repoze.bfg 1.3a7

The repoze.bfg web application framework

repoze.bfg

repoze.bfg is a small, fast, down-to-earth, open source Python web development framework. It makes real-world web application development and deployment more fun, more predictable, and more productive.

Support and Documentation

See the repoze.bfg website to view documentation, report bugs, and obtain support.

License

repoze.bfg is offered under the BSD-derived Repoze Public License.

Authors

repoze.bfg is made available by Agendaless Consulting and a team of contributors.

1.3a7 (2010-08-01)

Features

• The repoze.bfg.configuration.Configurator.add_route API now returns the route object that was added.

• A repoze.bfg.events.subscriber decorator was added. This decorator decorates module-scope functions, which are then treated as event listeners after a scan() is performed. See the Events narrative documentation chapter and the repoze.bfg.events module documentation for more information.

Bug Fixes

• When adding a view for a route which did not yet exist (“did not yet exist” meaning, temporally, a view was added with a route name for a route which had not yet been added via add_route), the value of the custom_predicate argument to add_view was lost. Symptom: wrong view matches when using URL dispatch and custom view predicates together.

• Pattern matches for a :segment marker in a URL dispatch route pattern now always match at least one character. See “Backwards Incompatibilities” below in this changelog.

Backwards Incompatibilities

• A bug existed in the regular expression to do URL matching. As an example, the URL matching machinery would cause the pattern /{foo} to match the root URL / resulting in a match dictionary of {'foo':u''} or the pattern /{fud}/edit might match the URL ``//edit resulting in a match dictionary of {'fud':u''}. It was always the intent that :segment markers in the pattern would need to match at least one character, and never match the empty string. This, however, means that in certain circumstances, a routing match which your application inadvertently depended upon may no longer happen.

Documentation

• Added description of the repoze.bfg.events.subscriber decorator to the Events narrative chapter.

• Added repoze.bfg.events.subscriber API documentation to repoze.bfg.events API docs.

• Added a section named “Zope 3 Enforces ‘TTW’ Authorization Checks By Default; BFG Does Not” to the “Design Defense” chapter.

1.3a6 (2010-07-25)

Features

• New argument to repoze.bfg.configuration.Configurator.add_route and the route ZCML directive: traverse. If you would like to cause the context to be something other than the root object when this route matches, you can spell a traversal pattern as the traverse argument. This traversal pattern will be used as the traversal path: traversal will begin at the root object implied by this route (either the global root, or the object returned by the factory associated with this route).

  The syntax of the traverse argument is the same as it is for path. For example, if the path provided is articles/:article/edit, and the traverse argument provided is /:article, when a request comes in that causes the route to match in such a way that the article match value is ‘1’ (when the request URI is /articles/1/edit), the traversal path will be generated as /1. This means that the root object’s __getitem__ will be called with the name 1 during the traversal phase. If the 1 object exists, it will become the context of the request. The Traversal narrative has more information about traversal.

  If the traversal path contains segment marker names which are not present in the path argument, a runtime error will occur. The traverse pattern should not contain segment markers that do not exist in the path.

  A similar combining of routing and traversal is available when a route is matched which contains a *traverse remainder marker in its path. The traverse argument allows you to associate route patterns with an arbitrary traversal path without using a a *traverse remainder marker; instead you can use other match information.

  Note that the traverse argument is ignored when attached to a route that has a *traverse remainder marker in its path.

• A new method of the Configurator exists: set_request_factory. If used, this method will set the factory used by the repoze.bfg router to create all request objects.

• The Configurator constructor takes an additional argument: request_factory. If used, this argument will set the factory used by the repoze.bfg router to create all request objects.

• The Configurator constructor takes an additional argument: request_factory. If used, this argument will set the factory used by the repoze.bfg router to create all request objects.

• A new method of the Configurator exists: set_renderer_globals_factory. If used, this method will set the factory used by the repoze.bfg router to create renderer globals.

• A new method of the Configurator exists: get_settings. If used, this method will return the current settings object (performs the same job as the repoze.bfg.settings.get_settings API).

• The Configurator constructor takes an additional argument: renderer_globals_factory. If used, this argument will set the factory used by the repoze.bfg router to create renderer globals.

• Add repoze.bfg.renderers.render, repoze.bfg.renderers.render_to_response and repoze.bfg.renderers.get_renderer functions. These are imperative APIs which will use the same rendering machinery used by view configurations with a renderer= attribute/argument to produce a rendering or renderer. Because these APIs provide a central API for all rendering, they now form the preferred way to perform imperative template rendering. Using functions named render_* from modules such as repoze.bfg.chameleon_zpt and repoze.bfg.chameleon_text is now discouraged (although not deprecated). The code the backing older templating-system-specific APIs now calls into the newer repoze.bfg.renderer code.

• The repoze.bfg.configuration.Configurator.testing_add_template has been renamed to testing_add_renderer. A backwards compatibility alias is present using the old name.

Documentation

• The Hybrid narrative chapter now contains a description of the traverse route argument.

• The Hooks narrative chapter now contains sections about changing the request factory and adding a renderer globals factory.

• The API documentation includes a new module: repoze.bfg.renderers.

• The Templates chapter was updated; all narrative that used templating-specific APIs within examples to perform rendering (such as the repoze.bfg.chameleon_zpt.render_template_to_response method) was changed to use repoze.bfg.renderers.render_* functions.

Bug Fixes

• The header predicate (when used as either a view predicate or a route predicate) had a problem when specified with a name/regex pair. When the header did not exist in the headers dictionary, the regex match could be fed None, causing it to throw a TypeError: expected string or buffer exception. Now, the predicate returns False as intended.

Deprecations

• The repoze.bfg.renderers.rendered_response function was never an official API, but may have been imported by extensions in the wild. It is officially deprecated in this release. Use repoze.bfg.renderers.render_to_response instead.

• The following APIs are documentation deprecated (meaning they are officially deprecated in documentation but do not raise a deprecation error upon their usage, and may continue to work for an indefinite period of time):

  In the repoze.bfg.chameleon_zpt module: get_renderer, get_template, render_template, render_template_to_response. The suggested alternatives are documented within the docstrings of those methods (which are still present in the documentation).

  In the repoze.bfg.chameleon_text module: get_renderer, get_template, render_template, render_template_to_response. The suggested alternatives are documented within the docstrings of those methods (which are still present in the documentation).

  In general, to perform template-related functions, one should now use the various methods in the repoze.bfg.renderers module.

Backwards Incompatibilities

• A new internal exception class (not an API) named repoze.bfg.exceptions.PredicateMismatch now exists. This exception is currently raised when no constituent view of a multiview can be called (due to no predicate match). Previously, in this situation, a repoze.bfg.exceptions.NotFound was raised. We provide backwards compatibility for code that expected a NotFound to be raised when no predicates match by causing repoze.bfg.exceptions.PredicateMismatch to inherit from NotFound. This will cause any exception view registered for NotFound to be called when a predicate mismatch occurs, as was the previous behavior.

  There is however, one perverse case that will expose a backwards incompatibility. If 1) you had a view that was registered as a member of a multiview 2) this view explicitly raised a NotFound exception in order to proceed to the next predicate check in the multiview, that code will now behave differently: rather than skipping to the next view match, a NotFound will be raised to the top-level exception handling machinery instead. For code to be depending upon the behavior of a view raising NotFound to proceed to the next predicate match, would be tragic, but not impossible, given that NotFound is a public interface. repoze.bfg.exceptions.PredicateMismatch is not a public API and cannot be depended upon by application code, so you should not change your view code to raise PredicateMismatch. Instead, move the logic which raised the NotFound exception in the view out into a custom view predicate.

• If, when you run your application’s unit test suite under BFG 1.3, a KeyError naming a template or a ValueError indicating that a ‘renderer factory’ is not registered may is raised (e.g. ValueError: No factory for renderer named '.pt' when looking up karl.views:templates/snippets.pt), you may need to perform some extra setup in your test code.

  The best solution is to use the repoze.bfg.configuration.Configurator.testing_add_renderer (or, alternately the deprecated repoze.bfg.testing.registerTemplateRenderer or registerDummyRenderer) API within the code comprising each individual unit test suite to register a “dummy” renderer for each of the templates and renderers used by code under test. For example:

  config = Configurator()
  config.testing_add_renderer('karl.views:templates/snippets.pt')

  This will register a basic dummy renderer for this particular missing template. The testing_add_renderer API actually returns the renderer, but if you don’t care about how the render is used, you don’t care about having a reference to it either.

  A more rough way to solve the issue exists. It causes the “real” template implementations to be used while the system is under test, which is suboptimal, because tests will run slower, and unit tests won’t actually be unit tests, but it is easier. Always ensure you call the setup_registry() method of the Configurator . Eg:

  reg = MyRegistry()
  config = Configurator(registry=reg)
  config.setup_registry()

  Calling setup_registry only has an effect if you’re passing in a registry argument to the Configurator constructor. setup_registry is called by the course of normal operations anyway if you do not pass in a registry.

  If your test suite isn’t using a Configurator yet, and is still using the older repoze.bfg.testing APIs name setUp or cleanUp, these will register the renderers on your behalf.

  A variant on the symptom for this theme exists: you may already be dutifully registering a dummy template or renderer for a template used by the code you’re testing using testing_register_renderer or registerTemplateRenderer, but (perhaps unbeknownst to you) the code under test expects to be able to use a “real” template renderer implementation to retrieve or render another template that you forgot was being rendered as a side effect of calling the code you’re testing. This happened to work because it found the real template while the system was under test previously, and now it cannot. The solution is the same.

  It may also help reduce confusion to use a resource specification to specify the template path in the test suite and code rather than a relative path in either. A resource specification is unambiguous, while a relative path needs to be relative to “here”, where “here” isn’t always well-defined (“here” in a test suite may or may not be the same as “here” in the code under test).

1.3a5 (2010-07-14)

Features

• New internal exception: repoze.bfg.exceptions.URLDecodeError. This URL is a subclass of the built-in Python exception named UnicodeDecodeError.

• When decoding a URL segment to Unicode fails, the exception raised is now repoze.bfg.exceptions.URLDecodeError instead of UnicodeDecodeError. This makes it possible to register an exception view invoked specifically when repoze.bfg cannot decode a URL.

Bug Fixes

• Fix regression in repoze.bfg.configuration.Configurator.add_static_view. Before 1.3a4, view names that contained a slash were supported as route prefixes. 1.3a4 broke this by trying to treat them as full URLs.

Documentation

• The repoze.bfg.exceptions.URLDecodeError exception was added to the exceptions chapter of the API documentation.

Backwards Incompatibilities

• in previous releases, when a URL could not be decoded from UTF-8 during traversal, a TypeError was raised. Now the error which is raised is a repoze.bfg.exceptions.URLDecodeError.

1.3a4 (2010-07-03)

Features

• Undocumented hook: make get_app and get_root of the repoze.bfg.paster.BFGShellCommand hookable in cases where endware may interfere with the default versions.

• In earlier versions, a custom route predicate associated with a url dispatch route (each of the predicate functions fed to the custom_predicates argument of repoze.bfg.configuration.Configurator.add_route) has always required a 2-positional argument signature, e.g. (context, request). Before this release, the context argument was always None.

  As of this release, the first argument passed to a predicate is now a dictionary conventionally named info consisting of route, and match. match is a dictionary: it represents the arguments matched in the URL by the route. route is an object representing the route which was matched.

  This is useful when predicates need access to the route match. For example:

  def any_of(segment_name, *args):
      def predicate(info, request):
          if info['match'][segment_name] in args:
              return True
      return predicate
  
  num_one_two_or_three = any_of('num, 'one', 'two', 'three')
  
  add_route('num', '/:num', custom_predicates=(num_one_two_or_three,))

  The route object is an object that has two useful attributes: name and path. The name attribute is the route name. The path attribute is the route pattern. An example of using the route in a set of route predicates:

  def twenty_ten(info, request):
      if info['route'].name in ('ymd', 'ym', 'y'):
          return info['match']['year'] == '2010'
  
  add_route('y', '/:year', custom_predicates=(twenty_ten,))
  add_route('ym', '/:year/:month', custom_predicates=(twenty_ten,))
  add_route('ymd', '/:year/:month:/day', custom_predicates=(twenty_ten,))

• The repoze.bfg.url.route_url API has changed. If a keyword _app_url is present in the arguments passed to route_url, this value will be used as the protocol/hostname/port/leading path prefix of the generated URL. For example, using an _app_url of http://example.com:8080/foo would cause the URL http://example.com:8080/foo/fleeb/flub to be returned from this function if the expansion of the route pattern associated with the route_name expanded to /fleeb/flub.

• It is now possible to use a URL as the name argument fed to repoze.bfg.configuration.Configurator.add_static_view. When the name argument is a URL, the repoze.bfg.url.static_url API will generate join this URL (as a prefix) to a path including the static file name. This makes it more possible to put static media on a separate webserver for production, while keeping static media package-internal and served by the development webserver during development.

Documentation

• The authorization chapter of the ZODB Wiki Tutorial (docs/tutorials/bfgwiki) was changed to demonstrate authorization via a group rather than via a direct username (thanks to Alex Marandon).

• The authorization chapter of the SQLAlchemy Wiki Tutorial (docs/tutorials/bfgwiki2) was changed to demonstrate authorization via a group rather than via a direct username.

• Redirect requests for tutorial sources to http://docs.repoze.org/bfgwiki-1.3 and http://docs.repoze.org/bfgwiki2-1.3/ respectively.

• A section named Custom Route Predicates was added to the URL Dispatch narrative chapter.

• The Static Resources chapter has been updated to mention using static_url to generate URLs to external webservers.

Internal

• Removed repoze.bfg.static.StaticURLFactory in favor of a new abstraction revolving around the (still-internal) repoze.bfg.static.StaticURLInfo helper class.

1.3a3 (2010-05-01)

Paster Templates

• The bfg_alchemy and bfg_routesalchemy templates no longer register a handle_teardown event listener which calls DBSession.remove. This was found by Chris Withers to be unnecessary.

Documentation

• The “bfgwiki2” (URL dispatch wiki) tutorial code and documentation was changed to remove the handle_teardown event listener which calls DBSession.remove.

• Any mention of the handle_teardown event listener as used by the paster templates was removed from the URL Dispatch narrative chapter.

• A section entitled Detecting Available Languages was added to the i18n narrative docs chapter.

1.3a2 (2010-04-28)

Features

• A locale negotiator no longer needs to be registered explicitly. The default locale negotiator at repoze.bfg.i18n.default_locale_negotiator is now used unconditionally as… um, the default locale negotiator.

• The default locale negotiator has become more complex.

  • First, the negotiator looks for the _LOCALE_ attribute of the request object (possibly set by a view or an event listener).

  • Then it looks for the request.params['_LOCALE_'] value.

  • Then it looks for the request.cookies['_LOCALE_'] value.

Backwards Incompatibilities

• The default locale negotiator now looks for the parameter named _LOCALE_ rather than a parameter named locale in request.params.

Behavior Changes

• A locale negotiator may now return None, signifying that the default locale should be used.

Documentation

• Documentation concerning locale negotiation in the Internationalizationa and Localization chapter was updated.

• Expanded portion of i18n narrative chapter docs which discuss working with gettext files.

1.3a1 (2010-04-26)

Features

• Added “exception views”. When you use an exception (anything that inherits from the Python Exception builtin) as view context argument, e.g.:

  from repoze.bfg.view import bfg_view
  from repoze.bfg.exceptions import NotFound
  from webob.exc import HTTPNotFound
  
  @bfg_view(context=NotFound)
  def notfound_view(request):
      return HTTPNotFound()

  For the above example, when the repoze.bfg.exceptions.NotFound exception is raised by any view or any root factory, the notfound_view view callable will be invoked and its response returned.

  Other normal view predicates can also be used in combination with an exception view registration:

  from repoze.bfg.view import bfg_view
  from repoze.bfg.exceptions import NotFound
  from webob.exc import HTTPNotFound
  
  @bfg_view(context=NotFound, route_name='home')
  def notfound_view(request):
      return HTTPNotFound()

  The above exception view names the route_name of home, meaning that it will only be called when the route matched has a name of home. You can therefore have more than one exception view for any given exception in the system: the “most specific” one will be called when the set of request circumstances which match the view registration. The only predicate that cannot be not be used successfully is name. The name used to look up an exception view is always the empty string.

  Existing (pre-1.3) normal views registered against objects inheriting from Exception will continue to work. Exception views used for user-defined exceptions and system exceptions used as contexts will also work.

  The feature can be used with any view registration mechanism (@bfg_view decorator, ZCML, or imperative config.add_view styles).

  This feature was kindly contributed by Andrey Popp.

• Use “Venusian” (http://docs.repoze.org/venusian) to perform bfg_view decorator scanning rather than relying on a BFG-internal decorator scanner. (Truth be told, Venusian is really just a generalization of the BFG-internal decorator scanner).

• Internationalization and localization features as documented in the narrative documentation chapter entitled Internationalization and Localization.

• A new deployment setting named default_locale_name was added. If this string is present as a Paster .ini file option, it will be considered the default locale name. The default locale name is used during locale-related operations such as language translation.

• It is now possible to turn on Chameleon template “debugging mode” for all Chameleon BFG templates by setting a BFG-related Paster .ini file setting named debug_templates. The exceptions raised by Chameleon templates when a rendering fails are sometimes less than helpful. debug_templates allows you to configure your application development environment so that exceptions generated by Chameleon during template compilation and execution will contain more helpful debugging information. This mode is on by default in all new projects.

• Add a new method of the Configurator named derive_view which can be used to generate a BFG view callable from a user-supplied function, instance, or class. This useful for external framework and plugin authors wishing to wrap callables supplied by their users which follow the same calling conventions and response conventions as objects that can be supplied directly to BFG as a view callable. See the derive_view method in the repoze.bfg.configuration.Configurator docs.

ZCML

• Add a translationdir ZCML directive to support localization.

• Add a localenegotiator ZCML directive to support localization.

Deprecations

• The exception views feature replaces the need for the set_notfound_view and set_forbidden_view methods of the Configurator as well as the notfound and forbidden ZCML directives. Those methods and directives will continue to work for the foreseeable future, but they are deprecated in the documentation.

Dependencies

• A new install-time dependency on the venusian distribution was added.

• A new install-time dependency on the translationstring distribution was added.

• Chameleon 1.2.3 or better is now required (internationalization and per-template debug settings).

Internal

• View registrations and lookups are now done with three “requires” arguments instead of two to accomodate orthogonality of exception views.

• The repoze.bfg.interfaces.IForbiddenView and repoze.bfg.interfaces.INotFoundView interfaces were removed; they weren’t APIs and they became vestigial with the addition of exception views.

• Remove repoze.bfg.compat.pkgutil_26.py and import alias repoze.bfg.compat.walk_packages. These were only required by internal scanning machinery; Venusian replaced the internal scanning machinery, so these are no longer required.

Documentation

• Exception view documentation was added to the Hooks narrative chapter.

• A new narrative chapter entitled Internationalization and Localization was added.

• The “Environment Variables and ini File Settings” chapter was changed: documentation about the default_locale_name setting was added.

• A new API chapter for the repoze.bfg.i18n module was added.

• Documentation for the new translationdir and localenegotiator ZCML directives were added.

• A section was added to the Templates chapter entitled “Nicer Exceptions in Templates” describing the result of setting debug_templates = true.

Paster Templates

• All paster templates now create a setup.cfg which includes commands related to nose testing and Babel message catalog extraction/compilation.

• A default_locale_name = en setting was added to each existing paster template.

• A debug_templates = true setting was added to each existing paster template.

Licensing

• The Edgewall (BSD) license was added to the LICENSES.txt file, as some code in the repoze.bfg.i18n derives from Babel source.