def flatten_xml(xml: etree._Element):
pages = xml.xpath('/pdf2xml/page')
children = []
for page in pages:
for child in page:
children.append(child)
xml.remove(page)
for child in children:
xml.append(child)
def sign(
*,
element: Element,
private_key: RSAPrivateKey,
certificate: Certificate,
config: SigningConfig = SigningConfig.default(),
index: int = 0,
) -> bytes:
try:
element_id = element.attrib["ID"]
except KeyError:
raise NoIDAttribute(element)
# Generate the digest value of the element/content to be signed
content_digest_value = utils.ascii_b64(
utils.hash_digest(config.digest_method, utils.serialize_xml(element)))
# Build the SignedInfo tag, referencing the element we got passed,
# including the digest value we just created.
signed_info = ds.SignedInfo(
ds.CanonicalizationMethod(Algorithm=XML_EXC_C14N),
ds.SignatureMethod(Algorithm=utils.signature_method_algorithm(
config.signature_method)),
ds.Reference(
ds.Transforms(
ds.Transform(Algorithm=XMLDSIG_ENVELOPED_SIGNATURE),
ds.Transform(Algorithm=XML_EXC_C14N),
),
ds.DigestMethod(
Algorithm=utils.digest_method_algorithm(config.digest_method)),
ds.DigestValue(content_digest_value), # Embed the digest value
URI="#" + element_id, # Reference the element to sign
),
)
# Sign the digest of the SignedInfo element
signature = utils.sign(utils.serialize_xml(signed_info), private_key,
config.signature_method)
signature_value = utils.ascii_b64(signature)
# Encode the certificate to embed into the signature.
cert_data = utils.ascii_b64(certificate.public_bytes(Encoding.DER))
signature_element = ds.Signature(
signed_info,
ds.SignatureValue(signature_value),
ds.KeyInfo(ds.X509Data(ds.X509Certificate(cert_data))),
)
element.insert(index, signature_element)
root = utils.get_root(element)
result = utils.serialize_xml(root)
element.remove(signature_element)
return result
def _set_nvpair(nvset_element: _Element, id_provider: IdProvider, name: str,
value: str) -> None:
"""
Ensure name-value pair is set / removed in specified nvset
nvset_element -- container for nvpair elements to update
id_provider -- elements' ids generator
name -- name of the nvpair to be set
value -- value of the nvpair to be set, if "" the nvpair will be removed
"""
nvpair_el_list = cast(
# The xpath method has a complicated return value, but we know our xpath
# expression returns only elements.
List[_Element],
nvset_element.xpath("./nvpair[@name=$name]", name=name),
)
if not nvpair_el_list:
if value != "":
etree.SubElement(
nvset_element,
"nvpair",
{
"id":
create_subelement_id(
nvset_element,
# limit id length to prevent excessively long ids
name[:20],
id_provider,
),
"name":
name,
"value":
value,
},
)
return
if value != "":
nvpair_el_list[0].attrib["value"] = value
else:
nvset_element.remove(nvpair_el_list[0])
for nvpair_el in nvpair_el_list[1:]:
nvset_element.remove(nvpair_el)
