Updated ElementBase.__getitem__ with docs and unit tests.

sleekxmpp/xmlstream/stanzabase.py

@@ -183,6 +183,48 @@ class ElementBase(object):
                 self.plugins[interface].setStanzaValues(value)
         return self
 
+    def __getitem__(self, attrib):
+        """
+        Return the value of a stanza interface using dictionary-like syntax.
+
+        Example:
+            >>> msg['body']
+            'Message contents'
+
+        Stanza interfaces are typically mapped directly to the underlying XML
+        object, but can be overridden by the presence of a getAttrib method
+        (or getFoo where the interface is named foo, etc).
+
+        The search order for interface value retrieval for an interface
+        named 'foo' is:
+            1. The list of substanzas.
+            2. The result of calling getFoo.
+            3. The contents of the foo subelement, if foo is a sub interface.
+            4. The value of the foo attribute of the XML object.
+            5. The plugin named 'foo'
+            6. An empty string.
+
+        Arguments:
+            attrib -- The name of the requested stanza interface.
+        """
+        if attrib == 'substanzas':
+            return self.iterables
+        elif attrib in self.interfaces:
+            get_method = "get%s" % attrib.title()
+            if hasattr(self, get_method):
+                return getattr(self, get_method)()
+            else:
+                if attrib in self.sub_interfaces:
+                    return self._getSubText(attrib)
+                else:
+                    return self._getAttr(attrib)
+        elif attrib in self.plugin_attrib_map:
+            if attrib not in self.plugins:
+                self.initPlugin(attrib)
+            return self.plugins[attrib]
+        else:
+            return ''
+
     @property
     def attrib(self): #backwards compatibility
             return self
@@ -266,23 +308,6 @@ class ElementBase(object):
     def findall(self, xpath):
             return self.xml.findall(xpath)
 
-    def __getitem__(self, attrib):
-            if attrib == 'substanzas':
-                    return self.iterables
-            elif attrib in self.interfaces:
-                    if hasattr(self, "get%s" % attrib.title()):
-                            return getattr(self, "get%s" % attrib.title())()
-                    else:
-                            if attrib in self.sub_interfaces:
-                                    return self._getSubText(attrib)
-                            else:
-                                    return self._getAttr(attrib)
-            elif attrib in self.plugin_attrib_map:
-                    if attrib not in self.plugins: self.initPlugin(attrib)
-                    return self.plugins[attrib]
-            else:
-                    return ''
-
     def __setitem__(self, attrib, value):
             if attrib in self.interfaces:
                     if value is not None:

tests/test_elementbase.py

@@ -109,5 +109,46 @@ class TestElementBase(SleekTest):
           </foo>
         """)
 
+    def testGetItem(self):
+        """Test accessing stanza interfaces."""
+
+        class TestStanza(ElementBase):
+            name = "foo"
+            namespace = "foo"
+            interfaces = set(('bar', 'baz'))
+            sub_interfaces = set(('baz',))
+
+        class TestStanzaPlugin(ElementBase):
+            name = "foobar"
+            namespace = "foo"
+            plugin_attrib = "foobar"
+            interfaces = set(('fizz',))
+
+        TestStanza.subitem = (TestStanza,)
+        registerStanzaPlugin(TestStanza, TestStanzaPlugin)
+
+        stanza = TestStanza()
+        substanza = TestStanza()
+        stanza.append(substanza)
+        stanza.setStanzaValues({'bar': 'a',
+                                'baz': 'b',
+                                'foobar': {'fizz': 'c'}})
+
+        # Test non-plugin interfaces
+        expected = {'substanzas': [substanza],
+                    'bar': 'a',
+                    'baz': 'b',
+                    'meh': ''}
+        for interface, value in expected.items():
+            result = stanza[interface]
+            self.failUnless(result == value,
+                "Incorrect stanza interface access result: %s" % result)
+
+        # Test plugin interfaces
+        self.failUnless(isinstance(stanza['foobar'], TestStanzaPlugin),
+                        "Incorrect plugin object result.")
+        self.failUnless(stanza['foobar']['fizz'] == 'c',
+                        "Incorrect plugin subvalue result.")
+
 
 suite = unittest.TestLoader().loadTestsFromTestCase(TestElementBase)