Polishing up the twisted interface

jetforce.py

@@ -57,6 +57,7 @@ from cryptography.hazmat.primitives import hashes, serialization
 from cryptography.hazmat.primitives.asymmetric import rsa
 from OpenSSL import SSL
 from twisted.internet import reactor
+from twisted.internet.address import IPv4Address, IPv6Address
 from twisted.internet.base import ReactorBase
 from twisted.internet.endpoints import SSL4ServerEndpoint
 from twisted.internet.protocol import Factory
@@ -626,6 +627,8 @@ class GeminiProtocol(LineOnlyReceiver):
 
     TIMESTAMP_FORMAT = "%d/%b/%Y:%H:%M:%S %z"
 
+    client_addr: typing.Union[IPv4Address, IPv6Address]
+    client_cert: typing.Optional[x509.Certificate]
     connected_timestamp: time.struct_time
     request: bytes
     url: str
@@ -645,6 +648,12 @@ class GeminiProtocol(LineOnlyReceiver):
         self.connected_timestamp = time.localtime()
         self.response_size = 0
         self.response_buffer = ""
+        self.client_addr = self.transport.getPeer()
+        self.client_cert = None
+
+        peer_cert = self.transport.getPeerCertificate()
+        if peer_cert:
+            self.client_cert = peer_cert.to_cryptography()
 
     def lineReceived(self, line):
         """
@@ -656,25 +665,19 @@ class GeminiProtocol(LineOnlyReceiver):
         """
         self.request = line
         try:
-            try:
-                self.handle()
+            self.handle_request()
         finally:
-                self.flush_status()
-                try:
             self.log_request()
-                except Exception:
-                    # Malformed request or dropped connection
-                    pass
-        finally:
             self.transport.loseConnection()
 
-    def handle(self):
+    def handle_request(self):
         try:
             self.parse_header()
         except Exception:
             # Malformed request, throw it away and exit immediately
             self.write_status(Status.BAD_REQUEST, "Malformed request")
-            return
+            self.flush_status()
+            raise
 
         try:
             environ = self.build_environ()
@@ -683,6 +686,9 @@ class GeminiProtocol(LineOnlyReceiver):
                 self.write_body(data)
         except Exception:
             self.write_status(Status.CGI_ERROR, "An unexpected error occurred")
+            raise
+        finally:
+            self.flush_status()
 
     def build_environ(self) -> typing.Dict[str, typing.Any]:
         """
@@ -691,25 +697,22 @@ class GeminiProtocol(LineOnlyReceiver):
         Variable names conform to the CGI spec defined in RFC 3875.
         """
         url_parts = urllib.parse.urlparse(self.url)
-        client_addr = self.transport.getPeer()
         environ = {
             "GEMINI_URL": self.url,
             "HOSTNAME": self.server.hostname,
             "PATH_INFO": url_parts.path,
             "QUERY_STRING": url_parts.query,
-            "REMOTE_ADDR": client_addr.host,
-            "REMOTE_HOST": client_addr.host,
+            "REMOTE_ADDR": self.client_addr.host,
+            "REMOTE_HOST": self.client_addr.host,
             "SERVER_NAME": self.server.hostname,
-            "SERVER_PORT": str(client_addr.port),
+            "SERVER_PORT": str(self.client_addr.port),
             "SERVER_PROTOCOL": "GEMINI",
             "SERVER_SOFTWARE": f"jetforce/{__version__}",
         }
-
-        openssl_cert = self.transport.getPeerCertificate()
-        if openssl_cert:
+        if self.client_cert:
             # Extract useful information from the client certificate. These
             # mostly follow the naming convention from GLV-1.12556
-            cert = openssl_cert.to_cryptography()
+            cert = self.client_cert
             name_attrs = cert.subject.get_attributes_for_oid(CN)
             common_name = name_attrs[0].value if name_attrs else ""
             fingerprint_bytes = cert.fingerprint(hashes.SHA256())
@@ -726,7 +729,6 @@ class GeminiProtocol(LineOnlyReceiver):
                     "TLS_CLIENT_SERIAL_NUMBER": cert.serial_number,
                 }
             )
-
         return environ
 
     def parse_header(self) -> None:
@@ -781,14 +783,19 @@ class GeminiProtocol(LineOnlyReceiver):
         """
         Log a gemini request using a format derived from the Common Log Format.
         """
+        try:
             message = '{} [{}] "{}" {} {} {}'.format(
-            self.transport.getPeer().host,
+                self.client_addr.host,
                 time.strftime(self.TIMESTAMP_FORMAT, self.connected_timestamp),
                 self.url,
                 self.status,
                 self.meta,
                 self.response_size,
             )
+        except AttributeError:
+            # The connection ended before we got far enough to log anything
+            pass
+        else:
             self.server.log_message(message)
 
 
@@ -873,13 +880,17 @@ class GeminiServer(Factory):
             cafile=self.cafile,
             capath=self.capath,
         )
+
+        interfaces = [self.host] if self.host else ["0.0.0.0", "::"]
+        for interface in interfaces:
             endpoint = self.endpoint_class(
                 reactor=self.reactor,
                 port=self.port,
                 sslContextFactory=tls_context_factory,
-            interface=self.host,
+                interface=interface,
             )
             endpoint.listen(self).addCallback(self.on_bind_interface)
+
         self.reactor.run()