glossary.rst

Glossary

request

A WebOb request object. See webob_chapter (narrative) and request_module (API documentation) for information about request objects.

request factory

An object which, provided a WSGI environment as a single positional argument, returns a WebOb compatible request.

response

An object returned by a view callable that represents response data returned to the requesting user agent. It must implements the pyramid.interfaces.IResponse interface. A response object is typically an instance of the pyramid.response.Response class or a subclass such as pyramid.httpexceptions.HTTPFound. See webob_chapter for information about response objects.

response adapter

A callable which accepts an arbitrary object and "converts" it to a pyramid.response.Response object. See using_iresponse for more information.

Repoze

"Repoze" is essentially a "brand" of software developed by Agendaless Consulting and a set of contributors. The term has no special intrinsic meaning. The project's website has more information. The software developed "under the brand" is available in a Subversion repository. Pyramid was originally known as repoze.bfg.

setuptools

Setuptools builds on Python's distutils to provide easier building, distribution, and installation of libraries and applications.

pkg_resources

A module which ships with setuptools that provides an API for addressing "asset files" within a Python package. Asset files are static files, template files, etc; basically anything non-Python-source that lives in a Python package can be considered a asset file. See also PkgResources

asset

Any file contained within a Python package which is not a Python source code file.

asset specification

A colon-delimited identifier for an asset. The colon separates a Python package name from a package subpath. For example, the asset specification my.package:static/baz.css identifies the file named baz.css in the static subdirectory of the my.package Python package. See asset_specifications for more info.

package

A directory on disk which contains an __init__.py file, making it recognizable to Python as a location which can be import -ed. A package exists to contain module files.

module

A Python source file; a file on the filesystem that typically ends with the extension .py or .pyc. Modules often live in a package.

project

(Setuptools/distutils terminology). A directory on disk which contains a setup.py file and one or more Python packages. The setup.py file contains code that allows the package(s) to be installed, distributed, and tested.

distribution

(Setuptools/distutils terminology). A file representing an installable library or application. Distributions are usually files that have the suffix of .egg, .tar.gz, or .zip. Distributions are the target of Setuptools commands such as easy_install.

entry point

A setuptools indirection, defined within a setuptools distribution setup.py. It is usually a name which refers to a function somewhere in a package which is held by the distribution.

dotted Python name

A reference to a Python object by name using a string, in the form path.to.modulename:attributename. Often used in Paste and setuptools configurations. A variant is used in dotted names within configurator method arguments that name objects (such as the "add_view" method's "view" and "context" attributes): the colon (:) is not used; in its place is a dot.

view

Common vernacular for a view callable.

view callable

A "view callable" is a callable Python object which is associated with a view configuration; it returns a response object . A view callable accepts a single argument: request, which will be an instance of a request object. An alternate calling convention allows a view to be defined as a callable which accepts a pair of arguments: context and request: this calling convention is useful for traversal-based applications in which a context is always very important. A view callable is the primary mechanism by which a developer writes user interface code within Pyramid. See views_chapter for more information about Pyramid view callables.

view configuration

View configuration is the act of associating a view callable with configuration information. This configuration information helps map a given request to a particular view callable and it can influence the response of a view callable. Pyramid views can be configured via imperative configuration, or by a special @view_config decorator coupled with a scan. See view_config_chapter for more information about view configuration.

view name

The "URL name" of a view, e.g index.html. If a view is configured without a name, its name is considered to be the empty string (which implies the default view).

Default view

The default view of a resource is the view invoked when the view name is the empty string (''). This is the case when traversal exhausts the path elements in the PATH_INFO of a request before it returns a context resource.

virtualenv

An isolated Python environment. Allows you to control which packages are used on a particular project by cloning your main Python. virtualenv was created by Ian Bicking.

resource

An object representing a node in the resource tree of an application. If traversal is used, a resource is an element in the resource tree traversed by the system. When traversal is used, a resource becomes the context of a view. If url dispatch is used, a single resource is generated for each request and is used as the context resource of a view.

resource tree

A nested set of dictionary-like objects, each of which is a resource. The act of traversal uses the resource tree to find a context resource.

domain model

Persistent data related to your application. For example, data stored in a relational database. In some applications, the resource tree acts as the domain model.

traversal

The act of descending "up" a tree of resource objects from a root resource in order to find a context resource. The Pyramid router performs traversal of resource objects when a root factory is specified. See the traversal_chapter chapter for more information. Traversal can be performed instead of URL dispatch or can be combined with URL dispatch. See hybrid_chapter for more information about combining traversal and URL dispatch (advanced).

router

The WSGI application created when you start a Pyramid application. The router intercepts requests, invokes traversal and/or URL dispatch, calls view functions, and returns responses to the WSGI server on behalf of your Pyramid application.

URL dispatch

An alternative to traversal as a mechanism for locating a context resource for a view. When you use a route in your Pyramid application via a route configuration, you are using URL dispatch. See the urldispatch_chapter for more information.

context

A resource in the resource tree that is found during traversal or URL dispatch based on URL data; if it's found via traversal, it's usually a resource object that is part of a resource tree; if it's found via URL dispatch, it's an object manufactured on behalf of the route's "factory". A context resource becomes the subject of a view, and often has security information attached to it. See the traversal_chapter chapter and the urldispatch_chapter chapter for more information about how a URL is resolved to a context resource.

application registry

A registry of configuration information consulted by Pyramid while servicing an application. An application registry maps resource types to views, as well as housing other application-specific component registrations. Every Pyramid application has one (and only one) application registry.

template

A file with replaceable parts that is capable of representing some text, XML, or HTML when rendered.

location

The path to an object in a resource tree. See location_aware for more information about how to make a resource object location-aware.

permission

A string or unicode object that represents an action being taken against a context resource. A permission is associated with a view name and a resource type by the developer. Resources are decorated with security declarations (e.g. an ACL), which reference these tokens also. Permissions are used by the active security policy to match the view permission against the resources's statements about which permissions are granted to which principal in a context in order to answer the question "is this user allowed to do this". Examples of permissions: read, or view_blog_entries.

default permission

A permission which is registered as the default for an entire application. When a default permission is in effect, every view configuration registered with the system will be effectively amended with a permission argument that will require that the executing user possess the default permission in order to successfully execute the associated view callable See also setting_a_default_permission.

ACE

An access control entry. An access control entry is one element in an ACL. An access control entry is a three-tuple that describes three things: an action (one of either Allow or Deny), a principal (a string describing a user or group), and a permission. For example the ACE, (Allow, 'bob', 'read') is a member of an ACL that indicates that the principal bob is allowed the permission read against the resource the ACL is attached to.

ACL

An access control list. An ACL is a sequence of ACE tuples. An ACL is attached to a resource instance. An example of an ACL is [ (Allow, 'bob', 'read'), (Deny, 'fred', 'write')]. If an ACL is attached to a resource instance, and that resource is findable via the context resource, it will be consulted any active security policy to determine wither a particular request can be fulfilled given the authentication information in the request.

authentication

The act of determining that the credentials a user presents during a particular request are "good". Authentication in Pyramid is performed via an authentication policy.

authorization

The act of determining whether a user can perform a specific action. In pyramid terms, this means determining whether, for a given resource, any principal (or principals) associated with the request have the requisite permission to allow the request to continue. Authorization in Pyramid is performed via its authorization policy.

principal

A principal is a string or unicode object representing a userid or a group id. It is provided by an authentication policy. For example, if a user had the user id "bob", and Bob was part of two groups named "group foo" and "group bar", the request might have information attached to it that would indicate that Bob was represented by three principals: "bob", "group foo" and "group bar".

authorization policy

An authorization policy in Pyramid terms is a bit of code which has an API which determines whether or not the principals associated with the request can perform an action associated with a permission, based on the information found on the context resource.

authentication policy

An authentication policy in Pyramid terms is a bit of code which has an API which determines the current principal (or principals) associated with a request.

WSGI

Web Server Gateway Interface. This is a Python standard for connecting web applications to web servers, similar to the concept of Java Servlets. Pyramid requires that your application be served as a WSGI application.

middleware

Middleware is a WSGI concept. It is a WSGI component that acts both as a server and an application. Interesting uses for middleware exist, such as caching, content-transport encoding, and other functions. See WSGI.org or PyPI to find middleware for your application.

pipeline

The Paste term for a single configuration of a WSGI server, a WSGI application, with a set of middleware in-between.

Zope

The Z Object Publishing Framework, a full-featured Python web framework.

Grok

A web framework based on Zope 3.

Django

A full-featured Python web framework.

Pylons

A lightweight Python web framework and a predecessor of Pyramid.

ZODB

Zope Object Database, a persistent Python object store.

ZEO

Zope Enterprise Objects allows multiple simultaneous processes to access a single ZODB database.

WebOb

WebOb is a WSGI request/response library created by Ian Bicking.

Paste

Paste is a WSGI development and deployment system developed by Ian Bicking.

PasteDeploy

PasteDeploy is a library used by Pyramid which makes it possible to configure WSGI components together declaratively within an .ini file. It was developed by Ian Bicking as part of Paste.

Chameleon

chameleon is an attribute language template compiler which supports both the ZPT and Genshi templating specifications. It is written and maintained by Malthe Borch. It has several extensions, such as the ability to use bracketed (Genshi-style) ${name} syntax, even within ZPT. It is also much faster than the reference implementations of both ZPT and Genshi. Pyramid offers Chameleon templating out of the box in ZPT and text flavors.

ZPT

The Zope Page Template templating language.

METAL

Macro Expansion for TAL, a part of ZPT which makes it possible to share common look and feel between templates.

Genshi

An XML templating language by Christopher Lenz.

Jinja2

A text templating language by Armin Ronacher.

Routes

A system by Ben Bangert which parses URLs and compares them against a number of user defined mappings. The URL pattern matching syntax in Pyramid is inspired by the Routes syntax (which was inspired by Ruby On Rails pattern syntax).

route

A single pattern matched by the url dispatch subsystem, which generally resolves to a root factory (and then ultimately a view). See also url dispatch.

route configuration

Route configuration is the act of associating request parameters with a particular route using pattern matching and route predicate statements. See urldispatch_chapter for more information about route configuration.

Zope Component Architecture

The Zope Component Architecture (aka ZCA) is a system which allows for application pluggability and complex dispatching based on objects which implement an interface. Pyramid uses the ZCA "under the hood" to perform view dispatching and other application configuration tasks.

reStructuredText

A plain text format that is the defacto standard for descriptive text shipped in distribution files, and Python docstrings. This documentation is authored in ReStructuredText format.

root

The object at which traversal begins when Pyramid searches for a context resource (for URL Dispatch, the root is always the context resource unless the traverse= argument is used in route configuration).

subpath

A list of element "left over" after the router has performed a successful traversal to a view. The subpath is a sequence of strings, e.g. ['left', 'over', 'names']. Within Pyramid applications that use URL dispatch rather than traversal, you can use *subpath in the route pattern to influence the subpath. See star_subpath for more information.

interface

A Zope interface object. In Pyramid, an interface may be attached to a resource object or a request object in order to identify that the object is "of a type". Interfaces are used internally by Pyramid to perform view lookups and other policy lookups. The ability to make use of an interface is exposed to an application programmers during view configuration via the context argument, the request_type argument and the containment argument. Interfaces are also exposed to application developers when they make use of the event system. Fundamentally, Pyramid programmers can think of an interface as something that they can attach to an object that stamps it with a "type" unrelated to its underlying Python type. Interfaces can also be used to describe the behavior of an object (its methods and attributes), but unless they choose to, Pyramid programmers do not need to understand or use this feature of interfaces.

event

An object broadcast to zero or more subscriber callables during normal Pyramid system operations during the lifetime of an application. Application code can subscribe to these events by using the subscriber functionality described in events_chapter.

subscriber

A callable which receives an event. A callable becomes a subscriber via imperative configuration or via configuration decoration. See events_chapter for more information.

request type

An attribute of a request that allows for specialization of view invocation based on arbitrary categorization. The every request object that Pyramid generates and manipulates has one or more interface objects attached to it. The default interface attached to a request object is pyramid.interfaces.IRequest.

repoze.lemonade

Zope2 CMF-like data structures and helper facilities for CA-and-ZODB-based applications useful within Pyramid applications.

repoze.catalog

An indexing and search facility (fielded and full-text) based on zope.index. See the documentation for more information.

repoze.who

Authentication middleware for WSGI applications. It can be used by Pyramid to provide authentication information.

repoze.workflow

Barebones workflow for Python apps . It can be used by Pyramid to form a workflow system.

virtual root

A resource object representing the "virtual" root of a request; this is typically the physical root object (the object returned by the application root factory) unless vhosting_chapter is in use.

lineage

An ordered sequence of objects based on a "location -aware" resource. The lineage of any given resource is composed of itself, its parent, its parent's parent, and so on. The order of the sequence is resource-first, then the parent of the resource, then its parent's parent, and so on. The parent of a resource in a lineage is available as its __parent__ attribute.

root factory

The "root factory" of a Pyramid application is called on every request sent to the application. The root factory returns the traversal root of an application. It is conventionally named get_root. An application may supply a root factory to Pyramid during the construction of a Configurator. If a root factory is not supplied, the application uses a default root object. Use of the default root object is useful in application which use URL dispatch for all URL-to-view code mappings.

SQLAlchemy

SQLAlchemy is an object relational mapper used in tutorials within this documentation.

JSON

JavaScript Object Notation is a data serialization format.

jQuery

A popular Javascript library.

renderer

A serializer that can be referred to via view configuration which converts a non-Response return values from a view into a string (and ultimately a response). Using a renderer can make writing views that require templating or other serialization less tedious. See views_which_use_a_renderer for more information.

renderer factory

A factory which creates a renderer. See adding_and_overriding_renderers for more information.

mod_wsgi

mod_wsgi is an Apache module developed by Graham Dumpleton. It allows WSGI applications (such as applications developed using Pyramid) to be served using the Apache web server.

view predicate

An argument to a view configuration which evaluates to True or False for a given request. All predicates attached to a view configuration must evaluate to true for the associated view to be considered as a possible callable for a given request.

route predicate

An argument to a route configuration which implies a value that evaluates to True or False for a given request. All predicates attached to a route configuration must evaluate to True for the associated route to "match" the current request. If a route does not match the current request, the next route (in definition order) is attempted.

routes mapper

An object which compares path information from a request to an ordered set of route patterns. See urldispatch_chapter.

predicate

A test which returns True or False. Two different types of predicates exist in Pyramid: a view predicate and a route predicate. View predicates are attached to view configuration and route predicates are attached to route configuration.

decorator

A wrapper around a Python function or class which accepts the function or class as its first argument and which returns an arbitrary object. Pyramid provides several decorators, used for configuration and return value modification purposes. See also PEP 318.

configuration declaration

An individual method call made to an instance of a Pyramid Configurator object which performs an arbitrary action, such as registering a view configuration (via the add_view method of the configurator) or route configuration (via the add_route method of the configurator). A set of configuration declarations is also implied by the configuration decoration detected by a scan of code in a package.

configuration decoration

Metadata implying one or more configuration declaration invocations. Often set by configuration Python decorator attributes, such as pyramid.view.view_config, aka @view_config.

scan

The term used by Pyramid to define the process of importing and examining all code in a Python package or module for configuration decoration.

configurator

An object used to do configuration declaration within an application. The most common configurator is an instance of the pyramid.config.Configurator class.

imperative configuration

The configuration mode in which you use Python to call methods on a Configurator in order to add each configuration declaration required by your application.

declarative configuration

The configuration mode in which you use the combination of configuration decoration and a scan to configure your Pyramid application.

Not Found view

An exception view invoked by Pyramid when the developer explicitly raises a pyramid.httpexceptions.HTTPNotFound exception from within view code or root factory code, or when the current request doesn't match any view configuration. Pyramid provides a default implementation of a not found view; it can be overridden. See changing_the_notfound_view.

Forbidden view

An exception view invoked by Pyramid when the developer explicitly raises a pyramid.httpexceptions.HTTPForbidden exception from within view code or root factory code, or when the view configuration and authorization policy found for a request disallows a particular view invocation. Pyramid provides a default implementation of a forbidden view; it can be overridden. See changing_the_forbidden_view.

Exception view

An exception view is a view callable which may be invoked by Pyramid when an exception is raised during request processing. See exception_views for more information.

HTTP Exception

The set of exception classes defined in pyramid.httpexceptions. These can be used to generate responses with various status codes when raised or returned from a view callable. See also http_exceptions.

thread local

A thread-local variable is one which is essentially a global variable in terms of how it is accessed and treated, however, each thread used by the application may have a different value for this same "global" variable. Pyramid uses a small number of thread local variables, as described in threadlocals_chapter. See also the threading.local documentation for more information.

multidict

An ordered dictionary that can have multiple values for each key. Adds the methods getall, getone, mixed, add and dict_of_lists to the normal dictionary interface. See multidict_narr and pyramid.interfaces.IMultiDict.

PyPI

The Python Package Index, a collection of software available for Python.

Agendaless Consulting

A consulting organization formed by Paul Everitt, Tres Seaver, and Chris McDonough. See also http://agendaless.com .

Jython

A Python implementation written for the Java Virtual Machine.

Python

The programming language in which Pyramid is written.

CPython

The C implementation of the Python language. This is the reference implementation that most people refer to as simply "Python"; Jython, Google's App Engine, and PyPy are examples of non-C based Python implementations.

View Lookup

The act of finding and invoking the "best" view callable given a request and a context resource.

Resource Location

The act of locating a context resource given a request. Traversal and URL dispatch are the resource location subsystems used by Pyramid.

Google App Engine

Google App Engine (aka "GAE") is a Python application hosting service offered by Google. Pyramid runs on GAE.

Venusian

Venusian is a library which allows framework authors to defer decorator actions. Instead of taking actions when a function (or class) decorator is executed at import time, the action usually taken by the decorator is deferred until a separate "scan" phase. Pyramid relies on Venusian to provide a basis for its scan feature.

Translation String

An instance of pyramid.i18n.TranslationString, which is a class that behaves like a Unicode string, but has several extra attributes such as domain, msgid, and mapping for use during translation. Translation strings are usually created by hand within software, but are sometimes created on the behalf of the system for automatic template translation. For more information, see i18n_chapter.

Translation Domain

A string representing the "context" in which a translation was made. For example the word "java" might be translated differently if the translation domain is "programming-languages" than would be if the translation domain was "coffee". A translation domain is represnted by a collection of .mo files within one or more translation directory directories.

Translator

A callable which receives a translation string and returns a translated Unicode object for the purposes of internationalization. A localizer supplies a translator to a Pyramid application accessible via its translate method.

Translation Directory

A translation directory is a gettext translation directory. It contains language folders, which themselves contain LC_MESSAGES folders, which contain .mo files. Each .mo file represents a set of translations for a language in a translation domain. The name of the .mo file (minus the .mo extension) is the translation domain name.

Localizer

An instance of the class pyramid.i18n.Localizer which provides translation and pluralization services to an application. It is retrieved via the pyramid.i18n.get_localizer function.

Locale Name

A string like en, en_US, de, or de_AT which uniquely identifies a particular locale.

Default Locale Name

The locale name used by an application when no explicit locale name is set. See localization_deployment_settings.

Locale Negotiator

An object supplying a policy determining which locale name best represents a given request. It is used by the pyramid.i18n.get_locale_name, and pyramid.i18n.negotiate_locale_name functions, and indirectly by pyramid.i18n.get_localizer. The pyramid.i18n.default_locale_negotiator function is an example of a locale negotiator.

Gettext

The GNU gettext library, used by the Pyramid translation machinery.

Babel

A collection of tools for internationalizing Python applications. Pyramid does not depend on Babel to operate, but if Babel is installed, additional locale functionality becomes available to your application.

Lingua

A package by Wichert Akkerman which provides Babel message extractors for Python source files and Chameleon ZPT template files.

Message Identifier

A string used as a translation lookup key during localization. The msgid argument to a translation string is a message identifier. Message identifiers are also present in a message catalog.

Message Catalog

A gettext .mo file containing translations.

Internationalization

The act of creating software with a user interface that can potentially be displayed in more than one language or cultural context. Often shortened to "i18n" (because the word "internationalization" is I, 18 letters, then N). See also: Localization.

Localization

The process of displaying the user interface of an internationalized application in a particular language or cultural context. Often shortened to "l10" (because the word "localization" is L, 10 letters, then N). See also: Internationalization.

renderer globals

Values injected as names into a renderer based on application policy. See adding_renderer_globals for more information.

response callback

A user-defined callback executed by the router at a point after a response object is successfully created. See using_response_callbacks.

finished callback

A user-defined callback executed by the router unconditionally at the very end of request processing . See using_finished_callbacks.

pregenerator

A pregenerator is a function associated by a developer with a route. It is called by pyramid.url.route_url in order to adjust the set of arguments passed to it by the user for special purposes. It will influence the URL returned by route_url. See pyramid.interfaces.IRoutePregenerator for more information.

session

A namespace that is valid for some period of continual activity that can be used to represent a user's interaction with a web application.

session factory

A callable, which, when called with a single argument named request (a request object), returns a session object.

Mako

Mako is a template language language which refines the familiar ideas of componentized layout and inheritance using Python with Python scoping and calling semantics.

View handler

A view handler ties together pyramid.config.Configurator.add_route and pyramid.config.Configurator.add_view to make it more convenient to register a collection of views as a single class when using url dispatch. View handlers ship as part of the pyramid_handlers add-on package.

Deployment settings

Deployment settings are settings passed to the Configurator as a settings argument. These are later accessible via a request.registry.settings dictionary. Deployment settings can be used as global application values.

WebTest

WebTest is a package which can help you write functional tests for your WSGI application.

view mapper

A view mapper is a class which implements the pyramid.interfaces.IViewMapperFactory interface, which performs view argument and return value mapping. This is a plug point for extension builders, not normally used by "civilians".

matchdict

The dictionary attached to the request object as request.matchdict when a URL dispatch route has been matched. Its keys are names as identified within the route pattern; its values are the values matched by each pattern name.

pyramid_zcml

An add-on package to Pyramid which allows applications to be configured via ZCML. It is available on PyPI. If you use pyramid_zcml, you can use ZCML as an alternative to imperative configuration.

ZCML

Zope Configuration Markup Language, an XML dialect used by Zope and pyramid_zcml for configuration tasks.

ZCML directive

A ZCML "tag" such as <view> or <route>.

ZCML declaration

The concrete use of a ZCML directive within a ZCML file.

pyramid_handlers

An add-on package which allows Pyramid users to create classes that are analogues of Pylons 1 "controllers". See http://docs.pylonsproject.org/projects/pyramid_handlers/dev/ .

pyramid_jinja2

Jinja2 templating system bindings for Pyramid, documented at http://docs.pylonsproject.org/projects/pyramid_jinja2/dev/ . This package also includes a scaffold named pyramid_jinja2_starter, which creates an application package based on the Jinja2 templating system.

Akhet

Akhet is a Pyramid-based development environment which provides a Pylons-esque scaffold which sports support for view handler application development, SQLAlchemy support, Mako templating by default, and other Pylons-like features. See http://docs.pylonsproject.org/projects/akhet/dev/index.html for more information.

Pyramid Cookbook

An additional documentation resource for Pyramid which presents topical, practical usages of Pyramid available via http://docs.pylonsproject.org/ .

distutils

The standard system for packaging and distributing Python packages. See http://docs.python.org/distutils/index.html for more information. setuptools is actually an extension of the Distutils.

exception response

A response that is generated as the result of a raised exception being caught by an exception view.

PyPy

PyPy is an "alternative implementation of the Python language":http://pypy.org/

tween

A bit of code that sits between the Pyramid router's main request handling function and the upstream WSGI component that uses Pyramid as its 'app'. The word "tween" is a contraction of "between". A tween may be used by Pyramid framework extensions, to provide, for example, Pyramid-specific view timing support, bookkeeping code that examines exceptions before they are returned to the upstream WSGI application, or a variety of other features. Tweens behave a bit like WSGI 'middleware' but they have the benefit of running in a context in which they have access to the Pyramid application registry as well as the Pyramid rendering machinery. See registering_tweens.

pyramid_debugtoolbar

A Pyramid add on which displays a helpful debug toolbar "on top of" HTML pages rendered by your application, displaying request, routing, and database information. pyramid_debugtoolbar is configured into the development.ini of all applications which use a Pyramid scaffold. For more information, see https://docs.pylonsproject.org/projects/pyramid_debugtoolbar/dev/ .

scaffold

A project template that helps users get started writing a Pyramid application quickly. Scaffolds are usually used via the paster create command.

pyramid_exclog

A package which logs Pyramid application exception (error) information to a standard Python logger. This add-on is most useful when used in production applications, because the logger can be configured to log to a file, to UNIX syslog, to the Windows Event Log, or even to email. See its documentation.