# coding: utf-8
"""
XML Validation by schemaLocation
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This snippet addresses the problem of validating XML documents that refer to
schemas using xsi:schemaLocation with lxml. The problem has been brought up
in the following locations:
http://stackoverflow.com/questions/2979824/in-document-schema-declarations-and-lxml
https://mailman-mail5.webfaction.com/pipermail/lxml/2011-September/006153.html
:copyright: Copright 2013 Mathias Loesch
"""
from lxml import etree
XSI = "http://www.w3.org/2001/XMLSchema-instance"
XS = '{http://www.w3.org/2001/XMLSchema}'
SCHEMA_TEMPLATE = """<?xml version = "1.0" encoding = "UTF-8"?>
<xs:schema xmlns="http://dummy.libxml2.validator"
targetNamespace="http://dummy.libxml2.validator"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
version="1.0"
elementFormDefault="qualified"
attributeFormDefault="unqualified">
</xs:schema>"""
def validate_XML(xml):
"""Validate an XML file represented as string. Follow all schemaLocations.
:param xml: XML represented as string.
:type xml: str
"""
tree = etree.XML(xml)
schema_tree = etree.XML(SCHEMA_TEMPLATE)
# Find all unique instances of 'xsi:schemaLocation="<namespace> <path-to-schema.xsd> ..."'
schema_locations = set(tree.xpath("//*/@xsi:schemaLocation", namespaces={'xsi': XSI}))
for schema_location in schema_locations:
# Split namespaces and schema locations ; use strip to remove leading
# and trailing whitespace.
namespaces_locations = schema_location.strip().split()
# Import all found namspace/schema location pairs
for namespace, location in zip(*[iter(namespaces_locations)] * 2):
xs_import = etree.Element(XS + "import")
xs_import.attrib['namespace'] = namespace
xs_import.attrib['schemaLocation'] = location
schema_tree.append(xs_import)
# Contstruct the schema
schema = etree.XMLSchema(schema_tree)
# Validate!
schema.assertValid(tree)
Diff to Previous Revision
--- revision 2 2013-03-28 10:24:09
+++ revision 3 2013-03-28 10:24:55
@@ -1,3 +1,18 @@
+# coding: utf-8
+"""
+ XML Validation by schemaLocation
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+ This snippet addresses the problem of validating XML documents that refer to
+ schemas using xsi:schemaLocation with lxml. The problem has been brought up
+ in the following locations:
+
+ http://stackoverflow.com/questions/2979824/in-document-schema-declarations-and-lxml
+ https://mailman-mail5.webfaction.com/pipermail/lxml/2011-September/006153.html
+
+ :copyright: Copright 2013 Mathias Loesch
+"""
+
from lxml import etree
XSI = "http://www.w3.org/2001/XMLSchema-instance"
