Merge banana-receive-wrong-dialect-7662

Author: wolfgang61, exarkun Reviewer: exarkun Fixes: twisted#7662 Check the active Banana dialect before processing dialect-specific features in the Banana protocol implementation. Previously features of the PB dialect could be used even when the None dialect was active. git-svn-id: svn://svn.twistedmatrix.com/svn/Twisted/trunk@43224 bbbe8e31-12d6-0310-92fd-ac37d47ddeeb
yuankui · Oct 5, 2014 · 730e076 · 730e076
1 parent fbad806
commit 730e076
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diff --git a/docs/core/specifications/banana.rst b/docs/core/specifications/banana.rst
@@ -182,9 +182,7 @@ A profile is specified by a unique string. This specification defines two profil
 profile that should be supported by all Banana implementations.
 Additional profiles may be added in the future.
 
-
-
-
+Extensions defined by a profile may only be used if that profile has been selected by client and server.
 
 
 The ``"none"``  Profile

diff --git a/twisted/spread/banana.py b/twisted/spread/banana.py
@@ -87,6 +87,17 @@ def setPrefixLimit(limit):
 SIZE_LIMIT = 640 * 1024   # 640k is all you'll ever need :-)
 
 class Banana(protocol.Protocol, styles.Ephemeral):
+    """
+    L{Banana} implements the I{Banana} s-expression protocol, client and
+    server.
+
+    @ivar knownDialects: These are the profiles supported by this Banana
+        implementation.
+    @type knownDialects: L{list} of L{bytes}
+    """
+
+    # The specification calls these profiles but this implementation calls them
+    # dialects instead.
     knownDialects = ["pb", "none"]
 
     prefixLimit = None
@@ -212,7 +223,13 @@ def dataReceived(self, chunk):
             elif typebyte == VOCAB:
                 buffer = rest
                 num = b1282int(num)
-                gotItem(self.incomingVocabulary[num])
+                item = self.incomingVocabulary[num]
+                if self.currentDialect == b'pb':
+                    # the sender issues VOCAB only for dialect pb
+                    gotItem(item)
+                else:
+                    raise NotImplementedError(
+                        "Invalid item for pb protocol {0!r}".format(item))
             elif typebyte == FLOAT:
                 if len(rest) >= 8:
                     buffer = rest[8:]

diff --git a/twisted/test/test_banana.py b/twisted/test/test_banana.py
@@ -21,24 +21,60 @@ def testInt2b128(self):
             y = banana.b1282int(v)
             assert y == i, "y = %s; i = %s" % (y,i)
 
-class BananaTestCase(unittest.TestCase):
 
+
+def selectDialect(protocol, dialect):
+    """
+    Dictate a Banana dialect to use.
+
+    @param protocol: A L{banana.Banana} instance which has not yet had a
+        dialect negotiated.
+
+    @param dialect: A L{bytes} instance naming a Banana dialect to select.
+    """
+    # We can't do this the normal way by delivering bytes because other setup
+    # stuff gets in the way (for example, clients and servers have incompatible
+    # negotiations for this step).  So use the private API to make this happen.
+    protocol._selectDialect(dialect)
+
+
+
+class BananaTestBase(unittest.TestCase):
+    """
+    The base for test classes. It defines commonly used things and sets up a
+    connection for testing.
+    """
     encClass = banana.Banana
 
     def setUp(self):
         self.io = StringIO.StringIO()
         self.enc = self.encClass()
         self.enc.makeConnection(protocol.FileWrapper(self.io))
-        self.enc._selectDialect("none")
+        selectDialect(self.enc, b"none")
         self.enc.expressionReceived = self.putResult
 
+
     def putResult(self, result):
+        """
+        Store an expression received by C{self.enc}.
+
+        @param result: The object that was received.
+        @type result: Any type supported by Banana.
+        """
         self.result = result
 
+
     def tearDown(self):
         self.enc.connectionLost(failure.Failure(main.CONNECTION_DONE))
         del self.enc
 
+
+
+class BananaTestCase(BananaTestBase):
+    """
+    General banana tests.
+    """
+
     def testString(self):
         self.enc.sendEncoded("hello")
         l = []
@@ -306,18 +342,66 @@ def encoded(n):
 
 
 
+class DialectTests(BananaTestBase):
+    """
+    Tests for Banana's handling of dialects.
+    """
+    vocab = b'remote'
+    legalPbItem = chr(banana.Banana.outgoingVocabulary[vocab]) + banana.VOCAB
+    illegalPbItem = chr(122) + banana.VOCAB
+
+    def test_dialectNotSet(self):
+        """
+        If no dialect has been selected and a PB VOCAB item is received,
+        L{NotImplementedError} is raised.
+        """
+        self.assertRaises(
+            NotImplementedError,
+            self.enc.dataReceived, self.legalPbItem)
+
+
+    def test_receivePb(self):
+        """
+        If the PB dialect has been selected, a PB VOCAB item is accepted.
+        """
+        selectDialect(self.enc, b'pb')
+        self.enc.dataReceived(self.legalPbItem)
+        self.assertEqual(self.result, self.vocab)
+
+
+    def test_receiveIllegalPb(self):
+        """
+        If the PB dialect has been selected and an unrecognized PB VOCAB item
+        is received, L{banana.Banana.dataReceived} raises L{KeyError}.
+        """
+        selectDialect(self.enc, b'pb')
+        self.assertRaises(KeyError, self.enc.dataReceived, self.illegalPbItem)
+
+
+    def test_sendPb(self):
+        """
+        if pb dialect is selected, the sender must be able to send things in
+        that dialect.
+        """
+        selectDialect(self.enc, b'pb')
+        self.enc.sendEncoded(self.vocab)
+        self.assertEqual(self.legalPbItem, self.io.getvalue())
+
+
+
 class GlobalCoderTests(unittest.TestCase):
     """
     Tests for the free functions L{banana.encode} and L{banana.decode}.
     """
     def test_statelessDecode(self):
         """
-        Test that state doesn't carry over between calls to L{banana.decode}.
+        Calls to L{banana.decode} are independent of each other.
         """
         # Banana encoding of 2 ** 449
-        undecodable = '\x7f' * 65 + '\x85'
+        undecodable = b'\x7f' * 65 + b'\x85'
         self.assertRaises(banana.BananaError, banana.decode, undecodable)
 
-        # Banana encoding of 1
-        decodable = '\x01\x81'
+        # Banana encoding of 1.  This should be decodable even though the
+        # previous call passed un-decodable data and triggered an exception.
+        decodable = b'\x01\x81'
         self.assertEqual(banana.decode(decodable), 1)
diff --git a/twisted/topfiles/7662.bugfix b/twisted/topfiles/7662.bugfix
@@ -0,0 +1 @@
+twisted.spread.banana.Banana now raises NotImplementedError when receiving pb messages without pb being the selected dialect
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		twisted.spread.banana.Banana now raises NotImplementedError when receiving pb messages without pb being the selected dialect