Programming Forums > Script Programming > Python

Infinite Recursion · Sep 28th, 2005, 2:57 PM

I have a Python program (listed below) that monitors a specific port... I want to reduce the time it takes to see if the port is listening. I only want to allow 10 seconds max and if it can't connect, I wan't it to be deemed offline. Could one of you Python wizards point me to the block where I need to set the delay on the thread and/or socket to do this?

(Toggle Plain Text)

import socket as sk
import sys
import threading
MAX_THREADS = 2
def usage():
	print "\nDaemon Status Utility 0.1"
	print "usage: updcheck.py <host> [start port] [end port]"
	
class Scanner(threading.Thread):
	def __init__(self, host, port):
		threading.Thread.__init__(self)
		# host and port
		self.host = host
		self.port = port
		# build up the socket obj
		self.sd = sk.socket(sk.AF_INET, sk.SOCK_STREAM)
	def run(self):
		try:
			# connect to the given host:port
			self.sd.connect((self.host, self.port))
			
			print "%s:%d ONLINE" % (self.host, self.port)
			self.sd.close()
		except: #pass
			print "%s:%d OFFLINE" % (self.host, self.port)
class pyScan:
	def __init__(self, args=[]):
		# arguments vector
		self.args = args
		# start port and end port
		self.start, self.stop = 1, 1024
		# host name
		self.host = ""
		# check the arguments
		if len(self.args) == 4:
			self.host = self.args[1]
			try:
				self.start = int(self.args[2])
				self.stop = int(self.args[3])
			except ValueError:
				usage()
				return
			if self.start > self.stop:
				usage()
				return
		elif len(self.args) == 2:
			self.host = self.args[1]
		else:
			usage()
			return
		try:
			sk.gethostbyname(self.host)
		except:
			print "hostname '%s' unknown" % self.host
		self.scan(self.host, self.start, self.stop)
	def scan(self, host, start, stop):
		self.port = start
		while self.port <= stop:
			while threading.activeCount() < MAX_THREADS:
				#print "Threading Active Count: %d" % (threading.activeCount())
				Scanner(host, self.port).start()
				#print "Start: %d  Stop: %d" %  (start, stop)
			   self.port += 1
		   
if __name__ == "__main__":
	pyScan(sys.argv)

Sane · Sep 28th, 2005, 5:38 PM

You could figure out how many seconds the port scan takes. Divide that in to 10, and set a recursion limit for that number under the "except:" in run().

(Toggle Plain Text)

		try:
			# connect to the given host:port
			self.sd.connect((self.host, self.port))
			
			print "%s:%d ONLINE" % (self.host, self.port)
			self.sd.close()
		except: #pass
			self.recurse += 1
			if self.recurse < self.limit: self.run()
			else:print "%s:%d OFFLINE" % (self.host, self.port)

Any other way will just require more imports. Like importing the win32api, and timing the execution from line a until b-a >= 10 (in the same manner as my recursive example). Same goes to "timeit".

Cerulean · Sep 29th, 2005, 10:55 AM

Quote:

Originally Posted by Sane

You could figure out how many seconds the port scan takes. Divide that in to 10, and set a recursion limit for that number under the "except:" in run().

That doesn't make much sense to me, and its not very clear exactly what your code is doing (please write what kind of error you're excepting, as i've mentioned many other times - it makes that part of your code much more readable)

As for setting a timeout, read the socket object documentation. The method 'settimeout' in particular ;-)

Sane · Sep 29th, 2005, 1:07 PM

Look at his code. I took his exact code that uses try and except to figure out if the port is online or offline. Then in the place where it decides if it's offline, I set a recursion limit. I only added one line of code... and it's quite simple to understand, it's all right there.

Cerulean · Sep 29th, 2005, 4:53 PM

Yeah, the part about the except wasn't directed at you

I think you read the question wrong though. I read it as though (s)he's trying to connect to different computers. The connect call blocks while it waits to see if it has connected to the other side correctly - he wants to set how long the socket object will wait until it raises the exception to say it could not connect correctly.

Sane · Sep 29th, 2005, 5:08 PM

Yeah. So under the location of the exception, you call the function again unless the time > 10 seconds, exactly as I did.

=S

Infinite Recursion · Sep 29th, 2005, 5:26 PM

The code is actually not mine either, I copied it from some script site that had it listed as a port scanner and made slight modifications to fit my particular needs... the exception handler not referencing the type of exception was like that when I got it. I was concerned about the core elements first

I wrote the program in Perl, if anyone is interested... I will try also what you guys suggest to get this Python program off the ground... just because I don't like broken code. Thanks for the help.

Infinite Recursion · Sep 29th, 2005, 5:32 PM

AttributeError: 'Scanner' object has no attribute 'recurse'
line referenced: self.recurse += 1

Trace back pointing too line 442 in __bootstrap self.run()

Looking into the other suggestion now

Sane · Sep 29th, 2005, 6:52 PM

Yeah ...

You have to declare self.recurse first. rofl (Sorry, I thought you knew that).

Same goes to self.limit.

self.recurse is declared as 0 before the run function takes place, and is reset to 0 once a solution has been reached.

selt.limit will be a constant for how many times you want it to test the port.

dannyp · Oct 3rd, 2005, 2:11 PM

Check out the Timeoutsocket module.

It's easy as:

[PHP]
import timeoutsocket

mysocket.set_timeout(10)

[/PHP]

www.steffensiebert.de/soft/python/timeoutsocket.py

Sep 28th, 2005, 2:57 PM	#1
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,467 Rep Power: 8	Threads \| Sockets in Python I have a Python program (listed below) that monitors a specific port... I want to reduce the time it takes to see if the port is listening. I only want to allow 10 seconds max and if it can't connect, I wan't it to be deemed offline. Could one of you Python wizards point me to the block where I need to set the delay on the thread and/or socket to do this? (Toggle Plain Text) import socket as sk import sys import threading MAX_THREADS = 2 def usage(): print "\nDaemon Status Utility 0.1" print "usage: updcheck.py <host> [start port] [end port]" class Scanner(threading.Thread): def __init__(self, host, port): threading.Thread.__init__(self) # host and port self.host = host self.port = port # build up the socket obj self.sd = sk.socket(sk.AF_INET, sk.SOCK_STREAM) def run(self): try: # connect to the given host:port self.sd.connect((self.host, self.port)) print "%s:%d ONLINE" % (self.host, self.port) self.sd.close() except: #pass print "%s:%d OFFLINE" % (self.host, self.port) class pyScan: def __init__(self, args=[]): # arguments vector self.args = args # start port and end port self.start, self.stop = 1, 1024 # host name self.host = "" # check the arguments if len(self.args) == 4: self.host = self.args[1] try: self.start = int(self.args[2]) self.stop = int(self.args[3]) except ValueError: usage() return if self.start > self.stop: usage() return elif len(self.args) == 2: self.host = self.args[1] else: usage() return try: sk.gethostbyname(self.host) except: print "hostname '%s' unknown" % self.host self.scan(self.host, self.start, self.stop) def scan(self, host, start, stop): self.port = start while self.port <= stop: while threading.activeCount() < MAX_THREADS: #print "Threading Active Count: %d" % (threading.activeCount()) Scanner(host, self.port).start() #print "Start: %d Stop: %d" % (start, stop) self.port += 1 if __name__ == "__main__": pyScan(sys.argv) import socket as sk import sys import threading MAX_THREADS = 2 def usage(): print "\nDaemon Status Utility 0.1" print "usage: updcheck.py <host> [start port] [end port]" class Scanner(threading.Thread): def __init__(self, host, port): threading.Thread.__init__(self) # host and port self.host = host self.port = port # build up the socket obj self.sd = sk.socket(sk.AF_INET, sk.SOCK_STREAM) def run(self): try: # connect to the given host:port self.sd.connect((self.host, self.port)) print "%s:%d ONLINE" % (self.host, self.port) self.sd.close() except: #pass print "%s:%d OFFLINE" % (self.host, self.port) class pyScan: def __init__(self, args=[]): # arguments vector self.args = args # start port and end port self.start, self.stop = 1, 1024 # host name self.host = "" # check the arguments if len(self.args) == 4: self.host = self.args[1] try: self.start = int(self.args[2]) self.stop = int(self.args[3]) except ValueError: usage() return if self.start > self.stop: usage() return elif len(self.args) == 2: self.host = self.args[1] else: usage() return try: sk.gethostbyname(self.host) except: print "hostname '%s' unknown" % self.host self.scan(self.host, self.start, self.stop) def scan(self, host, start, stop): self.port = start while self.port <= stop: while threading.activeCount() < MAX_THREADS: #print "Threading Active Count: %d" % (threading.activeCount()) Scanner(host, self.port).start() #print "Start: %d Stop: %d" % (start, stop) self.port += 1 if __name__ == "__main__": pyScan(sys.argv) __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Sep 28th, 2005, 5:38 PM	#2
Sane Programming Guru Join Date: Apr 2005 Location: Waterloo, Ontario Posts: 1,868 Rep Power: 5	You could figure out how many seconds the port scan takes. Divide that in to 10, and set a recursion limit for that number under the "except:" in run(). (Toggle Plain Text) try: # connect to the given host:port self.sd.connect((self.host, self.port)) print "%s:%d ONLINE" % (self.host, self.port) self.sd.close() except: #pass self.recurse += 1 if self.recurse < self.limit: self.run() else:print "%s:%d OFFLINE" % (self.host, self.port) try: # connect to the given host:port self.sd.connect((self.host, self.port)) print "%s:%d ONLINE" % (self.host, self.port) self.sd.close() except: #pass self.recurse += 1 if self.recurse < self.limit: self.run() else:print "%s:%d OFFLINE" % (self.host, self.port) Any other way will just require more imports. Like importing the win32api, and timing the execution from line a until b-a >= 10 (in the same manner as my recursive example). Same goes to "timeit".

Sep 29th, 2005, 5:26 PM	#7
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,467 Rep Power: 8	The code is actually not mine either, I copied it from some script site that had it listed as a port scanner and made slight modifications to fit my particular needs... the exception handler not referencing the type of exception was like that when I got it. I was concerned about the core elements first I wrote the program in Perl, if anyone is interested... I will try also what you guys suggest to get this Python program off the ground... just because I don't like broken code. Thanks for the help. __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Sep 29th, 2005, 5:32 PM	#8
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,467 Rep Power: 8	AttributeError: 'Scanner' object has no attribute 'recurse' line referenced: self.recurse += 1 Trace back pointing too line 442 in __bootstrap self.run() Looking into the other suggestion now __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Oct 3rd, 2005, 2:11 PM	#10
dannyp Newbie Join Date: Jul 2005 Location: Philadelphia, PA Posts: 11 Rep Power: 0	Check out the Timeoutsocket module. It's easy as: [PHP] import timeoutsocket mysocket.set_timeout(10) [/PHP] www.steffensiebert.de/soft/python/timeoutsocket.py Last edited by dannyp; Oct 3rd, 2005 at 2:24 PM.

Sep 29th, 2005, 1:07 PM	#4
Sane Programming Guru Join Date: Apr 2005 Location: Waterloo, Ontario Posts: 1,868 Rep Power: 5	Look at his code. I took his exact code that uses try and except to figure out if the port is online or offline. Then in the place where it decides if it's offline, I set a recursion limit. I only added one line of code... and it's quite simple to understand, it's all right there.

Sep 29th, 2005, 4:53 PM	#5
Cerulean Professional Programmer Join Date: Apr 2005 Location: London, England Posts: 459 Rep Power: 4	Yeah, the part about the except wasn't directed at you I think you read the question wrong though. I read it as though (s)he's trying to connect to different computers. The connect call blocks while it waits to see if it has connected to the other side correctly - he wants to set how long the socket object will wait until it raises the exception to say it could not connect correctly.

Sep 29th, 2005, 5:08 PM	#6
Sane Programming Guru Join Date: Apr 2005 Location: Waterloo, Ontario Posts: 1,868 Rep Power: 5	Yeah. So under the location of the exception, you call the function again unless the time > 10 seconds, exactly as I did. =S

Sep 29th, 2005, 6:52 PM	#9
Sane Programming Guru Join Date: Apr 2005 Location: Waterloo, Ontario Posts: 1,868 Rep Power: 5	Yeah ... You have to declare self.recurse first. rofl (Sorry, I thought you knew that). Same goes to self.limit. self.recurse is declared as 0 before the run function takes place, and is reset to 0 once a solution has been reached. selt.limit will be a constant for how many times you want it to test the port.

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