Examples

This chapter provides example workflows for common use cases.

Anonymize a Google Calendar export for a bug report

From your Google Calendar, export it to an iCalendar file via Settings ‣ Import & export ‣ Export, then click the Export button. Before attaching it to a bug report, run the exported file through the anonymizer with the following command.

ican calendar.ics -o anonymized.ics

The output preserves dates, recurrence, and timezone data while stripping names, emails, and personal text. Attach anonymized.ics to the bug report.

To keep event titles visible, use the --summary keep flag:

ican --summary keep calendar.ics -o anonymized.ics

Reproducible test data with custom salts

By default, each run generates a fresh random salt, so the same input produces different output each time. For tests that assert specific values, pass a fixed salt:

from icalendar import Calendar
from icalendar_anonymizer import anonymize

with open("calendar.ics", "rb") as f:
    cal = Calendar.from_ical(f.read())

# Same salt = same hashed output every time
anonymized = anonymize(cal, salt=b"test-fixture-salt-0123456789abcdef")

with open("tests/fixtures/anonymized.ics", "wb") as f:
    f.write(anonymized.to_ical())

Pin the salt in version control alongside the fixture. Changing the salt invalidates the fixture.

Batch process multiple calendar files

Anonymize every .ics file in a directory, writing results to a sibling directory:

from pathlib import Path
from icalendar import Calendar
from icalendar_anonymizer import anonymize

source = Path("calendars")
target = Path("anonymized")
target.mkdir(exist_ok=True)

for ics_path in source.glob("*.ics"):
    cal = Calendar.from_ical(ics_path.read_bytes())
    anonymized = anonymize(cal)
    (target / ics_path.name).write_bytes(anonymized.to_ical())

For a shell-only pipeline:

for f in calendars/*.ics; do
    ican "$f" -o "anonymized/$(basename "$f")"
done

Debug recurrence and timezone issues

When reporting a bug in recurrence expansion or timezone handling, the technical properties (RRULE, RDATE, EXDATE, DTSTART, TZID, and VTIMEZONE) are exactly what maintainers need. The anonymizer preserves all of these by default.

If the bug requires a specific SUMMARY or CATEGORIES value to reproduce (for example, a parser triggered by a specific string), use --summary keep or --categories keep and confirm the preserved fields don’t contain personal data before sharing.

To get reproducible hashed UID values so maintainers can match events across runs, use the Python API with a fixed salt as described in the above section, Reproducible test data with custom salts.