Crash in TeXKeys extraction

[kaplun]

Given the PDF available at: http://arxiv.org/pdf/1710.01077 refextract crashes in PyPDF2 code:

Traceback (most recent call last):
  File "/opt/inspire/lib/python2.7/site-packages/workflow/engine.py", line 529, in _process
    self.run_callbacks(callbacks, objects, obj)
  File "/opt/inspire/lib/python2.7/site-packages/workflow/engine.py", line 465, in run_callbacks
    indent + 1)
  File "/opt/inspire/lib/python2.7/site-packages/workflow/engine.py", line 465, in run_callbacks
    indent + 1)
  File "/opt/inspire/lib/python2.7/site-packages/workflow/engine.py", line 481, in run_callbacks
    self.execute_callback(callback_func, obj)
  File "/opt/inspire/lib/python2.7/site-packages/workflow/engine.py", line 564, in execute_callback
    callback(obj, self)
  File "/opt/inspire/src/inspire/inspirehep/modules/workflows/utils.py", line 135, in _decorator
    res = func(*args, **kwargs)
  File "/opt/inspire/src/inspire/inspirehep/modules/workflows/tasks/actions.py", line 238, in refextract
    references = extract_references(uri, source)
  File "/opt/inspire/lib/python2.7/site-packages/timeout_decorator/timeout_decorator.py", line 81, in new_function
    return function(*args, **kwargs)
  File "/opt/inspire/src/inspire/inspirehep/modules/workflows/tasks/refextract.py", line 95, in extract_references
    reference_format=u'{title},{volume},{page}'
  File "/opt/inspire/lib/python2.7/site-packages/refextract/references/api.py", line 149, in extract_references_from_file
    texkeys = extract_texkeys_from_pdf(path)
  File "/opt/inspire/lib/python2.7/site-packages/refextract/references/pdf.py", line 54, in extract_texkeys_from_pdf
    pdf = PdfFileReader(pdf_stream, strict=False)
  File "/opt/inspire/lib/python2.7/site-packages/PyPDF2/pdf.py", line 1084, in __init__
    self.read(stream)
  File "/opt/inspire/lib/python2.7/site-packages/PyPDF2/pdf.py", line 1803, in read
    idnum, generation = self.readObjectHeader(stream)
  File "/opt/inspire/lib/python2.7/site-packages/PyPDF2/pdf.py", line 1667, in readObjectHeader
    return int(idnum), int(generation)
ValueError: invalid literal for int() with base 10: 'f'

It should instead handle the exception and continue without extracting TeXKeys.

[michamos]

looks like PyPDF2 is really brittle. The crash happens when trying to parse the PDF, so nothing we could easily fix. Maybe we should wrap calls to PyPDF2 in a big

try:
    # call PyPDF2
except Exception as e:
    # log the exception

[kaplun]

Yeah exactly.

[michamos]

we wouldn't lose much anyway: texkey extraction is useful only for articles using Inspire texkeys (and maybe other platforms like ADS in the future). Those will in the vast majority of cases be produced by a standard TeX pipeline, which we know works well with PyPDF2.