added add_element() method

[sfa.git] / sfa / rspecs / rspec.py

diff --git a/sfa/rspecs/rspec.py b/sfa/rspecs/rspec.py
index cc42a87..96523f0 100755 (executable)
--- a/sfa/rspecs/rspec.py
+++ b/sfa/rspecs/rspec.py
@@ -8,10 +8,11 @@ from sfa.util.config import Config
 from sfa.util.faults import SfaNotImplemented, InvalidRSpec
 
 class RSpec:
-    xml = None
     header = '<?xml version="1.0"?>\n'
+    template = """<RSpec></RSpec>"""
     namespaces = {}
     config = Config()
+    xml = None
   
     def __init__(self, rspec="", namespaces={}):
         if rspec:
@@ -20,16 +21,22 @@ class RSpec:
             self.create()
 
     def create(self, type="advertisement"):
+        """
+        Create root element
+        """
         # eg. 2011-03-23T19:53:28Z 
         date_format = '%Y-%m-%dT%H:%M:%SZ'
         now = datetime.utcnow()
         generated_ts = now.strftime(date_format)
-        expires_ts = (now + timedelta(minutes=30)).strftime(date_format) 
-        self.xml = etree.Element("rspec", type = type, 
-                                 valid_until=expires_ts,   
-                                 generated=generated_ts)
+        expires_ts = (now + timedelta(hours=1)).strftime(date_format) 
+        self.parse_rspec(self.template, self.namespaces)
+        self.xml.set('valid_until', expires_ts)
+        self.xml.set('generated', generated_ts)
     
     def parse_rspec(self, rspec, namespaces={}):
+        """
+        parse rspec into etree
+        """
         parser = etree.XMLParser(remove_blank_text=True)
         try:
             tree = etree.parse(rspec, parser)
@@ -45,10 +52,32 @@ class RSpec:
            self.namespaces = namespaces
 
     def add_attribute(self, elem, name, value):
+        """
+        Add attribute to specified etree element    
+        """
         opt = etree.SubElement(elem, name)
         opt.text = value
 
+    def add_element(self, name, attrs={}, parent=None, text=""):
+        """
+        Generic wrapper around etree.SubElement(). Adds an element to 
+        specified parent node. Adds element to root node is parent is 
+        not specified. 
+        """
+        if parent == None:
+            parent = self.xml
+        element = etree.SubElement(parent, name)
+        if text:
+            element.text = text
+        if isinstance(attrs, dict):
+            for attr in attrs:
+                element.set(attr, attrs[attr])  
+        return element
+
     def remove_attribute(self, elem, name, value):
+        """
+        Removes an attribute from an element
+        """
         if elem is not None:
             opts = elem.iterfind(name)
             if opts is not None:
@@ -56,6 +85,21 @@ class RSpec:
                     if opt.text == value:
                         elem.remove(opt)
 
+
+    def validate(self, schema):
+        """
+        Validate against rng schema
+        """
+        
+        relaxng_doc = etree.parse(schema)
+        relaxng = etree.RelaxNG(relaxng_doc)
+        if not relaxng(self.xml):
+            error = relaxng.error_log.last_error
+            message = "%s (line %s)" % (error.message, error.line)
+            raise InvalidRSpec(message)
+        return True
+        
+
     def __str__(self):
         return self.toxml()