Best way to merge multiple PDF's into one, downloaded from Azure Blob Storage using Python?

Question

Am trying to download multiple PDF files from Azure and combine them (using PyPDF2 library) all into one PDF for re-upload into azure.

Am currently getting an error of PyPDF2.utils.PdfReadError: Unsupported PNG filter 4 on line pdf = PyPDF2.PdfFileReader(output).

    consolidated_pdf = review_level_str.title() + '.pdf'
    merger = PyPDF2.PdfFileMerger()
    
    for each_file in filename_lst:
        blob_client = blob_service.get_blob_client(container=f'{flask_env}-downloads', blob=each_file)
        blob_object = blob_client.download_blob()

        bytes_file = blob_object.readall()
        output = io.BytesIO()
        output.write(bytes_file)
        pdf = PyPDF2.PdfFileReader(output)
        merger.append(pdf)

    blob_client_pdf = blob_service.get_blob_client(container=f'{flask_env}-downloads', blob=consolidated_pdf)
    blob_client_pdf.upload_blob(pdf.getvalue())

Answer 1

Try this:

from azure.storage.blob import ContainerClient 
from PyPDF2 import PdfFileMerger
import shutil,os


pdf_list = ['test1.pdf','test2.pdf']
container = 'pdf'
storage_conn_str = ''

tempPath = 'd:/home/temp2/'
os.mkdir(tempPath)

mergedObject = PdfFileMerger()
ContainerClient = ContainerClient.from_connection_string(storage_conn_str,container)

for pdf in pdf_list:
    localPdfPath = tempPath + pdf
    with open(localPdfPath, "wb") as download_file:
        download_file.write(ContainerClient.download_blob(pdf).readall())
    mergedObject.append(localPdfPath)

mergedPDFPath = tempPath + 'merged.pdf'
mergedObject.write(mergedPDFPath)
mergedObject.close()

with open(mergedPDFPath, "rb") as stream:
    ContainerClient.upload_blob('merged.pdf',stream, overwrite=True)

#remove all temp files after upload.
shutil.rmtree(tempPath)

Result:

Check the merged.pdf:

Let me know if you have any more questions.