problem: ws_engine don't support WS RFC ping-pong

Solution: implement both PONG response and producing pings

src/stream_engine_base.hpp

@@ -87,7 +87,8 @@ class stream_engine_base_t : public io_object_t, public i_engine
     int push_msg_to_session (msg_t *msg_);
 
     int pull_and_encode (msg_t *msg_);
-    int decode_and_push (msg_t *msg_);
+    virtual int decode_and_push (msg_t *msg_);
+    int push_one_then_decode_and_push (msg_t *msg_);
 
     void set_handshake_timer ();
 
@@ -165,7 +166,6 @@ class stream_engine_base_t : public io_object_t, public i_engine
     void unplug ();
 
     int write_credential (msg_t *msg_);
-    int push_one_then_decode_and_push (msg_t *msg_);
 
     void mechanism_ready ();
 

src/ws_decoder.cpp

@@ -80,10 +80,10 @@ int zmq::ws_decoder_t::opcode_ready (unsigned char const *)
             _msg_flags = msg_t::command; // TODO: set the command name to CLOSE
             break;
         case zmq::ws_protocol_t::opcode_ping:
-            _msg_flags = msg_t::ping;
+            _msg_flags = msg_t::ping | msg_t::command;
             break;
         case zmq::ws_protocol_t::opcode_pong:
-            _msg_flags = msg_t::pong;
+            _msg_flags = msg_t::pong | msg_t::command;
             break;
         default:
             return -1;

src/ws_encoder.cpp

@@ -55,8 +55,13 @@ void zmq::ws_encoder_t::message_ready ()
 {
     int offset = 0;
 
-    // TODO: it might be close/ping/pong, which should be different op code
+    if (in_progress ()->is_ping ())
+        _tmp_buf[offset++] = 0x80 | zmq::ws_protocol_t::opcode_ping;
+    else if (in_progress ()->is_pong ())
+        _tmp_buf[offset++] = 0x80 | zmq::ws_protocol_t::opcode_pong;
+    else
         _tmp_buf[offset++] = 0x82; // Final | binary
+
     _tmp_buf[offset] = _must_mask ? 0x80 : 0x00;
 
     size_t size = in_progress ()->size ();

src/ws_engine.cpp

@@ -122,7 +122,8 @@ zmq::ws_engine_t::ws_engine_t (fd_t fd_,
     _header_name_position (0),
     _header_value_position (0),
     _header_upgrade_websocket (false),
-    _header_connection_upgrade (false)
+    _header_connection_upgrade (false),
+    _heartbeat_timeout (0)
 {
     memset (_websocket_key, 0, MAX_HEADER_VALUE_LENGTH + 1);
     memset (_websocket_accept, 0, MAX_HEADER_VALUE_LENGTH + 1);
@@ -130,6 +131,12 @@ zmq::ws_engine_t::ws_engine_t (fd_t fd_,
 
     _next_msg = &ws_engine_t::next_handshake_command;
     _process_msg = &ws_engine_t::process_handshake_command;
+
+    if (_options.heartbeat_interval > 0) {
+        _heartbeat_timeout = _options.heartbeat_timeout;
+        if (_heartbeat_timeout == -1)
+            _heartbeat_timeout = _options.heartbeat_interval;
+    }
 }
 
 zmq::ws_engine_t::~ws_engine_t ()
@@ -227,6 +234,13 @@ bool zmq::ws_engine_t::select_protocol (char *protocol_)
           &ws_engine_t::routing_id_msg);
         _process_msg = static_cast<int (stream_engine_base_t::*) (msg_t *)> (
           &ws_engine_t::process_routing_id_msg);
+
+        // No mechanism in place, enabling heartbeat
+        if (_options.heartbeat_interval > 0 && !_has_heartbeat_timer) {
+            add_timer (_options.heartbeat_interval, heartbeat_ivl_timer_id);
+            _has_heartbeat_timer = true;
+        }
+
         return true;
     }
     if (_options.mechanism == ZMQ_NULL
@@ -902,6 +916,75 @@ bool zmq::ws_engine_t::client_handshake ()
     return false;
 }
 
+int zmq::ws_engine_t::decode_and_push (msg_t *msg_)
+{
+    zmq_assert (_mechanism != NULL);
+
+    //  with WS engine, ping and pong commands are control messages and should not go through any mechanism
+    if (msg_->is_ping () || msg_->is_pong ()) {
+        if (process_command_message (msg_) == -1)
+            return -1;
+    } else if (_mechanism->decode (msg_) == -1)
+        return -1;
+
+    if (_has_timeout_timer) {
+        _has_timeout_timer = false;
+        cancel_timer (heartbeat_timeout_timer_id);
+    }
+
+    if (msg_->flags () & msg_t::command && !msg_->is_ping ()
+        && !msg_->is_pong ())
+        process_command_message (msg_);
+
+    if (_metadata)
+        msg_->set_metadata (_metadata);
+    if (session ()->push_msg (msg_) == -1) {
+        if (errno == EAGAIN)
+            _process_msg = &ws_engine_t::push_one_then_decode_and_push;
+        return -1;
+    }
+    return 0;
+}
+
+
+int zmq::ws_engine_t::produce_ping_message (msg_t *msg_)
+{
+    int rc = msg_->init ();
+    errno_assert (rc == 0);
+    msg_->set_flags (msg_t::command | msg_t::ping);
+
+    _next_msg = &ws_engine_t::pull_and_encode;
+    if (!_has_timeout_timer && _heartbeat_timeout > 0) {
+        add_timer (_heartbeat_timeout, heartbeat_timeout_timer_id);
+        _has_timeout_timer = true;
+    }
+
+    return rc;
+}
+
+
+int zmq::ws_engine_t::produce_pong_message (msg_t *msg_)
+{
+    int rc = msg_->init ();
+    errno_assert (rc == 0);
+    msg_->set_flags (msg_t::command | msg_t::pong);
+
+    _next_msg = &ws_engine_t::pull_and_encode;
+    return rc;
+}
+
+
+int zmq::ws_engine_t::process_command_message (msg_t *msg_)
+{
+    if (msg_->is_ping ()) {
+        _next_msg = static_cast<int (stream_engine_base_t::*) (msg_t *)> (
+          &ws_engine_t::produce_pong_message);
+        out_event ();
+    }
+
+    return 0;
+}
+
 static int
 encode_base64 (const unsigned char *in_, int in_len_, char *out_, int out_len_)
 {

src/ws_engine.hpp

@@ -135,6 +135,10 @@ class ws_engine_t : public stream_engine_base_t
     ~ws_engine_t ();
 
   protected:
+    int decode_and_push (msg_t *msg_);
+    int process_command_message (msg_t *msg_);
+    int produce_pong_message (msg_t *msg_);
+    int produce_ping_message (msg_t *msg_);
     bool handshake ();
     void plug_internal ();
     void start_ws_handshake ();
@@ -166,6 +170,8 @@ class ws_engine_t : public stream_engine_base_t
     char _websocket_protocol[256];
     char _websocket_key[MAX_HEADER_VALUE_LENGTH + 1];
     char _websocket_accept[MAX_HEADER_VALUE_LENGTH + 1];
+
+    int _heartbeat_timeout;
 };
 }
 

tests/test_ws_transport.cpp

@@ -52,6 +52,40 @@ void test_roundtrip ()
     test_context_socket_close (sb);
 }
 
+void test_heartbeat ()
+{
+    char connect_address[MAX_SOCKET_STRING + strlen ("/heartbeat")];
+    size_t addr_length = sizeof (connect_address);
+    void *sb = test_context_socket (ZMQ_REP);
+    TEST_ASSERT_SUCCESS_ERRNO (zmq_bind (sb, "ws://*:*/heartbeat"));
+    TEST_ASSERT_SUCCESS_ERRNO (
+      zmq_getsockopt (sb, ZMQ_LAST_ENDPOINT, connect_address, &addr_length));
+    strcat (connect_address, "/heartbeat");
+
+    void *sc = test_context_socket (ZMQ_REQ);
+
+    // Setting heartbeat settings
+    int ivl = 10;
+    TEST_ASSERT_SUCCESS_ERRNO (
+      zmq_setsockopt (sc, ZMQ_HEARTBEAT_IVL, &ivl, sizeof (ivl)));
+
+    // Disable reconnect, to make sure the ping-pong actually work
+    ivl = -1;
+    TEST_ASSERT_SUCCESS_ERRNO (
+      zmq_setsockopt (sc, ZMQ_RECONNECT_IVL, &ivl, sizeof (ivl)));
+
+    // Connect to server
+    TEST_ASSERT_SUCCESS_ERRNO (zmq_connect (sc, connect_address));
+
+    // Make sure some ping and pong going through
+    msleep (100);
+
+    bounce (sb, sc);
+
+    test_context_socket_close (sc);
+    test_context_socket_close (sb);
+}
+
 void test_short_message ()
 {
     char connect_address[MAX_SOCKET_STRING + strlen ("/short")];
@@ -170,6 +204,7 @@ int main ()
     RUN_TEST (test_roundtrip);
     RUN_TEST (test_short_message);
     RUN_TEST (test_large_message);
+    RUN_TEST (test_heartbeat);
 
     if (zmq_has ("curve"))
         RUN_TEST (test_curve);