def compare_output(writer: BasePdfFileWriter, expected_output_path):
with tempfile.TemporaryDirectory() as working_dir:
output_path = os.path.join(working_dir, 'output.pdf')
with open(output_path, 'wb') as outf:
writer.write(outf)
expected_png = _render_pdf(
expected_output_path, os.path.join(working_dir, 'expected')
)
actual_png = _render_pdf(
output_path, os.path.join(working_dir, 'actual')
)
result = subprocess.run(
# use the Absolute Error metric, since it's a single number
# and hence very easy to process
[
compare_path, '-metric', 'ae',
expected_png, actual_png, os.path.join(working_dir, 'diff.png')
],
capture_output=True
)
# TODO maintain a directory of failed test outputs?
if result.stderr != b'0':
raise RuntimeError(
f"Output compare test failed --- absolute error: "
f"{result.stderr.decode('utf8')}"
)
def fill(self,
writer: BasePdfFileWriter,
md_algorithm,
in_place=False,
output=None,
chunk_size=misc.DEFAULT_CHUNK_SIZE):
"""
Generator coroutine that handles the document hash computation and
the actual filling of the placeholder data.
.. danger::
This is internal API; you should use use :class:`.PdfSigner`
wherever possible. If you *really* need fine-grained control,
use :class:`~pyhanko.sign.signers.cms_embedder.PdfCMSEmbedder`
instead.
"""
if in_place:
if not isinstance(writer, IncrementalPdfFileWriter):
raise TypeError(
"in_place is only meaningful for incremental writers."
) # pragma: nocover
output = writer.prev.stream
writer.write_in_place()
else:
output = misc.prepare_rw_output_stream(output)
writer.write(output)
# retcon time: write the proper values of the /ByteRange entry
# in the signature object
eof = output.tell()
sig_start, sig_end = self.contents.offsets
self.byte_range.fill_offsets(output, sig_start, sig_end, eof)
# compute the digests
md_spec = get_pyca_cryptography_hash(md_algorithm)
md = hashes.Hash(md_spec)
# attempt to get a memoryview for automatic buffering
output_buffer = None
if isinstance(output, BytesIO):
output_buffer = output.getbuffer()
else:
try:
output_buffer = memoryview(output)
except (TypeError, IOError):
pass
if output_buffer is not None:
# these are memoryviews, so slices should not copy stuff around
# (also, the interface files for pyca/cryptography don't specify
# that memoryviews are allowed, but they are)
# noinspection PyTypeChecker
md.update(output_buffer[:sig_start])
# noinspection PyTypeChecker
md.update(output_buffer[sig_end:eof])
output_buffer.release()
else:
temp_buffer = bytearray(chunk_size)
output.seek(0)
misc.chunked_digest(temp_buffer, output, md, max_read=sig_start)
output.seek(sig_end)
misc.chunked_digest(temp_buffer,
output,
md,
max_read=eof - sig_end)
digest_value = md.finalize()
prepared_br_digest = PreparedByteRangeDigest(
document_digest=digest_value,
md_algorithm=md_algorithm,
reserved_region_start=sig_start,
reserved_region_end=sig_end)
cms_data = yield prepared_br_digest, output
yield prepared_br_digest.fill_with_cms(output, cms_data)