2017-01-26 16:38:59 -08:00

134 lines
4.0 KiB
Python

#!/usr/bin/env python3
# © 2015 James R. Barlow: github.com/jbarlow83
from subprocess import CalledProcessError, check_output, STDOUT, check_call
from functools import lru_cache
import sys
import os
import re
from ..exceptions import InputFileError, SubprocessOutputError, \
MissingDependencyError, EncryptedPdfError
from . import get_program
@lru_cache(maxsize=1)
def version():
args_qpdf = [
get_program('qpdf'),
'--version'
]
try:
versions = check_output(
args_qpdf, close_fds=True, universal_newlines=True,
stderr=STDOUT)
except CalledProcessError as e:
print("Could not find qpdf executable on system PATH.",
file=sys.stderr)
raise MissingDependencyError() from e
qpdf_version = re.match(r'qpdf version (.+)', versions).group(1)
return qpdf_version
def check(input_file, log=None):
args_qpdf = [
get_program('qpdf'),
'--check',
input_file
]
if log is None:
import logging as log
try:
check_output(args_qpdf, stderr=STDOUT, universal_newlines=True)
except CalledProcessError as e:
if e.returncode == 2:
log.error("{0}: not a valid PDF, and could not repair it.".format(
input_file))
log.error("Details:")
log.error(e.output)
elif e.returncode == 3:
log.info("qpdf --check returned warnings:")
log.info(e.output)
else:
log.warning(e.output)
return False
return True
def _probably_encrypted(e):
"""qpdf can report a false positive "file is encrypted" message for damaged
files - suppress this"""
return e.returncode == 2 and \
'invalid password' in e.output and \
'file is damaged' not in e.output
def repair(input_file, output_file, log):
args_qpdf = [
get_program('qpdf'), input_file, output_file
]
try:
check_output(args_qpdf, stderr=STDOUT, universal_newlines=True)
except CalledProcessError as e:
if e.returncode == 3 and e.output.find("operation succeeded"):
log.debug('qpdf found and fixed errors: ' + e.output)
log.debug(e.output)
return
if _probably_encrypted(e):
log.error("{0}: this PDF is password-protected - password must "
"be removed for OCR".format(input_file))
raise EncryptedPdfError() from e
elif e.returncode == 2:
log.error("{0}: not a valid PDF, and could not repair it.".format(
input_file))
log.error("Details: " + e.output)
raise InputFileError() from e
else:
log.error("{0}: unknown error".format(
input_file))
log.error(e.output)
raise SubprocessOutputError() from e
def get_npages(input_file, log):
try:
pages = check_output(
[get_program('qpdf'), '--show-npages', input_file],
universal_newlines=True, close_fds=True)
except CalledProcessError as e:
if e.returncode == 2 and e.output.find('No such file'):
log.error(e.output)
raise InputFileError() from e
return int(pages)
def split_pages(input_file, work_folder, npages):
"""Split multipage PDF into individual pages.
Incredibly enough, this multiple process approach is about 70 times
faster than using Ghostscript.
"""
for n in range(int(npages)):
args_qpdf = [
get_program('qpdf'), input_file,
'--pages', input_file, '{0}'.format(n + 1), '--',
os.path.join(work_folder, '{0:06d}.page.pdf'.format(n + 1))
]
check_call(args_qpdf)
def merge(input_files, output_file):
"""Merge the list of input files (all filenames) into the output file.
The input files may contain one or more pages.
"""
args_qpdf = [
get_program('qpdf'), input_files[0], '--pages'
] + input_files + ['--', output_file]
check_call(args_qpdf)