CSC/ECE 517 Fall 2014/ch1a 3 zq

CherryPy Framework

CherryPy is a python based, object-oriented web framework that enables developers to quickly create lightweight and fast web applications.<ref>http://www.cherrypy.org/</ref><ref>http://en.wikipedia.org/wiki/CherryPy</ref>

Some of the popular websites using it are Hulu<ref>http://tech.hulu.com/blog/2013/03/13/python-and-hulu/</ref> and Netflix<ref>http://techblog.netflix.com/2013/03/python-at-netflix.html</ref>. The full list of applications using it can be found here.<ref>http://docs.cherrypy.org/en/latest/intro.html#websites-running-atop-cherrypy</ref>

Basic Example

The following code demonstrates the most basic webserver using the CherryPy framework.

import cherrypy

class WebApp(object):
    @cherrypy.expose
    def index(self):
        return "Hello, CherryPy!"
   
cherrypy.quickstart(WebApp())

Run the application, and open your web browser to localhost:8080. The following page is displayed

Features

Logging

CherryPy provides the following method for application logging

cherrypy.log("Hello, CherryPy!")

By default, all logging is written to the console. The configuration keys log.access_file and log.error_file are also available for writing logging and errors to a text file.

Query Strings

CherryPy will automatically parse the query string of a URL. Fields are passed as method arguments with matching names, and can take advantage of default argument values.

import cherrypy

class WebApp(object):
    @cherrypy.expose
    def test(self, value=1):
        return "Value = " + str(value)
   
cherrypy.quickstart(WebApp())

A URL of localhost:8080/test?value=5 gives the following

Cookies

import cherrypy

class WebApp(object):
    @cherrypy.expose
    def set(self, value = "Test"):
        cookie = cherrypy.response.cookie
        cookie['Value'] = value
        return "Cookie set"
    
    @cherrypy.expose
    def get(self):
        cookie = cherrypy.request.cookie
        return "Cookie value = " + str(cookie['Value'].value)
   
cherrypy.quickstart(WebApp())

References

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