Fix port checking code preventing startup directly after a SG restart

CHANGES.md

@@ -25,6 +25,7 @@
 * Overhaul all Add Show pages
 * Fix Display Show next/previous when show list is split
 * Change Display Show next/previous when show list is not split to loop around
+* Fix port checking code preventing startup directly after a SG restart
 
 [develop changelog]
 * Add TVRage network name standardization

SickBeard.py

@@ -330,13 +330,11 @@ class SickGear(object):
         # start web server
         try:
             # used to check if existing SG instances have been started
-            s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-            s.bind((self.web_options['host'], self.web_options['port']))
-            s.close()
+            sickbeard.helpers.wait_for_free_port(self.web_options['host'], self.web_options['port'])
 
             self.webserver = WebServer(self.web_options)
             self.webserver.start()
-        except IOError:
+        except Exception:
             logger.log(u"Unable to start web server, is something else running on port %d?" % self.startPort,
                        logger.ERROR)
             if sickbeard.LAUNCH_BROWSER and not self.runAsDaemon:

sickbeard/helpers.py

@@ -1428,5 +1428,77 @@ def get_size(start_path='.'):
             total_size += ek.ek(os.path.getsize, fp)
     return total_size
 
+
 def remove_article(text=''):
-    return re.sub(r'(?i)^(?:(?:A(?!\s+to)n?)|The)\s(\w)', r'\1', text)
+    return re.sub(r'(?i)^(?:(?:A(?!\s+to)n?)|The)\s(\w)', r'\1', text)
+
+
+def client_host(server_host):
+    '''Extracted from cherrypy libs
+    Return the host on which a client can connect to the given listener.'''
+    if server_host == '0.0.0.0':
+        # 0.0.0.0 is INADDR_ANY, which should answer on localhost.
+        return '127.0.0.1'
+    if server_host in ('::', '::0', '::0.0.0.0'):
+        # :: is IN6ADDR_ANY, which should answer on localhost.
+        # ::0 and ::0.0.0.0 are non-canonical but common ways to write
+        # IN6ADDR_ANY.
+        return '::1'
+    return server_host
+
+
+def wait_for_free_port(host, port):
+    '''Extracted from cherrypy libs
+    Wait for the specified port to become free (drop requests).'''
+    if not host:
+        raise ValueError("Host values of '' or None are not allowed.")
+    for trial in range(50):
+        try:
+            # we are expecting a free port, so reduce the timeout
+            check_port(host, port, timeout=0.1)
+        except IOError:
+            # Give the old server thread time to free the port.
+            time.sleep(0.1)
+        else:
+            return
+
+    raise IOError("Port %r not free on %r" % (port, host))
+
+
+def check_port(host, port, timeout=1.0):
+    '''Extracted from cherrypy libs
+    Raise an error if the given port is not free on the given host.'''
+    if not host:
+        raise ValueError("Host values of '' or None are not allowed.")
+    host = client_host(host)
+    port = int(port)
+
+    import socket
+
+    # AF_INET or AF_INET6 socket
+    # Get the correct address family for our host (allows IPv6 addresses)
+    try:
+        info = socket.getaddrinfo(host, port, socket.AF_UNSPEC,
+                                  socket.SOCK_STREAM)
+    except socket.gaierror:
+        if ':' in host:
+            info = [(socket.AF_INET6, socket.SOCK_STREAM, 0, "", (host, port, 0, 0))]
+        else:
+            info = [(socket.AF_INET, socket.SOCK_STREAM, 0, "", (host, port))]
+
+    for res in info:
+        af, socktype, proto, canonname, sa = res
+        s = None
+        try:
+            s = socket.socket(af, socktype, proto)
+            # See http://groups.google.com/group/cherrypy-users/
+            #        browse_frm/thread/bbfe5eb39c904fe0
+            s.settimeout(timeout)
+            s.connect((host, port))
+            s.close()
+            raise IOError("Port %s is in use on %s; perhaps the previous "
+                          "httpserver did not shut down properly." %
+                          (repr(port), repr(host)))
+        except socket.error:
+            if s:
+                s.close()