This question will expand on: Best way to open a socket in Python
When opening a socket how can I test to see if it has been established, and that it did not timeout, or generally fail.
Edit: I tried this:
try: s.connect((address, '80')) except: alert('failed' + address, 'down') but the alert function is called even when that connection should have worked.
It seems that you catch not the exception you wanna catch out there :)
if the s is a socket.socket() object, then the right way to call .connect would be:
import socket s = socket.socket() address = '127.0.0.1' port = 80 # port number is a number, not string try: s.connect((address, port)) # originally, it was # except Exception, e: # but this syntax is not supported anymore. except Exception as e: print("something's wrong with %s:%d. Exception is %s" % (address, port, e)) finally: s.close() Always try to see what kind of exception is what you're catching in a try-except loop.
You can check what types of exceptions in a socket module represent what kind of errors (timeout, unable to resolve address, etc) and make separate except statement for each one of them - this way you'll be able to react differently for different kind of problems.
You can use the function connect_ex. It doesn't throw an exception. Instead of that, returns a C style integer value (referred to as errno in C):
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) result = s.connect_ex((host, port)) s.close() if result: print "problem with socket!" else: print "everything it's ok!" You should really post:
Here is my code, which works:
import socket, sys def alert(msg): print >>sys.stderr, msg sys.exit(1) (family, socktype, proto, garbage, address) = \ socket.getaddrinfo("::1", "http")[0] # Use only the first tuple s = socket.socket(family, socktype, proto) try: s.connect(address) except Exception, e: alert("Something's wrong with %s. Exception type is %s" % (address, e)) When the server listens, I get nothing (this is normal), when it doesn't, I get the expected message:
Something's wrong with ('::1', 80, 0, 0). Exception type is (111, 'Connection refused')