Handle XML parsing errors

apps/epp_proxy/include/epp_proxy.hrl

@@ -1,8 +1,19 @@
-%% This record is used by both epp_tcp_worker and epp_tls_worker.
+%% These records are used by both epp_tcp_worker and epp_tls_worker.
 -record(epp_request,
         {method,   % get | post (atom)
          url,      % "https://example.com/some-url"
          body,     % "" | {multipart [{{<<"raw_frame">>, "Some body"}}]}
-         cookies,  % "" | {multipart [{{<<"raw_frame">>, "Some body"}}]}
+         cookies,  % [<<"session=SomeSession; Version=1">>]
          headers   % [{"User-Agent", <<"EPP proxy">>}, {"Other", <<"Header">>}]
         }).
+
+-record(epp_error_request,
+       {method,       % get
+        url,          % "https://example.com/some-url"
+        query_params, % {[{<<"msg">>, <<"Some">>}, {<<"code">>, <<"2001">>}]}
+        cookies,      % [<<"session=SomeSession; Version=1">>]
+        headers        % [{"User-Agent", <<"EPP proxy">>}, {"Other", <<"Header">>}]
+       }).
+
+-type epp_request() :: #epp_request{}.
+-type epp_error_request() :: #epp_error_request{}.

apps/epp_proxy/src/epp_http_client.erl

@@ -0,0 +1,38 @@
+-module(epp_http_client).
+
+-include("epp_proxy.hrl").
+
+-behaviour(epp_http_client_behaviour).
+
+-export([request/1, error_request/1]).
+
+%% Callback API
+request(#epp_request{} = Request) ->
+    HackneyArgs = handle_args(Request),
+    {Status, _StatusCode, _Headers, ClientRef} =
+        apply(hackney, request, HackneyArgs),
+    {ok, Body} = hackney:body(ClientRef),
+    {Status, Body}.
+
+error_request(#epp_error_request{} = Request) ->
+    HackneyArgs = handle_error_args(Request),
+    {Status, _StatusCode, _Headers, ClientRef} =
+        apply(hackney, request, HackneyArgs),
+    {ok, Body} = hackney:body(ClientRef),
+    {Status, Body}.
+
+%% Private API
+-spec handle_args(epp_request()) -> list().
+handle_args(#epp_request{method=get, url=URL, headers=Headers, body="",
+                         cookies=Cookies}) ->
+    [get, URL, Headers, "", [{cookie, Cookies}, insecure]];
+handle_args(#epp_request{method=post, url=URL, headers=Headers, body=Body,
+                         cookies=Cookies}) ->
+    [post, URL, Headers, Body, [{cookie, Cookies}, insecure]].
+
+-spec handle_error_args(epp_error_request()) -> list().
+handle_error_args(#epp_error_request{method=get, url=URL, headers=Headers,
+                                     query_params=Params, cookies=Cookies}) ->
+    QueryString = hackney_url:qs(Params),
+    CompleteURL = [URL, <<"?">>, QueryString],
+    [get, CompleteURL, Headers, "", [{cookie, Cookies}, insecure]].

apps/epp_proxy/src/epp_http_client_behaviour.erl

@@ -0,0 +1,9 @@
+-module(epp_http_client_behaviour).
+
+-include("epp_proxy.hrl").
+
+-type http_response() :: {integer(), binary()}.
+
+%% Abstract module for http client behaviour. It should call EPP HTTP server
+%% and return a response back to the caller.
+-callback request(epp_request()) -> http_response().

apps/epp_proxy/src/epp_router.erl

@@ -18,6 +18,12 @@
             {ok, Value} -> Value
             end).
 
+-define(baseErrorUrl,
+        case application:get_env(epp_proxy, epp_error_url) of
+            undefined -> "https://registry.test/epp/error/";
+            {ok, Value} -> Value
+            end).
+
 %% Save yourself some checking beforehand.
 is_valid_epp_command(Command) ->
     lists:member(Command, ?validCommands).
@@ -27,6 +33,10 @@ request_method("hello") ->
     get;
 request_method(<<"hello">>) ->
     get;
+request_method("error") ->
+    get;
+request_method(<<"error">>) ->
+    get;
 request_method(_) ->
     post.
 
@@ -53,7 +63,9 @@ url_map(Command) when is_list(Command) ->
         "renew"   -> string:concat(base_command_url(), Command);
         "update"  -> string:concat(base_command_url(), Command);
         % Transfer is both poll and query
-        "transfer" -> string:concat(base_command_url(), Command)
+        "transfer" -> string:concat(base_command_url(), Command);
+        % Error route
+        "error" -> base_error_url()
         % Anything else should fail.
      end.
 
@@ -63,3 +75,6 @@ base_session_url() ->
 
 base_command_url() ->
     ?baseCommandUrl.
+
+base_error_url() ->
+    ?baseErrorUrl.

apps/epp_proxy/src/epp_tls_worker.erl

@@ -9,9 +9,17 @@
 -export([init/1, handle_cast/2, handle_call/3, start_link/1]).
 -export([code_change/3]).
 
--export([request/7]).
+-export([request_from_map/1]).
 
--record(state,{socket, session_id, common_name, client_cert, peer_ip}).
+-record(valid_frame, {command,
+                      cl_trid,
+                      raw_frame}).
+-record(invalid_frame, {code,
+                        cl_trid,
+                        message}).
+-record(state, {socket,
+                session_id,
+                headers }).
 
 init(Socket) ->
     lager:info("Created a worker process"),
@@ -21,63 +29,53 @@ init(Socket) ->
 start_link(Socket) ->
     gen_server:start_link(?MODULE, Socket, []).
 
+
 handle_cast(serve, State = #state{socket=Socket}) ->
     %% If certificate is revoked, this will fail right away here.
     %% mod_epp does exactly the same thing.
     {ok, SecureSocket} = ssl:handshake(Socket),
     NewState = state_from_socket(SecureSocket, State),
     {noreply, NewState};
-handle_cast(greeting, State = #state{socket=Socket, common_name=SSL_CLIENT_S_DN_CN,
-                                     client_cert=SSL_CLIENT_CERT,
+handle_cast(greeting, State = #state{socket=Socket,
                                      session_id=SessionId,
-                                     peer_ip=PeerIp}) ->
-    Request = request("hello", SessionId, "", SSL_CLIENT_S_DN_CN,
-                      SSL_CLIENT_CERT, PeerIp, nomatch),
+                                     headers=Headers}) ->
 
-    {_Status, _StatusCode, _Headers, ClientRef} =
-        hackney:request(Request#epp_request.method, Request#epp_request.url,
-                        Request#epp_request.headers, Request#epp_request.body,
-                        [{cookie, Request#epp_request.cookies}, insecure]),
+    Request = request_from_map(#{command => "hello",
+                                 session_id => SessionId,
+                                 raw_frame => "",
+                                 headers => Headers,
+                                 cl_trid => nomatch}),
 
-    {ok, Body} = hackney:body(ClientRef),
+    {_Status, Body} = epp_http_client:request(Request),
 
     frame_to_socket(Body, Socket),
     gen_server:cast(self(), process_command),
     {noreply, State#state{socket=Socket, session_id=SessionId}};
-handle_cast(process_command, State = #state{socket=Socket,
-                                            common_name=SSL_CLIENT_S_DN_CN,
-                                            client_cert=SSL_CLIENT_CERT,
-                                            session_id=SessionId,
-                                            peer_ip=PeerIp}) ->
-    Length = case read_length(Socket) of
-        {ok, Data} ->
-            Data;
-        {error, _Details} ->
-            {stop, normal, State}
+handle_cast(process_command,
+            State = #state{socket=Socket,session_id=SessionId,
+                           headers=Headers}) ->
+    RawFrame = frame_from_socket(Socket, State),
+
+    case parse_frame(RawFrame) of
+        #valid_frame{command=Command, cl_trid=ClTRID} ->
+            Request = request_from_map(#{command => Command,
+                                         session_id => SessionId,
+                                         raw_frame => RawFrame,
+                                         headers => Headers,
+                                         cl_trid => ClTRID}),
+
+            {_Status, Body} = epp_http_client:request(Request);
+        #invalid_frame{message=Message, code=Code, cl_trid=ClTRID} ->
+            Command = "error",
+            Request = request_from_map(#{command => Command,
+                                         session_id => SessionId,
+                                         headers => Headers,
+                                         code => Code,
+                                         message => Message,
+                                         cl_trid => ClTRID}),
+            {_Status, Body} = epp_http_client:error_request(Request)
         end,
 
-    Frame = case read_frame(Socket, Length) of
-        {ok, FrameData} ->
-            io:format("~p~n", [FrameData]),
-            FrameData;
-        {error, _FrameDetails} ->
-            {stop, normal, State}
-    end,
-
-    {ok, XMLRecord} = epp_xml:parse(Frame),
-    ClTRID= epp_xml:find_cltrid(Frame),
-    Command = epp_xml:get_command(XMLRecord),
-
-    Request = request(Command, SessionId, Frame, SSL_CLIENT_S_DN_CN,
-                      SSL_CLIENT_CERT, PeerIp, ClTRID),
-
-    {_Status, _StatusCode, _Headers, ClientRef} =
-        hackney:request(Request#epp_request.method, Request#epp_request.url,
-                        Request#epp_request.headers, Request#epp_request.body,
-                        [{cookie, Request#epp_request.cookies}, insecure]),
-
-    {ok, Body} = hackney:body(ClientRef),
-
     frame_to_socket(Body, Socket),
 
     %% On logout, close the socket.
@@ -90,10 +88,11 @@ handle_cast(process_command, State = #state{socket=Socket,
             gen_server:cast(self(), process_command),
             {noreply, State#state{socket=Socket, session_id=SessionId}}
     end.
+
 handle_call(_E, _From, State) -> {noreply, State}.
 code_change(_OldVersion, State, _Extra) -> {ok, State}.
 
-%% Private function
+%% Private functions
 write_line(Socket, Line) ->
     ok = ssl:send(Socket, Line).
 
@@ -118,31 +117,66 @@ read_frame(Socket, FrameLength) ->
     end.
 
 %% Map request and return values.
-%% TODO: Make arguments into a map.
-request(Command, SessionId, RawFrame, CommonName, ClientCert, PeerIp, ClTRID) ->
+request_from_map(#{command := "error", session_id := SessionId,
+                   code := Code, message := Message, headers:=Headers,
+                   cl_trid := ClTRID}) ->
+    URL = epp_router:route_request("error"),
+    RequestMethod = epp_router:request_method("error"),
+    Cookie = hackney_cookie:setcookie("session", SessionId, []),
+    QueryParams = query_params(Code, Message, ClTRID),
+    Headers=Headers,
+    Request = #epp_error_request{url=URL,
+                           method=RequestMethod,
+                           query_params=QueryParams,
+                           cookies=[Cookie],
+                           headers=Headers},
+    lager:info("Error Request from map: [~p]~n", [Request]),
+    Request;
+request_from_map(#{command := Command, session_id := SessionId,
+          raw_frame := RawFrame, headers:=Headers, cl_trid := ClTRID}) ->
     URL = epp_router:route_request(Command),
     RequestMethod = epp_router:request_method(Command),
     Cookie = hackney_cookie:setcookie("session", SessionId, []),
-    case Command of
-        "hello" ->
-            Body = "";
-        _ ->
-            Body = {multipart, request_body(RawFrame, ClTRID)}
-        end,
+    Body = request_body(Command, RawFrame, ClTRID),
+    Headers=Headers,
+    Request = #epp_request{url=URL,
+                           method=RequestMethod,
+                           body=Body,
+                           cookies=[Cookie],
+                           headers=Headers},
+    lager:info("Request from map: [~p]~n", [Request]),
+    Request;
+request_from_map(#{command := Command, session_id := SessionId,
+          raw_frame := RawFrame, common_name := CommonName,
+          client_cert := ClientCert, peer_ip := PeerIp, cl_trid := ClTRID}) ->
+    URL = epp_router:route_request(Command),
+    RequestMethod = epp_router:request_method(Command),
+    Cookie = hackney_cookie:setcookie("session", SessionId, []),
+    Body = request_body(Command, RawFrame, ClTRID),
     Headers = [{"SSL_CLIENT_CERT", ClientCert},
                {"SSL_CLIENT_S_DN_CN", CommonName},
                {"User-Agent", <<"EPP proxy">>},
                {"X-Forwarded-for", epp_util:readable_ip(PeerIp)}],
-    Request = #epp_request{url=URL, method=RequestMethod, body=Body, cookies=[Cookie],
+    Request = #epp_request{url=URL,
+                           method=RequestMethod,
+                           body=Body,
+                           cookies=[Cookie],
                            headers=Headers},
-    lager:info("Request to be sent: [~p]~n", [Request]),
+    lager:info("Request from map: [~p]~n", [Request]),
     Request.
 
-%% Return form data
-request_body(RawFrame, nomatch) ->
-    [{<<"raw_frame">>, RawFrame}];
-request_body(RawFrame, ClTRID) ->
-    [{<<"raw_frame">>, RawFrame}, {<<"clTRID">>, ClTRID}].
+%% Return form data or an empty list.
+request_body("hello", _, _) ->
+    "";
+request_body(_Command, RawFrame, nomatch) ->
+    {multipart, [{<<"raw_frame">>, RawFrame}]};
+request_body(_Command, RawFrame, ClTRID) ->
+    {multipart, [{<<"raw_frame">>, RawFrame}, {<<"clTRID">>, ClTRID}]}.
+
+query_params(Code, Message, nomatch) ->
+    [{<<"code">>, Code}, {<<"msg">>, Message}];
+query_params(Code, Message, ClTRID) ->
+    [{<<"code">>, Code}, {<<"msg">>, Message}, {<<"clTRID">>, ClTRID}].
 
 %% Wrap a message in EPP frame, and then send it to socket.
 frame_to_socket(Message, Socket) ->
@@ -151,13 +185,47 @@ frame_to_socket(Message, Socket) ->
     write_line(Socket, ByteSize),
     write_line(Socket, Message).
 
+%% First, listen for 4 bytes, then listen until the declared length.
+%% Return the frame binary at the very end.
+frame_from_socket(Socket, State) ->
+    Length = case read_length(Socket) of
+        {ok, Data} ->
+            Data;
+        {error, _Details} ->
+            {stop, normal, State}
+        end,
+
+    Frame = case read_frame(Socket, Length) of
+        {ok, FrameData} ->
+            io:format("~p~n", [FrameData]),
+            FrameData;
+        {error, _FrameDetails} ->
+            {stop, normal, State}
+    end,
+    Frame.
+
 %% Extract state info from socket. Fail if you must.
 state_from_socket(Socket, State) ->
     {ok, PeerCert} = ssl:peercert(Socket),
     {ok,  {PeerIp, _PeerPort}} = ssl:peername(Socket),
     {SSL_CLIENT_S_DN_CN, SSL_CLIENT_CERT} =
         epp_certs:headers_from_cert(PeerCert),
-    NewState = State#state{socket=Socket, common_name=SSL_CLIENT_S_DN_CN,
-                           client_cert=SSL_CLIENT_CERT, peer_ip=PeerIp},
+    Headers = [{"SSL_CLIENT_CERT", SSL_CLIENT_CERT},
+               {"SSL_CLIENT_S_DN_CN", SSL_CLIENT_S_DN_CN},
+               {"User-Agent", <<"EPP proxy">>},
+               {"X-Forwarded-for", epp_util:readable_ip(PeerIp)}],
+    NewState = State#state{socket=Socket, headers=Headers},
     lager:info("Established connection with: [~p]~n", [NewState]),
     NewState.
+
+%% Get status, XML record, command and clTRID if defined
+parse_frame(Frame) ->
+    ClTRID = epp_xml:find_cltrid(Frame),
+    case epp_xml:parse(Frame) of
+        {ok, XMLRecord} ->
+            Command = epp_xml:get_command(XMLRecord),
+            #valid_frame{command=Command, cl_trid=ClTRID, raw_frame=Frame};
+        {error, _} ->
+            ErrorMessage = <<"Command syntax error.">>,
+            #invalid_frame{code=2001, message=ErrorMessage, cl_trid=ClTRID}
+        end.

apps/epp_proxy/test/epp_router_tests.erl

@@ -13,6 +13,8 @@ is_valid_epp_command_test() ->
 request_method_test() ->
     ?assertEqual(get, epp_router:request_method("hello")),
     ?assertEqual(get, epp_router:request_method(<<"hello">>)),
+    ?assertEqual(get, epp_router:request_method("error")),
+    ?assertEqual(get, epp_router:request_method(<<"error">>)),
     ?assertEqual(post, epp_router:request_method("create")),
     ?assertEqual(post, epp_router:request_method(123)).
 
@@ -60,3 +62,7 @@ update_url_test() ->
 transfer_url_test() ->
     ?assertEqual("https://registry.test/epp/command/transfer", epp_router:route_request("transfer")),
     ?assertEqual("https://registry.test/epp/command/transfer", epp_router:route_request(<<"transfer">>)).
+
+error_url_test() ->
+    ?assertEqual("https://registry.test/epp/error/", epp_router:route_request("error")),
+    ?assertEqual("https://registry.test/epp/error/", epp_router:route_request(<<"error">>)).

config/sys.config

@@ -4,6 +4,7 @@
                {tls_port, 700},
                {epp_session_url, "https://registry.test/epp/session/"},
                {epp_command_url, "https://registry.test/epp/command/"},
+               {epp_error_url, "https://registry.test/epp/error/"},
                {cacertfile_path, "/opt/shared/ca/certs/ca.crt.pem"},
                {certfile_path, "/opt/shared/ca/certs/cert.pem"},
                {keyfile_path, "/opt/shared/ca/certs/key.pem"},
@@ -11,7 +12,7 @@
   {lager, [
     {handlers, [
                {lager_console_backend, info},
-               {lager_syslog_backend, ["epp_proxy", local1, info]},
-   ]}
-  }
+               {lager_syslog_backend, ["epp_proxy", local1, info]}
+    ]}
+  ]}
 ].

config/test.config

@@ -4,6 +4,7 @@
                {tls_port, 4444},
                {epp_session_url, "https://registry.test/epp/session/"},
                {epp_command_url, "https://registry.test/epp/command/"},
+               {epp_error_url, "https://registry.test/epp/error/"},
                {cacertfile_path, "/opt/shared/ca/certs/ca.crt.pem"},
                {certfile_path, "/opt/shared/ca/certs/apache.crt"},
                {keyfile_path, "/opt/shared/ca/private/apache.key"}]}