131 lines
3.9 KiB
Python
131 lines
3.9 KiB
Python
"""
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This file contains the necessary functions to determine whether we should tear
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the first page from a PDF file, and actually tear it.
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TODO: Unittests
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"""
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import shutil
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import tempfile
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from PyPDF2 import PdfFileWriter, PdfFileReader
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from PyPDF2.utils import PdfReadError
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# Dict of bad journals which adds an extra useless first page, which can be
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# teared. Please, submit a PR to include new ones which I may not be aware of!
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# This dict associates the journal string to look for and to a list of pages
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# to tear.
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BAD_JOURNALS = {
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"epl": [0],
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"journal of modern optics": [0],
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"new journal of physics": [0]
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}
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def fix_pdf(pdf_file, destination):
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"""
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Fix malformed pdf files when data are present after '%%EOF'
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..note ::
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Originally from sciunto, https://github.com/sciunto/tear-pages
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:param pdfFile: PDF filepath
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:param destination: destination
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"""
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tmp = tempfile.NamedTemporaryFile()
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with open(tmp.name, 'wb') as output:
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with open(pdf_file, "rb") as fh:
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for line in fh:
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output.write(line)
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if b'%%EOF' in line:
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break
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shutil.copy(tmp.name, destination)
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def tearpage_backend(filename, teared_pages=None):
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"""
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Copy filename to a tempfile, write pages to filename except the teared one.
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..note ::
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Adapted from sciunto's code, https://github.com/sciunto/tear-pages
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:param filename: PDF filepath
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:param teared_pages: Numbers of the pages to tear. Default to first page \
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only.
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"""
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# Handle default argument
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if teared_pages is None:
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teared_pages = [0]
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# Copy the pdf to a tmp file
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with tempfile.NamedTemporaryFile() as tmp:
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# Copy the input file to tmp
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shutil.copy(filename, tmp.name)
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# Read the copied pdf
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# TODO: Use with syntax
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try:
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input_file = PdfFileReader(open(tmp.name, 'rb'))
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except PdfReadError:
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fix_pdf(filename, tmp.name)
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input_file = PdfFileReader(open(tmp.name, 'rb'))
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# Seek for the number of pages
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num_pages = input_file.getNumPages()
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# Write pages excepted the first one
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output_file = PdfFileWriter()
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for i in range(num_pages):
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if i in teared_pages:
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continue
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output_file.addPage(input_file.getPage(i))
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tmp.close()
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outputStream = open(filename, "wb")
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output_file.write(outputStream)
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def tearpage_needed(bibtex):
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"""
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Check whether a given paper needs some pages to be teared or not.
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:params bibtex: The bibtex entry associated to the paper, to guess \
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whether tearing is needed.
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:returns: A list of pages to tear.
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"""
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for publisher in BAD_JOURNALS:
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if publisher in bibtex.get("journal", "").lower():
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# Bad journal is found, add pages to tear
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return BAD_JOURNALS[publisher]
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# If no bad journals are found, return an empty list
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return []
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def tearpage(filename, bibtex=None, force=None):
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"""
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Tear some pages of the file if needed.
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:params filename: Path to the file to handle.
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:params bibtex: BibTeX dict associated to this file, as the one given by \
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``bibtexparser``. (Mandatory if force is not specified)
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:params force: If a list of integers, force the tearing of the \
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specified pages. (Optional)
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:returns: A boolean indicating whether the file has been teared or not. \
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Side effect is tearing the necessary pages from the file.
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"""
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# Fetch pages to tear
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pages_to_tear = []
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if force is not None:
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pages_to_tear = force
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elif bibtex is not None:
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pages_to_tear = tearpage_needed(bibtex)
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if len(pages_to_tear) > 0:
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# If tearing is needed, do it and return True
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tearpage_backend(filename, teared_pages=pages_to_tear)
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return True
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# Else, simply return False
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return False
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