From 7c330e71fa5baef836dddb6b7157756f1d69be88 Mon Sep 17 00:00:00 2001
From: Andrew Godwin <andrew@aeracode.org>
Date: Mon, 4 Apr 2016 00:29:05 +0200
Subject: [PATCH] Add basic access logging (enabled by default to stdout)

---
 daphne/access.py | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
 daphne/cli.py    | 13 ++++++++++++
 2 files changed, 67 insertions(+)
 create mode 100644 daphne/access.py

diff --git a/daphne/access.py b/daphne/access.py
new file mode 100644
index 0000000..a3508ea
--- /dev/null
+++ b/daphne/access.py
@@ -0,0 +1,54 @@
+import datetime
+
+
+class AccessLogGenerator(object):
+    """
+    Object that implements the Daphne "action logger" internal interface in
+    order to provide an access log in something resembling NCSA format.
+    """
+
+    def __init__(self, stream):
+        self.stream = stream
+
+    def __call__(self, protocol, action, details):
+        """
+        Called when an action happens; use it to generate log entries.
+        """
+        # HTTP requests
+        if protocol == "http" and action == "complete":
+            self.write_entry(
+                host=details['client'],
+                date=datetime.datetime.now(),
+                request="%(method)s %(path)s" % details,
+                status=details['status'],
+            )
+        # Websocket requests
+        elif protocol == "websocket" and action == "connected":
+            self.write_entry(
+                host=details['client'],
+                date=datetime.datetime.now(),
+                request="WSCONNECT %(path)s" % details,
+            )
+        elif protocol == "websocket" and action == "disconnected":
+            self.write_entry(
+                host=details['client'],
+                date=datetime.datetime.now(),
+                request="WSDISCONNECT %(path)s" % details,
+            )
+
+    def write_entry(self, host, date, request, status=None, length=None, ident=None, user=None):
+        """
+        Writes an NCSA-style entry to the log file (some liberty is taken with
+        what the entries are for non-HTTP)
+        """
+        self.stream.write(
+            "%s %s %s [%s] \"%s\" %s %s\n" % (
+                host,
+                ident or "-",
+                user or "-",
+                date.strftime("%d/%b/%Y:%H:%M:%S"),
+                request,
+                status or "-",
+                length or "-",
+            )
+        )
diff --git a/daphne/cli.py b/daphne/cli.py
index 543c274..06762e1 100755
--- a/daphne/cli.py
+++ b/daphne/cli.py
@@ -3,6 +3,7 @@ import argparse
 import logging
 import importlib
 from .server import Server
+from .access import AccessLogGenerator
 
 
 logger = logging.getLogger(__name__)
@@ -54,6 +55,11 @@ class CommandLineInterface(object):
             help='How long to wait for worker server before timing out HTTP connections',
             default=120,
         )
+        self.parser.add_argument(
+            '--access-log',
+            help='Where to write the access log (- for stdout, the default for verbosity=1)',
+            default=None,
+        )
         self.parser.add_argument(
             '--ping-interval',
             type=int,
@@ -88,6 +94,12 @@ class CommandLineInterface(object):
             }[args.verbosity],
             format = "%(asctime)-15s %(levelname)-8s %(message)s" ,
         )
+        # If verbosity is 1 or greater, or they told us explicitly, set up access log
+        access_log_stream = None
+        if args.access_log:
+            access_log_stream = open(args.access_log, "a")
+        elif args.verbosity >= 1:
+            access_log_stream = sys.stdout
         # Import channel layer
         sys.path.insert(0, ".")
         module_path, object_path = args.channel_layer.split(":", 1)
@@ -107,4 +119,5 @@ class CommandLineInterface(object):
             unix_socket=args.unix_socket,
             http_timeout=args.http_timeout,
             ping_interval=args.ping_interval,
+            action_logger=AccessLogGenerator(access_log_stream) if access_log_stream else None,
         ).run()