Pypdf：'AttributeError：'str'对象没有属性'write_to_stream'在尝试更新注释中的“Author”字段时引发

Question

我已使用以下代码成功将注释从一个 pdf 复制到另一个 pdf：

def copy_and_update_annotations(src_pdf_file,dest_pdf_file): 

    #copies annotations from scr_file to a destination file
    reader = PdfReader(src_pdf_file)
    dest_reader=PdfReader(dest_pdf_file)
    writer=PdfWriter()

    first_page=dest_reader.pages[0]
    writer.add_page(first_page)

    for page in reader.pages:
        if "/Annots" in page:
            for annot in page["/Annots"]:
                obj = annot.get_object()


                writer.add_annotation(page_number=0, annotation=obj)

    writer.write(dest_pdf_file)

在下一步中，我想更改注释的一些属性，例如“作者”字段（obj['/T']）。但这一次，我在最后一行得到 'AttributeError: 'str' object has no attribute 'write_to_stream' ：

def copy_and_update_annotations(src_pdf_file,dest_pdf_file):
    #copies annotations from scr_file to a destination file
    reader = PdfReader(src_pdf_file)
    dest_reader=PdfReader(dest_pdf_file)
    writer=PdfWriter()

    first_page=dest_reader.pages[0]
    writer.add_page(first_page)

    for page in reader.pages:
        if "/Annots" in page:
            for annot in page["/Annots"]:
                obj = annot.get_object()
                if '/T' in obj: # Update Author
                    obj.update({'/T': 'NEW Author'}) #Update Author

                writer.add_annotation(page_number=0, annotation=obj) 

    writer.write(dest_pdf_file) # -->Here, I get:  'AttributeError: 'str' object has no attribute 'write_to_stream'

我尝试了不同的方法，例如 dest_pdf_file.encode() 或将 dest_pdf 转换为 StringIO 或 BytesIO。到目前为止没有任何效果。我正在使用 pypdf-3.12.0 和 python 3.9 64 位。

我做错了什么？

*** 更新：添加时

    with open(dest_pdf_file, "wb") as output_stream:
        writer.write(output_stream)

我仍然遇到同样的错误。也许包本身有错误？ 请在此处查看完整的错误消息：

  File "C:\AppData\Local\Programs\Python\Python39\lib\site-packages\pypdf\_writer.py", line 1287, in write
    self.write_stream(stream)
  File "C:\AppData\Local\Programs\Python\Python39\lib\site-packages\pypdf\_writer.py", line 1260, in write_stream
    object_positions = self._write_pdf_structure(stream)
  File "C:AppData\Local\Programs\Python\Python39\lib\site-packages\pypdf\_writer.py", line 1306, in _write_pdf_structure
    obj.write_to_stream(stream)
  File "C:\AppData\Local\Programs\Python\Python39\lib\site-packages\pypdf\generic\_data_structures.py", line 369, in write_to_stream
    value.write_to_stream(stream)
AttributeError: 'str' object has no attribute 'write_to_stream'

Answer 1

我认为这是因为你试图用“string”类型编写“/T”，而实际上在 pypdf 中它是“TextStringObject”类型。您应该将字符串转换为这种类型，例如这样：

obj.update({'/T': pypdf.generic._base.TextStringObject('NEW Author')}) #Update Author