If you want to get 'CreationDate', 'Author' and this kind of entries you can try this quick and dirty solution. Normally this information in a pdf should look like this:
obj
<<
/Author(NameOfAuthor)
/CreationDate(D:20040910110429)
/Producer(AcrobatPdfWriter)
>>
endobj
Not sure if applies for all pdf formats but I got some decent data that you can 'clean-up' after. Only works if the entries are on separate lines.
metadata_fields = ['Creator', 'CreationDate', 'Producer', 'ModDate']
with open('path_to_your_file.pdf') as my_pdf:
meta_values = [line.rstrip('\n') for line in my_pdf.readlines()
for item in metadata_fields if item in line]
print meta_values
Output:
['<</Producer(AFPL Ghostscript 8.11)', '/CreationDate(D:20040910110429)',
'/ModDate(D:20040910110429)', '/Creator(PDFCreator Version 0.8.0)']