From: Tony Mack <tmack@paris.CS.Princeton.EDU>
Date: Fri, 2 Sep 2011 20:57:06 +0000 (-0400)
Subject: initial checkin of xml_interface
X-Git-Tag: sfa-1.0-36~34
X-Git-Url: http://git.onelab.eu/?a=commitdiff_plain;h=084123c61ea96959023440492eb865e2e4c08b7d;p=sfa.git

initial checkin of xml_interface
---

diff --git a/sfa/rspecs/xml_interface.py b/sfa/rspecs/xml_interface.py
new file mode 100755
index 00000000..c03a4e84
--- /dev/null
+++ b/sfa/rspecs/xml_interface.py
@@ -0,0 +1,183 @@
+#!/usr/bin/python 
+from lxml import etree
+from StringIO import StringIO
+from datetime import datetime, timedelta
+from sfa.util.xrn import *
+from sfa.util.plxrn import hostname_to_urn
+from sfa.util.faults import SfaNotImplemented, InvalidRSpec, InvalidRSpecElement
+
+class XpathFilter:
+    @staticmethod
+    def xpath(filter={}):
+        xpath = ""
+        if filter:
+            filter_list = []
+            for (key, value) in filter.items():
+                if key == 'text':
+                    key = 'text()'
+                else:
+                    key = '@'+key
+                if isinstance(value, str):
+                    filter_list.append('%s="%s"' % (key, value))
+                elif isinstance(value, list):
+                    filter_list.append('contains("%s", %s)' % (' '.join(map(str, value)), key))
+            if filter_list:
+                xpath = ' and '.join(filter_list)
+                xpath = '[' + xpath + ']'
+        return xpath
+
+class XMLInterface:
+ 
+    def __init__(self, xml="", namespaces={}):
+        self.header = '<?xml version="1.0"?>\n'
+        self.template = """<RSpec></RSpec>"""
+        self.xml = None
+        self.namespaces = namespaces
+        if xml:
+            self.parse_xml(xml)
+        else:
+            self.create()
+
+    def create(self):
+        """
+        Create root element
+        """
+        self.parse_rspec(self.template, self.namespaces)
+    
+    def parse_xml(self, xml):
+        """
+        parse rspec into etree
+        """
+        parser = etree.XMLParser(remove_blank_text=True)
+        try:
+            tree = etree.parse(xml, parser)
+        except IOError:
+            # 'rspec' file doesnt exist. 'rspec' is proably an xml string
+            try:
+                tree = etree.parse(StringIO(xml), parser)
+            except Exception, e:
+                raise InvalidRSpec(str(e))
+        self.xml = tree.getroot()  
+
+    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 xpath(self, xpath):
+        return self.xml.xpath(xpath, namespaces=self.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:
+                for opt in opts:
+                    if opt.text == value:
+                        elem.remove(opt)
+
+    def remove_element(self, element_name, root_node = None):
+        """
+        Removes all occurences of an element from the tree. Start at 
+        specified root_node if specified, otherwise start at tree's root.   
+        """
+        if not root_node:
+            root_node = self.xml
+
+        if not element_name.startswith('//'):
+            element_name = '//' + element_name
+
+        elements = root_node.xpath('%s ' % element_name, namespaces=self.namespaces)
+        for element in elements:
+            parent = element.getparent()
+            parent.remove(element)
+
+    def attributes_list(self, elem):
+        # convert a list of attribute tags into list of tuples
+        # (tagnme, text_value)
+        opts = []
+        if elem is not None:
+            for e in elem:
+                opts.append((e.tag, str(e.text).strip()))
+        return opts
+
+    def get_element_attributes(self, elem=None, depth=0):
+        if elem == None:
+            elem = self.root_node
+        if not hasattr(elem, 'attrib'):
+            # this is probably not an element node with attribute. could be just and an
+            # attribute, return it
+            return elem
+        attrs = dict(elem.attrib)
+        attrs['text'] = str(elem.text).strip()
+        attrs['parent'] = elem.getparent()
+        if isinstance(depth, int) and depth > 0:
+            for child_elem in list(elem):
+                key = str(child_elem.tag)
+                if key not in attrs:
+                    attrs[key] = [self.get_element_attributes(child_elem, depth-1)]
+                else:
+                    attrs[key].append(self.get_element_attributes(child_elem, depth-1))
+        else:
+            attrs['child_nodes'] = list(elem)
+        return attrs
+
+    def merge(self, in_xml):
+        pass
+
+    def cleanup(self):
+        """
+        Optional method which inheriting classes can choose to implent. 
+        """
+        pass 
+
+    def __str__(self):
+        return self.toxml()
+
+    def toxml(self, cleanup=False):
+        if cleanup:
+            self.cleanup()
+        return self.header + etree.tostring(self.xml, pretty_print=True)  
+        
+    def save(self, filename):
+        f = open(filename, 'w')
+        f.write(self.toxml())
+        f.close()
+ 
+if __name__ == '__main__':
+    rspec = RSpec('/tmp/resources.rspec')
+    print rspec
+