如何在MySQL数据库中存储PDF而不在Python中生成PDF文件

Question

所以基本上，我在MySQL数据库中有一个base64编码的PDF数据，我想操纵该数据（更新PDF文件数据的表单字段），此后不创建/写入PDF文件，我想存储该操纵/更新的数据。数据存入数据库。如下所示的Python代码。

这里我正在使用PyPDF2并且代码正在运行

import base64, io, PyPDF2

try:
    data_dict = '{"firstName": "John", "lastName": "Joe"}'
    encodedDataOfPDF = base64.b64decode(data)  #base64 encoded data of pdf from database

    file = io.BytesIO(encodedDataOfPDF)
    pdfReader = PyPDF2.PdfFileReader(file)
    pdfWriter = PyPDF2.PdfFileWriter()
    pdfWriter.appendPagesFromReader(pdfReader)

    #Here form fields of PDF gets updated.
    pdfWriter.updatePageFormFieldValues(pdfWriter.getPage(0), data_dict)  


    #If I uncomment below code then it will create a PDF file with updated data.
    #But I Don't want a PDF File, 
    #I just need the base64 encoded data of that updated/manipulated file which I will store in the Database.

    # with open(data[1], 'wb') as f:
    #     pdfWriter.write(f)


except Exception as e:
    app.logger.info(str(e))

注意：请同时阅读代码中的注释

谢谢。

Answer 1

经过大量研究后，我得到了一种正确的方法来获取更新/经操纵的编码数据，称为流。

import base64, io, PyPDF2

try:
    tempMemory = io.BytesIO() #Added BytesIO
    data_dict = '{"firstName": "John", "lastName": "Joe"}'
    encodedDataOfPDF = base64.b64decode(data)  #base64 encoded data of pdf from database

    file = io.BytesIO(encodedDataOfPDF)
    pdfReader = PyPDF2.PdfFileReader(file)
    pdfWriter = PyPDF2.PdfFileWriter()
    pdfWriter.appendPagesFromReader(pdfReader)

    #Here form fields of PDF gets updated.
    pdfWriter.updatePageFormFieldValues(pdfWriter.getPage(0), data_dict)  

    pdfWriter.write(tempMemory)
    newFileData = tempMemory.getvalue()
    newEncodedPDF= base64.b64encode(newFileData) # Here I get what I want.


except Exception as e:
    app.logger.info(str(e))

我得到了base64编码的数据，但没有生成PDF文件。

谢谢