url_summary_refined.py

from urllib.parse import urlparse

url = "https://github.com/capjamesg/indieweb-utils/pulls/1"

def _python_pull_request(path):
    if len(path) > 2 or path[2] != "pulls":
        return "A comment on a pull request in the " + path[1] + " GitHub repository."

def _python_generic_comment(path):
    if len(path) >= 1:
        return "A comment on GitHub project " + path[1] + "."

callbacks = {
    "github.com": [
        _python_pull_request,
        _python_generic_comment
    ]
}

def get_url_summary(url) -> str:
    """
    Retrieve a URL summary for a provided URL.

    :refs: https://indieweb.org/auto-url-summary
    :param url: The URL to summarize.
    :return: A summary of the URL.
    :rtype: str
    """
    parsed_url = urlparse(url)
    domain = parsed_url.netloc
    path = parsed_url.path.split("/")

    path.remove("")

    functions = callbacks[domain]

    for f in functions:
        summary = f(path)

        if summary == None:
            continue

        return summary

print(get_url_summary(url))