import sys
import os
import shutil
import zipfile

class ZipReplace:
  def __init__(self, filename, search_string,
      replace_string):
    self.filename = filename
    self.search_string = search_string
    self.replace_string = replace_string
    self.temp_directory = "unzipped-{}".format(
      filename)

  def _full_filename(self, filename):
    return os.path.join(self.temp_directory, filename)
  
  def zip_find_replace(self):
    self.unzip_files()
    self.find_replace()
    self.zip_files()
  # END zip_find_replace

  def unzip_files(self):
    os.mkdir(self.temp_directory)
    zip = zipfile.ZipFile(self.filename)
    try:
      zip.extractall(self.temp_directory)
    finally:
      zip.close()

  def find_replace(self):
    for filename in os.listdir(self.temp_directory):
      with open(self._full_filename(filename)) as file:
          contents = file.read()
          contents = contents.replace(
          self.search_string, self.replace_string)
      with open(
          self._full_filename(filename), "w") as file:
          file.write(contents)

  def zip_files(self):
    file = zipfile.ZipFile(self.filename, 'w')
    for filename in os.listdir(self.temp_directory):
      file.write(
        self._full_filename(filename), filename)
    shutil.rmtree(self.temp_directory)

fred =  ZipReplace("filename.zip", "search_string", "replace_string")