Handle Presentation Context AC with no Transfer Syntax Sub-item (#362)

docs/changelog/v1.0.0.rst

@@ -33,7 +33,6 @@ Changes
   - Added ``AE.add_requested_context()``, ``AE.requested_contexts``,
     ``AE.remove_requested_context()`` for adding and removing the presentation
     contexts requested as an SCU.
-
 * Removed ``VerificationSOPClass``, ``StorageSOPClassList`` and
   ``QueryRetrieveSOPClassList``.
 * Added ``VerificationPresentationContexts``, ``StoragePresentationContexts``,

docs/changelog/v1.4.0.rst

@@ -19,15 +19,27 @@ Fixes
 Enhancements
 ............
 
-* Added support for Protocol Approval Query Retrieve service class
-  (:issue:`327`)
 * Added ``Event.move_destination`` and ``Event.event`` properties
   (:issue:`353`)
 * Added ``meta_uid`` keyword parameters to the ``Association.send_n_*()``
   methods to allow the use of Meta SOP Classes (such as those used in the
   Print Management service class)
 * Added *Basic Grayscale Print Management Meta SOP Class* and *Basic Color
   Print Management Meta SOP Class* to ``sop_class``.
+* Added full support for the following service classes:
+
+  * Protocol Approval Query Retrieve (:issue:`327`)
+  * Application Event Logging
+  * Instance Availability Notification
+  * Media Creation Management
+* Added partial support for the following service classes:
+
+  * Print Management
+  * Unified Procedure Step
+  * RT Machine Verification
+  * Storage Commitment
+* Added handling of non-conformant Presentation Context AC (reject) PDUs which
+  contain no Transfer Syntax Sub-item (:issue:`361`)
 
 
 Changes

pynetdicom/pdu_items.py

@@ -856,11 +856,8 @@ def to_primitive(self):
         primitive = PresentationContext()
         primitive.context_id = self.presentation_context_id
         primitive.result = self.result_reason
-        # May be `None` if context is rejected
-        if self.transfer_syntax_sub_item[0].transfer_syntax_name:
-            primitive.add_transfer_syntax(
-                self.transfer_syntax_sub_item[0].transfer_syntax_name
-            )
+        if self.transfer_syntax:
+            primitive.add_transfer_syntax(self.transfer_syntax)
 
         return primitive
 
@@ -976,6 +973,9 @@ def transfer_syntax(self):
         Returns
         -------
         pydicom.uid.UID or None
+            If no Transfer Syntax Sub-item or an empty Transfer Syntax Sub-item
+            has been sent by the Acceptor then returns None, otherwise returns
+            the Transfer Syntax Sub-item's transfer syntax UID.
         """
         if self.transfer_syntax_sub_item:
             return self.transfer_syntax_sub_item[0].transfer_syntax_name

pynetdicom/presentation.py

@@ -283,7 +283,9 @@ def add_transfer_syntax(self, syntax):
         elif isinstance(syntax, bytes):
             syntax = UID(syntax.decode('ascii'))
         else:
-            LOGGER.error("Attempted to add an invalid transfer syntax")
+            if syntax is not None:
+                LOGGER.error("Attempted to add an invalid transfer syntax")
+
             return
 
         if syntax is not None and not validate_uid(syntax):

pynetdicom/tests/encoded_pdu_items.py

@@ -282,7 +282,6 @@
                       b'\x59\x00\x00\x0a\x00\x08\x41\x63\x63\x65' \
                       b'\x70\x74\x65\x64'
 
-
 # Issue 342
 # Called AET: ANY-SCP
 # Calling AET: PYNETDICOM
@@ -321,6 +320,39 @@
     b'\x65\x43\x4f\x4d\x33\x5f\x33\x39\x30\x49\x42\x32'
 )
 
+# Issue 361
+# Called AET: ANY-SCP
+# Calling AET: PYNETDICOM
+# Application Context Name: 1.2.840.10008.3.1.1.1
+# Presentation Context Items:
+#   Presentation Context ID: 1
+#       Abstract Syntax: Verification SOP Class
+#       SCP/SCU Role: Default
+#       Result: Reject
+#       Transfer Syntax: (no Transfer Syntax Sub-Item)
+# User Information
+#   Max Length Received: 16382
+#   Implementation Class UID: 1.2.826.0.1.3680043.9.3811.1.4.0
+#   Implementation Version Name: PYNETDICOM_140
+# Extended Negotiation
+#   SOP Extended: None
+#   Async Ops: None
+#   User ID: None
+a_associate_ac_no_ts = (
+    b'\x02\x00\x00\x00\x00\xa7\x00\x01\x00\x00\x41\x4e\x59\x2d\x53\x43'
+    b'\x50\x20\x20\x20\x20\x20\x20\x20\x20\x20\x50\x59\x4e\x45\x54\x44'
+    b'\x49\x43\x4f\x4d\x20\x20\x20\x20\x20\x20\x00\x00\x00\x00\x00\x00'
+    b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
+    b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x00\x00\x15\x31\x2e'
+    b'\x32\x2e\x38\x34\x30\x2e\x31\x30\x30\x30\x38\x2e\x33\x2e\x31\x2e'
+    b'\x31\x2e\x31\x21\x00\x00\x04\x01\x00\x03\x00'
+    b'\x50\x00\x00\x3e\x51\x00\x00\x04\x00\x00\x3f\xfe\x52\x00\x00\x20'
+    b'\x31\x2e\x32\x2e\x38\x32\x36\x2e\x30\x2e\x31\x2e\x33\x36\x38\x30'
+    b'\x30\x34\x33\x2e\x39\x2e\x33\x38\x31\x31\x2e\x31\x2e\x34\x2e\x30'
+    b'\x55\x00\x00\x0e\x50\x59\x4e\x45\x54\x44\x49\x43\x4f\x4d\x5f\x31'
+    b'\x34\x30'
+)
+
 
 ############################# A-ASSOCIATE-RJ PDU ###############################
 # Result: Rejected (Permanent)

pynetdicom/tests/test_pdu.py

@@ -37,7 +37,7 @@
 from .encoded_pdu_items import (
     a_associate_rq, a_associate_ac, a_associate_rj, a_release_rq, a_release_rq,
     a_release_rp, a_abort, a_p_abort, p_data_tf,
-    a_associate_rq_user_id_ext_neg
+    a_associate_rq_user_id_ext_neg, a_associate_ac_no_ts
 )
 from pynetdicom.sop_class import VerificationSOPClass
 from pynetdicom.utils import pretty_bytes
@@ -660,6 +660,24 @@ def test_from_primitive(self):
 
         assert new == orig
 
+    def test_no_transfer_syntax(self):
+        """Regression test for #361 - ASSOC-AC has no transfer syntax"""
+        pdu = A_ASSOCIATE_AC()
+        pdu.decode(a_associate_ac_no_ts)
+
+        assert pdu.pdu_type == 0x02
+        assert pdu.pdu_length == 167
+        assert pdu.protocol_version == 0x0001
+        assert isinstance(pdu.pdu_type, int)
+        assert isinstance(pdu.pdu_length, int)
+        assert isinstance(pdu.protocol_version, int)
+
+        item = pdu.variable_items[1]
+        cx = item.to_primitive()
+        assert cx.transfer_syntax == []
+        assert cx.result == 3
+        assert cx.context_id == 1
+
 
 class TestASSOC_AC_ApplicationContext(object):
     def test_decode(self):

pynetdicom/tests/test_pdu_items.py

@@ -627,6 +627,12 @@ def test_decode_empty(self):
         assert len(item) == 12
         assert item.transfer_syntax is None
 
+        # Confirm we can still convert the PDU into a PresentationContext
+        primitive = item.to_primitive()
+        assert primitive.context_id == 1
+        assert primitive.transfer_syntax == []
+        assert primitive.result == 1
+
         assert "Item length: 8 bytes" in item.__str__()
 
         item = item.transfer_syntax_sub_item[0]