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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_form).
-export([handle_form_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_form_req(#httpd{method='GET',path_parts=[_, _, DesignName, FormName, Docid]}=Req, Db) ->
DesignId = <<"_design/", DesignName/binary>>,
% Anyway we can dry up this error handling?
case (catch couch_httpd_db:couch_doc_open(Db, DesignId, [], [])) of
{not_found, missing} ->
throw({not_found, missing_design_doc});
{not_found, deleted} ->
throw({not_found, deleted_design_doc});
DesignDoc ->
#doc{body={Props}} = DesignDoc,
Lang = proplists:get_value(<<"language">>, Props, <<"javascript">>),
case proplists:get_value(<<"forms">>, Props, nil) of
{Forms} ->
case proplists:get_value(FormName, Forms, nil) of
nil ->
throw({not_found, missing_form});
FormSrc ->
case (catch couch_httpd_db:couch_doc_open(Db, Docid, [], [])) of
{not_found, missing} ->
throw({not_found, missing});
{not_found, deleted} ->
throw({not_found, deleted});
Doc ->
% ok we have everythign we need. let's make it happen.
send_form_response(Lang, FormSrc, Doc, Req, Db)
end
end;
nil ->
throw({not_found, missing_form})
end
end;
handle_form_req(#httpd{method='GET'}=Req, _Db) ->
send_error(Req, 404, <<"form_error">>, <<"Invalid path.">>);
handle_form_req(Req, _Db) ->
send_method_not_allowed(Req, "GET,HEAD").
send_form_response(Lang, FormSrc, #doc{revs=[DocRev|_]}=Doc, #httpd{mochi_req=MReq}=Req, Db) ->
% make a term with etag-effecting Req components, but not always changing ones.
Headers = MReq:get(headers),
Hlist = mochiweb_headers:to_list(Headers),
Accept = proplists:get_value('Accept', Hlist),
<<SigInt:128/integer>> = erlang:md5(term_to_binary({Lang, FormSrc, DocRev, Accept})),
CurrentEtag = list_to_binary("\"" ++ lists:flatten(io_lib:format("form_~.36B",[SigInt])) ++ "\""),
EtagsToMatch = string:tokens(
couch_httpd:header_value(Req, "If-None-Match", ""), ", "),
% We know our etag now
case lists:member(binary_to_list(CurrentEtag), EtagsToMatch) of
true ->
% the client has this in their cache.
couch_httpd:send_response(Req, 304, [{"Etag", CurrentEtag}], <<>>);
false ->
% Run the external form renderer.
{JsonResponse} = couch_query_servers:render_doc_form(Lang, FormSrc, Doc, Req, Db),
% 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.
JsonResponse2 = case proplists:get_value(<<"headers">>, JsonResponse, nil) of
nil ->
% no JSON headers
% add our Etag and Vary headers to the response
[{<<"headers">>, {[{<<"Etag">>, CurrentEtag}, {<<"Vary">>, <<"Accept">>}]}} | JsonResponse];
{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 <- JsonResponse]
end,
couch_httpd_external:send_external_response(Req, {JsonResponse2})
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].
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