(Chilkat2-Python) SII Chile - FRMA Signature Computation and Add to XML

Compute the FRMA signature of a <DA> element enclosed inside a <CAF> element of the XML to be signed.

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import sys
import chilkat2

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# Also see:  Compute the FRMT Signature and Add to XML

xml = chilkat2.Xml()

# Load the unsigned XML that contains the following:

# <DTE version="1.0">
#   <Documento ID="F60T33">
#         <TED version="1.0">
#             <DD>
# 		...
#                 <CAF version="1.0">
#                     <DA>
# 			...
#                     </DA>
# 			... The FRMA will be added here ...
#                 </CAF>
#                 ...
#             </DD>
#             ... The FRMT will be added here in another example ...
#         </TED>
#   </Documento>
# </DTE>

success = xml.LoadXmlFile("qa_data/xml_dsig/sii_cl/test_0.xml")
if (success == False):
    print("Failed to load initial XML file.")
    sys.exit()

# Get a reference to the "DA" element
# daXml is a CkXml
daXml = xml.FindChild("Documento|TED|DD|CAF|DA")
if (xml.LastMethodSuccess == False):
    print("Failed to find DA element")
    sys.exit()

#  We need to get the "flattened" DA XML where:
#    - No whitespace between elements.
#    - The 5 pre-defined entities are converted.
#    - The text is encoded in the ISO-8859-1 character set (Latin-1), 
sbFlattened = chilkat2.StringBuilder()
daXml.EmitCompact = True
daXml.EmitXmlDecl = False
daXml.GetXmlSb(sbFlattened)

# Compute the SHA-1 message digest of the iso-8859-1 byte representation, 
# and sign it with our RSA private key, getting the result in base64 format.

privKey = chilkat2.PrivateKey()
success = privKey.LoadAnyFormatFile("qa_data/rsa/rsaPrivKey_pkcs8.pem","")
if (success == False):
    print(privKey.LastErrorText)
    sys.exit()

rsa = chilkat2.Rsa()
rsa.ImportPrivateKeyObj(privKey)

rsa.EncodingMode = "base64"
rsa.Charset = "iso-8859-1"
sig = rsa.SignStringENC(sbFlattened.GetAsString(),"sha1")

# Add the FRMA signature element to the XML.
xml.UpdateChildContent("Documento|TED|DD|CAF|FRMA",sig)
xml.UpdateAttrAt("Documento|TED|DD|CAF|FRMA",True,"algoritmo","SHA1withRSA")

# See what we have:
xml.EmitCompact = False
xml.EmitXmlDecl = True
print(xml.GetXml())

xml.SaveXml("qa_data/xml_dsig/sii_cl/test_1.xml")