%% @author Justin Sheehy <justin@basho.com>
%% @author Andy Gross <andy@basho.com>
%% @copyright 2007-2009 Basho Technologies
%% @end
%%
%% 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(cowmachine_controller).
-author('Justin Sheehy <justin@basho.com>').
-author('Andy Gross <andy@basho.com>').
-author('Marc Worrell <marc@worrell.nl>').
-export([
do/3,
do_process/3
]).
-include("cowmachine_state.hrl").
-export_type([cmstate/0]).
%% @doc Get default value by Key.
-spec default(DefaultID, Context) -> Result when
DefaultID:: service_available | resource_exists | auth_required | is_authorized | forbidden | upgrades_provided | allow_missing_post | malformed_request | uri_too_long | known_content_type | valid_content_headers | valid_entity_length | options | allowed_methods | known_methods | validate_content_checksum | content_types_provided | content_types_accepted | delete_resource | delete_completed | post_is_create | create_path | base_uri | process_post | language_available | charsets_provided | content_encodings_provided | transfer_encodings_provided | variances | is_conflict | multiple_choices | previously_existed | moved_permanently | moved_temporarily | last_modified | expires | generate_etag | finish_request,
Context :: cowmachine_req:context(),
Result :: no_charset | no_default | undefined | boolean() | list(binary()).
default(service_available, _Context) ->
true;
default(resource_exists, _Context) ->
true;
default(auth_required, _Context) ->
true;
default(is_authorized, _Context) ->
true;
default(forbidden, _Context) ->
false;
default(upgrades_provided, _Context) ->
[];
default(allow_missing_post, _Context) ->
false;
default(malformed_request, _Context) ->
false;
default(uri_too_long, _Context) ->
false;
default(known_content_type, _Context) ->
true;
default(valid_content_headers, _Context) ->
true;
default(valid_entity_length, _Context) ->
true;
default(options, _Context) ->
[];
default(allowed_methods, _Context) ->
[ <<"GET">>, <<"HEAD">> ];
default(known_methods, _Context) ->
[ <<"GET">>, <<"HEAD">>,
<<"POST">>, <<"PUT">>, <<"PATCH">>, <<"DELETE">>,
<<"TRACE">>, <<"CONNECT">>, <<"OPTIONS">> ];
default(validate_content_checksum, _Context) ->
not_validated;
default(content_types_provided, _Context) ->
[ {<<"text">>, <<"html">>, []} ];
default(content_types_accepted, _Context) ->
[];
default(delete_resource, _Context) ->
false;
default(delete_completed, _Context) ->
true;
default(post_is_create, _Context) ->
false;
default(create_path, _Context) ->
undefined;
default(base_uri, _Context) ->
undefined;
default(process_post, _Context) ->
false;
default(language_available, _Context) ->
true;
% The default setting is needed for non-charset responses such as image/png
% An example of how one might do actual negotiation:
% [ <<"iso-8859-1">>, <<"utf-8">> ];
default(charsets_provided, Context) ->
case is_text( cowmachine_req:resp_content_type(Context) ) of
true -> [ <<"utf-8">> ];
false -> no_charset
end;
% The content variations available to the controller.
default(content_encodings_provided, _Context) ->
[<<"identity">>];
% How the content is transferred, this is handy for auto-gzip of GET-only resources.
% "identity" and "chunked" are always available to HTTP/1.1 clients.
% Example:
% [{"gzip", fun(X) -> zlib:gzip(X) end}];
default(transfer_encodings_provided, _Context) ->
[];
default(variances, _Context) ->
[];
default(is_conflict, _Context) ->
false;
default(multiple_choices, _Context) ->
false;
default(previously_existed, _Context) ->
false;
default(moved_permanently, _Context) ->
false;
default(moved_temporarily, _Context) ->
false;
default(last_modified, _Context) ->
undefined;
default(expires, _Context) ->
undefined;
default(generate_etag, _Context) ->
undefined;
default(finish_request, _Context) ->
true;
default(_, _Context) ->
no_default.
%% @doc Content types that are textual and should have a charset defined.
-spec is_text(ContentType) -> Result when
ContentType :: cow_http_hd:media_type(),
Result :: boolean().
is_text({<<"text">>, _, _}) -> true;
is_text({<<"application">>, <<"x-javascript">>, _}) -> true;
is_text({<<"application">>, <<"javascript">>, _}) -> true;
is_text({<<"application">>, <<"xhtml+xml">>, _}) -> true;
is_text({<<"application">>, <<"xml">>, _}) -> true;
is_text(_Mime) -> false.
%% @TODO Re-add logging code
%% @doc Export and run function `Fun'.
-spec do(Fun, State, Context) -> Result when
Fun :: atom(),
State :: cmstate(),
Context :: cowmachine_req:context(),
Result :: {ContentType, Context},
ContentType :: cow_http_hd:media_type().
do(Fun, #cmstate{ controller = Controller }, Context) when is_atom(Fun) ->
case erlang:function_exported(Controller, Fun, 1) of
true ->
Controller:Fun(Context);
false ->
case default(Fun, Context) of
no_default -> Controller:Fun(Context);
Default -> {Default, Context}
end
end.
%% @doc Export and process `State' with `Context'.
-spec do_process(ContentType, State, Context) -> Result when
ContentType :: cow_http_hd:media_type(),
State :: cmstate(),
Context :: cowmachine_req:context(),
Result :: {Res, Context},
Res :: boolean() | cowmachine_req:halt() | {error, any(), any()} | {error, any()} |
cowmachine_req:resp_body().
do_process(ContentType, #cmstate{ controller = Controller }, Context) ->
case erlang:function_exported(Controller, process, 4) of
true ->
Controller:process(
cowmachine_req:method(Context),
ContentType,
cowmachine_req:resp_content_type(Context),
Context);
false ->
{true, Context}
end.