Pimoroni Inky image download script

download-image.py

"""
Set a cron job to run this script every 5 minutes
It will download the image from the given URL and render it.
The ETag header is used to check if the image has changed.
If it has, the image is downloaded and rendered.
If not, the script exits early.
The ETag is saved to a file and checked on the next run.

Requires pimoroni/inky library: https://github.com/pimoroni/inky#installation

sudo apt install libopenblas-base libopenblas-dev
python -m venv venv
source venv venv/bin/activate
pip install Pillow
pip install inky
pip install requests
pip install RPi.GPIO

Example crontab entry per minute:
* * * * * pi /home/pi/env/bin/python /home/pi/download-image.py https://example.com/image.jpg 0.5
"""

import os
import sys

import requests
from PIL import Image
from inky.auto import auto


if len(sys.argv) == 1:
    print("""
Usage: {file} image-url [saturation]
""".format(file=sys.argv[0]))
    sys.exit(1)


image_url = sys.argv[1]

etag_filename = "etag.txt"
etag_filepath = os.path.join(os.path.dirname(__file__), etag_filename)
image_filename = "image.jpg"
image_filepath = os.path.join(os.path.dirname(__file__), image_filename)

head_response = requests.head(image_url)
etag = head_response.headers.get("ETag")

if etag is None:
    print("ETag not found in response headers. Skipping download and render")
    sys.exit(0)

if os.path.exists(etag_filename):
    with open(etag_filename, "r") as file:
        old_etag = file.read()
        if old_etag == etag:
            print(f"Etag {etag} is current. Skipping download and render")
            sys.exit(0)

print(f"Downloading image at {image_url}")
with open(etag_filename, "w") as etag_file:
    response = requests.get(image_url)
    with open(image_filepath, "wb") as image_file:
        image_file.write(response.content)
    updated_etag = response.headers.get("ETag")
    print(f"Updating etag to {updated_etag}")
    etag_file.write(updated_etag)

inky = auto(ask_user=True, verbose=True)
saturation = 0.5
image = Image.open(image_filepath)
resizedimage = image.resize(inky.resolution)

if len(sys.argv) > 2:
    saturation = float(sys.argv[2])

inky.set_image(resizedimage, saturation=saturation)
inky.show()