rep.erl
index e0c4d470..3df2d821 100644
--- a/src/couchdb/couch_rep.erl
+++ b/src/couchdb/couch_rep.erl
@@ -11,170 +11,343 @@
 % the License.
 
 -module(couch_rep).
+-behaviour(gen_server).
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, 
+    code_change/3]).
+
+-export([replicate/3]).
+
+-include_lib("couch_db.hrl").
+
+%% @spec replicate(Source::binary(), Target::binary(), Options::proplist()) -> 
+%%      {ok, Stats} | {error, Reason}
+%% @doc Triggers a replication.  Stats is a JSON Object with the following 
+%%      keys: session_id (UUID), source_last_seq (integer), and history (array).
+%%      Each element of the history is an Object with keys start_time, end_time,
+%%      start_last_seq, end_last_seq, missing_checked, missing_found, docs_read,
+%%      and docs_written.
+%%
+%%      The supervisor will try to restart the replication in case of any error
+%%      other than shutdown.  Just call this function again to listen for the 
+%%      result of the retry.
+replicate(Source, Target, Options) ->
+    Id = <<Source/binary, ":", Target/binary>>,
+    Args = [?MODULE, [Source,Target,Options], []],
+    
+    Replicator = {Id,
+        {gen_server, start_link, Args},
+        transient,
+        10000,
+        worker,
+        [?MODULE]
+    },
+    
+    Server = case supervisor:start_child(couch_rep_sup, Replicator) of
+        {ok, Pid} -> 
+            ?LOG_INFO("starting new replication ~p at ~p", [Id, Pid]),
+            Pid;
+        {error, already_present} ->
+            case supervisor:restart_child(couch_rep_sup, Id) of
+                {ok, Pid} -> 
+                    ?LOG_INFO("starting replication ~p at ~p", [Id, Pid]),
+                    Pid;
+                {error, running} -> 
+                    %% this error occurs if multiple replicators are racing
+                    %% each other to start and somebody else won.  Just grab
+                    %% the Pid by calling start_child again.
+                    {error, {already_started, Pid}} = 
+                        supervisor:start_child(couch_rep_sup, Replicator),
+                    ?LOG_INFO("replication ~p already running at ~p", [Id, Pid]),
+                    Pid
+            end;
+        {error, {already_started, Pid}} -> 
+            ?LOG_INFO("replication ~p already running at ~p", [Id, Pid]),
+            Pid
+    end,
+    
+    case gen_server:call(Server, get_result, infinity) of 
+        retry -> replicate(Source, Target, Options);
+        Else -> Else
+    end.
 
--include("couch_db.hrl").
+%%=============================================================================
+%% gen_server callbacks
+%%=============================================================================
 
 -record(http_db, {
     uri,
     headers
 }).
 
--export([replicate/2, replicate/3]).
-
-url_encode(Bin) when is_binary(Bin) ->
-    url_encode(binary_to_list(Bin));
-url_encode([H|T]) ->
-    if
-    H >= $a, $z >= H ->
-        [H|url_encode(T)];
-    H >= $A, $Z >= H ->
-        [H|url_encode(T)];
-    H >= $0, $9 >= H ->
-        [H|url_encode(T)];
-    H == $_; H == $.; H == $-; H == $: ->
-        [H|url_encode(T)];
-    true ->
-        case lists:flatten(io_lib:format("~.16.0B", [H])) of
-        [X, Y] ->
-            [$%, X, Y | url_encode(T)];
-        [X] ->
-            [$%, $0, X | url_encode(T)]
-        end
-    end;
-url_encode([]) ->
-    [].
-
-
-replicate(DbNameA, DbNameB) ->
-    replicate(DbNameA, DbNameB, []).
+-record(state, {
+    context,
+    current_seq,
+    source,
+    target,
+    stats,
+    enum_pid,
+    docs_buffer = [],
+    listeners = []
+}).
 
-replicate(Source, Target, Options) ->
-    {ok, DbSrc} = open_db(Source,
-            proplists:get_value(source_options, Options, [])),
-    try
-        {ok, DbTgt} = open_db(Target,
-                proplists:get_value(target_options, Options, [])),
-        try
-            replicate2(Source, DbSrc, Target, DbTgt, Options)
-        after
-            close_db(DbTgt)
-        end        
-    after
-        close_db(DbSrc)
-    end.
+init([Source, Target, Options]) ->
+    {ok, DbSrc} = 
+        open_db(Source, proplists:get_value(source_options, Options, [])),
+    {ok, DbTgt} = 
+        open_db(Target, proplists:get_value(target_options, Options, [])),
     
-replicate2(Source, DbSrc, Target, DbTgt, Options) ->
-    {ok, HostName} = inet:gethostname(),
-    HostNameBin = list_to_binary(HostName),
-    RepRecKey = <<?LOCAL_DOC_PREFIX, HostNameBin/binary, 
-            ":", Source/binary, ":", Target/binary>>,
-    
-    ReplicationStartTime = httpd_util:rfc1123_date(),
+    {ok, Host} = inet:gethostname(),
+    HostBin = list_to_binary(Host),
+    DocKey = <<?LOCAL_DOC_PREFIX, HostBin/binary, ":", Source/binary, ":", 
+        Target/binary>>,
     
     {ok, InfoSrc} = get_db_info(DbSrc),
     {ok, InfoTgt} = get_db_info(DbTgt),
     
+    ReplicationStartTime = httpd_util:rfc1123_date(),
     SrcInstanceStartTime = proplists:get_value(instance_start_time, InfoSrc),
     TgtInstanceStartTime = proplists:get_value(instance_start_time, InfoTgt),
     
     case proplists:get_value(full, Options, false)
         orelse proplists:get_value("full", Options, false) of
     true ->
-         RepRecSrc = RepRecTgt = #doc{id=RepRecKey};
+        RepRecSrc = RepRecTgt = #doc{id=DocKey};
     false ->
-        RepRecSrc =
-        case open_doc(DbSrc, RepRecKey, []) of
-        {ok, SrcDoc} ->
-            ?LOG_DEBUG("Found existing replication record on source", []),
-            SrcDoc;
-        _ -> #doc{id=RepRecKey}
+        RepRecSrc = case open_doc(DbSrc, DocKey, []) of
+            {ok, SrcDoc} ->
+                ?LOG_DEBUG("Found existing replication record on source", []),
+                SrcDoc;
+            _ -> #doc{id=DocKey}
         end,
 
-        RepRecTgt =
-        case open_doc(DbTgt, RepRecKey, []) of
-        {ok, TgtDoc} ->
-            ?LOG_DEBUG("Found existing replication record on target", []),
-            TgtDoc;
-        _ -> #doc{id=RepRecKey}
+        RepRecTgt = case open_doc(DbTgt, DocKey, []) of
+            {ok, TgtDoc} ->
+                ?LOG_DEBUG("Found existing replication record on target", []),
+                TgtDoc;
+            _ -> #doc{id=DocKey}
         end
     end,
 
     #doc{body={OldRepHistoryProps}} = RepRecSrc,
     #doc{body={OldRepHistoryPropsTrg}} = RepRecTgt,
 
-    SeqNum =
-    case OldRepHistoryProps == OldRepHistoryPropsTrg of
-    true ->
-        % if the records are identical, then we have a valid replication history
-        proplists:get_value(<<"source_last_seq">>, OldRepHistoryProps, 0);
-    false ->
-        ?LOG_INFO("Replication records differ. "
+    SeqNum = case OldRepHistoryProps == OldRepHistoryPropsTrg of
+        true ->
+            % if the records are identical, then we have a valid replication history
+            proplists:get_value(<<"source_last_seq">>, OldRepHistoryProps, 0);
+        false ->
+            ?LOG_INFO("Replication records differ. "
                 "Performing full replication instead of incremental.", []),
-        ?LOG_DEBUG("Record on source:~p~nRecord on target:~p~n", [OldRepHistoryProps, OldRepHistoryPropsTrg]),
+            ?LOG_DEBUG("Record on source:~p~nRecord on target:~p~n", 
+                [OldRepHistoryProps, OldRepHistoryPropsTrg]),
         0
     end,
+    
+    Context = [
+        {start_seq, SeqNum},
+        {history, OldRepHistoryProps},
+        {rep_starttime, ReplicationStartTime},
+        {src_starttime, SrcInstanceStartTime},
+        {tgt_starttime, TgtInstanceStartTime},
+        {src_record, RepRecSrc},
+        {tgt_record, RepRecTgt}
+    ],
+    
+    Stats = ets:new(replication_stats, [set, private]),
+    ets:insert(Stats, {total_revs,0}),
+    ets:insert(Stats, {missing_revs, 0}),
+    ets:insert(Stats, {docs_read, 0}),
+    ets:insert(Stats, {docs_written, 0}),
+    
+    couch_task_status:add_task("Replication", <<Source/binary, " -> ",
+        Target/binary>>, "Starting"),
+    
+    Parent = self(),
+    Pid = spawn_link(fun() -> enum_docs_since(Parent,DbSrc,DbTgt,{SeqNum,0}) end),
+    
+    State = #state{
+        context = Context,
+        current_seq = SeqNum,
+        enum_pid = Pid,
+        source = DbSrc,
+        target = DbTgt,
+        stats = Stats
+    },
+    
+    {ok, State}.
+
 
-    {NewSeqNum, Stats} = pull_rep(DbTgt, DbSrc, SeqNum),    
+handle_call(get_result, From, #state{listeners=L} = State) ->
+    {noreply, State#state{listeners=[From|L]}};
+
+handle_call({replicate_doc, {Id, Revs}}, {Pid,_}, #state{enum_pid=Pid} = State) ->
+    #state{
+        docs_buffer = Buffer,
+        source = Source,
+        target = Target,
+        stats = Stats
+    } = State,
     
-    case NewSeqNum == SeqNum andalso OldRepHistoryProps /= [] of
-    true ->
-        % nothing changed, don't record results
-        {ok, {OldRepHistoryProps}};
-    false ->
-        % commit changes to both src and tgt. The src because if changes
-        % we replicated are lost, we'll record the a seq number of ahead 
-        % of what was committed and therefore lose future changes with the
-        % same seq nums.
-        
-        {ok, SrcInstanceStartTime2} = ensure_full_commit(DbSrc),
-        {ok, TgtInstanceStartTime2} = ensure_full_commit(DbTgt),
-        
-        RecordSeqNum =
-        if SrcInstanceStartTime2 == SrcInstanceStartTime andalso
-                TgtInstanceStartTime2 == TgtInstanceStartTime ->
-            NewSeqNum;
+    ets:update_counter(Stats, missing_revs, length(Revs)),
+    
+    %% get document(s)
+    {ok, DocResults} = open_doc_revs(Source, Id, Revs, [latest]),
+    Docs = [RevDoc || {ok, RevDoc} <- DocResults],
+    ets:update_counter(Stats, docs_read, length(Docs)),
+    
+    %% save them (maybe in a buffer)
+    NewBuffer = case couch_util:should_flush() of
         true ->
-            ?LOG_INFO("A server has restarted sinced replication start. "
-                "Not recording the new sequence number to ensure the "
-                "replication is redone and documents reexamined.", []),
-            SeqNum
-        end,
-        
-        HistEntries =[
-            {
-                [{<<"start_time">>, list_to_binary(ReplicationStartTime)},
-                {<<"end_time">>, list_to_binary(httpd_util:rfc1123_date())},
-                {<<"start_last_seq">>, SeqNum},
-                {<<"end_last_seq">>, NewSeqNum} | Stats]}
-            | proplists:get_value("history", OldRepHistoryProps, [])],
-        % something changed, record results
-        NewRepHistory =
-            {
-                [{<<"session_id">>, couch_util:new_uuid()},
-                {<<"source_last_seq">>, RecordSeqNum},
-                {<<"history">>, lists:sublist(HistEntries, 50)}]},
-
-        {ok, _} = update_doc(DbSrc, RepRecSrc#doc{body=NewRepHistory}, []),
-        {ok, _} = update_doc(DbTgt, RepRecTgt#doc{body=NewRepHistory}, []),
-        {ok, NewRepHistory}
+            Docs2 = lists:flatten([Docs|Buffer]),
+            ok = update_docs(Target, Docs2, [], false),
+            ets:update_counter(Stats, docs_written, length(Docs2)),
+            [];
+        false ->
+            [Docs | Buffer]
+    end,
+    
+    {reply, ok, State#state{docs_buffer=NewBuffer}};
+
+handle_call({fin, {LastSeq, RevsCount}}, {Pid,_}, #state{enum_pid=Pid} = State) ->
+    ets:update_counter(State#state.stats, total_revs, RevsCount),
+    {stop, normal, ok, State#state{current_seq=LastSeq}}.
+
+handle_cast({increment_update_seq, Seq}, State) ->
+    couch_task_status:update("Processed source update #~p", [Seq]),
+    {noreply, State#state{current_seq=Seq}}.
+
+handle_info(_Msg, State) ->
+    {noreply, State}.
+
+terminate(normal, State) ->
+    #state{
+        context = Context,
+        current_seq = Seq,
+        docs_buffer = Buffer,
+        listeners = Listeners,
+        source = Source,
+        target = Target,
+        stats = Stats
+    } = State,
+    
+    ok = update_docs(Target, lists:flatten(Buffer), [], false),
+    ets:update_counter(Stats, docs_written, lists:flatlength(Buffer)),
+    
+    couch_task_status:update("Finishing"),
+    
+    %% format replication history
+    JsonStats = [
+        {<<"missing_checked">>, ets:lookup_element(Stats, total_revs, 2)},
+        {<<"missing_found">>, ets:lookup_element(Stats, missing_revs, 2)},
+        {<<"docs_read">>, ets:lookup_element(Stats, docs_read, 2)},
+        {<<"docs_written">>, ets:lookup_element(Stats, docs_written, 2)}
+    ],
+    ets:delete(Stats),
+    {ok, NewRepHistory} = finalize_response(Source, Target, Context, Seq, JsonStats),
+    
+    %% update local documents
+    RepRecSrc = proplists:get_value(src_record, Context),
+    RepRecTgt = proplists:get_value(tgt_record, Context),
+    {ok, _} = update_local_doc(Source, RepRecSrc#doc{body=NewRepHistory}, []),
+    {ok, _} = update_local_doc(Target, RepRecTgt#doc{body=NewRepHistory}, []),
+    
+    close_db(Target),
+    
+    %% reply to original requester
+    [Original|Rest] = Listeners,
+    gen_server:reply(Original, {ok, NewRepHistory}),
+    
+    %% maybe trigger another replication. If this replicator uses a local 
+    %% source Db, changes to that Db since we started will not be included in 
+    %% this pass.
+    case up_to_date(Source, Seq) of
+        true ->
+            [gen_server:reply(R, {ok, NewRepHistory}) || R <- Rest];
+        false ->
+            [gen_server:reply(R, retry) || R <- Rest]
+    end,
+    close_db(Source);
+terminate(Reason, State) ->
+    #state{
+        listeners = Listeners,
+        source = Source,
+        target = Target,
+        stats = Stats
+    } = State,
+    
+    [gen_server:reply(L, {error, Reason}) || L <- Listeners],
+    
+    ets:delete(Stats),
+    close_db(Target),
+    close_db(Source).
+
+code_change(_OldVsn, State, _Extra) ->
+    {ok, State}.
+
+%%=============================================================================
+%% internal functions
+%%=============================================================================
+
+attachment_loop(ReqId) ->
+    couch_util:should_flush(),
+    receive 
+        {From, {set_req_id, NewId}} ->
+            From ! {self(), {ok, NewId}},
+            attachment_loop(NewId);
+        {ibrowse_async_headers, ReqId, _Status, _Headers} ->
+            attachment_loop(ReqId);
+        {ibrowse_async_response, ReqId, {chunk_start,_}} ->
+            attachment_loop(ReqId);
+        {ibrowse_async_response, ReqId, chunk_end} ->
+            attachment_loop(ReqId);
+        {ibrowse_async_response, ReqId, Data} -> 
+            receive {From, gimme_data} -> From ! {self(), Data} end,
+            attachment_loop(ReqId);
+        {ibrowse_async_response_end, ReqId} -> ok
     end.
 
-pull_rep(DbTarget, DbSource, SourceSeqNum) ->
-    {ok, {NewSeq, Stats}} = 
-        enum_docs_since(DbSource, DbTarget, SourceSeqNum, {SourceSeqNum, []}),
-    {NewSeq, Stats}.
+attachment_stub_converter(DbS, Id, {Name, {stub, Type, Length}}) ->
+    #http_db{uri=DbUrl, headers=Headers} = DbS,
+    % TODO worry about revisions
+    Url = DbUrl ++ url_encode(Id) ++ "/" ++ ?b2l(Name),
+    ?LOG_DEBUG("Attachment URL ~p", [Url]),
+    
+    %% start the process that receives attachment data from ibrowse
+    Pid = spawn_link(fun() -> attachment_loop(nil) end),
+    
+    %% make the async request
+    Options = [{stream_to, Pid}, {response_format, binary}],
+    {ibrowse_req_id, ReqId} = ibrowse:send_req(Url, Headers, get, [], Options),
+    
+    %% tell our receiver about the ReqId it needs to look for
+    Pid ! {self(), {set_req_id, ReqId}},
+    receive {Pid, {ok, ReqId}} -> ok end,
+    
+    %% this is the function that goes into the streaming attachment code.
+    %% It gets executed by the replication gen_server, so it can't
+    %% be the one to actually receive the ibrowse data.
+    RcvFun = fun() -> 
+        Pid ! {self(), gimme_data}, 
+        receive {Pid, Data} -> Data end
+    end,
+    {Name, {Type, {RcvFun, Length}}}.
+
+close_db(#http_db{})->
+    ok;
+close_db(Db)->
+    couch_db:close(Db).
 
 do_http_request(Url, Action, Headers) ->
     do_http_request(Url, Action, Headers, []).
 
 do_http_request(Url, Action, Headers, JsonBody) ->
-    do_http_request(Url, Action, Headers, JsonBody, 10).
+    do_http_request(?b2l(?l2b(Url)), Action, Headers, JsonBody, 10).
 
 do_http_request(Url, Action, _Headers, _JsonBody, 0) ->
-    ?LOG_ERROR("couch_rep HTTP ~p request failed after 10 retries: ~p", 
+    ?LOG_ERROR("couch_rep HTTP ~p request failed after 10 retries: ~s", 
         [Action, Url]);
 do_http_request(Url, Action, Headers, JsonBody, Retries) ->
-    ?LOG_DEBUG("couch_rep HTTP ~p request: ~p", [Action, Url]),
+    ?LOG_DEBUG("couch_rep HTTP ~p request: ~s", [Action, Url]),
     Body =
     case JsonBody of
     [] ->
@@ -187,9 +360,10 @@ do_http_request(Url, Action, Headers, JsonBody, Retries) ->
         _ -> [{transfer_encoding, {chunked, 65535}}]
     end ++ [
         {content_type, "application/json; charset=utf-8"},
-        {max_pipeline_size, 101}
+        {max_pipeline_size, 101},
+        {response_format, binary}
     ],
-    case ibrowse:send_req(Url, Headers, Action, Body, Options) of
+    case ibrowse:send_req(Url, Headers, Action, Body, Options, infinity) of
     {ok, Status, ResponseHeaders, ResponseBody} ->
         ResponseCode = list_to_integer(Status),
         if
@@ -202,139 +376,113 @@ do_http_request(Url, Action, Headers, JsonBody, Retries) ->
         ResponseCode >= 400, ResponseCode < 500 -> 
             ?JSON_DECODE(ResponseBody);        
         ResponseCode == 500 ->
-            ?LOG_INFO("retrying couch_rep HTTP ~p request due to 500 error: ~p",
+            ?LOG_INFO("retrying couch_rep HTTP ~p request due to 500 error: ~s",
                 [Action, Url]),
             do_http_request(Url, Action, Headers, JsonBody, Retries - 1)
         end;
     {error, Reason} ->
-        ?LOG_INFO("retrying couch_rep HTTP ~p request due to {error, ~p}: ~p", 
+        ?LOG_INFO("retrying couch_rep HTTP ~p request due to {error, ~p}: ~s", 
             [Action, Reason, Url]),
         do_http_request(Url, Action, Headers, JsonBody, Retries - 1)
     end.
 
-save_docs_buffer(DbTarget, DocsBuffer, []) ->
-    receive
-    {Src, shutdown} ->
-        ok = update_docs(DbTarget, lists:reverse(DocsBuffer), [], false),
-        Src ! {done, self(), [{<<"docs_written">>, length(DocsBuffer)}]}
-    end;
-save_docs_buffer(DbTarget, DocsBuffer, UpdateSequences) ->
-    [NextSeq|Rest] = UpdateSequences,
-    receive
-    {Src, skip, NextSeq} ->
-        Src ! got_it,
-        save_docs_buffer(DbTarget, DocsBuffer, Rest);
-    {Src, docs, {NextSeq, Docs}} ->
-        Src ! got_it,
-        case couch_util:should_flush() of
-            true ->
-                ok = update_docs(DbTarget, lists:reverse(Docs++DocsBuffer), [], 
-                    false),
-                save_docs_buffer(DbTarget, [], Rest);
-            false ->
-                save_docs_buffer(DbTarget, Docs++DocsBuffer, Rest)
-        end;
-        {Src, shutdown} ->
-        ?LOG_ERROR("received shutdown while waiting for more update_seqs", []),
-        ok = update_docs(DbTarget, lists:reverse(DocsBuffer), [], false),
-        Src ! {done, self(), [{<<"docs_written">>, length(DocsBuffer)}]}
+ensure_full_commit(#http_db{uri=DbUrl, headers=Headers}) ->
+    {ResultProps} = do_http_request(DbUrl ++ "_ensure_full_commit", post, 
+        Headers, true),
+    true = proplists:get_value(<<"ok">>, ResultProps),
+    {ok, proplists:get_value(<<"instance_start_time">>, ResultProps)};
+ensure_full_commit(Db) ->
+    couch_db:ensure_full_commit(Db).
+
+enum_docs_since(Pid, DbSource, DbTarget, {StartSeq, RevsCount}) ->
+    case get_doc_info_list(DbSource, StartSeq) of
+    [] ->
+        gen_server:call(Pid, {fin, {StartSeq, RevsCount}}, infinity);
+    DocInfoList ->
+        % UpdateSeqs = [D#doc_info.update_seq || D <- DocInfoList],
+        SrcRevsList = lists:map(fun(SrcDocInfo) ->
+            #doc_info{id=Id,
+                rev=Rev,
+                conflict_revs=Conflicts,
+                deleted_conflict_revs=DelConflicts
+            } = SrcDocInfo,
+            SrcRevs = [Rev | Conflicts] ++ DelConflicts,
+            {Id, SrcRevs}
+        end, DocInfoList),        
+        {ok, MissingRevs} = get_missing_revs(DbTarget, SrcRevsList),
+        
+        %% do we need to check for success here?
+        [ gen_server:call(Pid, {replicate_doc, Info}, infinity) 
+            || Info <- MissingRevs ],
+        
+        #doc_info{update_seq=LastSeq} = lists:last(DocInfoList),
+        RevsCount2 = RevsCount + length(SrcRevsList),
+        gen_server:cast(Pid, {increment_update_seq, LastSeq}),
+        
+        enum_docs_since(Pid, DbSource, DbTarget, {LastSeq, RevsCount2})
     end.
 
-pmap(F,List) ->
-    [wait_result(Worker) || Worker <- [spawn_worker(self(),F,E) || E <- List]].
-
-spawn_worker(Parent, F, E) ->
-    erlang:spawn_monitor(fun() -> Parent ! {self(), F(E)} end).
-
-wait_result({Pid,Ref}) ->
-    receive
-    {'DOWN', Ref, _, _, normal} -> receive {Pid,Result} -> Result end;
-    {'DOWN', Ref, _, _, Reason} -> exit(Reason)
-end.
-
-enum_docs_parallel(DbS, DbT, InfoList) ->
-    UpdateSeqs = [Seq || {_, Seq, _, _} <- InfoList],
-    SaveDocsPid = spawn_link(fun() -> save_docs_buffer(DbT,[],UpdateSeqs) end),
-    
-    Stats = pmap(fun({Id, Seq, SrcRevs, MissingRevs}) ->
-        case MissingRevs of
-        [] ->
-            SaveDocsPid ! {self(), skip, Seq},
-            receive got_it -> ok end,
-            [{missing_checked, length(SrcRevs)}];
-        _ ->
-            {ok, DocResults} = open_doc_revs(DbS, Id, MissingRevs, [latest]),
-            
-            % only save successful reads
-            Docs = [RevDoc || {ok, RevDoc} <- DocResults],
-            
-            % include update_seq so we save docs in order
-            SaveDocsPid ! {self(), docs, {Seq, Docs}},
-            receive got_it -> ok end,
-            [{missing_checked, length(SrcRevs)},
-             {missing_found, length(MissingRevs)},
-             {docs_read, length(Docs)}]
-        end
-    end, InfoList),
+finalize_response(Source, Target, Context, NewSeqNum, Stats) ->
+    [
+        {start_seq, SeqNum},
+        {history, OldRepHistoryProps},
+        {rep_starttime, ReplicationStartTime},
+        {src_starttime, SrcInstanceStartTime},
+        {tgt_starttime, TgtInstanceStartTime}
+    |_] = Context,
     
-    SaveDocsPid ! {self(), shutdown},
-    
-    {MissingChecked, MissingFound, DocsRead} = lists:foldl(fun(S, {C, F, R}) ->
-        C1 = C + proplists:get_value(missing_checked, S, 0),
-        F1 = F + proplists:get_value(missing_found, S, 0),
-        R1 = R + proplists:get_value(docs_read, S, 0),
-        {C1, F1, R1}
-    end, {0, 0, 0}, Stats),
-    
-    receive
-        {done, SaveDocsPid, [{<<"docs_written">>, DocsWritten}]} -> ok
-    end,
-    
-    [ {<<"missing_checked">>, MissingChecked},
-      {<<"missing_found">>, MissingFound}, 
-      {<<"docs_read">>, DocsRead},
-      {<<"docs_written">>, DocsWritten} ].
+    case NewSeqNum == SeqNum andalso OldRepHistoryProps /= [] of
+    true ->
+        % nothing changed, don't record results
+        {ok, {OldRepHistoryProps}};
+    false ->
+        % commit changes to both src and tgt. The src because if changes
+        % we replicated are lost, we'll record the a seq number of ahead 
+        % of what was committed and therefore lose future changes with the
+        % same seq nums.
+        {ok, SrcInstanceStartTime2} = ensure_full_commit(Source),
+        {ok, TgtInstanceStartTime2} = ensure_full_commit(Target),
+        
+        RecordSeqNum =
+        if SrcInstanceStartTime2 == SrcInstanceStartTime andalso
+                TgtInstanceStartTime2 == TgtInstanceStartTime ->
+            NewSeqNum;
+        true ->
+            ?LOG_INFO("A server has restarted sinced replication start. "
+                "Not recording the new sequence number to ensure the "
+                "replication is redone and documents reexamined.", []),
+            SeqNum
+        end,
+        
+        HistEntries =[
+            {
+                [{<<"start_time">>, list_to_binary(ReplicationStartTime)},
+                {<<"end_time">>, list_to_binary(httpd_util:rfc1123_date())},
+                {<<"start_last_seq">>, SeqNum},
+                {<<"end_last_seq">>, NewSeqNum} | Stats]}
+            | proplists:get_value(<<"history">>, OldRepHistoryProps, [])],
+        % something changed, record results
+        NewRepHistory =
+            {
+                [{<<"session_id">>, couch_util:new_uuid()},
+                {<<"source_last_seq">>, RecordSeqNum},
+                {<<"history">>, lists:sublist(HistEntries, 50)}]},
+        {ok, NewRepHistory}
+    end.
 
 fix_url(UrlBin) ->
     Url = binary_to_list(UrlBin),
     case lists:last(Url) of
-    $/ ->
-        Url;
-    _ ->
-        Url ++ "/"
+        $/ -> Url;
+        _ ->  Url ++ "/"
     end.
 
-open_http_db(UrlBin, Options) ->
-    Headers = proplists:get_value(headers, Options, {[]}),
-    {ok, #http_db{uri=fix_url(UrlBin), headers=Headers}}.
-            
-open_db(<<"http://", _/binary>>=Url, Options)->
-    open_http_db(Url, Options);
-open_db(<<"https://", _/binary>>=Url, Options)->
-    open_http_db(Url, Options);
-open_db(DbName, Options)->
-    couch_db:open(DbName, Options).
-
-close_db(#http_db{})->
-    ok;
-close_db(Db)->
-    couch_db:close(Db).
-
 get_db_info(#http_db{uri=DbUrl, headers=Headers}) ->
     {DbProps} = do_http_request(DbUrl, get, Headers),
     {ok, [{list_to_existing_atom(?b2l(K)), V} || {K,V} <- DbProps]};
 get_db_info(Db) ->
     couch_db:get_db_info(Db).
 
-
-ensure_full_commit(#http_db{uri=DbUrl, headers=Headers}) ->
-    {ResultProps} = do_http_request(DbUrl ++ "_ensure_full_commit", post, Headers, true),
-    true = proplists:get_value(<<"ok">>, ResultProps),
-    {ok, proplists:get_value(<<"instance_start_time">>, ResultProps)};
-ensure_full_commit(Db) ->
-    couch_db:ensure_full_commit(Db).
-    
-    
 get_doc_info_list(#http_db{uri=DbUrl, headers=Headers}, StartSeq) ->
     Url = DbUrl ++ "_all_docs_by_seq?limit=100&startkey=" 
         ++ integer_to_list(StartSeq),
@@ -361,82 +509,26 @@ get_doc_info_list(DbSource, StartSeq) ->
     end, {0, []}),
     lists:reverse(DocInfoList).
 
-enum_docs_since(DbSource, DbTarget, StartSeq, InAcc) ->
-    DocInfoList = get_doc_info_list(DbSource, StartSeq),
-    case DocInfoList of
-    [] ->
-        {ok, InAcc};
-    _ ->
-        UpdateSeqs = [D#doc_info.update_seq || D <- DocInfoList],
-        SrcRevsList = lists:map(fun(SrcDocInfo) ->
-            #doc_info{id=Id,
-                rev=Rev,
-                conflict_revs=Conflicts,
-                deleted_conflict_revs=DelConflicts
-            } = SrcDocInfo,
-            SrcRevs = [Rev | Conflicts] ++ DelConflicts,
-            {Id, SrcRevs}
-        end, DocInfoList),        
-        {ok, MissingRevsList} = get_missing_revs(DbTarget, SrcRevsList),
-        InfoList = lists:map(fun({{Id, SrcRevs}, Seq}) ->
-            MissingRevs = proplists:get_value(Id, MissingRevsList, []),
-            {Id, Seq, SrcRevs, MissingRevs}
-        end, lists:zip(SrcRevsList, UpdateSeqs)),
-        Stats = enum_docs_parallel(DbSource, DbTarget, InfoList),
-        OldStats = element(2, InAcc),
-        TotalStats = [
-            {<<"missing_checked">>, 
-                proplists:get_value(<<"missing_checked">>, OldStats, 0) +
-                proplists:get_value(<<"missing_checked">>, Stats, 0)},
-            {<<"missing_found">>, 
-                proplists:get_value(<<"missing_found">>, OldStats, 0) +
-                proplists:get_value(<<"missing_found">>, Stats, 0)},
-            {<<"docs_read">>, 
-                proplists:get_value(<<"docs_read">>, OldStats, 0) +
-                proplists:get_value(<<"docs_read">>, Stats, 0)},
-            {<<"docs_written">>, 
-                proplists:get_value(<<"docs_written">>, OldStats, 0) +
-                proplists:get_value(<<"docs_written">>, Stats, 0)}
-        ],
-        
-        #doc_info{update_seq=LastSeq} = lists:last(DocInfoList),
-        enum_docs_since(DbSource, DbTarget, LastSeq, {LastSeq, TotalStats})
-    end.
-
 get_missing_revs(#http_db{uri=DbUrl, headers=Headers}, DocIdRevsList) ->
     {ResponseMembers} = do_http_request(DbUrl ++ "_missing_revs", post, Headers,
             {DocIdRevsList}),
-    {DocMissingRevsList} = proplists:get_value(<<"missing_revs">>, ResponseMembers),
-    {ok, DocMissingRevsList};
+    {MissingRevs} = proplists:get_value(<<"missing_revs">>, ResponseMembers),
+    {ok, MissingRevs};
 get_missing_revs(Db, DocId) ->
     couch_db:get_missing_revs(Db, DocId).
 
+open_http_db(UrlBin, Options) ->
+    Headers = proplists:get_value(headers, Options, {[]}),
+    {ok, #http_db{uri=fix_url(UrlBin), headers=Headers}}.
+            
+open_db(<<"http://", _/binary>>=Url, Options)->
+    open_http_db(Url, Options);
+open_db(<<"https://", _/binary>>=Url, Options)->
+    open_http_db(Url, Options);
+open_db(DbName, Options)->
+    couch_db:open(DbName, Options).
 
-update_doc(#http_db{uri=DbUrl, headers=Headers}, #doc{id=DocId}=Doc, Options) ->
-    [] = Options,
-    Url = DbUrl ++ url_encode(DocId),
-    {ResponseMembers} = do_http_request(Url, put, Headers,
-            couch_doc:to_json_obj(Doc, [revs,attachments])),
-    RevId = proplists:get_value(<<"_rev">>, ResponseMembers),
-    {ok, RevId};
-update_doc(Db, Doc, Options) ->
-    couch_db:update_doc(Db, Doc, Options).
-
-update_docs(_, [], _, _) ->
-    ok;
-update_docs(#http_db{uri=DbUrl, headers=Headers}, Docs, [], NewEdits) ->
-    JsonDocs = [couch_doc:to_json_obj(Doc, [revs,attachments]) || Doc <- Docs],
-    {Returned} =
-        do_http_request(DbUrl ++ "_bulk_docs", post, Headers,
-                {[{new_edits, NewEdits}, {docs, JsonDocs}]}),
-    true = proplists:get_value(<<"ok">>, Returned),
-    ok;
-update_docs(Db, Docs, Options, NewEdits) ->
-    couch_db:update_docs(Db, Docs, Options, NewEdits).
-
-
-open_doc(#http_db{uri=DbUrl, headers=Headers}, DocId, Options) ->
-    [] = Options,
+open_doc(#http_db{uri=DbUrl, headers=Headers}, DocId, []) ->
     case do_http_request(DbUrl ++ url_encode(DocId), get, Headers) of
     {[{<<"error">>, ErrId}, {<<"reason">>, Reason}]} ->
         {couch_util:to_existing_atom(ErrId), Reason};
@@ -446,16 +538,8 @@ open_doc(#http_db{uri=DbUrl, headers=Headers}, DocId, Options) ->
 open_doc(Db, DocId, Options) ->
     couch_db:open_doc(Db, DocId, Options).
 
-
-open_doc_revs(#http_db{uri=DbUrl, headers=Headers}, DocId, Revs, Options) ->
-    QueryOptionStrs =
-    lists:map(fun(latest) ->
-            % latest is only option right now
-            "latest=true"
-        end, Options),
-    
-    BaseUrl = DbUrl ++ url_encode(DocId) ++ "?" ++ couch_util:implode(
-        ["revs=true", "attachments=true"] ++ QueryOptionStrs, "&"),
+open_doc_revs(#http_db{uri=DbUrl, headers=Headers} = DbS, DocId, Revs, _Opts) ->
+    BaseUrl = DbUrl ++ url_encode(DocId) ++ "?revs=true&latest=true",
     
     %% MochiWeb expects URLs < 8KB long, so maybe split into multiple requests
     MaxN = trunc((8192 - length(BaseUrl))/14),
@@ -477,15 +561,66 @@ open_doc_revs(#http_db{uri=DbUrl, headers=Headers}, DocId, Revs, Options) ->
             lists:flatten(?JSON_ENCODE(lists:reverse(Rest))), get, Headers)
     end,
     
-    Results =
-    lists:map(
-        fun({[{<<"missing">>, Rev}]}) ->
-            {{not_found, missing}, Rev};
-        ({[{<<"ok">>, JsonDoc}]}) ->
-            {ok, couch_doc:from_json_obj(JsonDoc)}
-        end, JsonResults),
+    Results = 
+    lists:map(fun({[{<<"missing">>, Rev}]}) ->
+        {{not_found, missing}, Rev};
+    ({[{<<"ok">>, JsonDoc}]}) ->
+        #doc{id=Id, attachments=Attach} = Doc = couch_doc:from_json_obj(JsonDoc),
+        Attach2 = [attachment_stub_converter(DbS,Id,A) || A <- Attach],
+        {ok, Doc#doc{attachments=Attach2}}
+    end, JsonResults),
     {ok, Results};
 open_doc_revs(Db, DocId, Revs, Options) ->
     couch_db:open_doc_revs(Db, DocId, Revs, Options).
 
+update_docs(_, [], _, _) ->
+    ok;
+update_docs(#http_db{uri=DbUrl, headers=Headers}, Docs, [], NewEdits) ->
+    JsonDocs = [couch_doc:to_json_obj(Doc, [revs,attachments]) || Doc <- Docs],
+    {Returned} =
+        do_http_request(DbUrl ++ "_bulk_docs", post, Headers,
+                {[{new_edits, NewEdits}, {docs, JsonDocs}]}),
+    true = proplists:get_value(<<"ok">>, Returned),
+    ok;
+update_docs(Db, Docs, Options, NewEdits) ->
+    couch_db:update_docs(Db, Docs, Options, NewEdits).
+
+update_local_doc(#http_db{uri=DbUrl, headers=Headers}, #doc{id=DocId}=Doc, []) ->
+    Url = DbUrl ++ url_encode(DocId),
+    {ResponseMembers} = do_http_request(Url, put, Headers,
+            couch_doc:to_json_obj(Doc, [revs,attachments])),
+    RevId = proplists:get_value(<<"_rev">>, ResponseMembers),
+    {ok, RevId};
+update_local_doc(Db, Doc, Options) ->
+    couch_db:update_doc(Db, Doc, Options).
 
+up_to_date(#http_db{}, _Seq) ->
+    true;
+up_to_date(Source, Seq) ->
+    {ok, NewDb} = couch_db:open(Source#db.name, []),
+    T = NewDb#db.update_seq == Seq,
+    couch_db:close(NewDb),
+    T.
+
+url_encode(Bin) when is_binary(Bin) ->
+    url_encode(binary_to_list(Bin));
+url_encode([H|T]) ->
+    if
+    H >= $a, $z >= H ->
+        [H|url_encode(T)];
+    H >= $A, $Z >= H ->
+        [H|url_encode(T)];
+    H >= $0, $9 >= H ->
+        [H|url_encode(T)];
+    H == $_; H == $.; H == $-; H == $: ->
+        [H|url_encode(T)];
+    true ->
+        case lists:flatten(io_lib:format("~.16.0B", [H])) of
+        [X, Y] ->
+            [$%, X, Y | url_encode(T)];
+        [X] ->
+            [$%, $0, X | url_encode(T)]
+        end
+    end;
+url_encode([]) ->
+    [].
diff --git a/src/couchdb/couch_server_sup.erl b/src/couchdb/couch_server_sup.erl
index 942de092..15867ad7 100644
--- a/src/couchdb/couch_server_sup.erl
+++ b/src/couchdb/couch_server_sup.erl
@@ -133,6 +133,12 @@ start_primary_services() ->
                 brutal_kill,
                 worker,
                 [couch_log]},
+            {couch_replication_supervisor,
+                {couch_rep_sup, start_link, []},
+                permanent,
+                infinity,
+                supervisor,
+                [couch_rep_sup]},
             {couch_task_status,
                 {couch_task_status, start_link, []},
                 permanent,
@@ -150,7 +156,9 @@ start_primary_services() ->
                 permanent,
                 brutal_kill,
                 supervisor,
-                dynamic}]}).
+                dynamic}
+            ]
+        }).
 
 start_secondary_services() ->
     DaemonChildSpecs = [
diff --git a/src/couchdb/couch_util.erl b/src/couchdb/couch_util.erl
index d0f0c0b6..21d6eb4c 100644
--- a/src/couchdb/couch_util.erl
+++ b/src/couchdb/couch_util.erl
@@ -184,19 +184,18 @@ should_flush() ->
     should_flush(?FLUSH_MAX_MEM).
     
 should_flush(MemThreshHold) ->
-    case process_info(self(), memory) of
-    {memory, Mem} when Mem > 2*MemThreshHold ->
+    {memory, ProcMem} = process_info(self(), memory),
+    BinMem = lists:foldl(fun({_Id, Size, _NRefs}, Acc) -> Size+Acc end, 
+        0, element(2,process_info(self(), binary))),
+    if ProcMem+BinMem > 2*MemThreshHold ->
         garbage_collect(),
-        case process_info(self(), memory) of
-        {memory, Mem} when Mem > MemThreshHold ->
+        {memory, ProcMem2} = process_info(self(), memory),
+        BinMem2 = lists:foldl(fun({_Id, Size, _NRefs}, Acc) -> Size+Acc end, 
+            0, element(2,process_info(self(), binary))),
+        if ProcMem2+BinMem2 > MemThreshHold ->
             true;
-        _ ->
-            false
-        end;
-    _ ->
-        false
-    end.
-
+        true -> false end;
+    true -> false end.
 
 
 %%% Purpose : Base 64 encoding and decoding.
diff --git a/src/ibrowse/ibrowse.erl b/src/ibrowse/ibrowse.erl
index 4e6404ad..3390e58a 100644
--- a/src/ibrowse/ibrowse.erl
+++ b/src/ibrowse/ibrowse.erl
@@ -192,6 +192,8 @@ send_req(Url, Headers, Method, Body) ->
 %% @spec send_req(Url::string(), Headers::headerList(), Method::method(), Body::body(), Options::optionList()) -> response()
 %% optionList() = [option()]
 %% option() = {max_sessions, integer()}        |
+%%          {response_format,response_format()}| 
+%%          {stream_chunk_size, integer()}     |
 %%          {max_pipeline_size, integer()}     |
 %%          {trace, boolean()}                 | 
 %%          {is_ssl, boolean()}                |
@@ -219,7 +221,7 @@ send_req(Url, Headers, Method, Body) ->
 %% ChunkSize = integer()
 %% srtf() = boolean() | filename()
 %% filename() = string()
-%% 
+%% response_format() = list | binary
 send_req(Url, Headers, Method, Body, Options) ->
     send_req(Url, Headers, Method, Body, Options, 30000).
 
@@ -230,7 +232,8 @@ send_req(Url, Headers, Method, Body, Options) ->
 send_req(Url, Headers, Method, Body, Options, Timeout) ->
     case catch parse_url(Url) of
 	#url{host = Host,
-	     port = Port} = Parsed_url ->
+	     port = Port,
+	     protocol = Protocol} = Parsed_url ->
 	    Lb_pid = case ets:lookup(ibrowse_lb, {Host, Port}) of
 			 [] ->
 			     get_lb_pid(Parsed_url);
@@ -241,9 +244,10 @@ send_req(Url, Headers, Method, Body, Options, Timeout) ->
 	    Max_pipeline_size = get_max_pipeline_size(Host, Port, Options),
 	    Options_1 = merge_options(Host, Port, Options),
 	    {SSLOptions, IsSSL} =
-		case get_value(is_ssl, Options_1, false) of
+		case (Protocol == https) orelse
+		     get_value(is_ssl, Options_1, false) of
 		    false -> {[], false};
-		    true -> {get_value(ssl_options, Options_1), true}
+		    true -> {get_value(ssl_options, Options_1, []), true}
 		end,
 	    case ibrowse_lb:spawn_connection(Lb_pid, Parsed_url,
 					     Max_sessions, 
@@ -316,6 +320,13 @@ do_send_req(Conn_Pid, Parsed_url, Headers, Method, Body, Options, Timeout) ->
 	    {error, req_timedout};
 	{'EXIT', Reason} ->
 	    {error, {'EXIT', Reason}};
+	{ok, St_code, Headers, Body} = Ret when is_binary(Body) ->
+	    case get_value(response_format, Options, list) of
+		list ->
+		    {ok, St_code, Headers, binary_to_list(Body)};
+		binary ->
+		    Ret
+	    end;
 	Ret ->
 	    Ret
     end.
diff --git a/src/ibrowse/ibrowse_http_client.erl b/src/ibrowse/ibrowse_http_client.erl
index 9a0e4d3b..9455bc20 100644
--- a/src/ibrowse/ibrowse_http_client.erl
+++ b/src/ibrowse/ibrowse_http_client.erl
@@ -38,19 +38,23 @@
 
 -include("ibrowse.hrl").
 
--record(state, {host, port, 
+-record(state, {host, port,
 		use_proxy = false, proxy_auth_digest,
-		ssl_options = [], is_ssl = false, socket, 
-		reqs=queue:new(), cur_req, status=idle, http_status_code, 
-		reply_buffer=[], rep_buf_size=0, recvd_headers=[],
+		ssl_options = [], is_ssl = false, socket,
+		reqs=queue:new(), cur_req, status=idle, http_status_code,
+		reply_buffer=[], rep_buf_size=0, streamed_size = 0,
+		recvd_headers=[],
 		is_closing, send_timer, content_length,
-		deleted_crlf = false, transfer_encoding, chunk_size, 
-		chunks=[], lb_ets_tid, cur_pipeline_size = 0}).
+		deleted_crlf = false, transfer_encoding, chunk_size,
+		chunks=[], lb_ets_tid, cur_pipeline_size = 0
+	       }).
 
 -record(request, {url, method, options, from,
 		  stream_to, req_id,
-		  save_response_to_file = false,
-		  tmp_file_name, tmp_file_fd}).
+		  stream_chunk_size,
+		  save_response_to_file = false, 
+		  tmp_file_name, tmp_file_fd,
+		  response_format}).
 
 -import(ibrowse_lib, [
 		      parse_url/1,
@@ -60,6 +64,8 @@
 		      do_trace/2
 		     ]).
 
+-define(DEFAULT_STREAM_CHUNK_SIZE, 1024*1024).
+
 %%====================================================================
 %% External functions
 %%====================================================================
@@ -127,15 +133,16 @@ init({Host, Port}) ->
 %%--------------------------------------------------------------------
 %% Received a request when the remote server has already sent us a
 %% Connection: Close header
-handle_call({send_req, _}, 
+handle_call({send_req, _},
 	    _From,
 	    #state{is_closing=true}=State) ->
     {reply, {error, connection_closing}, State};
 
-handle_call({send_req, {Url, Headers, Method, Body, Options, Timeout}}, 
+handle_call({send_req, {Url, Headers, Method, Body, Options, Timeout}},
 	    From,
 	    #state{socket=undefined,
 		   host=Host, port=Port}=State) ->
+    Resp_format = get_value(response_format, Options, list),
     {Host_1, Port_1, State_1} =
 	case get_value(proxy_host, Options, false) of
 	    false ->
@@ -151,12 +158,14 @@ handle_call({send_req, {Url, Headers, Method, Body, Options, Timeout}},
     StreamTo = get_value(stream_to, Options, undefined),
     ReqId = make_req_id(),
     SaveResponseToFile = get_value(save_response_to_file, Options, false),
-    NewReq = #request{url=Url, 
+    NewReq = #request{url=Url,
 		      method=Method,
 		      stream_to=StreamTo,
-		      options=Options, 
+		      options=Options,
 		      req_id=ReqId,
 		      save_response_to_file = SaveResponseToFile,
+		      stream_chunk_size = get_stream_chunk_size(Options),
+		      response_format = Resp_format,
 		      from=From},
     Reqs = queue:in(NewReq, State#state.reqs),
     State_2 = check_ssl_options(Options, State_1#state{reqs = Reqs}),
@@ -208,15 +217,18 @@ handle_call({send_req, {Url, Headers, Method,
 	    From,
 	    #state{socket=Sock, status=Status, reqs=Reqs}=State) ->
     do_trace("Recvd request in connected state. Status -> ~p NumPending: ~p~n", [Status, length(queue:to_list(Reqs))]),
+    Resp_format = get_value(response_format, Options, list),
     StreamTo = get_value(stream_to, Options, undefined),
     SaveResponseToFile = get_value(save_response_to_file, Options, false),
     ReqId = make_req_id(),
-    NewReq = #request{url=Url, 
+    NewReq = #request{url=Url,
 		      stream_to=StreamTo,
 		      method=Method,
-		      options=Options, 
+		      options=Options,
 		      req_id=ReqId,
 		      save_response_to_file = SaveResponseToFile,
+		      stream_chunk_size = get_stream_chunk_size(Options),
+		      response_format = Resp_format,
 		      from=From},
     State_1 = State#state{reqs=queue:in(NewReq, State#state.reqs)},
     case send_req_1(Url, Headers, Method, Body, Options, Sock, State_1) of
@@ -359,14 +371,14 @@ handle_sock_data(Data, #state{status=get_header, socket=Sock}=State) ->
 
 handle_sock_data(Data, #state{status=get_body, content_length=CL,
 			      http_status_code = StatCode,
-			      recvd_headers=Headers, 
+			      recvd_headers=Headers,
 			      chunk_size=CSz, socket=Sock}=State) ->
     case (CL == undefined) and (CSz == undefined) of
 	true ->
 	    case accumulate_response(Data, State) of
 		{error, Reason} ->
 		    shutting_down(State),
-		    fail_pipelined_requests(State, 
+		    fail_pipelined_requests(State,
 					    {error, {Reason, {stat_code, StatCode}, Headers}}),
 		    {stop, normal, State};
 		State_1 ->
@@ -377,7 +389,7 @@ handle_sock_data(Data, #state{status=get_body, content_length=CL,
 	    case parse_11_response(Data, State) of
 		{error, Reason} ->
 		    shutting_down(State),
-		    fail_pipelined_requests(State, 
+		    fail_pipelined_requests(State,
 					    {error, {Reason, {stat_code, StatCode}, Headers}}),
 		    {stop, normal, State};
 		stop ->
@@ -433,14 +445,27 @@ accumulate_response(Data, #state{cur_req = #request{save_response_to_file = Save
 accumulate_response([], State) ->
     State;
 accumulate_response(Data, #state{reply_buffer = RepBuf,
+				 rep_buf_size = RepBufSize,
+				 streamed_size = Streamed_size,
 				 cur_req = CurReq}=State) ->
-    #request{stream_to=StreamTo, req_id=ReqId} = CurReq,
+    #request{stream_to=StreamTo, req_id=ReqId,
+	     stream_chunk_size = Stream_chunk_size,
+	     response_format = Response_format} = CurReq,
+    RepBuf_1 = [Data | RepBuf],
+    New_data_size = RepBufSize - Streamed_size,
     case StreamTo of
 	undefined ->
-	    State#state{reply_buffer = [Data | RepBuf]};
+	    State#state{reply_buffer = RepBuf_1};
+	_ when New_data_size < Stream_chunk_size ->
+	    State#state{reply_buffer = RepBuf_1};
 	_ ->
-	    do_interim_reply(StreamTo, ReqId, Data),
-	    State
+	    {Stream_chunk, Rem_data} = split_list_at(flatten(lists:reverse(RepBuf_1)), Stream_chunk_size),
+	    do_interim_reply(StreamTo, Response_format, ReqId, Stream_chunk),
+	    accumulate_response(
+	      Rem_data,
+	      State#state{
+		reply_buffer = [],
+		streamed_size = Streamed_size + Stream_chunk_size})
     end.
 
 make_tmp_filename() ->
@@ -463,7 +488,7 @@ handle_sock_closed(#state{status=get_header}=State) ->
 handle_sock_closed(#state{cur_req=undefined} = State) ->
     shutting_down(State);
 
-%% We check for IsClosing because this the server could have sent a 
+%% We check for IsClosing because this the server could have sent a
 %% Connection-Close header and has closed the socket to indicate end
 %% of response. There maybe requests pipelined which need a response.
 handle_sock_closed(#state{reply_buffer=Buf, reqs=Reqs, http_status_code=SC,
@@ -471,18 +496,18 @@ handle_sock_closed(#state{reply_buffer=Buf, reqs=Reqs, http_status_code=SC,
 			  cur_req=#request{tmp_file_name=TmpFilename,
 					   tmp_file_fd=Fd} = CurReq,
 			  status=get_body, recvd_headers=Headers}=State) ->
-    #request{from=From, stream_to=StreamTo, req_id=ReqId} = CurReq,
+    #request{from=From, stream_to=StreamTo, req_id=ReqId,
+	     response_format = Resp_format} = CurReq,
     case IsClosing of
 	true ->
 	    {_, Reqs_1} = queue:out(Reqs),
 	    case TmpFilename of
 		undefined ->
-		    do_reply(State, From, StreamTo, ReqId,
-			     {ok, SC, Headers,
-			      lists:flatten(lists:reverse(Buf))});
+		    do_reply(State, From, StreamTo, ReqId, Resp_format,
+			     {ok, SC, Headers, lists:reverse(Buf)});
 		_ ->
 		    file:close(Fd),
-		    do_reply(State, From, StreamTo, ReqId,
+		    do_reply(State, From, StreamTo, ReqId, Resp_format,
 			     {ok, SC, Headers, {file, TmpFilename}})
 	    end,
 	    do_error_reply(State#state{reqs = Reqs_1}, connection_closed),
@@ -493,9 +518,13 @@ handle_sock_closed(#state{reply_buffer=Buf, reqs=Reqs, http_status_code=SC,
     end.
 
 do_connect(Host, Port, _Options, #state{is_ssl=true, ssl_options=SSLOptions}, Timeout) ->
-    ssl:connect(Host, Port, [{nodelay, true}, {active, false} | SSLOptions], Timeout);
+    ssl:connect(Host, Port,
+		[{nodelay, true}, {active, false} | SSLOptions],
+		Timeout);
 do_connect(Host, Port, _Options, _State, Timeout) ->
-    gen_tcp:connect(Host, Port, [{nodelay, true}, {active, false}], Timeout).
+    gen_tcp:connect(Host, Port,
+		    [{nodelay, true}, {active, false}],
+		    Timeout).
 
 do_send(Sock, Req, true)  ->  ssl:send(Sock, Req);
 do_send(Sock, Req, false) ->  gen_tcp:send(Sock, Req).
@@ -542,7 +571,7 @@ check_ssl_options(Options, State) ->
 
 send_req_1(#url{abspath = AbsPath,
 		host = Host,
-		port = Port, 
+		port = Port,
 		path = RelPath} = Url,
 	   Headers, Method, Body, Options, Sock, State) ->
     Headers_1 = add_auth_headers(Url, Options, Headers, State),
@@ -555,10 +584,10 @@ send_req_1(#url{abspath = AbsPath,
 			  {value, {_, Host_h_val}} ->
 			      Host_h_val
 		      end,
-    {Req, Body_1} = make_request(Method, 
+    {Req, Body_1} = make_request(Method,
 				 [{"Host", HostHeaderValue} | Headers_1],
 				 AbsPath, RelPath, Body, Options, State#state.use_proxy),
-    case get(my_trace_flag) of 
+    case get(my_trace_flag) of
 	true ->
 	    %%Avoid the binary operations if trace is not on...
 	    NReq = binary_to_list(list_to_binary(Req)),
@@ -569,7 +598,7 @@ send_req_1(#url{abspath = AbsPath,
     end,
     SndRes = case do_send(Sock, Req, State#state.is_ssl) of
 		 ok -> do_send_body(Sock, Body_1, State#state.is_ssl);
-		 Err -> 
+		 Err ->
 		     io:format("Err: ~p~n", [Err]),
 		     Err
 	     end,
@@ -577,9 +606,9 @@ send_req_1(#url{abspath = AbsPath,
     SndRes.
 
 add_auth_headers(#url{username = User,
-		      password = UPw}, 
+		      password = UPw},
 		 Options,
-		 Headers, 
+		 Headers,
 		 #state{use_proxy = UseProxy,
 		        proxy_auth_digest = ProxyAuthDigest}) ->
     Headers_1 = case User of
@@ -601,7 +630,7 @@ add_auth_headers(#url{username = User,
 	true ->
 	    [{"Proxy-Authorization", ["Basic ", ProxyAuthDigest]} | Headers_1]
     end.
-			
+
 http_auth_digest([], []) ->
     [];
 http_auth_digest(Username, Password) ->
@@ -617,7 +646,7 @@ encode_base64([A,B,C|Ls]) ->
     encode_base64_do(A,B,C, Ls).
 encode_base64_do(A,B,C, Rest) ->
     BB = (A bsl 16) bor (B bsl 8) bor C,
-    [e(BB bsr 18), e((BB bsr 12) band 63), 
+    [e(BB bsr 18), e((BB bsr 12) band 63),
      e((BB bsr 6) band 63), e(BB band 63)|encode_base64(Rest)].
 
 e(X) when X >= 0, X < 26 -> X+65;
@@ -643,12 +672,12 @@ make_request(Method, Headers, AbsPath, RelPath, Body, Options, UseProxy) ->
 	    _ ->
 		Headers
 	end,
-    {Headers_2, Body_1} = 
+    {Headers_2, Body_1} =
 	case get_value(transfer_encoding, Options, false) of
 	    false ->
 		{Headers_1, Body};
 	    {chunked, ChunkSize} ->
-		{[{X, Y} || {X, Y} <- Headers_1, 
+		{[{X, Y} || {X, Y} <- Headers_1,
 			    X /= "Content-Length",
 			    X /= "content-length",
 			    X /= content_length] ++
@@ -659,7 +688,7 @@ make_request(Method, Headers, AbsPath, RelPath, Body, Options, UseProxy) ->
     Uri = case get_value(use_absolute_uri, Options, false) or UseProxy of
 	      true ->
 		  AbsPath;
-	      false -> 
+	      false ->
 		  RelPath
 	  end,
     {[method(Method), " ", Uri, " ", HttpVsn, crnl(), Headers_3, crnl()], Body_1}.
@@ -732,7 +761,7 @@ parse_response(_Data, #state{cur_req = undefined}=State) ->
 parse_response(Data, #state{reply_buffer=Acc, reqs=Reqs,
 			    cur_req=CurReq}=State) ->
     #request{from=From, stream_to=StreamTo, req_id=ReqId,
-	     method=Method} = CurReq,
+	     method=Method, response_format = Resp_format} = CurReq,
     MaxHeaderSize = ibrowse:get_config_value(max_headers_size, infinity),
     case scan_header(Data, Acc) of
 	{yes, Headers, Data_1}  ->
@@ -749,7 +778,8 @@ parse_response(Data, #state{reply_buffer=Acc, reqs=Reqs,
 		false ->
 		    ok
 	    end,
-	    State_1 = State#state{recvd_headers=Headers_1, status=get_body, 
+	    State_1 = State#state{recvd_headers=Headers_1, status=get_body,
+				  reply_buffer = [],
 				  http_status_code=StatCode, is_closing=IsClosing},
 	    put(conn_close, ConnClose),
 	    TransferEncoding = to_lower(get_value("transfer-encoding", LCHeaders, "false")),
@@ -757,7 +787,8 @@ parse_response(Data, #state{reply_buffer=Acc, reqs=Reqs,
 		_ when Method == head ->
 		    {_, Reqs_1} = queue:out(Reqs),
 		    send_async_headers(ReqId, StreamTo, StatCode, Headers_1),
-		    State_1_1 = do_reply(State_1, From, StreamTo, ReqId, {ok, StatCode, Headers_1, []}),
+		    State_1_1 = do_reply(State_1, From, StreamTo, ReqId, Resp_format,
+					 {ok, StatCode, Headers_1, []}),
 		    cancel_timer(State_1_1#state.send_timer, {eat_message, {req_timedout, From}}),
 		    State_2 = reset_state(State_1_1),
 		    State_3 = set_cur_request(State_2#state{reqs = Reqs_1}),
@@ -776,7 +807,8 @@ parse_response(Data, #state{reply_buffer=Acc, reqs=Reqs,
 		    %% RFC2616 - Sec 4.4
 		    {_, Reqs_1} = queue:out(Reqs),
 		    send_async_headers(ReqId, StreamTo, StatCode, Headers_1),
-		    State_1_1 = do_reply(State_1, From, StreamTo, ReqId, {ok, StatCode, Headers_1, []}),
+		    State_1_1 = do_reply(State_1, From, StreamTo, ReqId, Resp_format,
+					 {ok, StatCode, Headers_1, []}),
 		    cancel_timer(State_1_1#state.send_timer, {eat_message, {req_timedout, From}}),
 		    State_2 = reset_state(State_1_1),
 		    State_3 = set_cur_request(State_2#state{reqs = Reqs_1}),
@@ -788,7 +820,7 @@ parse_response(Data, #state{reply_buffer=Acc, reqs=Reqs,
 								 chunk_size=chunk_start,
 								 reply_buffer=[], chunks=[]}) of
 			{error, Reason} ->
-			    fail_pipelined_requests(State_1, 
+			    fail_pipelined_requests(State_1,
 						    {error, {Reason,
 							     {stat_code, StatCode}, Headers_1}}),
 			    {error, Reason};
@@ -800,7 +832,7 @@ parse_response(Data, #state{reply_buffer=Acc, reqs=Reqs,
 		    send_async_headers(ReqId, StreamTo, StatCode, Headers_1),
 		    State_1#state{reply_buffer=[Data_1]};
 		undefined ->
-		    fail_pipelined_requests(State_1, 
+		    fail_pipelined_requests(State_1,
 					    {error, {content_length_undefined,
 						     {stat_code, StatCode}, Headers}}),
 		    {error, content_length_undefined};
@@ -814,7 +846,7 @@ parse_response(Data, #state{reply_buffer=Acc, reqs=Reqs,
 						    content_length=V_1},
 			    case parse_11_response(Data_1, State_2) of
 				{error, Reason} ->
-				    fail_pipelined_requests(State_1, 
+				    fail_pipelined_requests(State_1,
 							    {error, {Reason,
 								     {stat_code, StatCode}, Headers_1}}),
 				    {error, Reason};
@@ -822,7 +854,7 @@ parse_response(Data, #state{reply_buffer=Acc, reqs=Reqs,
 				    State_3
 			    end;
 			_ ->
-			    fail_pipelined_requests(State_1, 
+			    fail_pipelined_requests(State_1,
 					    {error, {content_length_undefined,
 						     {stat_code, StatCode}, Headers}}),
 			    {error, content_length_undefined}
@@ -843,25 +875,28 @@ is_connection_closing("HTTP/1.0", "false") -> true;
 is_connection_closing(_, _)                -> false.
 
 %% This clause determines the chunk size when given data from the beginning of the chunk
-parse_11_response(DataRecvd, 
-		  #state{transfer_encoding=chunked,
+parse_11_response(DataRecvd,
+		  #state{transfer_encoding=chunked, 
 			 chunk_size=chunk_start,
 			 cur_req=CurReq,
-			 reply_buffer=Buf}=State) ->
+			 reply_buffer=Buf
+			}=State) ->
     case scan_crlf(DataRecvd, Buf) of
 	{yes, ChunkHeader, Data_1} ->
 	    case parse_chunk_header(ChunkHeader) of
 		{error, Reason} ->
 		    {error, Reason};
 		ChunkSize ->
-		    #request{stream_to=StreamTo, req_id=ReqId} = CurReq,
+		    #request{stream_to=StreamTo, req_id=ReqId,
+			     response_format = Response_format} = CurReq,
 		    %%
 		    %% Do we have to preserve the chunk encoding when streaming?
 		    %%
-		    do_interim_reply(StreamTo, ReqId, {chunk_start, ChunkSize}),
+		    do_interim_reply(StreamTo, Response_format,
+				     ReqId, {chunk_start, ChunkSize}),
 		    RemLen = length(Data_1),
 		    do_trace("Determined chunk size: ~p. Already recvd: ~p~n", [ChunkSize, RemLen]),
-		    parse_11_response(Data_1, State#state{rep_buf_size=0, 
+		    parse_11_response(Data_1, State#state{rep_buf_size=0,
 							  reply_buffer=[],
 							  deleted_crlf=true,
 							  chunk_size=ChunkSize})
@@ -871,29 +906,34 @@ parse_11_response(DataRecvd,
     end;
 
 %% This clause is there to remove the CRLF between two chunks
-%% 
-parse_11_response(DataRecvd, 
-		  #state{transfer_encoding=chunked,
+%%
+parse_11_response(DataRecvd,
+		  #state{transfer_encoding=chunked, 
 			 chunk_size=tbd,
 			 chunks = Chunks,
 			 cur_req=CurReq,
 			 reply_buffer=Buf}=State) ->
     case scan_crlf(DataRecvd, Buf) of
 	{yes, _, NextChunk} ->
-	    #request{stream_to=StreamTo, req_id=ReqId} = CurReq,
+	    #request{stream_to=StreamTo, req_id=ReqId,
+		     response_format = Response_format} = CurReq,
 	    %%
 	    %% Do we have to preserve the chunk encoding when streaming?
 	    %%
 	    State_1 = State#state{chunk_size=chunk_start,
-				  rep_buf_size=0, 
+				  rep_buf_size=0,
 				  reply_buffer=[],
 				  deleted_crlf=true},
 	    State_2 = case StreamTo of
 			  undefined ->
 			      State_1#state{chunks = [Buf | Chunks]};
-		_ ->
-			      do_interim_reply(StreamTo, ReqId, chunk_end),
-			      State_1
+			  _ ->
+			      %% Flush out all buffered data as chunk is ending
+			      do_interim_reply(StreamTo, Response_format, ReqId,
+					       lists:reverse([Buf | Chunks])),
+			      do_interim_reply(StreamTo, Response_format,
+					       ReqId, chunk_end),
+			      State_1#state{chunks = [], streamed_size = 0}
 		      end,
 	    parse_11_response(NextChunk, State_2);
 	{no, Data_1} ->
@@ -901,26 +941,27 @@ parse_11_response(DataRecvd,
     end;
 
 %% This clause deals with the end of a chunked transfer
-parse_11_response(DataRecvd, 
-		  #state{transfer_encoding=chunked, chunk_size=0,
+parse_11_response(DataRecvd,
+		  #state{transfer_encoding=chunked, chunk_size=0, 
 			 cur_req=CurReq,
 			 deleted_crlf = DelCrlf,
 			 reply_buffer=Trailer, reqs=Reqs}=State) ->
     do_trace("Detected end of chunked transfer...~n", []),
     DataRecvd_1 = case DelCrlf of
-		      false -> 
+		      false ->
 			  DataRecvd;
 		      true ->
 			  [$\r, $\n | DataRecvd]
 		  end,
-    #request{stream_to=StreamTo, req_id=ReqId} = CurReq,
+    #request{stream_to=StreamTo, req_id=ReqId,
+	     response_format = Response_format} = CurReq,
     case scan_header(DataRecvd_1, Trailer) of
 	{yes, _TEHeaders, Rem} ->
 	    {_, Reqs_1} = queue:out(Reqs),
 	    %%
-	    %% Do we have to preserve the chunk encoding when streaming?
+	    %% Do we have to preserve the chunk encoding when streaming? Nope.
 	    %%
-	    do_interim_reply(StreamTo, ReqId, chunk_end),
+	    do_interim_reply(StreamTo, Response_format, ReqId, chunk_end),
 	    State_1 = handle_response(CurReq, State#state{reqs=Reqs_1}),
 	    parse_response(Rem, reset_state(State_1));
 	{no, Rem} ->
@@ -928,7 +969,7 @@ parse_11_response(DataRecvd,
     end;
 
 %% This clause extracts a chunk, given the size.
-parse_11_response(DataRecvd, 
+parse_11_response(DataRecvd,
 		  #state{transfer_encoding=chunked, chunk_size=CSz,
 			 rep_buf_size=RepBufSz}=State) ->
     NeedBytes = CSz - RepBufSz,
@@ -952,12 +993,12 @@ parse_11_response(DataRecvd,
 		    parse_11_response(RemData, State_2)
 	    end;
 	false ->
-	    accumulate_response(DataRecvd, State#state{rep_buf_size=RepBufSz + DataLen})
+	    accumulate_response(DataRecvd, State#state{rep_buf_size=(RepBufSz + DataLen)})
     end;
 
 %% This clause to extract the body when Content-Length is specified
-parse_11_response(DataRecvd, 
-		  #state{content_length=CL, rep_buf_size=RepBufSz, 
+parse_11_response(DataRecvd,
+		  #state{content_length=CL, rep_buf_size=RepBufSz,
 			 reqs=Reqs}=State) ->
     NeedBytes = CL - RepBufSz,
     DataLen = length(DataRecvd),
@@ -970,11 +1011,12 @@ parse_11_response(DataRecvd,
 	    State_3 = reset_state(State_2),
 	    parse_response(Rem, State_3);
 	false ->
-	    accumulate_response(DataRecvd, State#state{rep_buf_size=RepBufSz+DataLen})
+	    accumulate_response(DataRecvd, State#state{rep_buf_size = (RepBufSz+DataLen)})
     end.
 
 handle_response(#request{from=From, stream_to=StreamTo, req_id=ReqId,
-			 save_response_to_file = SaveResponseToFile, 
+			 response_format = Resp_format,
+			 save_response_to_file = SaveResponseToFile,
 			 tmp_file_name = TmpFilename,
 			 tmp_file_fd = Fd
 			},
@@ -986,9 +1028,9 @@ handle_response(#request{from=From, stream_to=StreamTo, req_id=ReqId,
 		       recvd_headers = RespHeaders}=State) when SaveResponseToFile /= false ->
     Body = case TEnc of
 	       chunked ->
-		   lists:flatten(lists:reverse(Chunks));
+		   lists:reverse(Chunks);
 	       _ ->
-		   lists:flatten(lists:reverse(RepBuf))
+		   lists:reverse(RepBuf)
 	   end,
     State_1 = set_cur_request(State),
     file:close(Fd),
@@ -998,32 +1040,38 @@ handle_response(#request{from=From, stream_to=StreamTo, req_id=ReqId,
 		       _ ->
 			   {file, TmpFilename}
 		   end,
-    State_2 = do_reply(State_1, From, StreamTo, ReqId, {ok, SCode, RespHeaders, ResponseBody}),
+    State_2 = do_reply(State_1, From, StreamTo, ReqId, Resp_format,
+		       {ok, SCode, RespHeaders, ResponseBody}),
     cancel_timer(ReqTimer, {eat_message, {req_timedout, From}}),
     State_2;
-handle_response(#request{from=From, stream_to=StreamTo, req_id=ReqId},
+handle_response(#request{from=From, stream_to=StreamTo, req_id=ReqId,
+			 response_format = Resp_format},
 		#state{http_status_code=SCode, recvd_headers=RespHeaders,
 		       reply_buffer=RepBuf, transfer_encoding=TEnc,
 		       chunks=Chunks, send_timer=ReqTimer}=State) ->
     Body = case TEnc of
 	       chunked ->
-		   lists:flatten(lists:reverse(Chunks));
+		   lists:reverse(Chunks);
 	       _ ->
-		   lists:flatten(lists:reverse(RepBuf))
+		   lists:reverse(RepBuf)
 	   end,
-    State_1 = set_cur_request(State),
-    case get(conn_close) of
+%%    State_1 = set_cur_request(State),
+    State_1 = case get(conn_close) of
 	"close" ->
-	    do_reply(State_1, From, StreamTo, ReqId, {ok, SCode, RespHeaders, Body}),
+	    do_reply(State, From, StreamTo, ReqId, Resp_format,
+		     {ok, SCode, RespHeaders, Body}),
 	    exit(normal);
 	_ ->
-	    State_2 = do_reply(State_1, From, StreamTo, ReqId, {ok, SCode, RespHeaders, Body}),
+	    State_1_1 = do_reply(State, From, StreamTo, ReqId, Resp_format,
+				 {ok, SCode, RespHeaders, Body}),
 	    cancel_timer(ReqTimer, {eat_message, {req_timedout, From}}),
-	    State_2
-    end.
+	    State_1_1
+    end,
+    set_cur_request(State_1).
 
 reset_state(State) ->
-    State#state{status=get_header, rep_buf_size=0,content_length=undefined,
+    State#state{status=get_header, rep_buf_size=0, streamed_size = 0,
+		content_length=undefined,
 		reply_buffer=[], chunks=[], recvd_headers=[], deleted_crlf=false,
 		http_status_code=undefined, chunk_size=undefined, transfer_encoding=undefined}.
 
@@ -1063,18 +1111,18 @@ parse_headers_1(String) ->
     parse_headers_1(String, [], []).
 
 parse_headers_1([$\n, H |T], [$\r | L], Acc) when H == 32;
-						  H == $\t -> 
+						  H == $\t ->
     parse_headers_1(lists:dropwhile(fun(X) ->
 					    is_whitespace(X)
 				    end, T), [32 | L], Acc);
-parse_headers_1([$\n|T], [$\r | L], Acc) -> 
+parse_headers_1([$\n|T], [$\r | L], Acc) ->
     case parse_header(lists:reverse(L)) of
 	invalid ->
 	    parse_headers_1(T, [], Acc);
 	NewHeader ->
 	    parse_headers_1(T, [], [NewHeader | Acc])
     end;
-parse_headers_1([H|T],  L, Acc) -> 
+parse_headers_1([H|T],  L, Acc) ->
     parse_headers_1(T, [H|L], Acc);
 parse_headers_1([], [], Acc) ->
     lists:reverse(Acc);
@@ -1185,7 +1233,7 @@ parse_chunk_header([H | T], Acc) ->
 parse_chunk_header([], Acc) ->
     hexlist_to_integer(lists:reverse(Acc)).
 
-is_whitespace(32)  -> true;
+is_whitespace($\s)  -> true;
 is_whitespace($\r) -> true;
 is_whitespace($\n) -> true;
 is_whitespace($\t) -> true;
@@ -1197,36 +1245,62 @@ send_async_headers(_ReqId, undefined, _StatCode, _Headers) ->
 send_async_headers(ReqId, StreamTo, StatCode, Headers) ->
     catch StreamTo ! {ibrowse_async_headers, ReqId, StatCode, Headers}.
 
-do_reply(State, From, undefined, _, Msg) ->
+format_response_data(Resp_format, Body) ->
+    case Resp_format of
+	list when is_list(Body) ->
+	    flatten(Body);
+	binary when is_list(Body) ->
+	    list_to_binary(Body);
+	_ ->
+	    %% This is to cater for sending messages such as
+	    %% {chunk_start, _}, chunk_end etc
+	    Body
+    end.
+
+do_reply(State, From, undefined, _, Resp_format, {ok, St_code, Headers, Body}) ->
+    Msg_1 = {ok, St_code, Headers, format_response_data(Resp_format, Body)},
+    gen_server:reply(From, Msg_1),
+    dec_pipeline_counter(State);
+do_reply(State, From, undefined, _, _, Msg) ->
     gen_server:reply(From, Msg),
     dec_pipeline_counter(State);
-do_reply(State, _From, StreamTo, ReqId, {ok, _, _, _}) ->
+do_reply(State, _From, StreamTo, ReqId, Resp_format, {ok, _, _, Body}) ->
     State_1 = dec_pipeline_counter(State),
+    case Body of
+	[] ->
+	    ok;
+	_ ->
+	    Body_1 = format_response_data(Resp_format, Body),
+	    catch StreamTo ! {ibrowse_async_response, ReqId, Body_1}
+    end,
     catch StreamTo ! {ibrowse_async_response_end, ReqId},
     State_1;
-do_reply(State, _From, StreamTo, ReqId, Msg) ->
+do_reply(State, _From, StreamTo, ReqId, Resp_format, Msg) ->
     State_1 = dec_pipeline_counter(State),
-    catch StreamTo ! {ibrowse_async_response, ReqId, Msg},
+    Msg_1 = format_response_data(Resp_format, Msg),
+    catch StreamTo ! {ibrowse_async_response, ReqId, Msg_1},
     State_1.
 
-do_interim_reply(undefined, _ReqId, _Msg) ->
+do_interim_reply(undefined, _, _ReqId, _Msg) ->
     ok;
-do_interim_reply(StreamTo, ReqId, Msg) ->
-    catch StreamTo ! {ibrowse_async_response, ReqId, Msg}.
+do_interim_reply(StreamTo, Response_format, ReqId, Msg) ->
+    Msg_1 = format_response_data(Response_format, Msg),
+    catch StreamTo ! {ibrowse_async_response, ReqId, Msg_1}.
 
 do_error_reply(#state{reqs = Reqs} = State, Err) ->
     ReqList = queue:to_list(Reqs),
-    lists:foreach(fun(#request{from=From, stream_to=StreamTo, req_id=ReqId}) ->
-                          do_reply(State, From, StreamTo, ReqId, {error, Err})
+    lists:foreach(fun(#request{from=From, stream_to=StreamTo, req_id=ReqId,
+			       response_format = Resp_format}) ->
+                          do_reply(State, From, StreamTo, ReqId, Resp_format, {error, Err})
 		  end, ReqList).
 
 fail_pipelined_requests(#state{reqs = Reqs, cur_req = CurReq} = State, Reply) ->
     {_, Reqs_1} = queue:out(Reqs),
-    #request{from=From, stream_to=StreamTo, req_id=ReqId} = CurReq,
-    do_reply(State, From, StreamTo, ReqId, Reply),
+    #request{from=From, stream_to=StreamTo, req_id=ReqId,
+	     response_format = Resp_format} = CurReq,
+    do_reply(State, From, StreamTo, ReqId, Resp_format, Reply),
     do_error_reply(State#state{reqs = Reqs_1}, previous_request_failed).
 
-
 split_list_at(List, N) ->
     split_list_at(List, N, []).
 split_list_at([], _, Acc) ->
@@ -1271,7 +1345,7 @@ cancel_timer(Ref)       -> erlang:cancel_timer(Ref).
 
 cancel_timer(Ref, {eat_message, Msg}) ->
     cancel_timer(Ref),
-    receive 
+    receive
 	Msg ->
 	    ok
     after 0 ->
@@ -1310,3 +1384,19 @@ dec_pipeline_counter(#state{cur_pipeline_size = Pipe_sz,
     ets:delete(Tid, {Pipe_sz, self()}),
     ets:insert(Tid, {{Pipe_sz - 1, self()}, []}),
     State#state{cur_pipeline_size = Pipe_sz - 1}.
+
+flatten([H | _] = L) when is_integer(H) ->
+    L;
+flatten([H | _] = L) when is_list(H) ->
+    lists:flatten(L);
+flatten([]) ->
+    [].
+
+get_stream_chunk_size(Options) ->
+    case lists:keysearch(stream_chunk_size, 1, Options) of
+	{value, {_, V}} when V > 0 ->
+	    V;
+	_ ->
+	    ?DEFAULT_STREAM_CHUNK_SIZE
+    end.
+	
diff --git a/src/ibrowse/ibrowse_test.erl b/src/ibrowse/ibrowse_test.erl
index b4429c9b..de8865ff 100644
--- a/src/ibrowse/ibrowse_test.erl
+++ b/src/ibrowse/ibrowse_test.erl
@@ -14,7 +14,10 @@
 	 drv_ue_test/0,
 	 drv_ue_test/1,
 	 ue_test/0,
-	 ue_test/1
+	 ue_test/1,
+	 verify_chunked_streaming/0,
+	 verify_chunked_streaming/1,
+	 i_do_async_req_list/4
 	]).
 
 -import(ibrowse_lib, [printable_date/0]).
@@ -88,7 +91,7 @@ do_wait() ->
 		    do_wait()
 	    end
     end.
-		     
+
 do_send_req(Url, NumReqs) ->
     do_send_req_1(Url, NumReqs).
 
@@ -149,7 +152,7 @@ dump_errors(Key, Iod) ->
 -define(TEST_LIST, [{"http://intranet/messenger", get},
 		    {"http://www.google.co.uk", get},
 		    {"http://www.google.com", get},
-		    {"http://www.google.com", options}, 
+		    {"http://www.google.com", options},
 		    {"http://www.sun.com", get},
 		    {"http://www.oracle.com", get},
 		    {"http://www.bbc.co.uk", get},
@@ -172,7 +175,8 @@ dump_errors(Key, Iod) ->
 		    {"http://jigsaw.w3.org/HTTP/400/toolong/", get},
 		    {"http://jigsaw.w3.org/HTTP/300/", get},
 		    {"http://jigsaw.w3.org/HTTP/Basic/", get, [{basic_auth, {"guest", "guest"}}]},
-		    {"http://jigsaw.w3.org/HTTP/CL/", get}
+		    {"http://jigsaw.w3.org/HTTP/CL/", get},
+		    {"http://www.httpwatch.com/httpgallery/chunked/", get}
 		   ]).
 
 unit_tests() ->
@@ -185,13 +189,104 @@ unit_tests(Options) ->
 			  execute_req(Url, Method, X_Opts ++ Options)
 		  end, ?TEST_LIST).
 
-execute_req(Url, Method) ->
-    execute_req(Url, Method, []).
+verify_chunked_streaming() ->
+    verify_chunked_streaming([]).
+
+verify_chunked_streaming(Options) ->
+    Url = "http://www.httpwatch.com/httpgallery/chunked/",
+    io:format("URL: ~s~n", [Url]),
+    io:format("Fetching data without streaming...~n", []),
+    Result_without_streaming = ibrowse:send_req(
+				 Url, [], get, [],
+				 [{response_format, binary} | Options]),
+    io:format("Fetching data with streaming as list...~n", []),
+    Async_response_list = do_async_req_list(
+			    Url, get, [{response_format, list}]),
+    io:format("Fetching data with streaming as binary...~n", []),
+    Async_response_bin = do_async_req_list(
+			   Url, get, [{response_format, binary}]),
+    compare_responses(Result_without_streaming, Async_response_list, Async_response_bin).
+
+compare_responses({ok, St_code, _, Body}, {ok, St_code, _, Body}, {ok, St_code, _, Body}) ->
+    success;
+compare_responses({ok, St_code, _, Body_1}, {ok, St_code, _, Body_2}, {ok, St_code, _, Body_3}) ->
+    case Body_1 of
+	Body_2 ->
+	    io:format("Body_1 and Body_2 match~n", []);
+	Body_3 ->
+	    io:format("Body_1 and Body_3 match~n", []);
+	_ when Body_2 == Body_3 ->
+	    io:format("Body_2 and Body_3 match~n", []);
+	_ ->
+	    io:format("All three bodies are different!~n", [])
+    end,
+    fail_bodies_mismatch;
+compare_responses(R1, R2, R3) ->
+    io:format("R1 -> ~p~n", [R1]),
+    io:format("R2 -> ~p~n", [R2]),
+    io:format("R3 -> ~p~n", [R3]),
+    fail.
+
+do_async_req_list(Url) ->
+    do_async_req_list(Url, get).
+
+do_async_req_list(Url, Method) ->
+    do_async_req_list(Url, Method, [{stream_to, self()},
+				    {stream_chunk_size, 1000}]).
+
+do_async_req_list(Url, Method, Options) ->
+    {Pid,_} = erlang:spawn_monitor(?MODULE, i_do_async_req_list,
+				   [self(), Url, Method, 
+				    Options ++ [{stream_chunk_size, 1000}]]),
+    io:format("Spawned process ~p~n", [Pid]),
+    wait_for_resp(Pid).
+
+wait_for_resp(Pid) ->
+    receive
+	{async_result, Pid, Res} ->
+	    Res;
+	{'DOWN', _, _, Pid, Reason} ->
+	    {'EXIT', Reason};
+	{'DOWN', _, _, _, _} ->
+	    wait_for_resp(Pid);
+	Msg ->
+	    io:format("Recvd unknown message: ~p~n", [Msg]),
+	    wait_for_resp(Pid)
+    after 10000 ->
+	  {error, timeout}
+    end.
+
+i_do_async_req_list(Parent, Url, Method, Options) ->
+    Res = ibrowse:send_req(Url, [], Method, [], [{stream_to, self()} | Options]),
+    case Res of
+	{ibrowse_req_id, Req_id} ->
+	    Result = wait_for_async_resp(Req_id, undefined, undefined, []),
+	    Parent ! {async_result, self(), Result};
+	Err ->
+	    Parent ! {async_result, self(), Err}
+    end.
+
+wait_for_async_resp(Req_id, Acc_Stat_code, Acc_Headers, Body) ->
+    receive
+	{ibrowse_async_headers, Req_id, StatCode, Headers} ->
+	    wait_for_async_resp(Req_id, StatCode, Headers, Body);
+	{ibrowse_async_response, Req_id, {chunk_start, _}} ->
+	    wait_for_async_resp(Req_id, Acc_Stat_code, Acc_Headers, Body);
+	{ibrowse_async_response, Req_id, chunk_end} ->
+	    wait_for_async_resp(Req_id, Acc_Stat_code, Acc_Headers, Body);
+	{ibrowse_async_response_end, Req_id} ->
+	    Body_1 = list_to_binary(lists:reverse(Body)),
+	    {ok, Acc_Stat_code, Acc_Headers, Body_1};
+	{ibrowse_async_response, Req_id, Data} ->
+	    wait_for_async_resp(Req_id, Acc_Stat_code, Acc_Headers, [Data | Body]);
+	Err ->
+	    {ok, Acc_Stat_code, Acc_Headers, Err}
+    end.
 
 execute_req(Url, Method, Options) ->
     io:format("~s, ~p: ", [Url, Method]),
     Result = (catch ibrowse:send_req(Url, [], Method, [], Options)),
-    case Result of 
+    case Result of
 	{ok, SCode, _H, _B} ->
 	    io:format("Status code: ~p~n", [SCode]);
 	Err ->