CHANGES.txt

Next Release
============

Features
--------

- New environment setting ``PYRAMID_PREVENT_HTTP_CACHE`` and new
  configuration file value ``prevent_http_cache``.  These are synomymous and
  allow you to prevent HTTP cache headers from being set by Pyramid's
  ``http_cache`` machinery globally in a process.  see the "Influencing HTTP
  Caching" section of the "View Configuration" narrative chapter and the
  detailed documentation for this setting in the "Environment Variables and
  Configuration Settings" narrative chapter.

Behavior Changes
----------------

- Previously, If a ``BeforeRender`` event subscriber added a value via the
  ``__setitem__`` or ``update`` methods of the event object with a key that
  already existed in the renderer globals dictionary, a ``KeyError`` was
  raised.  With the deprecation of the "add_renderer_globals" feature of the
  configurator, there was no way to override an existing value in the
  renderer globals dictionary that already existed.  Now, the event object
  will overwrite an older value that is already in the globals dictionary
  when its ``__setitem__`` or ``update`` is called (as well as the new
  ``setdefault`` method), just like a plain old dictionary.  As a result, for
  maximum interoperability with other third-party subscribers, if you write
  an event subscriber meant to be used as a BeforeRender subscriber, your
  subscriber code will now need to (using ``.get`` or ``__contains__`` of the
  event object) ensure no value already exists in the renderer globals
  dictionary before setting an overriding value.

Bug Fixes
---------

- The ``Configurator.add_route`` method allowed two routes with the same
  route to be added without an intermediate ``config.commit()``.  If you now
  receive a ``ConfigurationError`` at startup time that appears to be
  ``add_route`` related, you'll need to either a) ensure that all of your
  route names are unique or b) call ``config.commit()`` before adding a
  second route with the name of a previously added name or c) use a
  Configurator that works in ``autocommit`` mode.

- The ``pyramid_routesalchemy`` and ``pyramid_alchemy`` scaffolds
  inappropriately used ``DBSession.rollback()`` instead of
  ``transaction.abort()`` in one place.

- We now clear ``request.response`` before we invoke an exception view; an
  exception view will be working with a request.response that has not been
  touched by any code prior to the exception.

Documentation
-------------

- Wiki2 (SQLAlchemy + URL Dispatch) tutorial ``models.initialize_sql`` didn't
  match the ``pyramid_routesalchemy`` scaffold function of the same name; it
  didn't get synchronized when it was changed in the scaffold.

- New documentation section in View Configuration narrative chapter:
  "Influencing HTTP Caching".

1.1b1 (2011-07-10)
==================

Features
--------

- It is now possible to invoke ``paster pshell`` even if the paste ini file
  section name pointed to in its argument is not actually a Pyramid WSGI
  application.  The shell will work in a degraded mode, and will warn the
  user.  See "The Interactive Shell" in the "Creating a Pyramid Project"
  narrative documentation section.

- ``paster pshell`` now offers more built-in global variables by default
  (including ``app`` and ``settings``).  See "The Interactive Shell" in the
  "Creating a Pyramid Project" narrative documentation section.

- It is now possible to add a ``[pshell]`` section to your application's .ini
  configuration file, which influences the global names available to a pshell
  session.  See "Extending the Shell" in the "Creating a Pyramid Project"
  narrative documentation chapter.

- The ``config.scan`` method has grown a ``**kw`` argument.  ``kw`` argument
  represents a set of keyword arguments to pass to the Venusian ``Scanner``
  object created by Pyramid.  (See the Venusian documentation for more
  information about ``Scanner``).

- New request property: ``json_body``. This property will return the
  JSON-decoded variant of the request body.  If the request body is not
  well-formed JSON, this property will raise an exception.

- A new value ``http_cache`` can be used as a view configuration
  parameter.

  When you supply an ``http_cache`` value to a view configuration, the
  ``Expires`` and ``Cache-Control`` headers of a response generated by the
  associated view callable are modified.  The value for ``http_cache`` may be
  one of the following:

  - A nonzero integer.  If it's a nonzero integer, it's treated as a number
    of seconds.  This number of seconds will be used to compute the
    ``Expires`` header and the ``Cache-Control: max-age`` parameter of
    responses to requests which call this view.  For example:
    ``http_cache=3600`` instructs the requesting browser to 'cache this
    response for an hour, please'.

  - A ``datetime.timedelta`` instance.  If it's a ``datetime.timedelta``
    instance, it will be converted into a number of seconds, and that number
    of seconds will be used to compute the ``Expires`` header and the
    ``Cache-Control: max-age`` parameter of responses to requests which call
    this view.  For example: ``http_cache=datetime.timedelta(days=1)``
    instructs the requesting browser to 'cache this response for a day,
    please'.

  - Zero (``0``).  If the value is zero, the ``Cache-Control`` and
    ``Expires`` headers present in all responses from this view will be
    composed such that client browser cache (and any intermediate caches) are
    instructed to never cache the response.

  - A two-tuple.  If it's a two tuple (e.g. ``http_cache=(1,
    {'public':True})``), the first value in the tuple may be a nonzero
    integer or a ``datetime.timedelta`` instance; in either case this value
    will be used as the number of seconds to cache the response.  The second
    value in the tuple must be a dictionary.  The values present in the
    dictionary will be used as input to the ``Cache-Control`` response
    header.  For example: ``http_cache=(3600, {'public':True})`` means 'cache
    for an hour, and add ``public`` to the Cache-Control header of the
    response'.  All keys and values supported by the
    ``webob.cachecontrol.CacheControl`` interface may be added to the
    dictionary.  Supplying ``{'public':True}`` is equivalent to calling
    ``response.cache_control.public = True``.

  Providing a non-tuple value as ``http_cache`` is equivalent to calling
  ``response.cache_expires(value)`` within your view's body.

  Providing a two-tuple value as ``http_cache`` is equivalent to calling
  ``response.cache_expires(value[0], **value[1])`` within your view's body.

  If you wish to avoid influencing, the ``Expires`` header, and instead wish
  to only influence ``Cache-Control`` headers, pass a tuple as ``http_cache``
  with the first element of ``None``, e.g.: ``(None, {'public':True})``.

Bug Fixes
---------

- Framework wrappers of the original view (such as http_cached and so on)
  relied on being able to trust that the response they were receiving was an
  IResponse.  It wasn't always, because the response was resolved by the
  router instead of early in the view wrapping process.  This has been fixed.

Documentation
-------------

- Added a section in the "Webob" chapter named "Dealing With A JSON-Encoded
  Request Body" (usage of ``request.json_body``).

Behavior Changes
----------------

- The ``paster pshell``, ``paster proutes``, and ``paster pviews`` commands
  now take a single argument in the form ``/path/to/config.ini#sectionname``
  rather than the previous 2-argument spelling ``/path/to/config.ini
  sectionname``.  ``#sectionname`` may be omitted, in which case ``#main`` is
  assumed.

1.1a4 (2011-07-01)
==================

Bug Fixes
---------

- ``pyramid.testing.DummyRequest`` now raises deprecation warnings when
  attributes deprecated for ``pyramid.request.Request`` are accessed (like
  ``response_content_type``).  This is for the benefit of folks running unit
  tests which use DummyRequest instead of a "real" request, so they know
  things are deprecated without necessarily needing a functional test suite.

- The ``pyramid.events.subscriber`` directive behaved contrary to the
  documentation when passed more than one interface object to its
  constructor.  For example, when the following listener was registered::

     @subscriber(IFoo, IBar)
     def expects_ifoo_events_and_ibar_events(event):
         print event

  The Events chapter docs claimed that the listener would be registered and
  listening for both ``IFoo`` and ``IBar`` events.  Instead, it registered an
  "object event" subscriber which would only be called if an IObjectEvent was
  emitted where the object interface was ``IFoo`` and the event interface was
  ``IBar``.

  The behavior now matches the documentation. If you were relying on the
  buggy behavior of the 1.0 ``subscriber`` directive in order to register an
  object event subscriber, you must now pass a sequence to indicate you'd
  like to register a subscriber for an object event. e.g.::

     @subscriber([IFoo, IBar])
     def expects_object_event(object, event):
         print object, event

Features
--------

- Add JSONP renderer (see "JSONP renderer" in the Renderers chapter of the
  documentation).

Deprecations
------------

- Deprecated the ``set_renderer_globals_factory`` method of the Configurator
  and the ``renderer_globals`` Configurator constructor parameter.

Documentation
-------------

- The Wiki and Wiki2 tutorial "Tests" chapters each had two bugs: neither did
  told the user to depend on WebTest, and 2 tests failed in each as the
  result of changes to Pyramid itself.  These issues have been fixed.

- Move 1.0.X CHANGES.txt entries to HISTORY.txt.

1.1a3 (2011-06-26)
==================

Features
--------

- Added ``mako.preprocessor`` config file parameter; allows for a Mako
  preprocessor to be specified as a Python callable or Python dotted name.
  See https://github.com/Pylons/pyramid/pull/183 for rationale.

Bug fixes
---------

- Pyramid would raise an AttributeError in the Configurator when attempting
  to set a ``__text__`` attribute on a custom predicate that was actually a
  classmethod.  See https://github.com/Pylons/pyramid/pull/217 .

- Accessing or setting deprecated response_* attrs on request
  (e.g. ``response_content_type``) now issues a deprecation warning at access
  time rather than at rendering time.

1.1a2 (2011-06-22)
==================

Bug Fixes
---------

- 1.1a1 broke Akhet by not providing a backwards compatibility import shim
  for ``pyramid.paster.PyramidTemplate``.  Now one has been added, although a
  deprecation warning is emitted when Akhet imports it.

- If multiple specs were provided in a single call to
  ``config.add_translation_dirs``, the directories were inserted into the
  beginning of the directory list in the wrong order: they were inserted in
  the reverse of the order they were provided in the ``*specs`` list (items
  later in the list were added before ones earlier in the list).  This is now
  fixed.

Backwards Incompatibilities
---------------------------

- The pyramid Router attempted to set a value into the key
  ``environ['repoze.bfg.message']`` when it caught a view-related exception
  for backwards compatibility with applications written for ``repoze.bfg``
  during error handling.  It did this by using code that looked like so::

                    # "why" is an exception object
                    try: 
                        msg = why[0]
                    except:
                        msg = ''

                    environ['repoze.bfg.message'] = msg

  Use of the value ``environ['repoze.bfg.message']`` was docs-deprecated in
  Pyramid 1.0.  Our standing policy is to not remove features after a
  deprecation for two full major releases, so this code was originally slated
  to be removed in Pyramid 1.2.  However, computing the
  ``repoze.bfg.message`` value was the source of at least one bug found in
  the wild (https://github.com/Pylons/pyramid/issues/199), and there isn't a
  foolproof way to both preserve backwards compatibility and to fix the bug.
  Therefore, the code which sets the value has been removed in this release.
  Code in exception views which relies on this value's presence in the
  environment should now use the ``exception`` attribute of the request
  (e.g. ``request.exception[0]``) to retrieve the message instead of relying
  on ``request.environ['repoze.bfg.message']``.

1.1a1 (2011-06-20)
==================

Documentation
-------------

- The term "template" used to refer to both "paster templates" and "rendered
  templates" (templates created by a rendering engine.  i.e. Mako, Chameleon,
  Jinja, etc.).  "Paster templates" will now be refered to as "scaffolds",
  whereas the name for "rendered templates" will remain as "templates."

- The ``wiki`` (ZODB+Traversal) tutorial was updated slightly.

- The ``wiki2`` (SQLA+URL Dispatch) tutorial was updated slightly.

- Make ``pyramid.interfaces.IAuthenticationPolicy`` and
  ``pyramid.interfaces.IAuthorizationPolicy`` public interfaces, and refer to
  them within the ``pyramid.authentication`` and ``pyramid.authorization``
  API docs.

- Render the function definitions for each exposed interface in
  ``pyramid.interfaces``.

- Add missing docs reference to
  ``pyramid.config.Configurator.set_view_mapper`` and refer to it within
  Hooks chapter section named "Using a View Mapper".

- Added section to the "Environment Variables and ``.ini`` File Settings"
  chapter in the narrative documentation section entitled "Adding a Custom
  Setting".

- Added documentation for a "multidict" (e.g. the API of ``request.POST``) as
  interface API documentation.

- Added a section to the "URL Dispatch" narrative chapter regarding the new
  "static" route feature.

- Added "What's New in Pyramid 1.1" to HTML rendering of documentation.

- Added API docs for ``pyramid.authentication.SessionAuthenticationPolicy``.

- Added API docs for ``pyramid.httpexceptions.exception_response``.

- Added "HTTP Exceptions" section to Views narrative chapter including a
  description of ``pyramid.httpexceptions.exception_response``.

Features
--------

- Add support for language fallbacks: when trying to translate for a
  specific territory (such as ``en_GB``) fall back to translations
  for the language (ie ``en``). This brings the translation behaviour in line
  with GNU gettext and fixes partially translated texts when using C
  extensions.

- New authentication policy:
  ``pyramid.authentication.SessionAuthenticationPolicy``, which uses a session
  to store credentials.

- Accessing the ``response`` attribute of a ``pyramid.request.Request``
  object (e.g. ``request.response`` within a view) now produces a new
  ``pyramid.response.Response`` object.  This feature is meant to be used
  mainly when a view configured with a renderer needs to set response
  attributes: all renderers will use the Response object implied by
  ``request.response`` as the response object returned to the router.

  ``request.response`` can also be used by code in a view that does not use a
  renderer, however the response object that is produced by
  ``request.response`` must be returned when a renderer is not in play (it is
  not a "global" response).

- Integers and longs passed as ``elements`` to ``pyramid.url.resource_url``
  or ``pyramid.request.Request.resource_url`` e.g. ``resource_url(context,
  request, 1, 2)`` (``1`` and ``2`` are the ``elements``) will now be
  converted implicitly to strings in the result.  Previously passing integers
  or longs as elements would cause a TypeError.

- ``pyramid_alchemy`` paster template now uses ``query.get`` rather than
  ``query.filter_by`` to take better advantage of identity map caching.

- ``pyramid_alchemy`` paster template now has unit tests.

- Added ``pyramid.i18n.make_localizer`` API (broken out from
  ``get_localizer`` guts).

- An exception raised by a NewRequest event subscriber can now be caught by
  an exception view.

- It is now possible to get information about why Pyramid raised a Forbidden
  exception from within an exception view.  The ``ACLDenied`` object returned
  by the ``permits`` method of each stock authorization policy
  (``pyramid.interfaces.IAuthorizationPolicy.permits``) is now attached to
  the Forbidden exception as its ``result`` attribute.  Therefore, if you've
  created a Forbidden exception view, you can see the ACE, ACL, permission,
  and principals involved in the request as
  eg. ``context.result.permission``, ``context.result.acl``, etc within the
  logic of the Forbidden exception view.

- Don't explicitly prevent the ``timeout`` from being lower than the
  ``reissue_time`` when setting up an ``AuthTktAuthenticationPolicy``
  (previously such a configuration would raise a ``ValueError``, now it's
  allowed, although typically nonsensical).  Allowing the nonsensical
  configuration made the code more understandable and required fewer tests.

- A new paster command named ``paster pviews`` was added.  This command
  prints a summary of potentially matching views for a given path.  See the
  section entitled "Displaying Matching Views for a Given URL" in the "View
  Configuration" chapter of the narrative documentation for more information.

- The ``add_route`` method of the Configurator now accepts a ``static``
  argument.  If this argument is ``True``, the added route will never be
  considered for matching when a request is handled.  Instead, it will only
  be useful for URL generation via ``route_url`` and ``route_path``.  See the
  section entitled "Static Routes" in the URL Dispatch narrative chapter for
  more information.

- A default exception view for the context
  ``pyramid.interfaces.IExceptionResponse`` is now registered by default.
  This means that an instance of any exception response class imported from
  ``pyramid.httpexceptions`` (such as ``HTTPFound``) can now be raised from
  within view code; when raised, this exception view will render the
  exception to a response.

- A function named ``pyramid.httpexceptions.exception_response`` is a
  shortcut that can be used to create HTTP exception response objects using
  an HTTP integer status code.

- The Configurator now accepts an additional keyword argument named
  ``exceptionresponse_view``.  By default, this argument is populated with a
  default exception view function that will be used when a response is raised
  as an exception. When ``None`` is passed for this value, an exception view
  for responses will not be registered.  Passing ``None`` returns the
  behavior of raising an HTTP exception to that of Pyramid 1.0 (the exception
  will propagate to middleware and to the WSGI server).

- The ``pyramid.request.Request`` class now has a ``ResponseClass`` interface
  which points at ``pyramid.response.Response``.

- The ``pyramid.response.Response`` class now has a ``RequestClass``
  interface which points at ``pyramid.request.Request``.

- It is now possible to return an arbitrary object from a Pyramid view
  callable even if a renderer is not used, as long as a suitable adapter to
  ``pyramid.interfaces.IResponse`` is registered for the type of the returned
  object by using the new
  ``pyramid.config.Configurator.add_response_adapter`` API.  See the section
  in the Hooks chapter of the documentation entitled "Changing How Pyramid
  Treats View Responses".

- The Pyramid router will now, by default, call the ``__call__`` method of
  WebOb response objects when returning a WSGI response.  This means that,
  among other things, the ``conditional_response`` feature of WebOb response
  objects will now behave properly.

- New method named ``pyramid.request.Request.is_response``.  This method
  should be used instead of the ``pyramid.view.is_response`` function, which
  has been deprecated.

Bug Fixes
---------

- URL pattern markers used in URL dispatch are permitted to specify a custom
  regex. For example, the pattern ``/{foo:\d+}`` means to match ``/12345``
  (foo==12345 in the match dictionary) but not ``/abc``. However, custom
  regexes in a pattern marker which used squiggly brackets did not work. For
  example, ``/{foo:\d{4}}`` would fail to match ``/1234`` and
  ``/{foo:\d{1,2}}`` would fail to match ``/1`` or ``/11``. One level of
  inner squiggly brackets is now recognized so that the prior two patterns
  given as examples now work. See also
  https://github.com/Pylons/pyramid/issues/#issue/123.

- Don't send port numbers along with domain information in cookies set by
  AuthTktCookieHelper (see https://github.com/Pylons/pyramid/issues/131).

- ``pyramid.url.route_path`` (and the shortcut
  ``pyramid.request.Request.route_url`` method) now include the WSGI
  SCRIPT_NAME at the front of the path if it is not empty (see
  https://github.com/Pylons/pyramid/issues/135).

- ``pyramid.testing.DummyRequest`` now has a ``script_name`` attribute (the
  empty string).

- Don't quote ``:@&+$,`` symbols in ``*elements`` passed to
  ``pyramid.url.route_url`` or ``pyramid.url.resource_url`` (see
  https://github.com/Pylons/pyramid/issues#issue/141).

- Include SCRIPT_NAME in redirects issued by
  ``pyramid.view.append_slash_notfound_view`` (see
  https://github.com/Pylons/pyramid/issues#issue/149).

- Static views registered with ``config.add_static_view`` which also included
  a ``permission`` keyword argument would not work as expected, because
  ``add_static_view`` also registered a route factory internally.  Because a
  route factory was registered internally, the context checked by the Pyramid
  permission machinery never had an ACL.  ``add_static_view`` no longer
  registers a route with a factory, so the default root factory will be used.

- ``config.add_static_view`` now passes extra keyword arguments it receives
  to ``config.add_route`` (calling add_static_view is mostly logically
  equivalent to adding a view of the type ``pyramid.static.static_view``
  hooked up to a route with a subpath).  This makes it possible to pass e.g.,
  ``factory=`` to ``add_static_view`` to protect a particular static view
  with a custom ACL.

- ``testing.DummyRequest`` used the wrong registry (the global registry) as
  ``self.registry`` if a dummy request was created *before* ``testing.setUp``
  was executed (``testing.setUp`` pushes a local registry onto the
  threadlocal stack). Fixed by implementing ``registry`` as a property for
  DummyRequest instead of eagerly assigning an attribute.
  See also https://github.com/Pylons/pyramid/issues/165

- When visiting a URL that represented a static view which resolved to a
  subdirectory, the ``index.html`` of that subdirectory would not be served
  properly.  Instead, a redirect to ``/subdir`` would be issued.  This has
  been fixed, and now visiting a subdirectory that contains an ``index.html``
  within a static view returns the index.html properly.  See also
  https://github.com/Pylons/pyramid/issues/67.

- Redirects issued by a static view did not take into account any existing
  ``SCRIPT_NAME`` (such as one set by a url mapping composite).  Now they do.

- The ``pyramid.wsgi.wsgiapp2`` decorator did not take into account the
  ``SCRIPT_NAME`` in the origin request.

- The ``pyramid.wsgi.wsgiapp2`` decorator effectively only worked when it
  decorated a view found via traversal; it ignored the ``PATH_INFO`` that was
  part of a url-dispatch-matched view.

Deprecations
------------

- Deprecated all assignments to ``request.response_*`` attributes (for
  example ``request.response_content_type = 'foo'`` is now deprecated).
  Assignments and mutations of assignable request attributes that were
  considered by the framework for response influence are now deprecated:
  ``response_content_type``, ``response_headerlist``, ``response_status``,
  ``response_charset``, and ``response_cache_for``.  Instead of assigning
  these to the request object for later detection by the rendering machinery,
  users should use the appropriate API of the Response object created by
  accessing ``request.response`` (e.g. code which does
  ``request.response_content_type = 'abc'`` should be changed to
  ``request.response.content_type = 'abc'``).

- Passing view-related parameters to
  ``pyramid.config.Configurator.add_route`` is now deprecated.  Previously, a
  view was permitted to be connected to a route using a set of ``view*``
  parameters passed to the ``add_route`` method of the Configurator.  This
  was a shorthand which replaced the need to perform a subsequent call to
  ``add_view``. For example, it was valid (and often recommended) to do::

     config.add_route('home', '/', view='mypackage.views.myview',
                       view_renderer='some/renderer.pt')

  Passing ``view*`` arguments to ``add_route`` is now deprecated in favor of
  connecting a view to a predefined route via ``Configurator.add_view`` using
  the route's ``route_name`` parameter.  As a result, the above example
  should now be spelled::

     config.add_route('home', '/')
     config.add_view('mypackage.views.myview', route_name='home')
                     renderer='some/renderer.pt')

  This deprecation was done to reduce confusion observed in IRC, as well as
  to (eventually) reduce documentation burden (see also
  https://github.com/Pylons/pyramid/issues/164).  A deprecation warning is
  now issued when any view-related parameter is passed to
  ``Configurator.add_route``.

- Passing an ``environ`` dictionary to the ``__call__`` method of a
  "traverser" (e.g. an object that implements
  ``pyramid.interfaces.ITraverser`` such as an instance of
  ``pyramid.traversal.ResourceTreeTraverser``) as its ``request`` argument
  now causes a deprecation warning to be emitted.  Consumer code should pass a
  ``request`` object instead.  The fact that passing an environ dict is
  permitted has been documentation-deprecated since ``repoze.bfg`` 1.1, and
  this capability will be removed entirely in a future version.

- The following (undocumented, dictionary-like) methods of the
  ``pyramid.request.Request`` object have been deprecated: ``__contains__``,
  ``__delitem__``, ``__getitem__``, ``__iter__``, ``__setitem__``, ``get``,
  ``has_key``, ``items``, ``iteritems``, ``itervalues``, ``keys``, ``pop``,
  ``popitem``, ``setdefault``, ``update``, and ``values``.  Usage of any of
  these methods will cause a deprecation warning to be emitted.  These
  methods were added for internal compatibility in ``repoze.bfg`` 1.1 (code
  that currently expects a request object expected an environ object in BFG
  1.0 and before).  In a future version, these methods will be removed
  entirely.

- Deprecated ``pyramid.view.is_response`` function in favor of (newly-added)
  ``pyramid.request.Request.is_response`` method.  Determining if an object
  is truly a valid response object now requires access to the registry, which
  is only easily available as a request attribute.  The
  ``pyramid.view.is_response`` function will still work until it is removed,
  but now may return an incorrect answer under some (very uncommon)
  circumstances.

Behavior Changes
----------------

- The default Mako renderer is now configured to escape all HTML in
  expression tags. This is intended to help prevent XSS attacks caused by
  rendering unsanitized input from users. To revert this behavior in user's
  templates, they need to filter the expression through the 'n' filter.
  For example, ${ myhtml | n }.
  See https://github.com/Pylons/pyramid/issues/193.

- A custom request factory is now required to return a request object that
  has a ``response`` attribute (or "reified"/lazy property) if they the
  request is meant to be used in a view that uses a renderer.  This
  ``response`` attribute should be an instance of the class
  ``pyramid.response.Response``.

- The JSON and string renderer factories now assign to
  ``request.response.content_type`` rather than
  ``request.response_content_type``.

- Each built-in renderer factory now determines whether it should change the
  content type of the response by comparing the response's content type
  against the response's default content type; if the content type is the
  default content type (usually ``text/html``), the renderer changes the
  content type (to ``application/json`` or ``text/plain`` for JSON and string
  renderers respectively).

- The ``pyramid.wsgi.wsgiapp2`` now uses a slightly different method of
  figuring out how to "fix" ``SCRIPT_NAME`` and ``PATH_INFO`` for the
  downstream application.  As a result, those values may differ slightly from
  the perspective of the downstream application (for example, ``SCRIPT_NAME``
  will now never possess a trailing slash).

- Previously, ``pyramid.request.Request`` inherited from
  ``webob.request.Request`` and implemented ``__getattr__``, ``__setattr__``
  and ``__delattr__`` itself in order to overidde "adhoc attr" WebOb behavior
  where attributes of the request are stored in the environ.  Now,
  ``pyramid.request.Request`` object inherits from (the more recent)
  ``webob.request.BaseRequest`` instead of ``webob.request.Request``, which
  provides the same behavior.  ``pyramid.request.Request`` no longer
  implements its own ``__getattr__``, ``__setattr__`` or ``__delattr__`` as a
  result.

- ``pyramid.response.Response`` is now a *subclass* of
  ``webob.response.Response`` (in order to directly implement the
  ``pyramid.interfaces.IResponse`` interface).

- The "exception response" objects importable from ``pyramid.httpexceptions``
  (e.g. ``HTTPNotFound``) are no longer just import aliases for classes that
  actually live in ``webob.exc``.  Instead, we've defined our own exception
  classes within the module that mirror and emulate the ``webob.exc``
  exception response objects almost entirely.  See the "Design Defense" doc
  section named "Pyramid Uses its Own HTTP Exception Classes" for more
  information.

Backwards Incompatibilities
---------------------------

- Pyramid no longer supports Python 2.4.  Python 2.5 or better is required to
  run Pyramid 1.1+.

- The Pyramid router now, by default, expects response objects returned from
  view callables to implement the ``pyramid.interfaces.IResponse`` interface.
  Unlike the Pyramid 1.0 version of this interface, objects which implement
  IResponse now must define a ``__call__`` method that accepts ``environ``
  and ``start_response``, and which returns an ``app_iter`` iterable, among
  other things.  Previously, it was possible to return any object which had
  the three WebOb ``app_iter``, ``headerlist``, and ``status`` attributes as
  a response, so this is a backwards incompatibility.  It is possible to get
  backwards compatibility back by registering an adapter to IResponse from
  the type of object you're now returning from view callables.  See the
  section in the Hooks chapter of the documentation entitled "Changing How
  Pyramid Treats View Responses".

- The ``pyramid.interfaces.IResponse`` interface is now much more extensive.
  Previously it defined only ``app_iter``, ``status`` and ``headerlist``; now
  it is basically intended to directly mirror the ``webob.Response`` API,
  which has many methods and attributes.

- The ``pyramid.httpexceptions`` classes named ``HTTPFound``,
  ``HTTPMultipleChoices``, ``HTTPMovedPermanently``, ``HTTPSeeOther``,
  ``HTTPUseProxy``, and ``HTTPTemporaryRedirect`` now accept ``location`` as
  their first positional argument rather than ``detail``.  This means that
  you can do, e.g. ``return pyramid.httpexceptions.HTTPFound('http://foo')``
  rather than ``return
  pyramid.httpexceptions.HTTPFound(location='http//foo')`` (the latter will
  of course continue to work).

Dependencies
------------

- Pyramid now depends on WebOb >= 1.0.2 as tests depend on the bugfix in that
  release: "Fix handling of WSGI environs with missing ``SCRIPT_NAME``".
  (Note that in reality, everyone should probably be using 1.0.4 or better
  though, as WebOb 1.0.2 and 1.0.3 were effectively brownbag releases.)