hook up output for comm messages

IPython/html/static/notebook/js/comm.js

@@ -97,35 +97,35 b' var IPython = (function (IPython) {'
     //-----------------------------------------------------------------------
     
     var Comm = function (comm_id, target) {
-        this.comm_id = comm_id;
+        this.comm_id = comm_id || new IPython.utils.uuid();
         this.target = target || 'comm';
         this._msg_callback = this._open_callback = this._close_callback = null;
     };
     
     // methods for sending messages
-    Comm.prototype.open = function (data) {
+    Comm.prototype.open = function (data, callbacks) {
         var content = {
             comm_id : this.comm_id,
             target : this.target,
             data : data || {},
         };
-        this.kernel.send_shell_message("comm_open", content);
+        return this.kernel.send_shell_message("comm_open", content, callbacks);
     };
     
-    Comm.prototype.send = function (data) {
+    Comm.prototype.send = function (data, callbacks) {
         var content = {
             comm_id : this.comm_id,
             data : data || {},
         };
-        return this.kernel.send_shell_message("comm_msg", content);
+        return this.kernel.send_shell_message("comm_msg", content, callbacks);
     };
     
-    Comm.prototype.close = function (data) {
+    Comm.prototype.close = function (data, callbacks) {
         var content = {
             comm_id : this.comm_id,
             data : data || {},
         };
-        return this.kernel.send_shell_message("comm_close", content);
+        return this.kernel.send_shell_message("comm_close", content, callbacks);
     };
     
     // methods for registering callbacks for incoming messages

IPython/kernel/comm/manager.py

@@ -11,6 +11,8 b''
 # Imports
 #-----------------------------------------------------------------------------
 
+import sys
+
 from IPython.config import LoggingConfigurable
 from IPython.core.prompts import LazyEvaluate
 from IPython.core.getipython import get_ipython
@@ -33,6 +35,23 b' def lazy_keys(dikt):'
     return LazyEvaluate(lambda d: list(d.keys()))
 
 
+def with_output(method):
+    """method decorator for ensuring output is handled properly in a message handler
+    
+    - sets parent header before entering the method
+    - flushes stdout/stderr after
+    """
+    def method_with_output(self, stream, ident, msg):
+        self.shell.set_parent(msg['header'])
+        try:
+            return method(self, stream, ident, msg)
+        finally:
+            sys.stdout.flush()
+            sys.stderr.flush()
+    
+    return method_with_output
+
+
 class CommManager(LoggingConfigurable):
     """Manager for Comms in the Kernel"""
     
@@ -97,7 +116,7 b' class CommManager(LoggingConfigurable):'
         return comm
     
     # Message handlers
-    
+    @with_output
     def comm_open(self, stream, ident, msg):
         """Handler for comm_open messages"""
         content = msg['content']
@@ -117,6 +136,7 b' class CommManager(LoggingConfigurable):'
         comm.handle_open(msg)
         self.register_comm(comm)
     
+    @with_output
     def comm_msg(self, stream, ident, msg):
         """Handler for comm_msg messages"""
         content = msg['content']
@@ -127,6 +147,7 b' class CommManager(LoggingConfigurable):'
             return
         comm.handle_msg(msg)
     
+    @with_output
     def comm_close(self, stream, ident, msg):
         """Handler for comm_close messages"""
         content = msg['content']