Getting started with CherryPy
I mentioned briefly last week that I was getting started with CherryPy and how impressed I was with the ease of the install. I also finally figured out that Ubuntu has a psycopg package (python-psycopg), although I still couldn’t get web.py to work with it.
Here’s a list of the packages that I had to install on my Ubuntu 9.0.4 server to get CherryPy running
apt-get install python
apt-get install python-setuptools
apt-get install flup
apt-get install postgres
apt-get install postgresql postgresql-client postgresql-contrib
apt-get install pgdb
apt-get install postgresql-python
apt-get install python-pygresql
apt-get install gcc
apt-get install g++
apt-get install postgresql-dev
apt-get install libpq-dev
apt-get install python-psycopg
Want to get a “Hello World” example of CherryPy working? It’s incredible easy, especially if you use CherryPy’s built-in webserver (which seems like it’ll handle the sort of loads I’m going to be dealing with).
Here’s the code:
import cherrypy
cherrypy.config.update( {'server.socket_host': '127.0.0.1',
'server.socket_port': 80,
})
class HelloWorld:
def index(self):
return "Hello World"
index.exposed = True
cherrypy.quickstart(HelloWorld())
Then, as root, run the following command to start the built-in webserver (assuming the code above is in the file /var/www/hello.py):
python /var/www/hello.py
If all goes well, you should see something like this:
[16/Jun/2009:21:08:00] ENGINE Listening for SIGHUP.
[16/Jun/2009:21:08:00] ENGINE Listening for SIGTERM.
[16/Jun/2009:21:08:00] ENGINE Listening for SIGUSR1.
[16/Jun/2009:21:08:00] ENGINE Bus STARTING
Go to http://localhost in your browser and you should see the text “Hello World.”
And here’s a quick database example that connects to a PostgreSQL database called testdb with a single table called todo.
CREATE TABLE todo (
id integer NOT NULL,
title text,
created timestamp without time zone DEFAULT now(),
done boolean DEFAULT false
);
INSERT INTO todo (id, title, created, done) VALUES (1, 'Learn CherryPy', '2009-06-15 11:31:38.106307', false);
import cherrypy
import psycopg
import sys
cherrypy.config.update( {'server.socket_host': '10.0.0.4',
'server.socket_port': 80,
})
class HelloWorld:
def index(self):
conn = psycopg.connect('dbname=testdb', 'user=myuser', 'password=mypass')
mark = conn.cursor()
mark.execute('SELECT * FROM todo');
rec = mark.fetchall()
body = ''
for row in rec:
body += str(row)
return body
index.exposed = True
cherrypy.quickstart(HelloWorld())
That’s a very basic intro to CherryPy. The complete documentation has lots of great stuff and I’ll be back to write more about it after I’ve had a chance to write something real.
