stale-echo-client-hints.py

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import random

import string

from wptserve.utils import isomorphic_encode

import importlib

client_hints_full_list = importlib.import_module("client-hints.resources.clienthintslist").client_hints_full_list

def id_token():

   letters = string.ascii_lowercase

   return u''.join(random.choice(letters) for i in range(20))

def main(request, response):

    client_hint_headers = client_hints_full_list()

    client_hints_curr = {i:request.headers.get(i) for i in client_hint_headers}

    token = request.GET.first(b"token", None)

    is_query = request.GET.first(b"query", None) is not None

    with request.server.stash.lock:

      stash = request.server.stash.take(token)

      if stash != None:

        (value, client_hints_prev) = stash

        count = int(value)

      else:

        count = 0

        client_hints_prev = {}

      if is_query:

        if count < 2:

          request.server.stash.put(token, (count, client_hints_curr))

      else:

        count = count + 1

        request.server.stash.put(token, (count, client_hints_curr))

    for header in client_hint_headers:

      if client_hints_curr[header] is not None:

        response.headers.set(header+b"-recieved", client_hints_curr[header])

      if (header in client_hints_prev) and (client_hints_prev[header] is not None):

        response.headers.set(header+b"-previous", client_hints_prev[header])

    if is_query:

      headers = [(b"Count", count)]

      content = u""

      return 200, headers, content

    else:

      unique_id = id_token()

      headers = [(b"Content-Type", b"text/html"),

                 (b"Cache-Control", b"private, max-age=0, stale-while-revalidate=60"),

                 (b"Unique-Id", isomorphic_encode(unique_id))]

      content = u"report('{}')".format(unique_id)

      return 200, headers, content