Parser initial commit

ikiril01 · ikiril01 · commit 5dc2e8621894 · 2014-02-26T11:30:11.000-05:00
diff --git a/maec/utils/parser.py b/maec/utils/parser.py
@@ -0,0 +1,115 @@
+# Copyright (c) 2014, The MITRE Corporation. All rights reserved.
+# See LICENSE.txt for complete terms.
+
+import maec
+from distutils.version import StrictVersion
+from lxml import etree
+
+class UnsupportedVersionError(Exception):
+    pass
+
+class UnknownVersionError(Exception):
+    pass
+
+class UnsupportedRootElement(Exception):
+    pass
+
+class EntityParser(object):
+    def __init__(self):
+        self.is_bundle = False
+        self.is_package = False
+
+    def _check_version(self, tree):
+        '''Returns true of the instance document @tree is a version supported by python-maec'''
+
+        try:
+            root = tree.getroot() # is tree an lxml.Element or lxml.ElementTree
+        except AttributeError:
+            root = tree
+
+        if not root.attrib.get('schema_version'):
+            raise UnknownVersionError("No version attribute set on xml instance. Unable to determine version compatibility")
+
+        python_maec_version = maec.__version__ # ex: '4.1.0.0'
+        supported_maec_version = ('4.1', '2.1') # ex: '4.1.0'
+        document_version = root.attrib['schema_version']
+
+        if document_version not in supported_maec_version:
+            raise UnsupportedVersionError("Your python-maec library supports MAEC %s, or the MAEC Bundle Schema at %s and MAEC Package Schema at %s. Document version was %s" % (supported_maec_version[0], supported_maec_version[0], supported_maec_version[1], document_version))
+
+        return True
+
+    def _check_root(self, tree):
+        try:
+            root = tree.getroot() # is tree an lxml.Element or lxml.ElementTree
+        except AttributeError:
+            root = tree
+        # General compatibility check
+        if root.tag != "{http://maec.mitre.org/XMLSchema/maec-bundle-4}MAEC_Bundle" or "{http://maec.mitre.org/XMLSchema/maec-package-2}MAEC_Package":
+            raise UnsupportedRootElement("Document root element must be an instance of MAEC_Package or MAEC_Bundle")
+
+        # Determine if we're dealing with a MAEC Bundle or MAEC Package
+        if "MAEC_Bundle" in root.tag:
+            self.is_bundle = True
+        elif "MAEC_Package" in root.tag:
+            self.is_package = True
+
+        return True
+
+    def _apply_input_namespaces(self, tree, entity):
+        try:
+            root = tree.getroot() # is tree an lxml.Element or lxml.ElementTree
+        except AttributeError:
+            root = tree
+        
+        entity.__input_namespaces__ = {}
+        for alias,ns in root.nsmap.iteritems():
+            entity.__input_namespaces__[ns] = alias
+
+    def parse_xml_to_obj(self, xml_file, check_version=True):
+        """Creates a MAEC binding object from the supplied xml file.
+
+        Arguments:
+        xml_file -- A filename/path or a file-like object reprenting a MAEC instance document
+        check_version -- Inspect the version before parsing.
+        """
+        parser = etree.ETCompatXMLParser(huge_tree=True)
+        tree = etree.parse(xml_file, parser=parser)
+
+        # Check the root and determine the type of document we're dealing with
+        self._check_root(tree)
+
+        if check_version:
+            self._check_version(tree)
+
+        binding_obj = None
+        if self.is_package:
+            import maec.bindings.maec_package as maec_package_binding
+            binding_obj = maec_package_binding.PackageType().factory()
+            binding_obj.build(tree.getroot())
+        elif self.is_bundle:
+            import maec.bindings.maec_bundle as maec_bundle_binding
+            binding_obj = maec_bundle_binding.BundleType().factory()
+            binding_obj.build(tree.getroot())
+
+        return binding_obj
+
+    def parse_xml(self, xml_file, check_version=True):
+        """Creates a python-maec Bundle or Package object from the supplied xml_file.
+
+        Arguments:
+        xml_file -- A filename/path or a file-like object reprenting a MAEC instance (i.e. Package or Bundle) document
+        check_version -- Inspect the version before parsing.
+        """
+
+        api_obj = None
+        binding_obj = self.parse_xml_to_obj(xml_file, check_version)
+        if self.is_package:
+            from maec.package.package import Package # resolve circular dependencies
+            api_obj = Package().from_obj(binding_obj)
+        elif self.is_bundle:
+            from maec.bundle.bundle import Bundle # resolve circular dependencies
+            api_obj = Bundle().from_obj(binding_obj)
+        self._apply_input_namespaces(tree, api_obj)
+
+        return api_obj
