PyPDF2写入对某些PDF文件不起作用(Python 3.5.1)

Question

首先我使用的是Python 3.5.1(32位版本)我编写了以下程序,使用PyPDF2和reportlab在我的pdf文件的所有页面上添加页面编号:

#import modules
from os import listdir
from PyPDF2 import PdfFileWriter, PdfFileReader
import io
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import A4
#initial values of variable declarations
PDFlist=[]
X_value=460
Y_value=820
#Make a list of al files in de directory
filelist = listdir()
#Make a list of all pdf files in the directory
for i in range(0,len(filelist)):
    filename=filelist[i]
    for j in range(0,len(filename)):
        char=filename[j]
        if char=='.':
            extension=filename[j+1:j+4]
            if extension=='pdf':
                PDFlist.append(filename)
        j=j+1
    i=i+1
# Give the horizontal position for the page number (Enter = use default value of 480)
User = input('Give horizontal position page number (ENTER = default 460): ')
if User != "":
    X_value=int(User)
# Give the vertical position for the page number (Enter = use default value of 820)
User = input('Give horizontal position page number (ENTER = default 820): ')
if User != "":
    Y_value=int(User)

for i in range(0,len(PDFlist)):
    filename=PDFlist[i]

    # read the PDF
    existing_pdf = PdfFileReader(open(filename, "rb"))
    print("File: "+filename)
    # count the number of pages
    number_of_pages = existing_pdf.getNumPages()
    print("Number of pages detected:"+str(number_of_pages))
    output = PdfFileWriter()

    for k in range(0,number_of_pages):
        packet = io.BytesIO()

        # create a new PDF with Reportlab
        can = canvas.Canvas(packet, pagesize=A4)
        Pagenumber=" Page "+str(k+1)+"/"+str(number_of_pages)
        # we first make a white rectangle to cover any existing text in the pdf
        can.setFillColorRGB(1,1,1)
        can.setStrokeColorRGB(1,1,1)
        can.rect(X_value-10,Y_value-5,120,20,fill=1)
        # set the font and size
        can.setFont("Helvetica",14)
        # choose color of page numbers (red)
        can.setFillColorRGB(1,0,0)
        can.drawString(X_value, Y_value, Pagenumber)
        can.save()
        print(Pagenumber)

        #move to the beginning of the StringIO buffer
        packet.seek(0)
        new_pdf = PdfFileReader(packet)
        # add the "watermark" (which is the new pdf) on the existing page
        page = existing_pdf.getPage(k)
        page.mergePage(new_pdf.getPage(0))
        output.addPage(page)
        k=k+1
    # finally, write "output" to a real file

    ResultPDF="Output/"+filename
    outputStream = open(ResultPDF, "wb")
    output.write(outputStream)
    outputStream.close()
    i=i+1

这个程序适用于相当多的PDF文件(虽然警告有时会像' PdfReadWarning: Superfluous whitespace found in object header b'16' b'0' [pdf.py:1666]' 那样产生,但结果输出文件对我来说没问题).但是,该程序对某些PDF文件不起作用,尽管这些文件对我的Adobe Acrobat来说是完全可读和可编辑的.我的印象是错误主要出现在已扫描的PDF文件上,但不会出现在所有这些文件上(我还编号扫描的PDF文件没有产生任何错误).我收到以下错误消息(前8行是我自己的打印命令的结果):

File: Scanned file.pdf
Number of pages detected:6
 Page 1/6
 Page 2/6
 Page 3/6
 Page 4/6
 Page 5/6
 Page 6/6
PdfReadWarning: Object 25 1 not defined. [pdf.py:1629]
Traceback (most recent call last):
  File "C:\Users\User\AppData\Local\Programs\Python\Python35-32\Sourcecode\PDFPager.py", line 83, in <module>
    output.write(outputStream)
  File "C:\Users\User\AppData\Local\Programs\Python\Python35-32\lib\site-packages\PyPDF2\pdf.py", line 482, in write
    self._sweepIndirectReferences(externalReferenceMap, self._root)
  File "C:\Users\User\AppData\Local\Programs\Python\Python35-32\lib\site-packages\PyPDF2\pdf.py", line 571, in _sweepIndirectReferences
    self._sweepIndirectReferences(externMap, realdata)
  File "C:\Users\User\AppData\Local\Programs\Python\Python35-32\lib\site-packages\PyPDF2\pdf.py", line 547, in _sweepIndirectReferences
    value = self._sweepIndirectReferences(externMap, value)
  File "C:\Users\User\AppData\Local\Programs\Python\Python35-32\lib\site-packages\PyPDF2\pdf.py", line 571, in _sweepIndirectReferences
    self._sweepIndirectReferences(externMap, realdata)
  File "C:\Users\User\AppData\Local\Programs\Python\Python35-32\lib\site-packages\PyPDF2\pdf.py", line 547, in _sweepIndirectReferences
    value = self._sweepIndirectReferences(externMap, value)
  File "C:\Users\User\AppData\Local\Programs\Python\Python35-32\lib\site-packages\PyPDF2\pdf.py", line 556, in _sweepIndirectReferences
    value = self._sweepIndirectReferences(externMap, data[i])
  File "C:\Users\User\AppData\Local\Programs\Python\Python35-32\lib\site-packages\PyPDF2\pdf.py", line 571, in _sweepIndirectReferences
    self._sweepIndirectReferences(externMap, realdata)
  File "C:\Users\User\AppData\Local\Programs\Python\Python35-32\lib\site-packages\PyPDF2\pdf.py", line 547, in _sweepIndirectReferences
    value = self._sweepIndirectReferences(externMap, value)
  File "C:\Users\User\AppData\Local\Programs\Python\Python35-32\lib\site-packages\PyPDF2\pdf.py", line 556, in _sweepIndirectReferences
    value = self._sweepIndirectReferences(externMap, data[i])
  File "C:\Users\User\AppData\Local\Programs\Python\Python35-32\lib\site-packages\PyPDF2\pdf.py", line 577, in _sweepIndirectReferences
    newobj = data.pdf.getObject(data)
  File "C:\Users\User\AppData\Local\Programs\Python\Python35-32\lib\site-packages\PyPDF2\pdf.py", line 1631, in getObject
    raise utils.PdfReadError("Could not find object.")
PyPDF2.utils.PdfReadError: Could not find object.

显然,这些页面与reportlab创建的PDF合并(参见第6/6页的行),但最终PyPDF2无法生成输出PDF文件(我得到一个0字节的不可读输出文件).有人可以解释如何解决这个问题吗？我搜索了互联网,但无法找到答案.

Answer 1

在 pdf.py 上做以下更改：

在 pdf 的第 1633 行。py（这意味着取消对 if self.strict 的注释）

    if self.strict:
        raise utils.PdfReadError("Could not find object.")

并在 pdf.py 上的第 501 行进行以下更改（添加尝试，块除外）

    try:
        obj.writeToStream(stream, key)
        stream.write(b_("\nendobj\n"))
    except:
        pass

干杯。

Answer 2

使用“strict = false”让事情对我有用。

from PyPDF2 import PdfFileMerger

pdfs = [r'file 1.pdf', r'file 2.pdf']

merger = PdfFileMerger(strict=False)

for pdf in pdfs:
    merger.append(pdf)

merger.write(r"thanks mate.pdf")