Handle 'null' attribute value

src/saml2/saml.py

@@ -20,6 +20,7 @@ XSI_NAMESPACE = 'http://www.w3.org/2001/XMLSchema-instance'
 XS_NAMESPACE = 'http://www.w3.org/2001/XMLSchema'
 
 XSI_TYPE = '{%s}type' % XSI_NAMESPACE
+XSI_NIL = '{%s}nil' % XSI_NAMESPACE
 
 NAMEID_FORMAT_EMAILADDRESS = (
     "urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress")
@@ -97,19 +98,58 @@ def _verify_value_type(typ, val):
         import base64
         return base64.decodestring(val)
 
-TYPE_EXTENSION = '{%s}type' % XSI_NAMESPACE
-
 class AttributeValueBase(SamlBase):
 
+
+    def __setattr__(self, key, value):
+        if key == "text":
+            self.set_text(value)
+        else:
+            SamlBase.__setattr__(self,key, value)
+            
+    def __init__(self,
+                 text=None,
+                 extension_elements=None,
+                 extension_attributes=None,
+                 ):
+        self._extatt = {}
+
+        SamlBase.__init__(self,
+                          text=None,
+                          extension_elements=extension_elements,
+                          extension_attributes=extension_attributes,
+                          )
+        if self._extatt:
+            self.extension_attributes = self._extatt
+
+        if not text:
+            self.extension_attributes = {XSI_NIL: 'true'}
+        else:
+            self.set_text(text)
+
+    def verify(self):
+        if not self.text:
+            assert self.extension_attributes
+            assert self.extension_attributes[XSI_NIL] == "true"
+            return True
+        else:
+            SamlBase.verify(self)
+
     def set_type(self, typ):
-        self.extension_attributes[TYPE_EXTENSION] = typ
+        try:
+            self.extension_attributes[XSI_TYPE] = typ
+        except AttributeError:
+            self._extatt[XSI_TYPE] = typ
 
     def get_type(self):
         try:
-            return self.extension_attributes[TYPE_EXTENSION]
-        except KeyError:
-            return ""
-        
+            return self.extension_attributes[XSI_TYPE]
+        except (KeyError, AttributeError):
+            try:
+                return self._extatt[XSI_TYPE]
+            except KeyError:
+                return ""
+
     def set_text(self, val, base64encode=False):
         typ = self.get_type()
         if base64encode:
@@ -120,6 +160,8 @@ class AttributeValueBase(SamlBase):
             if isinstance(val, basestring):
                 if not typ:
                     self.set_type("xs:string")
+                else:
+                    assert typ == "xs:string"
             elif isinstance(val, bool):
                 if val:
                     val = "true"
@@ -127,20 +169,33 @@ class AttributeValueBase(SamlBase):
                     val = "false"
                 if not typ:
                     self.set_type("xs:boolean")
+                else:
+                    assert typ == "xs:boolean"
             elif isinstance(val, int):
                 val = str(val)
                 if not typ:
                     self.set_type("xs:integer")
+                else:
+                    assert typ == "xs:integer"
             elif isinstance(val, float):
                 val = str(val)
                 if not typ:
                     self.set_type("xs:float")
-            elif val is None:
+                else:
+                    assert typ == "xs:float"
+            elif not val:
+                try:
+                    self.extension_attributes[XSI_TYPE] = typ
+                except AttributeError:
+                    self._extatt[XSI_TYPE] = typ
                 val = ""
             else:
-                raise ValueError
-                
-        setattr(self, "text", val)
+                if typ == "xs:anyType":
+                    pass
+                else:
+                    raise ValueError
+
+        SamlBase.__setattr__(self, "text", val)
         return self
 
     def harvest_element_tree(self, tree):
@@ -153,7 +208,7 @@ class AttributeValueBase(SamlBase):
             #print "set_text:", tree.text
             self.set_text(tree.text)
             try:
-                typ = self.extension_attributes[TYPE_EXTENSION]
+                typ = self.extension_attributes[XSI_TYPE]
                 _verify_value_type(typ, getattr(self, "text"))
             except KeyError:
                 pass

src/saml2/validate.py

@@ -1,11 +1,14 @@
 import calendar
-import sys
 import urlparse
 import re
 import time_util
 import struct
 import base64
 
+# Also defined in saml2.saml but can't import from there
+XSI_NAMESPACE = 'http://www.w3.org/2001/XMLSchema-instance'
+XSI_NIL = '{%s}nil' % XSI_NAMESPACE
+# ---------------------------------------------------------
 
 class NotValid(Exception):
     pass
@@ -48,24 +51,27 @@ def valid_any_uri(item):
     #     raise NotValid("AnyURI")
 
     return True
-    
+
+
 def valid_date_time(item):
     try:
         time_util.str_to_time(item)
     except Exception:
         raise NotValid("dateTime")
     return True
-    
+
+
 def valid_url(url):
     try:
-        part = urlparse.urlparse(url)
+        _ = urlparse.urlparse(url)
     except Exception:
         raise NotValid("URL")
         
     # if part[1] == "localhost" or part[1] == "127.0.0.1":
     #     raise NotValid("URL")
     return True
-    
+
+
 def validate_on_or_after(not_on_or_after, slack):
     if not_on_or_after:
         now = time_util.utc_now()
@@ -309,6 +315,11 @@ def valid_instance(instance):
     instclass = instance.__class__
     class_name = instclass.__name__
 
+    if instance.text:
+        _has_val = True
+    else:
+        _has_val = False
+
     if instclass.c_value_type and instance.text:
         try:
             validate_value_type(instance.text.strip(),
@@ -356,6 +367,7 @@ def valid_instance(instance):
             _cmin = _cmax = _card = None
 
         if value:
+            _has_val = True
             if isinstance(value, list):
                 _list = True
                 vlen = len(value)
@@ -387,6 +399,11 @@ def valid_instance(instance):
                     "Class '%s' instance cardinality error: %s" % \
                     (class_name, "too few values on %s" % name))
 
+        if not _has_val:
+            # Not allow unless xsi:nil="true"
+            assert instance.extension_attributes
+            assert instance.extension_attributes[XSI_NIL] == "true"
+
     return True
 
 def valid_domain_name(dns_name):