Pdfminer，struct.error：需要 x 字节的缓冲区

Question

我在 macOS 上使用 python 3.10

我有这段代码，我从另一篇文章中得到了一些改动，

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")

但是，当我在某些 pdf 上使用它时，它给了我这个错误：

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

是我的代码、pdfminer.six 库有问题，还是某些 pdf 有问题？ 我该如何解决？

Answer 1

我解决了它，出于某种原因这部分代码：

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

必须介于这些之间：

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

所以最终的代码是这样的：

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")

如果有人知道为什么，请你回答这个帖子，我很高兴学习