Merge pull request #37 from hubertmis/add-option-size2

Add Size2 option handling according to RFC7959

coapthon/defines.py

@@ -125,7 +125,7 @@ class OptionRegistry(object):
     LOCATION_QUERY = OptionItem(20,"Location-Query",STRING,  True, None)
     BLOCK2 =        OptionItem(23, "Block2",        INTEGER, False, None)
     BLOCK1 =        OptionItem(27, "Block1",        INTEGER, False, None)
-    SIZE2 =         OptionItem(28, "Size2",         INTEGER, False, None)
+    SIZE2 =         OptionItem(28, "Size2",         INTEGER, False, 0)
     PROXY_URI =     OptionItem(35, "Proxy-Uri",     STRING,  False, None)
     PROXY_SCHEME =  OptionItem(39, "Proxy-Schema",  STRING,  False, None)
     SIZE1 =         OptionItem(60, "Size1",         INTEGER, False, None)

coapthon/layers/blocklayer.py

@@ -233,6 +233,7 @@ class BlockLayer(object):
 
                 self._block2_receive[key_token] = BlockItem(byte, num, m, size)
 
+                
             # correct m
             m = 0 if ((num * size) + size) > len(transaction.response.payload) else 1
             # add size2 if requested or if payload is bigger than one datagram
@@ -240,6 +241,7 @@ class BlockLayer(object):
             if (transaction.request.size2 is not None and transaction.request.size2 == 0) or \
                (transaction.response.payload is not None and len(transaction.response.payload) > defines.MAX_PAYLOAD):
                 transaction.response.size2 = len(transaction.response.payload)
+
             transaction.response.payload = transaction.response.payload[byte:byte + size]
             del transaction.response.block2
             transaction.response.block2 = (num, m, size)

coapthon/messages/message.py

@@ -645,8 +645,7 @@ class Message(object):
         Delete the Block2 option.
         """
         self.del_option_by_number(defines.OptionRegistry.BLOCK2.number)
-
-    @property
+        
     def size1(self):
         value = None
         for option in self.options:
@@ -667,14 +666,24 @@ class Message(object):
 
     @property
     def size2(self):
+        """
+        Get the Size2 option.
+
+        :return: the Size2 value
+        """
         value = None
         for option in self.options:
             if option.number == defines.OptionRegistry.SIZE2.number:
-                value = option.value if option.value is not None else 0
+                value = option.value 
         return value
 
     @size2.setter
     def size2(self, value):
+        """
+        Set the Size2 option.
+
+        :param value: the Block2 value
+        """
         option = Option()
         option.number = defines.OptionRegistry.SIZE2.number
         option.value = value
@@ -682,6 +691,9 @@ class Message(object):
 
     @size2.deleter
     def size2(self):
+        """
+        Delete the Size2 option.
+        """
         self.del_option_by_number(defines.OptionRegistry.SIZE2.number)
 
     @property