portable python

[Marc 'BlackJack' Rintsch]

On Fri, 24 Oct 2008 10:42:21 -0700, asit wrote:

> I code in both windows and Linux. As python is portable, the o/p should
> be same in both cases. But why the following code is perfect in windows
> but error one   in Linux ???

So what *is* the error on Linux!?

> def scan(ip,port,timeout):
>         s = socket(AF_INET, SOCK_STREAM)
>         s.settimeout(timeout)
>         try:
>             result= s.connect_ex((ip, port))
>         except:
>             print "Cannot connect to IP"
>             return
>         s.close()
>         return status[result]

The bare ``except`` catches *all* errors in the ``try`` block, even those 
you might know about because they don't belong to the set of exceptions 
you expected.  Like `NameError`, `MemoryError`, `KeyboardInterrupt`, …

And the function can return two quite different types…

> if (len(sys.argv) == 4):
>         ip=sys.argv[1]
>         minrange = int(sys.argv[2])
>         maxrange = int(sys.argv[3])
>         timeout = 3
> 
>         ports=range(minrange,maxrange+1)
> 
>         for port in ports:
>                 print str(port) + " : " + scan(ip,port,timeout)

…one of which is `None` and that will blow up here, regardless of 
platform.

In [18]: " : " + None
---------------------------------------------------------------------------
<type 'exceptions.TypeError'>             Traceback (most recent call 
last)

/home/bj/<ipython console> in <module>()

<type 'exceptions.TypeError'>: cannot concatenate 'str' and 'NoneType' 
objects

Ciao,
	Marc 'BlackJack' Rintsch