Add Python3 compatibility (RobotWebTools#300)

* First pass at Python 3 compatibility
* message_conversion: Only call encode on a Python2 str or bytes type
* protocol.py: Changes for dict in Python3. Compatible with Python 2 too.
* More Python 3 fixes, all tests pass
* Move definition of string_types to rosbridge_library.util

rosapi/src/rosapi/objectutils.py

@@ -31,33 +31,31 @@
 # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
-from string import find
-
 from rosbridge_library.internal import ros_loader
 
 # Keep track of atomic types and special types
 atomics = ['bool', 'byte','int8', 'uint8', 'int16', 'uint16', 'int32', 'uint32', 'int64', 'uint64', 'float32', 'float64', 'string']
 specials = ['time', 'duration']
-    
+
 
 def get_typedef(type):
     """ A typedef is a dict containing the following fields:
          - string type
          - string[] fieldnames
          - string[] fieldtypes
          - int[] fieldarraylen
-         - string[] examples 
+         - string[] examples
     get_typedef will return a typedef dict for the specified message type """
     if type in atomics:
         # Atomics don't get a typedef
-        return None 
-    
+        return None
+
     if type in specials:
         # Specials get their type def mocked up
         return _get_special_typedef(type)
-    
+
     # Fetch an instance and return its typedef
-    instance = ros_loader.get_message_instance(type)    
+    instance = ros_loader.get_message_instance(type)
     return _get_typedef(instance)
 
 def get_service_request_typedef(servicetype):
@@ -68,7 +66,7 @@ def get_service_request_typedef(servicetype):
 
 def get_service_response_typedef(servicetype):
     """ Returns a typedef dict for the service response class for the specified service type """
-    # Get an instance of the service response class and return its typedef 
+    # Get an instance of the service response class and return its typedef
     instance = ros_loader.get_service_response_instance(servicetype)
     return _get_typedef(instance)
 
@@ -82,7 +80,7 @@ def get_service_request_typedef_recursive(servicetype):
     # Get an instance of the service request class and get its typedef
     instance = ros_loader.get_service_request_instance(servicetype)
     typedef = _get_typedef(instance)
-    
+
     # Return the list of sub-typedefs
     return _get_subtypedefs_recursive(typedef, [])
 
@@ -91,24 +89,24 @@ def get_service_response_typedef_recursive(servicetype):
     # Get an instance of the service response class and get its typedef
     instance = ros_loader.get_service_response_instance(servicetype)
     typedef = _get_typedef(instance)
-    
+
     # Return the list of sub-typedefs
     return _get_subtypedefs_recursive(typedef, [])
 
 def _get_typedef(instance):
     """ Gets a typedef dict for the specified instance """
     if instance is None or not hasattr(instance, "__slots__") or not hasattr(instance, "_slot_types"):
         return None
-    
+
     fieldnames = []
     fieldtypes = []
     fieldarraylen = []
     examples = []
     for i in xrange(len(instance.__slots__)):
         # Pull out the name
-        name = instance.__slots__[i]        
+        name = instance.__slots__[i]
         fieldnames.append(name)
-        
+
         # Pull out the type and determine whether it's an array
         field_type = instance._slot_types[i]
         arraylen = -1
@@ -117,33 +115,33 @@ def _get_typedef(instance):
                 arraylen = 0
                 field_type = field_type[:-2]
             else:
-                split = find(field_type, '[')
+                split = field_type.find('[')
                 arraylen = int(field_type[split+1:-1])
                 field_type = field_type[:split]
         fieldarraylen.append(arraylen)
-        
+
         # Get the fully qualified type
         field_instance = getattr(instance, name)
         fieldtypes.append(_type_name(field_type, field_instance))
-        
+
         # Set the example as appropriate
         example = field_instance
         if arraylen>=0:
             example = []
         elif field_type not in atomics:
             example = {}
         examples.append(str(example))
-    
+
     typedef = {
        "type": _type_name_from_instance(instance),
        "fieldnames": fieldnames,
        "fieldtypes": fieldtypes,
        "fieldarraylen": fieldarraylen,
        "examples": examples
     }
-    
+
     return typedef
-    
+
 def _get_special_typedef(type):
     example = None
     if type=="time" or type=="duration":
@@ -161,43 +159,43 @@ def _get_typedefs_recursive(type, typesseen):
     if type in typesseen:
         # Don't put a type if it's already been seen
         return []
-    
+
     # Note that we have now seen this type
     typesseen.append(type)
-    
+
     # Get the typedef for this type and make sure it's not None
     typedef = get_typedef(type)
-    
+
     return _get_subtypedefs_recursive(typedef, typesseen)
-    
+
 def _get_subtypedefs_recursive(typedef, typesseen):
     if typedef is None:
         return []
-    
+
     # Create the list of subtypes and get the typedefs for fields
     typedefs = [ typedef ]
     for fieldtype in typedef["fieldtypes"]:
         typedefs = typedefs + _get_typedefs_recursive(fieldtype, typesseen)
-        
+
     return typedefs
 
 def _type_name(type, instance):
-    """ given a short type, and an object instance of that type, 
-    determines and returns the fully qualified type """    
+    """ given a short type, and an object instance of that type,
+    determines and returns the fully qualified type """
     # The fully qualified type of atomic and special types is just their original name
     if type in atomics or type in specials:
         return type
-            
+
     # If the instance is a list, then we can get no more information from the instance.
     # However, luckily, the 'type' field for list types is usually already inflated to the full type.
     if isinstance(instance, list):
         return type
-    
-    # Otherwise, the type will come from the module and class name of the instance                
+
+    # Otherwise, the type will come from the module and class name of the instance
     return _type_name_from_instance(instance)
-    
+
 def _type_name_from_instance(instance):
     mod = instance.__module__
-    type = mod[0:find(mod, '.')]+"/"+instance.__class__.__name__
-    return type 
-    
+    type = mod[0:mod.find('.')]+"/"+instance.__class__.__name__
+    return type
+

rosbridge_library/src/rosbridge_library/capabilities/advertise.py

@@ -34,6 +34,7 @@
 import fnmatch
 from rosbridge_library.capability import Capability
 from rosbridge_library.internal.publishers import manager
+from rosbridge_library.util import string_types
 
 
 class Registration():
@@ -73,8 +74,8 @@ def is_empty(self):
 
 class Advertise(Capability):
 
-    advertise_msg_fields = [(True, "topic", (str, unicode)), (True, "type", (str, unicode))]
-    unadvertise_msg_fields = [(True, "topic", (str, unicode))]
+    advertise_msg_fields = [(True, "topic", string_types), (True, "type", string_types)]
+    unadvertise_msg_fields = [(True, "topic", string_types)]
 
     topics_glob = None
 

rosbridge_library/src/rosbridge_library/capabilities/advertise_service.py

@@ -1,6 +1,7 @@
 from rosbridge_library.internal.ros_loader import get_service_class
 from rosbridge_library.internal import message_conversion
 from rosbridge_library.capability import Capability
+from rosbridge_library.util import string_types
 import fnmatch
 import rospy
 import time
@@ -49,7 +50,7 @@ def handle_request(self, req):
 
 class AdvertiseService(Capability):
 
-    advertise_service_msg_fields = [(True, "service", (str, unicode)), (True, "type", (str, unicode))]
+    advertise_service_msg_fields = [(True, "service", string_types), (True, "type", string_types)]
 
     def __init__(self, protocol):
         # Call superclass constructor

rosbridge_library/src/rosbridge_library/capabilities/call_service.py

@@ -34,13 +34,14 @@
 from functools import partial
 from rosbridge_library.capability import Capability
 from rosbridge_library.internal.services import ServiceCaller
+from rosbridge_library.util import string_types
 
 
 class CallService(Capability):
 
-    call_service_msg_fields = [(True, "service", (str, unicode)),
+    call_service_msg_fields = [(True, "service", string_types),
                                (False, "fragment_size", (int, type(None))),
-                               (False, "compression", (str, unicode))]
+                               (False, "compression", string_types)]
 
     services_glob = None
 
@@ -77,7 +78,7 @@ def call_service(self, message):
                 return
         else:
             self.protocol.log("debug", "No service security glob, not checking service call.")
- 
+
         # Check for deprecated service ID, eg. /rosbridge/topics#33
         cid = extract_id(service, cid)
 

rosbridge_library/src/rosbridge_library/capabilities/publish.py

@@ -34,11 +34,12 @@
 import fnmatch
 from rosbridge_library.capability import Capability
 from rosbridge_library.internal.publishers import manager
+from rosbridge_library.util import string_types
 
 
 class Publish(Capability):
 
-    publish_msg_fields = [(True, "topic", (str, unicode))]
+    publish_msg_fields = [(True, "topic", string_types)]
 
     topics_glob = None
 
@@ -83,7 +84,7 @@ def publish(self, message):
 
         # Publish the message
         manager.publish(client_id, topic, msg, latch=latch, queue_size=queue_size)
- 
+
     def finish(self):
         client_id = self.protocol.client_id
         for topic in self._published:

rosbridge_library/src/rosbridge_library/capabilities/service_response.py

@@ -1,12 +1,13 @@
 from rosbridge_library.capability import Capability
 from rosbridge_library.internal import ros_loader, message_conversion
+from rosbridge_library.util import string_types
 
 
 class ServiceResponse(Capability):
 
     service_response_msg_fields = [
-        (True, "service", (str, unicode)), (False, "id", (str, unicode)),
-        (False, "values", (str, unicode)), (True, "result", bool)
+        (True, "service", string_types), (False, "id", string_types),
+        (False, "values", string_types), (True, "result", bool)
     ]
 
     def __init__(self, protocol):

rosbridge_library/src/rosbridge_library/capabilities/subscribe.py

@@ -47,6 +47,8 @@
     except ImportError:
         from json import dumps
 
+from rosbridge_library.util import string_types
+
 
 class Subscription():
     """ Keeps track of the clients multiple calls to subscribe.
@@ -180,10 +182,10 @@ def f(fieldname):
 
 class Subscribe(Capability):
 
-    subscribe_msg_fields = [(True, "topic", (str, unicode)), (False, "type", (str, unicode)),
+    subscribe_msg_fields = [(True, "topic", string_types), (False, "type", string_types),
                             (False, "throttle_rate", int), (False, "fragment_size", int),
-                            (False, "queue_length", int), (False, "compression", (str, unicode))]
-    unsubscribe_msg_fields = [(True, "topic", (str, unicode))]
+                            (False, "queue_length", int), (False, "compression", string_types)]
+    unsubscribe_msg_fields = [(True, "topic", string_types)]
 
     topics_glob = None
 
@@ -242,7 +244,7 @@ def subscribe(self, msg):
     def unsubscribe(self, msg):
         # Pull out the ID
         sid = msg.get("id", None)
- 
+
         self.basic_type_check(msg, self.unsubscribe_msg_fields)
 
         topic = msg["topic"]