Tool to swap text from pdf files using Python

py-pdf-swap-text.py

'''
config.yml

path: /path/to/folder
text1:
  old: "xxxxx"
  new: "yyyyy"
'''

'''
my_config.yml

path: /path/to/folder
text1:
  old: "(1602975)"
  new: "(0000000)"
text2:
  old: "(06983770366\\040\\055\\040João\\040Wellington\\040Mendes\\040de\\040Souza)"
  new: "()"
'''

from PyPDF2 import PdfFileWriter, PdfFileReader
from reportlab.pdfgen import canvas
import os
import codecs
import yaml

PATH = ""
TEXTS = []

def create_wm_file():
    c = canvas.Canvas("wm.pdf")
    c.rect(0, 0, 1, 1, fill=1)
    c.save()
    return

def delete_wm_file():
    os.remove("wm.pdf")
    return

def generate_editable_pdf(filepath):
    wm = PdfFileReader(open("wm.pdf", "rb"))
    output_file = PdfFileWriter()
    input_file = PdfFileReader(open(filepath, "rb"))
    page_count = input_file.getNumPages()

    for page_number in range(page_count):
        input_page = input_file.getPage(page_number)
        input_page.mergePage(wm.getPage(0))
        output_file.addPage(input_page)

    with open("tmp.pdf", "wb") as outputStream:
        output_file.write(outputStream)
    
    return

def remove_refs_from_pdf():
    # get data
    f = codecs.open("tmp.pdf", encoding="ISO8859-1", mode="rb")
    data = f.read()
    f.close()
    # update data
    for T in TEXTS:
        data = data.replace(T[0], T[1])
    # write updated data
    f = codecs.open("tmp.pdf", encoding="ISO8859-1", mode="wb")
    f.write(data)
    f.close()
    return

def count_total_valid_files(files):
    files_updated = []
    for f in files:
        filepath = os.path.join(PATH,f)
        _,ext = os.path.splitext(filepath)
        if(os.path.isfile(filepath) and ext==".pdf"):
            files_updated.append(filepath)
    return files_updated

def read_config_file():
    global PATH, TEXTS
    with open("config.yml", 'r') as stream:
        try:
            yamlData = yaml.safe_load(stream)
            texts = list(yamlData.keys())
            PATH = yamlData["path"]
            texts.remove("path")
            for text in texts:
                T = [yamlData[text]["old"], yamlData[text]["new"]]
                TEXTS.append(T)
        except:
            print("Error: config file must have the following structure")
            print("config.yml")
            print("     path: /path/to/folder")
            print("     text1:")
            print("       old: 'xxxxxx'")
            print("       new: 'yyyyyy'")
            print("...")
            exit(-1)

if __name__ == "__main__":
    read_config_file()
    files = [os.path.join(dp, f) for dp, dn, fn in os.walk(os.path.expanduser(PATH)) for f in fn]
    files = count_total_valid_files(files)
    counter = 1

    create_wm_file()
    for filepath in files:
        print("> editing file [{}/{}]".format(counter, len(files)))
        counter += 1
        generate_editable_pdf(filepath)
        remove_refs_from_pdf()
        os.replace("tmp.pdf", filepath)
    delete_wm_file()