Immich Bulk Date Shift. The Immich web ui only supports setting one time for many assets, this code allows the date of many assets to be shifted by x days, seconds etc. This will shift the date/time for all photos in a given album

immich_date_shift.py

# under CC0/Public Domain. Do as you like. NO WARRANTY 

# make venv, pip install requests python-dateutil
# Replace the 3 variables at the top and adjust the function call for adjust_iso8601_time() to suit your desired time change for all photos in the album you give.
# Better code may exist but this is a quick fix to a problem I had 

import requests
from datetime import datetime, timedelta
from zoneinfo import ZoneInfo
import json

API_URL = "https://immich.example.com/api/"
API_KEY = "don't share me!"
ALBUM_ID = "uuid" # this can be copied from the album view url when viewing

def adjust_iso8601_time(iso_string: str, days=0, hours=0, minutes=0, timezone='UTC') -> str | None:
    try:
        # Parse the ISO 8601 string, handling time zones manually
        if 'Z' in iso_string:
            iso_string = iso_string.replace('Z', '+00:00')  # Convert 'Z' to UTC offset
        dt = datetime.fromisoformat(iso_string)

        # Convert to the specified time zone if necessary
        if timezone != 'UTC':
            dt = dt.astimezone(ZoneInfo(timezone))

        # Adjust the datetime object by specified amounts
        adjusted_dt = dt + timedelta(days=days, hours=hours, minutes=minutes)

        # Convert back to ISO 8601 format in UTC
        new_iso_string = adjusted_dt.astimezone(ZoneInfo('UTC')).isoformat(timespec='milliseconds').replace('+00:00', 'Z')
        return new_iso_string
    
    except ValueError as e:
        print(f"Error parsing date: {e}")
        return None

def change_date_immich(photo_uuid: str, new_date: str) -> requests.Response:
    url = f"{API_URL}assets"
    payload = json.dumps({
    "dateTimeOriginal": new_date,
    "ids": [
        photo_uuid
    ]
    })
    headers: dict[str, str] = {
    'Content-Type': 'application/json',
    'x-api-key': API_KEY
    }
    return requests.request("PUT", url, headers=headers, data=payload)


def main():
    album_url = f"{API_URL}albums/{ALBUM_ID}"

    payload = {}
    headers = {
    'Accept': 'application/json',
    'x-api-key': API_KEY
    }

    response = requests.request("GET", album_url, headers=headers, data=payload)

    for asset in response.json()["assets"]:
        exif_data = asset.get("exifInfo")
        if exif_data:
            og_time = exif_data.get("dateTimeOriginal")
            if og_time:
                new_time = adjust_iso8601_time(og_time, -31, 0, 0)
                print(f"Oldtime: {og_time}, adjusted: {new_time}")
                if new_time:
                    print(change_date_immich(asset["id"], new_time).text)


if __name__ == "__main__":
    main()