server: Check provided temperatures for validity

Temperatures should be floats otherwise fail.

django/server/views.py

@@ -321,13 +321,17 @@ def _get_temperatures():
             if room.temp_hosts == '':
                 temperatures[room.name] = 'N/A'
             else:
-                temps = []
-                for thost in room.temp_hosts.split(','):
-                    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-                    s.settimeout(1)
-                    s.connect((thost + '.cs.fau.de', 16842))
-                    temps.append(s.recv(1024).decode().strip())
-                temperatures[room.name] = '/'.join(temps)
+                try:
+                    temps = []
+                    for thost in room.temp_hosts.split(','):
+                        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+                        s.settimeout(1)
+                        s.connect((thost + '.cs.fau.de', 16842))
+                        temps.append(round(float(s.recv(1024).decode().strip()), 1))
+                    temperatures[room.name] = '/'.join([str(x) for x in temps])
+                except Exception as e:
+                    temperatures[room.name] = 'N/A'
+
             cache.set('temp_' + room.name, temperatures[room.name], 10)
 
     return temperatures