Pyramid is a general, open source, Python web application development framework. Its primary goal is to make it easier for a developer to create web applications. The type of application being created could be a spreadsheet, a corporate intranet, or a social networking platform; Pyramid’s generality enables it to be used to build an unconstrained variety of web applications.
The first release of Pyramid’s predecessor (named
repoze.bfg) was made
in July of 2008. We have worked hard to ensure that Pyramid continues to
follow the design and engineering principles that we consider to be the core
characteristics of a successful framework:
- Pyramid takes a “pay only for what you eat” approach. This means that you can get results even if you have only a partial understanding of Pyramid. It doesn’t force you to use any particular technology to produce an application, and we try to keep the core set of concepts that you need to understand to a minimum.
- Pyramid concentrates on providing fast, high-quality solutions to the fundamental problems of creating a web application: the mapping of URLs to code, templating, security and serving static assets. We consider these to be the core activities that are common to nearly all web applications.
- Pyramid’s minimalism means that it is relatively easy for us to maintain extensive and up-to-date documentation. It is our goal that no aspect of Pyramid remains undocumented.
- Pyramid is designed to provide noticeably fast execution for common tasks such as templating and simple response generation. Although the “hardware is cheap” mantra may appear to offer a ready solution to speed problems, the limits of this approach become painfully evident when one finds him or herself responsible for managing a great many machines.
- Pyramid is developed conservatively and tested exhaustively. Where Pyramid source code is concerned, our motto is: “If it ain’t tested, it’s broke”. Every release of Pyramid has 100% statement coverage via unit tests.
- As with Python, the Pyramid software is distributed under a permissive open source license.
What Is The Pylons Project?¶
Pyramid is a member of the collection of software published under the Pylons Project. Pylons software is written by a loose-knit community of contributors. The Pylons Project website includes details about how Pyramid relates to the Pylons Project.
Pyramid and Other Web Frameworks¶
Until the end of 2010, Pyramid was known as
repoze.bfg; it was
merged into the Pylons project as Pyramid in November of that year.
Many features of Pyramid trace their origins back to Zope. Like Zope applications, Pyramid applications can be configured via a set of declarative configuration files. Like Zope applications, Pyramid applications can be easily extended: if you obey certain constraints, the application you produce can be reused, modified, re-integrated, or extended by third-party developers without forking the original application. The concepts of traversal and declarative security in Pyramid were pioneered first in Zope.
The Pyramid concept of URL dispatch is inspired by the Routes system used by Pylons version 1.0. Like Pylons version 1.0, Pyramid is mostly policy-free. It makes no assertions about which database you should use, and its built-in templating facilities are included only for convenience. In essence, it only supplies a mechanism to map URLs to view code, along with a set of conventions for calling those views. You are free to use third-party components that fit your needs in your applications.
The concept of view is used by Pyramid mostly as it would be by Django. Pyramid has a documentation culture more like Django’s than like Zope’s.
Like Pylons version 1.0, but unlike Zope, a Pyramid application developer may use completely imperative code to perform common framework configuration tasks such as adding a view or a route. In Zope, ZCML is typically required for similar purposes. In Grok, a Zope-based web framework, decorator objects and class-level declarations are used for this purpose. Pyramid supports ZCML and decorator-based configuration, but does not require either. See Application Configuration for more information.
Also unlike Zope and unlike other “full-stack” frameworks such as Django, Pyramid makes no assumptions about which persistence mechanisms you should use to build an application. Zope applications are typically reliant on ZODB; Pyramid allows you to build ZODB applications, but it has no reliance on the ZODB software. Likewise, Django tends to assume that you want to store your application’s data in a relational database. Pyramid makes no such assumption; it allows you to use a relational database but doesn’t encourage or discourage the decision.
Other Python web frameworks advertise themselves as members of a class of web frameworks named model-view-controller frameworks. Insofar as this term has been claimed to represent a class of web frameworks, Pyramid also generally fits into this class.