Python elementtree find function reads Signature as empty (None)

问题

I'm trying to read Signature, SignatureValue and SignedInfo from signed XML in Python with ElementTree but it reads as None. Other xml attributes are read fine. How can I read Signature, SignatureValue and SignedInfo?

Here's my code snippet:

xml_file = open(settings.STATIC_ROOT + '/file/test.xml', 'rt').read()
response_xml = xml_et.fromstring(xml_file.encode('utf-8'))
print response_xml.find('Signature')  # prints None
print response_xml.find('SignatureValue')  # prints None
print response_xml.find('SignedInfo')  # prints None
print response_xml.find('OrderID').text  # works fine

Here's my test XML:

<?xml version="1.0" encoding="UTF-8"?>
<Message date="08/09/2016 06:47:20">
   <Version>1.0</Version>
   <OrderID>ABCD:123456</OrderID>
   <Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
      <SignedInfo>
         <CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315" />
         <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1" />
         <Reference URI="">
            <Transforms>
               <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
               <Transform Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315" />
            </Transforms>
            <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
            <DigestValue>blabla=</DigestValue>
         </Reference>
      </SignedInfo>
      <SignatureValue>blabla==</SignatureValue>
      <KeyInfo>
         <KeyName>Public key of certificate</KeyName>
         <KeyValue>
            <RSAKeyValue>
               <Modulus>blabla==</Modulus>
               <Exponent>AQAB</Exponent>
            </RSAKeyValue>
         </KeyValue>
         <X509Data>
            <X509Certificate>blabla</X509Certificate>
         </X509Data>
      </KeyInfo>
   </Signature>
</Message>

回答1:

Its because you have namespace on the Signature element, what you can do is find the element with the namespace

print response_xml.find('{http://www.w3.org/2000/09/xmldsig#}Signature')

then you will have to take the signature element and find all sub elements from it

something like this:

namespace = "{http://www.w3.org/2000/09/xmldsig#}"
signature_elem = response_xml.find(namespace +'Signature')
print signature_elem
print signature_elem.find(namespace+'SignatureValue')
print signature_elem.find(namespace+'SignedInfo')

来源：https://stackoverflow.com/questions/43451194/python-elementtree-find-function-reads-signature-as-empty-none

标签

python

xml

elementtree

xml-signature