urlcache: Support HTTP proxy

In some corners of the world, you will experience connection problems installing Asahi Linux
without a proxy. This adds basic HTTP proxy support to urlcache.py, honoring proxy settings
from environment variables.

Signed-off-by: Yunhao Tian <t123yh@outlook.com>

src/urlcache.py

@@ -50,9 +50,25 @@ def get_con(self):
  host, port = self.url.netloc, None
 
  if self.url.scheme == "http":
- self.con = HTTPConnection(host, port, timeout=self.TIMEOUT)
+ http_proxy = os.getenv('HTTP_PROXY') or os.getenv('http_proxy')
+ if http_proxy:
+ proxy_url = parse.urlparse(http_proxy)
+ if proxy_url.scheme != "http":
+ raise Exception(f"Unsupported scheme '{proxy_url.scheme}' for http proxy; only http proxy is supported.")
+ self.con = HTTPConnection(proxy_url.hostname, proxy_url.port or 80, timeout=self.TIMEOUT)
+ self.con.set_tunnel(host, port)
+ else:
+ self.con = HTTPConnection(host, port, timeout=self.TIMEOUT)
  elif self.url.scheme == "https":
- self.con = HTTPSConnection(host, port, timeout=self.TIMEOUT)
+ https_proxy = os.getenv('HTTPS_PROXY') or os.getenv('https_proxy')
+ if https_proxy:
+ proxy_url = parse.urlparse(https_proxy)
+ if proxy_url.scheme != "http":
+ raise Exception(f"Unsupported scheme '{proxy_url.scheme}' for https proxy; only http proxy is supported.")
+ self.con = HTTPSConnection(proxy_url.hostname, proxy_url.port or 80, timeout=self.TIMEOUT)
+ self.con.set_tunnel(host, port)
+ else:
+ self.con = HTTPSConnection(host, port, timeout=self.TIMEOUT)
  else:
  raise Exception(f"Unsupported scheme {self.url.scheme}")