Added files forgotten in the httpd refactoring checkin.

git-svn-id: https://svn.apache.org/repos/asf/incubator/couchdb/trunk@701174 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 340 insertions, 0 deletions

diff --git a/src/couchdb/couch_httpd_view.erl b/src/couchdb/couch_httpd_view.erl
new file mode 100644
index 00000000..0f3dd144
--- /dev/null
+++ b/src/couchdb/couch_httpd_view.erl
@@ -0,0 +1,340 @@
+% Licensed under the Apache License, Version 2.0 (the "License"); you may not
+% use this file except in compliance with the License.  You may obtain a copy of
+% the License at
+%
+%   http://www.apache.org/licenses/LICENSE-2.0
+%
+% Unless required by applicable law or agreed to in writing, software
+% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+% License for the specific language governing permissions and limitations under
+% the License.
+
+-module(couch_httpd_view).
+-include("couch_db.hrl").
+
+-export([handle_view_req/2,handle_temp_view_req/2]).
+
+-export([parse_view_query/1,make_view_fold_fun/4,finish_view_fold/3]).
+
+-import(couch_httpd,
+    [send_json/2,send_json/3,send_json/4,send_method_not_allowed/2,
+    start_json_response/2,send_chunk/2,end_json_response/1]).
+
+
+handle_view_req(#httpd{method='GET',path_parts=[_,_, Id, ViewName]}=Req, Db) ->
+    #view_query_args{
+        start_key = StartKey,
+        count = Count,
+        skip = SkipCount,
+        direction = Dir,
+        start_docid = StartDocId,
+        reduce = Reduce
+    } = QueryArgs = parse_view_query(Req),
+    
+    case couch_view:get_map_view({couch_db:name(Db), 
+            <<"_design/", Id/binary>>, ViewName}) of
+    {ok, View} ->    
+        {ok, RowCount} = couch_view:get_row_count(View),
+        Start = {StartKey, StartDocId},
+        FoldlFun = make_view_fold_fun(Req, QueryArgs, RowCount,
+                fun couch_view:reduce_to_count/1),
+        FoldAccInit = {Count, SkipCount, undefined, []},
+        FoldResult = couch_view:fold(View, Start, Dir, FoldlFun, FoldAccInit),
+        finish_view_fold(Req, RowCount, FoldResult);
+    {not_found, Reason} ->
+        case couch_view:get_reduce_view({couch_db:name(Db),
+                <<"_design/", Id/binary>>, ViewName}) of
+        {ok, View} ->
+            case Reduce of
+            false ->
+                {reduce, _N, _Lang, MapView} = View,
+                {ok, RowCount} = couch_view:get_row_count(MapView),
+                Start = {StartKey, StartDocId},
+                FoldlFun = make_view_fold_fun(Req, QueryArgs, RowCount,
+                    fun couch_view:reduce_to_count/1),
+                FoldAccInit = {Count, SkipCount, undefined, []},
+                FoldResult = couch_view:fold(MapView, Start, Dir, FoldlFun, FoldAccInit),
+                finish_view_fold(Req, RowCount, FoldResult);
+            _ ->
+                output_reduce_view(Req, View)
+            end;
+        _ ->
+            throw({not_found, Reason})
+        end
+    end;
+
+handle_view_req(Req, _Db) ->
+    send_method_not_allowed(Req, "GET,HEAD").
+
+handle_temp_view_req(#httpd{method='POST'}=Req, Db) ->
+    #view_query_args{
+        start_key = StartKey,
+        count = Count,
+        skip = SkipCount,
+        direction = Dir,
+        start_docid = StartDocId
+    } = QueryArgs = parse_view_query(Req),
+
+    case couch_httpd:primary_header_value(Req, "content-type") of
+        undefined -> ok;
+        "application/json" -> ok;
+        Else -> throw({incorrect_mime_type, Else})
+    end,
+    {Props} = couch_httpd:json_body(Req),
+    Language = proplists:get_value(<<"language">>, Props, <<"javascript">>),
+    MapSrc = proplists:get_value(<<"map">>, Props),
+    case proplists:get_value(<<"reduce">>, Props, null) of
+    null ->
+        {ok, View} = couch_view:get_map_view({temp, couch_db:name(Db), Language, MapSrc}),
+        Start = {StartKey, StartDocId},
+        
+        {ok, TotalRows} = couch_view:get_row_count(View),
+        
+        FoldlFun = make_view_fold_fun(Req, QueryArgs, TotalRows,
+                fun couch_view:reduce_to_count/1),
+        FoldAccInit = {Count, SkipCount, undefined, []},
+        FoldResult = couch_view:fold(View, Start, Dir, fun(A, B, C) ->
+            FoldlFun(A, B, C)
+        end, FoldAccInit),
+        finish_view_fold(Req, TotalRows, FoldResult);
+
+    RedSrc ->
+        {ok, View} = couch_view:get_reduce_view(
+                {temp,  couch_db:name(Db), Language, MapSrc, RedSrc}),
+        output_reduce_view(Req, View)
+    end;
+
+handle_temp_view_req(Req, _Db) ->
+    send_method_not_allowed(Req, "POST").
+
+
+output_reduce_view(Req, View) ->
+    #view_query_args{
+        start_key = StartKey,
+        end_key = EndKey,
+        count = Count,
+        skip = Skip,
+        direction = Dir,
+        start_docid = StartDocId,
+        end_docid = EndDocId,
+        group_level = GroupLevel
+    } = parse_view_query(Req),
+    GroupRowsFun =
+        fun({_Key1,_}, {_Key2,_}) when GroupLevel == 0 ->
+            true;
+        ({Key1,_}, {Key2,_})
+                when is_integer(GroupLevel) and is_list(Key1) and is_list(Key2) ->
+            lists:sublist(Key1, GroupLevel) == lists:sublist(Key2, GroupLevel);
+        ({Key1,_}, {Key2,_}) ->
+            Key1 == Key2
+        end,
+    {ok, Resp} = start_json_response(Req, 200),
+    send_chunk(Resp, "{\"rows\":["),
+    {ok, _} = couch_view:fold_reduce(View, Dir, {StartKey, StartDocId}, {EndKey, EndDocId},
+        GroupRowsFun,
+        fun(_Key, _Red, {AccSeparator,AccSkip,AccCount}) when AccSkip > 0 ->
+            {ok, {AccSeparator,AccSkip-1,AccCount}};
+        (_Key, _Red, {AccSeparator,0,AccCount}) when AccCount == 0 ->
+            {stop, {AccSeparator,0,AccCount}};
+        (_Key, Red, {AccSeparator,0,AccCount}) when GroupLevel == 0 ->
+            Json = ?JSON_ENCODE({[{key, null}, {value, Red}]}),
+            send_chunk(Resp, AccSeparator ++ Json),
+            {ok, {",",0,AccCount-1}};
+        (Key, Red, {AccSeparator,0,AccCount})
+                when is_integer(GroupLevel) 
+                andalso is_list(Key) ->
+            Json = ?JSON_ENCODE(
+                {[{key, lists:sublist(Key, GroupLevel)},{value, Red}]}),
+            send_chunk(Resp, AccSeparator ++ Json),
+            {ok, {",",0,AccCount-1}};
+        (Key, Red, {AccSeparator,0,AccCount}) ->
+            Json = ?JSON_ENCODE({[{key, Key}, {value, Red}]}),
+            send_chunk(Resp, AccSeparator ++ Json),
+            {ok, {",",0,AccCount-1}}
+        end, {"", Skip, Count}),
+    send_chunk(Resp, "]}"),
+    end_json_response(Resp).
+    
+
+reverse_key_default(nil) -> {};
+reverse_key_default({}) -> nil;
+reverse_key_default(Key) -> Key.
+
+parse_view_query(Req) ->
+    QueryList = couch_httpd:qs(Req),
+    lists:foldl(fun({Key,Value}, Args) ->
+        case {Key, Value} of
+        {"", _} ->
+            Args;
+        {"key", Value} ->
+            JsonKey = ?JSON_DECODE(Value),
+            Args#view_query_args{start_key=JsonKey,end_key=JsonKey};
+        {"startkey_docid", DocId} ->
+            Args#view_query_args{start_docid=list_to_binary(DocId)};
+        {"endkey_docid", DocId} ->
+            Args#view_query_args{end_docid=list_to_binary(DocId)};
+        {"startkey", Value} ->
+            Args#view_query_args{start_key=?JSON_DECODE(Value)};
+        {"endkey", Value} ->
+            Args#view_query_args{end_key=?JSON_DECODE(Value)};
+        {"count", Value} ->
+            case (catch list_to_integer(Value)) of
+            Count when is_integer(Count) ->
+                if Count < 0 ->
+                    Args#view_query_args {
+                        direction =
+                        if Args#view_query_args.direction == rev -> fwd;
+                        true -> rev
+                        end,
+                        count=Count,
+                        start_key = reverse_key_default(Args#view_query_args.start_key),
+                        start_docid = reverse_key_default(Args#view_query_args.start_docid),
+                        end_key = reverse_key_default(Args#view_query_args.end_key),
+                        end_docid =  reverse_key_default(Args#view_query_args.end_docid)};
+                true ->
+                    Args#view_query_args{count=Count}
+                end;
+            _Error ->
+                Msg = io_lib:format("Bad URL query value, number expected: count=~s", [Value]),
+                throw({query_parse_error, Msg})
+            end;
+        {"update", "false"} ->
+            Args#view_query_args{update=false};
+        {"descending", "true"} ->
+            case Args#view_query_args.direction of
+            fwd ->
+                Args#view_query_args {
+                    direction = rev,
+                    start_key = reverse_key_default(Args#view_query_args.start_key),
+                    start_docid = reverse_key_default(Args#view_query_args.start_docid),
+                    end_key = reverse_key_default(Args#view_query_args.end_key),
+                    end_docid =  reverse_key_default(Args#view_query_args.end_docid)};
+            _ ->
+                Args %already reversed
+            end;
+        {"descending", "false"} ->
+          % The descending=false behaviour is the default behaviour, so we
+          % simpply ignore it. This is only for convenience when playing with
+          % the HTTP API, so that a user doesn't get served an error when
+          % flipping true to false in the descending option.
+          Args;
+        {"skip", Value} ->
+            case (catch list_to_integer(Value)) of
+            Count when is_integer(Count) ->
+                Args#view_query_args{skip=Count};
+            _Error ->
+                Msg = lists:flatten(io_lib:format(
+                "Bad URL query value, number expected: skip=~s", [Value])),
+                throw({query_parse_error, Msg})
+            end;
+        {"group", "true"} ->
+            Args#view_query_args{group_level=exact};
+        {"group_level", LevelStr} ->
+            Args#view_query_args{group_level=list_to_integer(LevelStr)};
+        {"reduce", "true"} ->
+            Args#view_query_args{reduce=true};
+        {"reduce", "false"} ->
+            Args#view_query_args{reduce=false};
+        _ -> % unknown key
+            Msg = lists:flatten(io_lib:format(
+                "Bad URL query key:~s", [Key])),
+            throw({query_parse_error, Msg})
+        end
+    end, #view_query_args{}, QueryList).
+
+
+make_view_fold_fun(Req, QueryArgs, TotalViewCount, ReduceCountFun) ->
+    #view_query_args{
+        end_key = EndKey,
+        end_docid = EndDocId,
+        direction = Dir,
+        count = Count
+    } = QueryArgs,
+
+    PassedEndFun =
+    case Dir of
+    fwd ->
+        fun(ViewKey, ViewId) ->
+            couch_view:less_json([EndKey, EndDocId], [ViewKey, ViewId])
+        end;
+    rev->
+        fun(ViewKey, ViewId) ->
+            couch_view:less_json([ViewKey, ViewId], [EndKey, EndDocId])
+        end
+    end,
+
+    NegCountFun = fun({{Key, DocId}, Value}, OffsetReds,
+                      {AccCount, AccSkip, Resp, AccRevRows}) ->
+        Offset = ReduceCountFun(OffsetReds),
+        PassedEnd = PassedEndFun(Key, DocId),
+        case {PassedEnd, AccCount, AccSkip, Resp} of
+        {true, _, _, _} -> % The stop key has been passed, stop looping.
+            {stop, {AccCount, AccSkip, Resp, AccRevRows}};
+        {_, 0, _, _} -> % we've done "count" rows, stop foldling
+            {stop, {0, 0, Resp, AccRevRows}};
+        {_, _, AccSkip, _} when AccSkip > 0 ->
+            {ok, {AccCount, AccSkip - 1, Resp, AccRevRows}};
+        {_, _, _, undefined} ->
+            {ok, Resp2} = start_json_response(Req, 200),
+            Offset2 = TotalViewCount - Offset -
+                lists:min([TotalViewCount - Offset, - AccCount]),
+            JsonBegin = io_lib:format("{\"total_rows\":~w,\"offset\":~w,\"rows\":[\r\n",
+                    [TotalViewCount, Offset2]),
+            send_chunk(Resp2, JsonBegin),
+            JsonObj = {[{id, DocId}, {key, Key}, {value, Value}]},
+            {ok, {AccCount + 1, 0, Resp2, [?JSON_ENCODE(JsonObj) | AccRevRows]}};
+        {_, AccCount, _, Resp} ->
+            JsonObj = {[{id, DocId}, {key, Key}, {value, Value}]},
+            {ok, {AccCount + 1, 0, Resp, [?JSON_ENCODE(JsonObj), ",\r\n" | AccRevRows]}}
+        end
+    end,
+
+    PosCountFun = fun({{Key, DocId}, Value}, OffsetReds,
+                      {AccCount, AccSkip, Resp, AccRevRows}) ->
+        Offset = ReduceCountFun(OffsetReds), % I think we only need this call once per view
+        PassedEnd = PassedEndFun(Key, DocId),
+        case {PassedEnd, AccCount, AccSkip, Resp} of
+        {true, _, _, _} ->
+            % The stop key has been passed, stop looping.
+            {stop, {AccCount, AccSkip, Resp, AccRevRows}};
+        {_, 0, _, _} ->
+            % we've done "count" rows, stop foldling
+            {stop, {0, 0, Resp, AccRevRows}};
+        {_, _, AccSkip, _} when AccSkip > 0 ->
+            {ok, {AccCount, AccSkip - 1, Resp, AccRevRows}};
+        {_, _, _, undefined} ->
+            {ok, Resp2} = start_json_response(Req, 200),
+            JsonBegin = io_lib:format("{\"total_rows\":~w,\"offset\":~w,\"rows\":[\r\n",
+                    [TotalViewCount, Offset]),
+            JsonObj = {[{id, DocId}, {key, Key}, {value, Value}]},
+            
+            send_chunk(Resp2, JsonBegin ++ ?JSON_ENCODE(JsonObj)),
+            {ok, {AccCount - 1, 0, Resp2, AccRevRows}};
+        {_, AccCount, _, Resp} when (AccCount > 0) ->
+            JsonObj = {[{id, DocId}, {key, Key}, {value, Value}]},
+            send_chunk(Resp, ",\r\n" ++  ?JSON_ENCODE(JsonObj)),
+            {ok, {AccCount - 1, 0, Resp, AccRevRows}}
+        end
+    end,
+    case Count > 0 of
+    true ->     PosCountFun;
+    false ->    NegCountFun
+    end.
+
+finish_view_fold(Req, TotalRows, FoldResult) ->
+    case FoldResult of
+    {ok, {_, _, undefined, _}} ->
+        % nothing found in the view, nothing has been returned
+        % send empty view
+        send_json(Req, 200, {[
+            {total_rows, TotalRows},
+            {rows, []}
+        ]});
+    {ok, {_, _, Resp, AccRevRows}} ->
+        % end the view
+        send_chunk(Resp, AccRevRows ++ "\r\n]}"),
+        end_json_response(Resp);
+    Error ->
+        throw(Error)
+    end.
\ No newline at end of file