- The class method in a Pylons applications’ controller that handles
- Application Programming Interface. The means of communication between
a programmer and a software program or operating system.
The app_globals object is created on application instantiation by
the Globals class in a projects lib/app_globals.py
This object is created once when the application is loaded by the
projects config/environment.py module (See
Environment). It remains persistent
during the lifecycle of the web application, and is not thread-safe
which means that it is best used for global options that should be
read-only, or as an object to attach db connections or other objects
which ensure their own access is thread-safe.
- Commonly used alias for tmpl_context to save on the typing
when using lots of controller populated variables in templates.
- The storage of the results of expensive or length computations for
later re-use at a point more quickly accessed by the end user.
- Content Delivery Networks (CDN’s) are generally globally distributed
content delivery networks optimized for low latency for static file
distribution. They can significantly increase page-load times by
ensuring that the static resources on a page are delivered by servers
geographically close to the client in addition to lightening the load
placed on the application server.
- ColdFusion Components
- CFCs represent an attempt by Macromedia to bring ColdFusion closer
to an Object Oriented Programming (OOP) language. ColdFusion is in
no way an OOP language, but thanks in part to CFCs, it does boast
some of the attributes that make OOP languages so popular.
- The PylonsConfig instance for a given
application. This can be accessed as pylons.config after an
Pylons application has been loaded.
- The ‘C’ in MVC. The controller is given a request, does the necessary
logic to prepare data for display, then renders a template with
the data and returns it to the user. See Controllers.
A tool that lets you download, build, install and manage Python packages
and their dependencies. easy_install is the end-user facing component
Pylons can be installed with easy_install, and applications built
with Pylons can easily be deployed this way as well.
- dotted name string
- A reference to a Python module by name using a string to identify it,
e.g. pylons.controllers.util. These strings are evaluated to
import the module being referenced without having to import it in
the code used. This is generally used to avoid import-time
Python egg’s are bundled Python packages, generally installed by
a package called setuptools. Unlike normal Python package
installs, egg’s allow a few additional features, such as package
dependencies, and dynamic discovery.
- Enterprise JavaBeans (EJB) technology is the server-side component
architecture for Java Platform, Enterprise Edition (Java EE). EJB
technology enables rapid and simplified development of distributed,
transactional, secure and portable applications based on Java
- environ is a dictionary passed into all WSGI application. It
generally contains unparsed header information, CGI style variables
and other objects inserted by WSGI Middleware.
- An ETag (entity tag) is an HTTP response header returned by an
HTTP/1.1 compliant web server used to determine change in content
at a given URL. See http://wikipedia.org/wiki/HTTP_ETag
- Alias used in prior versions of Pylons for app_globals.
- Google App Engine
A cloud computing platform for hosting web applications implemented in
Python. Building Pylons applications for App Engine is facilitated by
Ian Bicking’s appengine-monkey project.
- The helpers reference, h, is made available for use inside
templates to assist with common rendering tasks. h is just a
reference to the lib/helpers.py module and can be used in the
same manner as any other module import.
An architectural pattern used in software engineering. In Pylons, the
MVC paradigm is extended slightly with a pipeline that may transform
and extend the data available to a controller, as well as the Pylons
WSGI app itself that determines the appropriate Controller
- See Model-View-Controller
- (Object-Relational Mapper) Maps relational databases such as
MySQL, Postgres, Oracle to objects providing a cleaner API.
Most ORM’s also make it easier to prevent SQL Injection attacks
by binding variables, and can handle generating sometimes
- A Python-based WSGI oriented web framework.
- Abbreviated as RoR, Ruby on Rails (also referred to as just
Rails) is an open source Web application framework, written in Ruby
- Refers to the current request being processed. Available to import
from pylons and is available for use in templates by the
same name. See Request.
- Refers to the response to the current request. Available to import
from pylons and is available for use in template by the same
name. See Response.
- Routes determine how the URL’s are mapped to the controllers and which
URL is generated. See URL Configuration
An extension to the basic distutils, setuptools allows packages to
specify package dependencies and have dynamic discovery of other
installed Python packages.
- One of the most popular Python database object-relational mappers
(ORM). SQLAlchemy is the default
ORM recommended in Pylons. SQLAlchemy at the ORM level can look similar
to Rails ActiveRecord, but uses the DataMapper
pattern for additional flexibility with the ability to map simple to
extremely complex databases.
- The tmpl_context is available in the pylons module, and
refers to the template context. Objects attached to it are available
in the template namespace as either tmpl_context or c for
- User interface. The means of communication between a person
and a software program or operating system.
A tool to create isolated Python environments, designed to supersede the
workingenv package and virtual python configurations. In addition
to isolating packages from possible system conflicts, virtualenv
makes it easy to install Python libraries using easy_install
without dumping lots of packages into the system-wide Python.
The other great benefit is that no root access is required since all
modules are kept under the desired directory. This makes it easy
to setup a working Pylons install on shared hosting providers and other
systems where system-wide access is unavailable.
virtualenv is employed automatically by the go-pylons.py script
described in Getting Started. The Pylons wiki has more
information on working with virtualenv.
- web server gateway interface
- A specification for web servers and application servers to
communicate with web applications. Also referred to by its
initials, as WSGI.
- The WSGI Specification,
also commonly referred to as PEP 333 and described by PEP 333.
- WSGI Middleware
WSGI Middleware refers to the ability of WSGI applications
to modify the environ, and/or the content of other WSGI applications
by being placed in between the request and the other WSGI application.