fix deprecated usage of request.accept in AcceptPredicate

docs/narr/extconfig.rst

@@ -255,6 +255,7 @@ Pre-defined Phases
 
 :const:`pyramid.config.PHASE1_CONFIG`
 
+- :meth:`pyramid.config.Configurator.add_accept_view_option`
 - :meth:`pyramid.config.Configurator.add_renderer`
 - :meth:`pyramid.config.Configurator.add_route_predicate`
 - :meth:`pyramid.config.Configurator.add_subscriber_predicate`

docs/narr/viewconfig.rst

@@ -285,6 +285,17 @@ Non-Predicate Arguments
  are just developing stock Pyramid applications. Pay no attention to the man
  behind the curtain.
 
+``exception_only``
+
+ When this value is ``True``, the ``context`` argument must be a subclass of
+ ``Exception``. This flag indicates that only an :term:`exception view` should
+ be created, and that this view should not match if the traversal
+ :term:`context` matches the ``context`` argument. If the ``context`` is a
+ subclass of ``Exception`` and this value is ``False`` (the default), then a
+ view will be registered to match the traversal :term:`context` as well.
+
+ .. versionadded:: 1.8
+
 Predicate Arguments
 +++++++++++++++++++
 
@@ -317,17 +328,6 @@ configured view.
  If ``context`` is not supplied, the value ``None``, which matches any
  resource, is used.
 
-``exception_only``
-
- When this value is ``True``, the ``context`` argument must be a subclass of
- ``Exception``. This flag indicates that only an :term:`exception view` should
- be created, and that this view should not match if the traversal
- :term:`context` matches the ``context`` argument. If the ``context`` is a
- subclass of ``Exception`` and this value is ``False`` (the default), then a
- view will be registered to match the traversal :term:`context` as well.
-
- .. versionadded:: 1.8
-
 ``route_name``
  If ``route_name`` is supplied, the view callable will be invoked only when
  the named route has matched.
@@ -344,6 +344,20 @@ configured view.
  request/context pair found via :term:`resource location` does not indicate it
  matched any configured route.
 
+``accept``
+ A :term:`media type` that will be matched against the ``Accept`` HTTP request header.
+ If this value is specified, it must be a specific media type, such as ``text/html``.
+ If the media type is acceptable by the ``Accept`` header of the request, or if the ``Accept`` header isn't set at all in the request, this predicate will match.
+ If this does not match the ``Accept`` header of the request, view matching continues.
+
+ If ``accept`` is not specified, the ``HTTP_ACCEPT`` HTTP header is not taken into consideration when deciding whether or not to invoke the associated view callable.
+
+ See :ref:`accept_content_negotation` for more information.
+
+ .. versionchanged:: 1.10
+ Media ranges such as ``text/*`` will now raise :class:`pyramid.exceptions.ConfigurationError`.
+ Previously these values had undefined behavior based on the version of WebOb being used and was never fully supported.
+
 ``request_type``
  This value should be an :term:`interface` that the :term:`request` must
  provide in order for this view to be found and called.
@@ -424,19 +438,6 @@ configured view.
  taken into consideration when deciding whether or not to invoke the
  associated view callable.
 
-``accept``
- The value of this argument represents a match query for one or more mimetypes
- in the ``Accept`` HTTP request header. If this value is specified, it must
- be in one of the following forms: a mimetype match token in the form
- ``text/plain``, a wildcard mimetype match token in the form ``text/*``, or a
- match-all wildcard mimetype match token in the form ``*/*``. If any of the
- forms matches the ``Accept`` header of the request, this predicate will be
- true.
-
- If ``accept`` is not specified, the ``HTTP_ACCEPT`` HTTP header is not taken
- into consideration when deciding whether or not to invoke the associated view
- callable.
-
 ``header``
  This value represents an HTTP header name or a header name/value pair.
 
@@ -1028,6 +1029,57 @@ these values.
 .. index::
  single: HTTP caching
 
+.. _accept_content_negotation:
+
+Accept Header Content Negotiation
+---------------------------------
+
+The ``accept`` argument to :meth:`pyramid.config.Configurator.add_view` can be used to control :term:`view lookup` by dispatching to different views based on the HTTP ``Accept`` request header. Consider the below example in which there are two views, sharing the same view callable. Each view specifies uses the accept header to trigger the appropriate response renderer.
+
+.. code-block:: python
+
+ from pyramid.view import view_config
+
+ @view_config(accept='application/json', renderer='json')
+ @view_config(accept='text/html', renderer='templates/hello.jinja2')
+ def myview(request):
+ return {
+ 'name': request.GET.get('name', 'bob'),
+ }
+
+Wildcard Accept header
+++++++++++++++++++++++
+
+The appropriate view is selected here when the client specifies an unambiguous header such as ``Accept: text/*`` or ``Accept: application/json``. However, by default, if a client specifies ``Accept: */*``, the ordering is undefined. This can be fixed by telling :app:`Pyramid` what the preferred relative ordering is between various accept mimetypes by using :meth:`pyramid.config.Configurator.add_accept_view_option`. For example:
+
+.. code-block:: python
+
+ from pyramid.config import Configurator
+
+ def main(global_config, **settings):
+ config = Configurator(settings=settings)
+ config.add_accept_view_option('text/html')
+ config.add_accept_view_option(
+ 'application/json',
+ weighs_more_than='text/html',
+ )
+ config.scan()
+ return config.make_wsgi_app()
+
+Missing Accept header
++++++++++++++++++++++
+
+The above example will not match any view if the ``Accept`` header is not specified by the client. This can be solved by adding a fallback view without an ``accept`` predicate, or by modifying one of the predicates to match ``*/*``. For example, below the html response will be returned in all cases unless ``application/json`` is requested specifically.
+
+.. code-block:: python
+
+ @view_config(accept='application/json', renderer='json')
+ @view_config(accept='*/*', renderer='templates/hello.jinja2')
+ def myview(request):
+ return {
+ 'name': request.GET.get('name', 'bob'),
+ }
+
 .. _influencing_http_caching:
 
 Influencing HTTP Caching

pyramid/config/__init__.py

@@ -394,6 +394,7 @@ def setup_registry(self,
 
  self.add_default_response_adapters()
  self.add_default_renderers()
+ self.add_default_accept_view_order()
  self.add_default_view_predicates()
  self.add_default_view_derivers()
  self.add_default_route_predicates()

pyramid/config/routes.py

@@ -139,18 +139,6 @@ def add_route(self,
 
  .. versionadded:: 1.1
 
- accept
-
- This value represents a match query for one or more mimetypes in the
- ``Accept`` HTTP request header. If this value is specified, it must
- be in one of the following forms: a mimetype match token in the form
- ``text/plain``, a wildcard mimetype match token in the form
- ``text/*`` or a match-all wildcard mimetype match token in the form
- ``*/*``. If any of the forms matches the ``Accept`` header of the
- request, or if the ``Accept`` header isn't set at all in the request,
- this will match the current route. If this does not match the
- ``Accept`` header of the request, route matching continues.
-
  Predicate Arguments
 
  pattern
@@ -233,6 +221,27 @@ def add_route(self,
  case of the header name is not significant. If this
  predicate returns ``False``, route matching continues.
 
+ accept
+
+ A media type that will be matched against the ``Accept`` HTTP
+ request header. If this value is specified, it must be a specific
+ media type, such as ``text/html``. If the media type is acceptable
+ by the ``Accept`` header of the request, or if the ``Accept`` header
+ isn't set at all in the request, this predicate will match. If this
+ does not match the ``Accept`` header of the request, route matching
+ continues.
+
+ If ``accept`` is not specified, the ``HTTP_ACCEPT`` HTTP header is
+ not taken into consideration when deciding whether or not to select
+ the route.
+
+
+ .. versionchanged:: 1.10
+ Media ranges such as ``text/*`` will now raise
+ :class:`pyramid.exceptions.ConfigurationError`. Previously,
+ these values had undefined behavior based on the version of
+ WebOb being used and was never fully supported.
+
  effective_principals
 
  If specified, this value should be a :term:`principal` identifier or
@@ -289,6 +298,10 @@ def add_route(self,
  DeprecationWarning,
  stacklevel=3
  )
+
+ if accept is not None:
+ accept = accept.lower()
+
  # these are route predicates; if they do not match, the next route
  # in the routelist will be tried
  if request_method is not None: