davidbgk
/
larlet-fr-david

#!/usr/bin/python3
import cgi
import cgitb
import os
import subprocess
import urllib.request

cgitb.enable()
form = cgi.FieldStorage()
source = form.getvalue("source", None)
target = form.getvalue("target", None)
server = os.environ.get("SERVER_NAME", None)
method = os.environ.get("REQUEST_METHOD", "GET")


def validate(source, target, server, method):
    status = 400
    if method != "POST":
        message = "Webmention MUST be performed through a POST request."
    elif source is None or target is None:
        message = "Please fill in the source and target fields."
    elif "://" not in source or "://" not in target:
        message = "Source and target fields should be URLs."
    elif not target.split("://", 1)[1].startswith(server):
        message = "Target should be a link to this domain: {0}".format(server)
    elif target not in urllib.request.urlopen(source).read().decode("utf-8"):
        message = "Source should have a link to the target: {0}".format(target)
    else:
        message = (
            "Success! With source={source} and target={target}."
            '<a href="{target}">Back to the target article</a>.'
        ).format(
            source=source,
            target=target,
        )
        status = 202
    return status, message, source, target


def send_response(callback, status, message, source, target):
    print("Content-type: text/html")
    print("Status: {0}".format(status))
    print()
    print(
        """<!doctype html><html lang=en>
    <head><meta charset=utf-8><title>Webmention</title></head>
    <body><p>{message}</p></body></html>""".format(
            message=message
        )
    )
    if status == 202:
        callback(source, target)


def on_valid_submission(source, target):
    commands = [
        "cd /home/larlet/www",
        "source /home/larlet/.virtualenvs/webmention/bin/activate",
        "fab --hide=everything add_webmention:{source},{target}".format(
            source=source,
            target=target,
        ),
    ]
    subprocess.call(" && ".join(commands), shell=True)


send_response(on_valid_submission, *validate(source, target, server, method))