I'm trying to use lxml.etree to reproduce the CDA example found in the CDA QuickStart Guide found here.
In particular, I'm running into issues with namespaces trying to recreate this element.
<ClinicalDocument xmlns="urn:hl7-org:v3" xmlns:mif="urn:hl7-org:v3/mif"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="urn:hl7-org:v3 CDA.xsd">
The code I'm using is as follows
root = etree.Element('ClinicalDocument',
nsmap={None: 'urn:hl7-org:v3',
'mif': 'urn:hl7-org:v3/mif',
'xsi': 'http://www.w3.org/2001/XMLSchema-instance',
'{http://www.w3.org/2001/XMLSchema-instance}schemaLocation': 'urn:hl7-org:v3 CDA.xsd'})
The problem is with the schemaLocation entry in nsmap. lxml appears to be trying to validate the value and gives the error
ValueError: Invalid namespace URI u'urn:hl7-org:v3 CDA.xsd'
Am I specifying the schemaLocation value incorrectly? Is there a way to force lxml to accept any string value? Or is the value in the example simply intended to be a placeholder that I am supposed to replace with something else?
nsmap is a mapping of prefixes to namespace URIs. urn:hl7-org:v3 CDA.xsd is a valid value for the xsi:schemaLocationattribute, but it is not a valid namespace URI.
The solution to a similar question, How to include the namespaces into a xml file using lxmf?, works here too. Use QName to create the xsi:schemaLocation attribute.
from lxml import etree
attr_qname = etree.QName("http://www.w3.org/2001/XMLSchema-instance", "schemaLocation")
root = etree.Element('ClinicalDocument',
{attr_qname: 'urn:hl7-org:v3 CDA.xsd'},
nsmap={None: 'urn:hl7-org:v3',
'mif': 'urn:hl7-org:v3/mif',
'xsi': 'http://www.w3.org/2001/XMLSchema-instance',
})