Masthead

URL:: http://www.karrigell.com

version::3.1 (2010-04-25)

licence::BSD revised

platforms::any platform that supports Python 2.3

Python versions::2.3 and above

Deployment Platforms

No requirement besides Python : Karrigell is provided with a web server and a Python database engine (PyDbLite). It can also run behind Apache (CGI mode or mod_python) an any web server that supports proxy mode

Suitability

Web programming with all the usual tasks (session management, cookies, user management, etc)

Development Interfaces

Servlet-style : the scripts, either pure Python or mixing HTML and Python, are executed in a namespace which provides all useful information, including HTTP headers, authentication data, etc. For instance, form fields are available as the REQUEST dictionary, or with a variable available in the namespace

The namespace also provides custom exceptions to stop its execution, such as HTTP_REDIRECTION (see the on-line documentation)

A function Include(script_or_file, **args) allows the inclusion of an html file or of a file inside a script. If script B is included inside script A, it is executed in script A's namespace ; additional **args can be added to this namespace

Environment Access

Standard Python mechanisms : environment data is available in the namespace where scripts are executed

Session, Identification and Authentication

Provided through functions available in scripts

Session() returns a session object, to which attributes can be set (arbitrary Python objects : user login, database connexion and cursor, etc.)

A user management framework allows the site administrator to manage a user database with roles(admin, editor, visitor). In scripts, function Login(role) checks if the user is logged in with the specified role, or redirects to an authentication script ; Role() returns user's role

Persistence Support

Karrigell is provided with the pure-Python PyDbLite database engine. It can be linked to all databases for which there is a Python API (SQLite, MySQL, PostGres, etc)

Presentation Support

• Python scripts, where the "print" statement is used to send output to the client
• "Karrigell services" : Python scripts where functions are mapped to URLs (allows to build a whole site with just one script)

• "Python Inside HTML" (PIH) which looks like PHP, ASP, etc : HTML code with Python code inserted inside <% and %>, with shortcuts for variables : <%= myVar %> and for translated strings which use the gettext mechanism (for which Karrigell provides a simple interface) : <%_ "string to translate" %>

• "HTML Inside Python" which are Python scripts, except that the lines beginning with a string are sent to standard output as if there were a "print" statement before
• plain CGI scripts, running much faster than usual because the interpreter is not loaded for each request

InTheirOwnWords

Karrigell aims at simplicity for web developers :

• a built-in web server, interfaces to run behind Apache

• no configuration needed to get started ; on Windows, an installer allows running an application from an USB drive, even on PCs without Python installed
  • a namespace for Python scripts in which developers will find all useful data and functions for the most ordinary tasks
  • a way to nest pages and scripts with the Include() function

The inspirations were EasyPHP, a package which provides Apache, PHP, mySql and PHPmyAdmin all in one, and saves the pain of installing each of them and make them all work together ; the wittily named Poor Man's Zope (PMZ) which showed how easy it was to make Python servlets (unfortunately unmaintained) ; and the pleasure I have programming things in Python

Performance and stability have been very much improved since the first versions. Karrigell can now be safely used in production environments

Comments

Hosting

WebFaction supports Karrigell

All web hosts using Apache and allowing CGI scripts can support it