"""Local-only browser cache lab. Uses memory, not project files or remote services."""
from http.server import BaseHTTPRequestHandler, HTTPServer
import json
from urllib.parse import parse_qs, urlsplit
class Demo(BaseHTTPRequestHandler):
updated = False
css_requests = 0
def log_message(self, *args):
pass
def reply(self, body, content_type, cache="no-store"):
body = body.encode("utf-8")
self.send_response(200)
self.send_header("Content-Type", content_type)
self.send_header("Cache-Control", cache)
self.send_header("Content-Length", str(len(body)))
self.end_headers()
self.wfile.write(body)
def do_GET(self):
path = urlsplit(self.path)
if path.path == "/style.css":
Demo.css_requests += 1
color = "#167349" if Demo.updated else "#a32635"
label = "UPDATED CSS" if Demo.updated else "INITIAL CSS"
self.reply(
'.sample{border-left:6px solid ' + color + ';padding:24px;background:#f4f5f6}'
'.sample::after{content:"' + label + '";display:block;color:' + color
+ ';font-size:24px;font-weight:700;margin-top:16px}',
"text/css; charset=utf-8", "max-age=3600",
)
elif path.path == "/state":
self.reply(json.dumps({"updated": Demo.updated, "css_requests": Demo.css_requests}),
"application/json")
elif path.path == "/":
version = "2" if parse_qs(path.query).get("v") == ["2"] else "1"
self.reply('''
CSS Cache Lab
CSS Cache Lab
HTML stylesheet URL: /style.css?v=''' + version + '''
Browser-applied stylesheet
-
- Open another page with the same CSS URL
- Open a page with a new CSS URL
Only this local demo changes. Stop with Ctrl+C; restart for a fresh server.
''', "text/html; charset=utf-8")
else:
self.send_error(404)
def do_POST(self):
if self.path != "/update":
self.send_error(404)
return
Demo.updated = True
self.reply('{"updated":true}', "application/json")
if __name__ == "__main__":
with HTTPServer(("127.0.0.1", 0), Demo) as server:
print("Open http://127.0.0.1:" + str(server.server_port) + "/", flush=True)
print("Local cache lab only. Stop with Ctrl+C.", flush=True)
try:
server.serve_forever()
except KeyboardInterrupt:
pass