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% 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_show).
-export([handle_doc_show_req/2, handle_view_list_req/2]).
-include("couch_db.hrl").
-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,
start_chunked_response/3, send_error/4]).
handle_doc_show_req(#httpd{
method='GET',
path_parts=[_, _, DesignName, ShowName, Docid]
}=Req, Db) ->
DesignId = <<"_design/", DesignName/binary>>,
#doc{body={Props}} = couch_httpd_db:couch_doc_open(Db, DesignId, [], []),
Lang = proplists:get_value(<<"language">>, Props, <<"javascript">>),
ShowSrc = get_nested_json_value({Props}, [<<"shows">>, ShowName]),
Doc = couch_httpd_db:couch_doc_open(Db, Docid, [], []),
send_doc_show_response(Lang, ShowSrc, Doc, Req, Db);
handle_doc_show_req(#httpd{
method='GET',
path_parts=[_, _, DesignName, ShowName]
}=Req, Db) ->
DesignId = <<"_design/", DesignName/binary>>,
#doc{body={Props}} = couch_httpd_db:couch_doc_open(Db, DesignId, [], []),
Lang = proplists:get_value(<<"language">>, Props, <<"javascript">>),
ShowSrc = get_nested_json_value({Props}, [<<"shows">>, ShowName]),
send_doc_show_response(Lang, ShowSrc, nil, Req, Db);
handle_doc_show_req(#httpd{method='GET'}=Req, _Db) ->
send_error(Req, 404, <<"show_error">>, <<"Invalid path.">>);
handle_doc_show_req(Req, _Db) ->
send_method_not_allowed(Req, "GET,HEAD").
handle_view_list_req(#httpd{method='GET',path_parts=[_, _, DesignName, ListName, ViewName]}=Req, Db) ->
DesignId = <<"_design/", DesignName/binary>>,
#doc{body={Props}} = couch_httpd_db:couch_doc_open(Db, DesignId, [], []),
Lang = proplists:get_value(<<"language">>, Props, <<"javascript">>),
ListSrc = get_nested_json_value({Props}, [<<"lists">>, ListName]),
send_view_list_response(Lang, ListSrc, ViewName, DesignId, Req, Db);
handle_view_list_req(Req, _Db) ->
send_method_not_allowed(Req, "GET,HEAD").
get_nested_json_value({Props}, [Key|Keys]) ->
case proplists:get_value(Key, Props, nil) of
nil -> throw({not_found, <<"missing json key: ", Key/binary>>});
Value -> get_nested_json_value(Value, Keys)
end;
get_nested_json_value(Value, []) ->
Value;
get_nested_json_value(_NotJSONObj, _) ->
throw({not_found, json_mismatch}).
send_view_list_response(Lang, ListSrc, ViewName, DesignId, Req, Db) ->
% TODO add etags when we get view etags
#view_query_args{
stale = Stale,
reduce = Reduce
} = QueryArgs = couch_httpd_view:parse_view_query(Req, nil, nil, true),
case couch_view:get_map_view(Db, DesignId, ViewName, Stale) of
{ok, View, Group} ->
output_map_list(Req, Lang, ListSrc, View, Group, Db, QueryArgs);
{not_found, _Reason} ->
case couch_view:get_reduce_view(Db, DesignId, ViewName, Stale) of
{ok, ReduceView, Group} ->
case Reduce of
false ->
MapView = couch_view:extract_map_view(ReduceView),
output_map_list(Req, Lang, ListSrc, MapView, Group, Db, QueryArgs);
_ ->
throw({not_implemented, reduce_view_lists})
end;
{not_found, Reason} ->
throw({not_found, Reason})
end
end.
output_map_list(#httpd{mochi_req=MReq}=Req, Lang, ListSrc, View, Group, Db, QueryArgs) ->
#view_query_args{
limit = Limit,
direction = Dir,
skip = SkipCount,
start_key = StartKey,
start_docid = StartDocId
} = QueryArgs,
{ok, RowCount} = couch_view:get_row_count(View),
Start = {StartKey, StartDocId},
Headers = MReq:get(headers),
Hlist = mochiweb_headers:to_list(Headers),
Accept = proplists:get_value('Accept', Hlist),
CurrentEtag = couch_httpd_view:view_group_etag(Group, {Lang, ListSrc, Accept}),
couch_httpd:etag_respond(Req, CurrentEtag, fun() ->
% get the os process here
% pass it into the view fold with closures
{ok, QueryServer} = couch_query_servers:start_view_list(Lang, ListSrc),
StartListRespFun = fun(Req2, _Etag, TotalViewCount, Offset) ->
ExternalResp = couch_query_servers:render_list_head(QueryServer,
Req2, Db, TotalViewCount, Offset),
JsonResp = apply_etag(ExternalResp, CurrentEtag),
#extern_resp_args{
code = Code,
data = BeginBody,
ctype = CType,
headers = ExtHeaders
} = couch_httpd_external:parse_external_response(JsonResp),
JsonHeaders = couch_httpd_external:default_or_content_type(CType, ExtHeaders),
% TODO use the Etag
{ok, Resp} = start_chunked_response(Req, Code, JsonHeaders),
{ok, Resp, binary_to_list(BeginBody)}
end,
SendListRowFun = fun(Resp, Db2, {{Key, DocId}, Value},
RowFront, _IncludeDocs) ->
JsonResp = couch_query_servers:render_list_row(QueryServer,
Req, Db2, {{Key, DocId}, Value}),
#extern_resp_args{
stop = StopIter,
data = RowBody
} = couch_httpd_external:parse_external_response(JsonResp),
RowFront2 = case RowFront of
nil -> [];
_ -> RowFront
end,
case StopIter of
true -> stop;
_ -> send_chunk(Resp, RowFront2 ++ binary_to_list(RowBody))
end
end,
FoldlFun = couch_httpd_view:make_view_fold_fun(Req, QueryArgs, CurrentEtag, Db, RowCount,
#view_fold_helper_funs{
reduce_count = fun couch_view:reduce_to_count/1,
start_response = StartListRespFun,
send_row = SendListRowFun
}),
FoldAccInit = {Limit, SkipCount, undefined, []},
FoldResult = couch_view:fold(View, Start, Dir, FoldlFun, FoldAccInit),
finish_view_list(Req, Db, QueryServer, RowCount, FoldResult, StartListRespFun)
end).
finish_view_list(Req, Db, QueryServer, TotalRows,
FoldResult, StartListRespFun) ->
case FoldResult of
{ok, {_, _, undefined, _}} ->
{ok, Resp, BeginBody} = StartListRespFun(Req, 200, TotalRows, null),
JsonTail = couch_query_servers:render_list_tail(QueryServer, Req, Db),
#extern_resp_args{
data = Tail
} = couch_httpd_external:parse_external_response(JsonTail),
send_chunk(Resp, BeginBody ++ Tail),
send_chunk(Resp, []);
{ok, {_, _, Resp, _AccRevRows}} ->
JsonTail = couch_query_servers:render_list_tail(QueryServer, Req, Db),
#extern_resp_args{
data = Tail
} = couch_httpd_external:parse_external_response(JsonTail),
send_chunk(Resp, Tail),
send_chunk(Resp, []);
Error ->
throw(Error)
end.
send_doc_show_response(Lang, ShowSrc, nil, #httpd{mochi_req=MReq}=Req, Db) ->
% compute etag with no doc
Headers = MReq:get(headers),
Hlist = mochiweb_headers:to_list(Headers),
Accept = proplists:get_value('Accept', Hlist),
CurrentEtag = couch_httpd:make_etag({Lang, ShowSrc, nil, Accept}),
couch_httpd:etag_respond(Req, CurrentEtag, fun() ->
ExternalResp = couch_query_servers:render_doc_show(Lang, ShowSrc,
nil, Req, Db),
JsonResp = apply_etag(ExternalResp, CurrentEtag),
couch_httpd_external:send_external_response(Req, JsonResp)
end);
send_doc_show_response(Lang, ShowSrc, #doc{revs=[DocRev|_]}=Doc, #httpd{mochi_req=MReq}=Req, Db) ->
% calculate the etag
Headers = MReq:get(headers),
Hlist = mochiweb_headers:to_list(Headers),
Accept = proplists:get_value('Accept', Hlist),
CurrentEtag = couch_httpd:make_etag({Lang, ShowSrc, DocRev, Accept}),
% We know our etag now
couch_httpd:etag_respond(Req, CurrentEtag, fun() ->
ExternalResp = couch_query_servers:render_doc_show(Lang, ShowSrc,
Doc, Req, Db),
JsonResp = apply_etag(ExternalResp, CurrentEtag),
couch_httpd_external:send_external_response(Req, JsonResp)
end).
set_or_replace_header(H, L) ->
set_or_replace_header(H, L, []).
set_or_replace_header({Key, NewValue}, [{Key, _OldVal} | Headers], Acc) ->
% drop matching keys
set_or_replace_header({Key, NewValue}, Headers, Acc);
set_or_replace_header({Key, NewValue}, [{OtherKey, OtherVal} | Headers], Acc) ->
% something else is next, leave it alone.
set_or_replace_header({Key, NewValue}, Headers, [{OtherKey, OtherVal} | Acc]);
set_or_replace_header({Key, NewValue}, [], Acc) ->
% end of list, add ours
[{Key, NewValue}|Acc].
apply_etag({ExternalResponse}, CurrentEtag) ->
% Here we embark on the delicate task of replacing or creating the
% headers on the JsonResponse object. We need to control the Etag and
% Vary headers. If the external function controls the Etag, we'd have to
% run it to check for a match, which sort of defeats the purpose.
case proplists:get_value(<<"headers">>, ExternalResponse, nil) of
nil ->
% no JSON headers
% add our Etag and Vary headers to the response
{[{<<"headers">>, {[{<<"Etag">>, CurrentEtag}, {<<"Vary">>, <<"Accept">>}]}} | ExternalResponse]};
{JsonHeaders} ->
{[case Field of
{<<"headers">>, {JsonHeaders}} -> % add our headers
JsonHeadersEtagged = set_or_replace_header({<<"Etag">>, CurrentEtag}, JsonHeaders),
JsonHeadersVaried = set_or_replace_header({<<"Vary">>, <<"Accept">>}, JsonHeadersEtagged),
{<<"headers">>, {JsonHeadersVaried}};
_ -> % skip non-header fields
Field
end || Field <- ExternalResponse]}
end.
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