Rebuilds Apple Calendar *.ics files so they can be safely reimported

regenerate_ics.py

#!/usr/bin/env python

"""
Looks at all the *.ics files in the current directory, removes the X- keys, 
and generates a new UUID. This is used for restoring an accidentally-deleted
calendar in Apple's Calendar program; it is a rewrite of the node.js version
that is linked to from here:

http://fokkezb.nl/2015/01/13/how-to-restore-a-deleted-icloud-calendar/
"""

import os
import sys
import uuid
import codecs
import argparse

# Standard UTF-8 Python header that fixes sucky python UTF-8 handling
reload(sys)
sys.setdefaultencoding('utf-8')
sys.stdin = codecs.getreader('utf-8')(sys.stdin)
sys.stdout = codecs.getwriter('utf-8')(sys.stdout)
sys.stdout.encoding = 'utf-8'

parser = argparse.ArgumentParser()
parser.add_argument('-output_dir', help='the output directory to write to', default='output')
args = parser.parse_args()

if not os.path.exists(args.output_dir):
    os.makedirs(args.output_dir)

for file in os.listdir('.'):
    if file.endswith('.ics'):
        lines = []
        outfile = None
        for line in codecs.open(file, 'r', 'utf-8'):
            if line.startswith('X-'):
                continue

            elif line.startswith('UID:'):
                parts = line.split(':')
                lines.append('UID:%s\r\n' % (str(uuid.uuid4()).upper()))
                outfile = '%s/%s.ics' % (args.output_dir, str(uuid.uuid4()).upper())
        
            else:
                lines.append(line)

        print file, '->', outfile

        out = codecs.open(outfile, 'w', 'utf-8')
        for line in lines:
            out.write(line)
        out.close()

Lovely, you saved my day with this script as iCloud was not able to restore my deleted calendars...

I only vaguely remember writing this and can't remember what problem I was solving, but I'm glad it was of some help to you!