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How to check xml file on XSD schema using Amara library in Python?

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Hello, Here is what I tried on Ubuntu 9.10 using Python 2.6, Amara2 (by the way, test.xsd was created using the xml2xsd tool):

g@spot:~$ cat test.xml; echo =====o=====; cat test.xsd; echo ==== 
o=====; cat test.py; echo =====o=====; ./test.py; echo =====o===== 
<?xml version="1.0" encoding="utf-8"?>==; ./test.py` > 
test.txttest.xsd; echo === 
<test>abcde</test> 
=====o===== 
<?xml version="1.0" encoding="UTF-8"?> 
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" 
elementFormDefault="qualified"> 
  <xs:element name="test" type="xs:NCName"/> 
</xs:schema> 
=====o===== 
#!/usr/bin/python2.6 
# I wish to validate an xml file against an external XSD schema. 
from amara import bindery, parse 
source = 'test.xml' 
schema = 'test.xsd' 
#help(bindery.parse) 
#doc = bindery.parse(source, uri=schema, validate=True) # These 2 seem 
to fail in the same way. 
doc = parse(source, uri=schema, validate=True) # So, what is the 
difference anyway? 
# 
=====o===== 
Traceback (most recent call last): 
  File "./test.py", line 14, in <module> 
    doc = parse(source, uri=schema, validate=True) 
  File "/usr/local/lib/python2.6/dist-packages/Amara-2.0a4-py2.6-linux- 
x86_64.egg/amara/tree.py", line 50, in parse 
    return _parse(inputsource(obj, uri), flags, 
entity_factory=entity_factory) 
amara.ReaderError: In file:///home/g/test.xml, line 2, column 0: 
Missing document type declaration 
g@spot:~$ 
=====o=====

So why am I seeing this error? Is this feature not supported? How can I check an XML file on an XSD, with the flexibility to point to any XSD file? Thank you and let me know if you have any questions.

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2 answers

If you are open to using a library other than amara, try lxml . It supports what you are trying to do quite easily:

from lxml import etree

source_file = 'test.xml'
schema_file = 'test.xsd'

with open(schema_file) as f_schema:

    schema_doc = etree.parse(f_schema)
    schema = etree.XMLSchema(schema_doc)
    parser = etree.XMLParser(schema = schema)

    with open(source_file) as f_source:
        try:
            doc = etree.parse(f_source, parser)
        except etree.XMLSyntaxError as e:
            # this exception is thrown on schema validation error
            print e
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noNamespaceSchemaLocation XML XSD. XML test.xml

<?xml version="1.0" encoding="utf-8"?>
<test xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:noNamespaceSchemaLocation="test.xsd">abcde</test>

test.xsd

<?xml version="1.0" encoding="utf-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
           elementFormDefault="qualified">
    <xs:element name="test" type="xs:NCName"/>
</xs:schema>

, test.xsd. XML- XML , Python.

, XML. (etree.parse) XML .

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