menekis/OCRmyPDF
Public Access
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Replace Ghostscript DOCINFO and fix 9.25 metadata date regression

Browse Source 
We no longer use Ghostscript to manage PDF metadata, instead
omitting the DOCINFO segment from the pdfmark file we generate.

Instead all of the relevant metadata code has been migrated to pikepdf,
and we use that API. This should be more consistent and fixes the
Ghostscript version-depedent quirks.

Also removes our python-xmp-toolkit dependency, except for
testing.
This commit is contained in:
James R. Barlow
2018-12-13 18:13:30 -08:00
parent 7647918f2d
commit 632dab2cc0
4 changed files with 24 additions and 96 deletions
Download Patch File Download Diff File Expand all files Collapse all files
setup.py
-1
View File
@@ -255,7 +255,6 @@ setup(
'Pillow >= 4.0.0, != 5.1.0 ; sys_platform == "darwin"',
# Pillow < 4 has BytesIO/TIFF bug w/img2pdf 0.2.3
# block 5.1.0, broken wheels
'python-xmp-toolkit >= 2, < 3',
'reportlab >= 3.3.0', # oldest released version with sane image handling
'ruffus >= 2.7.0',
],
src/ocrmypdf/_pipeline.py
+17 -26
View File
@@ -795,7 +795,7 @@ def ocr_tesseract_textonly_pdf(
log=log)
def get_pdfmark(base_pdf, options):
def get_docinfo(base_pdf, options):
def from_document_info(key):
try:
s = base_pdf.metadata[key]
@@ -840,21 +840,7 @@ def generate_postscript_stub(
context):
options = context.get_options()
pdf = pikepdf.open(input_file)
pdfmark = get_pdfmark(pdf, options)
ascii_docinfo = False
if ghostscript.version() >= '9.24':
ascii_docinfo = True
try:
for v in pdfmark.values():
v.encode('ascii', errors='strict')
except UnicodeEncodeError:
log.warning(
"Ghostscript 9.24+ does not support Unicode strings in "
" metadata. These will be converted to ASCII if possible."
)
generate_pdfa_ps(output_file, pdfmark, ascii_docinfo=ascii_docinfo)
generate_pdfa_ps(output_file)
def metadata_fixup(
@@ -874,6 +860,8 @@ def metadata_fixup(
ps = next(
(ii for ii in input_files if ii.endswith('.ps')), None
)
metadata = pikepdf.open(metadata_file)
docinfo = get_docinfo(metadata, options)
if options.output_type.startswith('pdfa'):
input_pdfinfo = context.get_pdfinfo()
@@ -886,18 +874,21 @@ def metadata_fixup(
threads=options.jobs or 1,
pdfa_part=options.output_type[-1] # is pdfa-1, pdfa-2, or pdfa-3
)
pdf = pikepdf.open(output_file)
with pdf.open_metadata() as meta:
# Note Ghostscript will populate xmp:CreateDate or /CreationDate
meta.load_from_docinfo(docinfo, delete_missing=False)
pdf.save(output_file)
else:
metadata = pikepdf.open(metadata_file)
pdfmark = get_pdfmark(metadata, options)
pdf = pikepdf.open(layers_file)
pdf.metadata = pdf.make_indirect(pikepdf.Dictionary(pdfmark))
try:
pdf.save(output_file, compress_streams=True,
object_stream_mode=pikepdf.ObjectStreamMode.generate)
except AttributeError:
# pikepdf <= 0.3.4
pdf.save(output_file,
stream_data_mode=pikepdf.StreamDataMode.compress)
with pdf.open_metadata() as meta:
meta.load_from_docinfo(docinfo, delete_missing=False)
# If xmp:CreateDate is missing, set it to the modify date to
# match Ghostscript, for consistency
if 'xmp:CreateDate' not in meta:
meta['xmp:CreateDate'] = meta.get('xmp:ModifyDate', '')
pdf.save(output_file, compress_streams=True,
object_stream_mode=pikepdf.ObjectStreamMode.generate)
def optimize_pdf(
src/ocrmypdf/pdfa.py
+6 -61
View File
@@ -61,9 +61,6 @@ pdfa_def_template = u"""%!
/ICCProfile $icc_profile
def
[$docinfo
/DOCINFO pdfmark
% Define an ICC profile :
[/_objdef {icc_PDFA} /type /stream /OBJ pdfmark
@@ -94,6 +91,7 @@ def
"""
@deprecated
def encode_text_string(s: str) -> str:
"""
Encode text string to hex string for use in a PDF
@@ -149,35 +147,7 @@ def decode_pdf_date(*args, **kwargs):
return _decode_date(*args, **kwargs)
def _get_pdfmark_dates(pdfmark):
"""
Encode dates in the expected format for pdfmark Postscript
The best way to deal with amissing date entry is set it to null, because if
the key is omitted Ghostscript will set it to now - we do not want to erase
the fact that the value was unknown. Setting to an empty string breaks
Ghostscript 9.22 as reported here:
https://bugs.ghostscript.com/show_bug.cgi?id=699182
"""
for key in ('/CreationDate', '/ModDate'):
if key not in pdfmark:
continue
if pdfmark[key].strip() == '':
yield ' {} null'.format(key)
continue
date_str = pdfmark[key]
if date_str.startswith('D:'):
date_str = date_str[2:]
try:
yield ' {} (D:{})'.format(
key,
_encode_date(_decode_date(date_str)))
except ValueError:
yield ' {} null'.format(key)
def _get_pdfa_def(icc_profile, icc_identifier, pdfmark, ascii_docinfo=False):
def _get_pdfa_def(icc_profile, icc_identifier, pdfmark=None, ascii_docinfo=None):
"""
Create a Postscript pdfmark file for Ghostscript.
@@ -187,43 +157,18 @@ def _get_pdfa_def(icc_profile, icc_identifier, pdfmark, ascii_docinfo=False):
:param icc_profile: filename of the ICC profile to include in pdfmark
:param icc_identifier: ICC identifier such as 'sRGB'
:param pdfmark: a dictionary containing keys to include the pdfmark
:param ascii_docinfo: if True, the docinfo block must be encoded in pure
ASCII and may not contain UTF-16BE-BOM-hex encoded strings, as
required for Ghostscript 9.24+
:param ascii_docinfo: parameter is no longer meaningful
:returns: a string containing the entire pdfmark
"""
# Ghostscript <= 9.21 has a bug where null entries in DOCINFO might produce
# ERROR: VMerror (-25) on closing pdfwrite device.
# https://bugs.ghostscript.com/show_bug.cgi?id=697684
# Work around this by only adding keys that have a nontrivial value
docinfo_keys = ('/Title', '/Author', '/Subject', '/Creator', '/Keywords')
def docinfo_gen():
if not ascii_docinfo:
docinfo_line_template = ' {key} <{value}>'
encode = encode_text_string
else:
docinfo_line_template = ' {key} ({value})'
encode = _encode_ascii
yield from _get_pdfmark_dates(pdfmark)
for key in docinfo_keys:
if key in pdfmark and pdfmark[key].strip() != '':
line = docinfo_line_template.format(
key=key, value=encode(pdfmark[key]))
yield line
docinfo = '\n'.join(docinfo_gen())
t = Template(pdfa_def_template)
result = t.substitute(icc_profile=icc_profile,
icc_identifier=icc_identifier,
docinfo=docinfo)
icc_identifier=icc_identifier)
return result
def generate_pdfa_ps(target_filename, pdfmark, icc='sRGB', ascii_docinfo=False):
def generate_pdfa_ps(target_filename, pdfmark=None, icc='sRGB', ascii_docinfo=None):
if icc == 'sRGB':
icc_profile = SRGB_ICC_PROFILE
else:
@@ -240,7 +185,7 @@ def generate_pdfa_ps(target_filename, pdfmark, icc='sRGB', ascii_docinfo=False):
hex_icc_profile = hexlify(bytes_icc_profile)
icc_profile = '<' + hex_icc_profile.decode('ascii') + '>'
ps = _get_pdfa_def(icc_profile, icc, pdfmark, ascii_docinfo=ascii_docinfo)
ps = _get_pdfa_def(icc_profile, icc, pdfmark)
# We should have encoded everything to pure ASCII by this point, and
# to be safe, only allow ASCII in PostScript
tests/test_metadata.py
+1 -8
View File
@@ -94,9 +94,6 @@ def test_override_metadata(spoof_tesseract_noop, output_type, resources,
before = pikepdf.open(input_file)
after = pikepdf.open(outpdf)
if ghostscript.version() >= '9.24':
pytest.xfail('Ghostscript 9.24+ does not support Unicode DOCINFO')
assert after.metadata.Title == german, after.metadata
assert after.metadata.Author == chinese, after.metadata
assert after.metadata.get('/Keywords', '') == ''
@@ -166,11 +163,7 @@ def test_creation_date_preserved(spoof_tesseract_noop, output_type, resources,
after = pdf_after.trailer.get('/Info', {})
if not before:
# If there was input creation date, none should be output
# because of Ghostscript quirks we set it to null
# This test would be better if we had a test file with /DocumentInfo but
# no /CreationDate, which we don't
assert after.get('/CreationDate', '') == ''
assert after.get('/CreationDate', '') != ''
else:
# We expect that the creation date stayed the same
date_before = decode_pdf_date(str(before['/CreationDate']))