tile_warmer.py

'''
   Script to generate tiles for an image viewed using the Mirador Viewer. Also takes
   a screenshot of the page for quick QA of results.

   Usage: python iiif_tile_warmer.py https://digital-ds.lib.sfu.ca/node/235 10 # Where 10 is the number of seconds to wait before closig the window; default is 5.

          python iiif_tile_warmer.py tiles.txt 10 # Where tiles.txt is a file containing a list of URLs, one per line.
'''

import sys
import os
from time import sleep
import re
import logging
from selenium import webdriver

log_file_path = 'generate_iiif_tiles.log'
# screenshots_dir_path must exist.
screenshots_dir_path = '/tmp/screenshots'

if len(sys.argv) == 3:
    sleep_length = sys.argv[2].strip()
else:
    sleep_length = 5

logging.basicConfig(
    filename=log_file_path,
    level=logging.INFO,
    format="%(asctime)s - %(levelname)s - %(message)s",
    datefmt="%d-%b-%y %H:%M:%S",
)

def warm_tiles(url, sleep_length):
    screenshot_filename = re.sub('[^0-9a-zA-Z]+', '_', url)

    logging.info(f'Generating IIIF tiles for {url}, Chrome is waiting {sleep_length} seconds.')

    try:
        driver = webdriver.Chrome()
        driver.get(url)
        sleep(sleep_length)
        driver.save_screenshot(os.path.join(screenshots_dir_path, screenshot_filename + '.png'))
        driver.quit()
    except Exception as e:
        logging.error(f'Attempt to generate IIIF tiles for {url_to_warm} encountered an error: {e}')


# Main script logic.
url_to_warm = sys.argv[1].strip()

if url_to_warm.startswith('http'):
    warm_tiles(url_to_warm, sleep_length)
else:
    with open(url_to_warm) as fh:
        for line in fh:
            warm_tiles(line.strip(), sleep_length)