Twisted TCP Server Example
Twisted is a Python based framework for networking. It does what a framework should accomplish and take a good deal of the muck (labor) out of creating a network connectivity for applications. I am fantastically excited about this framework.
Within a few minutes of reading the Twisted how-to tutorials for getting started with creating a simple TCP server I had the response page serving correctly on my local machine.
Twisted installed on my Mac running Mac OS X 10.5.2 Leopard without a single warning. This is notable only because A.) I’m a moron, normally needing to use the gcc equivalent of a crowbar to wedge software into my development system, and B.) Once again I find that Leopard’s pre-installed open-source software meets the minimal requirements for additional software so I can avoid dependence hell once again. FANTASTIC!
Below I have the Python script posted for the TCP server which follows the Twisted example for the most part. This service will respond with a predefined HTML statement to a request made to port 8007. The response doesn’t need to be as drab (stable) as HTML. The self.transport.write can be altered to what is needed for your application.
Everything a language/computer/technology should do is work and get out of the way so that the task it is created or used for can be accomplished without out too much of that muck. Since everything is just a more complex version of simple pieces, like binary code or even DNA, incredible possibilities are possible once the simple piece can be created.
This is why I like Twisted. It was simple to implement and in some respects has gotten out of the way and allowed my mind to begin wondering past the “first response” and on to further tasks such as “what this should do”.
#!/usr/bin/python
greeting = """
HELLO WORLD!
This is a TCP/IP Server written in Python using
the Twisted networking framework.
It will respond on port 8007 of the local host
With a predefined greeting.
"""
print greeting
from twisted.internet.protocol import Protocol, Factory
from twisted.internet import reactor
class QOTD(Protocol):
def connectionMade(self):
self.transport.write("""
<!DOCTYPE html PUBLIC>
<html>
<head>
<title>Twisted TCP Server Example</title>
</head>
<body>
<h1>HELLO WORLD!</h1>
<pre>
This is a TCP/IP Server written in Python using
the Twisted networking framework.
Further instruction can be found here:
<a href="http://twistedmatrix.com/projects/core/documentation/howto/servers.html">
Twisted Documentation: Writing Servers
</a>
This server will respond on port 8007 of the local host
With a predefined greeting.
</pre>
</body>
</html>""")
self.transport.loseConnection()
# Then lines are Twisted magic:
factory = Factory()
factory.protocol = QOTD
# Running under :8007
# Should be > :1024
reactor.listenTCP(8007, factory)
reactor.run()
Take away
Twisted is an amazing, simple to use, light weight Python based networking framework. Anyone interested in building applications that require networking connectivity should take a look at this project.
Open Directory and .htpasswd
Fascinating! I worked on a project* once that involved a complete rewrite of the command-line utility passwd in order to keep a number of system services including a .htpasswd file in sync with users account passwords. Mac OS X Hints noted this is made simple with Mac OS X Leopard (10.5) and Open Directory.
Virtualized Xserver
Media Temple labs has a private beta for what it’s calling Xserve-Virtual . This system has been added quickly added to my MT wish list along with the Django GridContainer which, perhaps I wont need if I move over to a full-on-mirror of my development environment using a virtual OS X Server.
A virtual Mac OS X Leopard Server running on a fully loaded cluster of Xserves virtualized using Parallels Server . I want one, … or three, … yeah that should be enough …. maybe four, for symmetry.
Fedora 9 root password mismatch resolution
Having started my journey down the command-line with Fedora 3, I was excited to try out Fedora 9. The install completed with ease (the first time around) but once I logged onto the system and attempted to configure some of the system settings, my root password didn’t work.
Why? CAPS LOCK bit was set by default during the install process making a different root password.