BSON Encoding for Binary Objects

rosbridge_library/package.xml

@@ -25,6 +25,7 @@
   <build_depend>python-imaging</build_depend>
   <build_depend>geometry_msgs</build_depend>
   <build_depend>message_generation</build_depend>
+  <build_depend>python-bson</build_depend>
 
   <run_depend>rospy</run_depend>
   <run_depend>roscpp</run_depend>
@@ -35,6 +36,7 @@
   <run_depend>python-imaging</run_depend>
   <run_depend>geometry_msgs</run_depend>
   <run_depend>message_runtime</run_depend>
+  <run_depend>python-bson</run_depend>
 
   <test_depend>actionlib_msgs</test_depend>
   <test_depend>diagnostic_msgs</test_depend>

rosbridge_library/src/rosbridge_library/internal/message_conversion.py

@@ -40,6 +40,7 @@
 import re
 import string
 from base64 import standard_b64encode, standard_b64decode
+import bson
 
 type_map = {
    "bool":    ["bool"],
@@ -64,6 +65,20 @@
 ros_binary_types_list_braces = [("uint8[]", re.compile(r'uint8\[[^\]]*\]')),
                                 ("char[]", re.compile(r'char\[[^\]]*\]'))]
 
+binary_encoder = None
+
+def get_encoder():
+    global binary_encoder
+    if binary_encoder is None:
+        binary_encoder_type = rospy.get_param('~binary_encoder', 'b64')
+        if binary_encoder_type == 'b64':
+            binary_encoder = standard_b64encode
+        elif binary_encoder_type == 'bson':
+            binary_encoder = bson.Binary   
+        else:
+            print "Unknown encoder type '%s'"%binary_encoder_type
+            exit(0)
+    return binary_encoder        
 
 class InvalidMessageException(Exception):
     def __init__(self, inst):
@@ -97,10 +112,10 @@ def populate_instance(msg, inst):
 
 
 def _from_inst(inst, rostype):
-    # Special case for uint8[], we base64 encode the string
+    # Special case for uint8[], we encode the string
     for binary_type, expression in ros_binary_types_list_braces:
         if expression.sub(binary_type, rostype) in ros_binary_types:
-            return standard_b64encode(inst)
+            return get_encoder()(inst)
 
     # Check for time or duration
     if rostype in ros_time_types:

rosbridge_library/src/rosbridge_library/protocol.py

@@ -32,7 +32,7 @@
 
 import rospy
 import time
-
+import bson
 from rosbridge_library.internal.exceptions import InvalidArgumentException
 from rosbridge_library.internal.exceptions import MissingArgumentException
 
@@ -47,6 +47,15 @@ def is_number(s):
         return True
     except ValueError:
         return False
+
+def has_binary(d):
+    if type(d)==bson.Binary:
+        return True
+    if type(d)==dict:
+        for k,v in d.iteritems():
+            if has_binary(v):
+                return True
+    return False                
 
 class Protocol:
     """ The interface for a single client to interact with ROS.
@@ -260,7 +269,10 @@ def serialize(self, msg, cid=None):
         Returns a JSON string representing the dictionary
         """
         try:
-            return json.dumps(msg)
+            if has_binary(msg):
+                return bson.BSON.encode(msg)
+            else:    
+                return json.dumps(msg)
         except:
             if cid is not None:
                 # Only bother sending the log message if there's an id

rosbridge_server/src/rosbridge_server/websocket_handler.py

@@ -41,7 +41,7 @@
 
 from rosbridge_library.rosbridge_protocol import RosbridgeProtocol
 from rosbridge_library.util import json
-
+import bson
 
 class RosbridgeWebSocket(WebSocketHandler):
     client_id_seed = 0
@@ -97,7 +97,8 @@ def on_close(self):
         rospy.loginfo("Client disconnected. %d clients total.", cls.clients_connected)
 
     def send_message(self, message):
-        IOLoop.instance().add_callback(partial(self.write_message, message))
+        binary = type(message)==bson.BSON
+        IOLoop.instance().add_callback(partial(self.write_message, message, binary))
 
     def check_origin(self, origin):
         return True