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%%
%% Licensed to the Apache Software Foundation (ASF) under one
%% or more contributor license agreements. See the NOTICE file
%% distributed with this work for additional information
%% regarding copyright ownership. The ASF licenses this file
%% to you 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(thrift_processor).
-export([init/1]).
-include("thrift_constants.hrl").
-include("thrift_protocol.hrl").
-record(thrift_processor, {handler, protocol, service}).
init({_Server, ProtoGen, Service, Handler}) when is_function(ProtoGen, 0) ->
{ok, Proto} = ProtoGen(),
loop(#thrift_processor{protocol = Proto,
service = Service,
handler = Handler}).
loop(State0 = #thrift_processor{protocol = Proto0,
handler = Handler}) ->
{Proto1, MessageBegin} = thrift_protocol:read(Proto0, message_begin),
State1 = State0#thrift_processor{protocol = Proto1},
case MessageBegin of
#protocol_message_begin{name = Function,
type = ?tMessageType_CALL,
seqid = Seqid} ->
case handle_function(State1, list_to_atom(Function), Seqid) of
{State2, ok} -> loop(State2);
{_State2, {error, Reason}} ->
Handler:handle_error(list_to_atom(Function), Reason),
thrift_protocol:close_transport(Proto1),
ok
end;
#protocol_message_begin{name = Function,
type = ?tMessageType_ONEWAY,
seqid = Seqid} ->
case handle_function(State1, list_to_atom(Function), Seqid) of
{State2, ok} -> loop(State2);
{_State2, {error, Reason}} ->
Handler:handle_error(list_to_atom(Function), Reason),
thrift_protocol:close_transport(Proto1),
ok
end;
{error, timeout = Reason} ->
Handler:handle_error(undefined, Reason),
thrift_protocol:close_transport(Proto1),
ok;
{error, closed = Reason} ->
%% error_logger:info_msg("Client disconnected~n"),
Handler:handle_error(undefined, Reason),
thrift_protocol:close_transport(Proto1),
exit(shutdown);
{error, Reason} ->
Handler:handle_error(undefined, Reason),
thrift_protocol:close_transport(Proto1),
exit(shutdown)
end.
handle_function(State0=#thrift_processor{protocol = Proto0,
handler = Handler,
service = Service},
Function,
Seqid) ->
InParams = Service:function_info(Function, params_type),
{Proto1, {ok, Params}} = thrift_protocol:read(Proto0, InParams),
State1 = State0#thrift_processor{protocol = Proto1},
try
Result = Handler:handle_function(Function, Params),
%% {Micro, Result} = better_timer(Handler, handle_function, [Function, Params]),
%% error_logger:info_msg("Processed ~p(~p) in ~.4fms~n",
%% [Function, Params, Micro/1000.0]),
handle_success(State1, Function, Result, Seqid)
catch
Type:Data when Type =:= throw orelse Type =:= error ->
handle_function_catch(State1, Function, Type, Data, Seqid)
end.
handle_function_catch(State = #thrift_processor{service = Service},
Function, ErrType, ErrData, Seqid) ->
IsOneway = Service:function_info(Function, reply_type) =:= oneway_void,
case {ErrType, ErrData} of
_ when IsOneway ->
Stack = erlang:get_stacktrace(),
error_logger:warning_msg(
"oneway void ~p threw error which must be ignored: ~p",
[Function, {ErrType, ErrData, Stack}]),
{State, ok};
{throw, Exception} when is_tuple(Exception), size(Exception) > 0 ->
%error_logger:warning_msg("~p threw exception: ~p~n", [Function, Exception]),
handle_exception(State, Function, Exception, Seqid);
% we still want to accept more requests from this client
{error, Error} ->
handle_error(State, Function, Error, Seqid)
end.
handle_success(State = #thrift_processor{service = Service},
Function,
Result,
Seqid) ->
ReplyType = Service:function_info(Function, reply_type),
StructName = atom_to_list(Function) ++ "_result",
case Result of
{reply, ReplyData} ->
Reply = {{struct, [{0, ReplyType}]}, {StructName, ReplyData}},
send_reply(State, Function, ?tMessageType_REPLY, Reply, Seqid);
ok when ReplyType == {struct, []} ->
send_reply(State, Function, ?tMessageType_REPLY, {ReplyType, {StructName}}, Seqid);
ok when ReplyType == oneway_void ->
%% no reply for oneway void
{State, ok}
end.
handle_exception(State = #thrift_processor{service = Service},
Function,
Exception,
Seqid) ->
ExceptionType = element(1, Exception),
%% Fetch a structure like {struct, [{-2, {struct, {Module, Type}}},
%% {-3, {struct, {Module, Type}}}]}
ReplySpec = Service:function_info(Function, exceptions),
{struct, XInfo} = ReplySpec,
true = is_list(XInfo),
%% Assuming we had a type1 exception, we'd get: [undefined, Exception, undefined]
%% e.g.: [{-1, type0}, {-2, type1}, {-3, type2}]
ExceptionList = [case Type of
ExceptionType -> Exception;
_ -> undefined
end
|| {_Fid, {struct, {_Module, Type}}} <- XInfo],
ExceptionTuple = list_to_tuple([Function | ExceptionList]),
% Make sure we got at least one defined
case lists:all(fun(X) -> X =:= undefined end, ExceptionList) of
true ->
handle_unknown_exception(State, Function, Exception, Seqid);
false ->
send_reply(State, Function, ?tMessageType_REPLY, {ReplySpec, ExceptionTuple}, Seqid)
end.
%%
%% Called when an exception has been explicitly thrown by the service, but it was
%% not one of the exceptions that was defined for the function.
%%
handle_unknown_exception(State, Function, Exception, Seqid) ->
handle_error(State, Function, {exception_not_declared_as_thrown,
Exception}, Seqid).
handle_error(State, Function, Error, Seqid) ->
Stack = erlang:get_stacktrace(),
error_logger:error_msg("~p had an error: ~p~n", [Function, {Error, Stack}]),
Message =
case application:get_env(thrift, exceptions_include_traces) of
{ok, true} ->
lists:flatten(io_lib:format("An error occurred: ~p~n",
[{Error, Stack}]));
_ ->
"An unknown handler error occurred."
end,
Reply = {?TApplicationException_Structure,
#'TApplicationException'{
message = Message,
type = ?TApplicationException_UNKNOWN}},
send_reply(State, Function, ?tMessageType_EXCEPTION, Reply, Seqid).
send_reply(State = #thrift_processor{protocol = Proto0}, Function, ReplyMessageType, Reply, Seqid) ->
try
{Proto1, ok} = thrift_protocol:write(Proto0, #protocol_message_begin{
name = atom_to_list(Function),
type = ReplyMessageType,
seqid = Seqid}),
{Proto2, ok} = thrift_protocol:write(Proto1, Reply),
{Proto3, ok} = thrift_protocol:write(Proto2, message_end),
{Proto4, ok} = thrift_protocol:flush_transport(Proto3),
{State#thrift_processor{protocol = Proto4}, ok}
catch
error:{badmatch, {_, {error, _} = Error}} ->
{State, Error}
end.
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