Pdfminer, struct.error: requires buffer of x bytes-CodePudding

I'm on macOS using python 3.10

I have this code which I got and slightly changed from another post,

from pdfminer.layout import LAParams, LTTextBox
from pdfminer.pdfpage import PDFPage
from pdfminer.pdfinterp import PDFResourceManager
from pdfminer.pdfinterp import PDFPageInterpreter
from pdfminer.converter import PDFPageAggregator


rsrcmgr, laparams = PDFResourceManager(), LAParams()
device = PDFPageAggregator(rsrcmgr, laparams=laparams)
interpreter = PDFPageInterpreter(rsrcmgr, device)


fp = open("my_pdf", 'rb')
pages = PDFPage.get_pages(fp)
for page in pages:
    interpreter.process_page(page)
    layout = device.get_result()
    print("It worked")

However, when I use it on some pdfs it gives me this error:

Traceback (most recent call last):
  File "MY_DIRECTORY/create_database.py", line 38, in <module>
    interpreter.process_page(page)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pdfminer/pdfinterp.py", line 991, in process_page
    self.render_contents(page.resources, page.contents, ctm=ctm)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pdfminer/pdfinterp.py", line 1010, in render_contents
    self.execute(list_value(streams))
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pdfminer/pdfinterp.py", line 1036, in execute
    func(*args)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pdfminer/pdfinterp.py", line 966, in do_Do
    interpreter.render_contents(
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pdfminer/pdfinterp.py", line 1010, in render_contents
    self.execute(list_value(streams))
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pdfminer/pdfinterp.py", line 1036, in execute
    func(*args)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pdfminer/pdfinterp.py", line 903, in do_Tj
    self.do_TJ([s])
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pdfminer/pdfinterp.py", line 896, in do_TJ
    self.device.render_string(
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pdfminer/pdfdevice.py", line 133, in render_string
    textstate.linematrix = self.render_string_horizontal(
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pdfminer/pdfdevice.py", line 170, in render_string_horizontal
    for cid in font.decode(obj):
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pdfminer/pdffont.py", line 1174, in decode
    return self.cmap.decode(bytes)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pdfminer/cmapdb.py", line 136, in decode
    return struct.unpack(">%dH" % n, code)
struct.error: unpack requires a buffer of 6 bytes

Is it a problem with my code, the library pdfminer.six, or a problem with some pdfs? And how can I fix it?

CodePudding user response：

I SOLVED IT, for some reason this part of the code:

rsrcmgr, laparams = PDFResourceManager(), LAParams()
device = PDFPageAggregator(rsrcmgr, laparams=laparams)
interpreter = PDFPageInterpreter(rsrcmgr, device)

has to be in between these:

fp = open("my_pdf", 'rb')
pages = PDFPage.get_pages(fp)

So the final code looks like this:

from pdfminer.layout import LAParams, LTTextBox
from pdfminer.pdfpage import PDFPage
from pdfminer.pdfinterp import PDFResourceManager
from pdfminer.pdfinterp import PDFPageInterpreter
from pdfminer.converter import PDFPageAggregator


fp = open("my_pdf", 'rb')
rsrcmgr, laparams = PDFResourceManager(), LAParams()
device = PDFPageAggregator(rsrcmgr, laparams=laparams)
interpreter = PDFPageInterpreter(rsrcmgr, device)
pages = PDFPage.get_pages(fp)


for page in pages:
    interpreter.process_page(page)
    layout = device.get_result()
    print("It worked")

If anyone knows why, could you please answer this post, I'd be glad to learn