From 542f86ba5cd3e2eec18224b2e4eff88fe58b6f43 Mon Sep 17 00:00:00 2001 From: Michael Merickel Date: Mon, 14 Mar 2016 14:20:26 -0500 Subject: add a new docs section on invoking exception views --- docs/narr/subrequest.rst | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) (limited to 'docs/narr/subrequest.rst') diff --git a/docs/narr/subrequest.rst b/docs/narr/subrequest.rst index daa3cc43f..ae1dd1b91 100644 --- a/docs/narr/subrequest.rst +++ b/docs/narr/subrequest.rst @@ -279,3 +279,49 @@ within a tween, because tweens already, by definition, have access to a function that will cause a subrequest (they are passed a ``handle`` function). It's fine to invoke :meth:`~pyramid.request.Request.invoke_subrequest` from within an event handler, however. + +Invoking an Exception View +-------------------------- + +.. versionadded:: 1.7 + +:app:`Pyramid` apps may define a :term:`exception views ` which +can handle any raised exceptions that escape from your code while processing +a request. By default, an unhandled exception will be caught by the `EXCVIEW` +:term:`tween` which will then lookup an exception view that can handle the +exception type, generating an appropriate error response. + +In :app:`Pyramid` 1.7 the :meth:`pyramid.request.Request.invoke_exception_view` +was introduced which allows a user to invoke an exception view while manually +handling an exception. This can be useful in a few different circumstances: + +- Manually handling an exception losing the current call stack / flow. + +- Handling exceptions outside of the context of the `EXCVIEW` tween. The + tween only covers certain parts of the request processing pipeline + (See :ref:`router chapter`) and there are some corner cases where an + exception can be raised which will still bubble up to middleware and possibly + to the web server where a generic ``500 Internal Server Error`` will be + returned to the client. + +Below is an example usage of +:meth:`pyramid.request.Request.invoke_exception_view`: + +.. code-block:: python + :linenos: + + def foo(request): + try: + some_func_that_errors() + return response + except Exception: + response = request.invoke_exception_view() + # there is no exception view for this exception, simply + # re-raise and let someone else handle it + if response is not None: + return response + else: + raise + +Please note that in most cases you do not need to write code like this an may +rely on the `EXCVIEW` tween to handle this for you. -- cgit v1.2.3 From 78cf75aef700f2db65d3dac379811c7f17eab1f7 Mon Sep 17 00:00:00 2001 From: Michael Merickel Date: Mon, 14 Mar 2016 14:28:18 -0500 Subject: fix broken ref --- docs/narr/subrequest.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'docs/narr/subrequest.rst') diff --git a/docs/narr/subrequest.rst b/docs/narr/subrequest.rst index ae1dd1b91..60972b156 100644 --- a/docs/narr/subrequest.rst +++ b/docs/narr/subrequest.rst @@ -299,7 +299,7 @@ handling an exception. This can be useful in a few different circumstances: - Handling exceptions outside of the context of the `EXCVIEW` tween. The tween only covers certain parts of the request processing pipeline - (See :ref:`router chapter`) and there are some corner cases where an + (See :ref:`router_chapter`) and there are some corner cases where an exception can be raised which will still bubble up to middleware and possibly to the web server where a generic ``500 Internal Server Error`` will be returned to the client. -- cgit v1.2.3 From 7175a51bec9491ff58a8ef3a94cc7804b476541d Mon Sep 17 00:00:00 2001 From: Michael Merickel Date: Mon, 14 Mar 2016 14:32:14 -0500 Subject: move comment closer to relevant logic --- docs/narr/subrequest.rst | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'docs/narr/subrequest.rst') diff --git a/docs/narr/subrequest.rst b/docs/narr/subrequest.rst index 60972b156..a943dca5d 100644 --- a/docs/narr/subrequest.rst +++ b/docs/narr/subrequest.rst @@ -316,11 +316,11 @@ Below is an example usage of return response except Exception: response = request.invoke_exception_view() - # there is no exception view for this exception, simply - # re-raise and let someone else handle it if response is not None: return response else: + # there is no exception view for this exception, simply + # re-raise and let someone else handle it raise Please note that in most cases you do not need to write code like this an may -- cgit v1.2.3 From dc3f79537f6901cf81a25f557c8d7bad1fe4f111 Mon Sep 17 00:00:00 2001 From: Steve Piercy Date: Mon, 14 Mar 2016 13:56:08 -0700 Subject: polish Invoking an Exception View docs - add index entry - minor grammar, syntax --- docs/narr/subrequest.rst | 28 ++++++++++++++++------------ 1 file changed, 16 insertions(+), 12 deletions(-) (limited to 'docs/narr/subrequest.rst') diff --git a/docs/narr/subrequest.rst b/docs/narr/subrequest.rst index a943dca5d..7c847de50 100644 --- a/docs/narr/subrequest.rst +++ b/docs/narr/subrequest.rst @@ -280,28 +280,32 @@ function that will cause a subrequest (they are passed a ``handle`` function). It's fine to invoke :meth:`~pyramid.request.Request.invoke_subrequest` from within an event handler, however. + +.. index:: + pair: subrequest; exception view + Invoking an Exception View -------------------------- .. versionadded:: 1.7 -:app:`Pyramid` apps may define a :term:`exception views ` which +:app:`Pyramid` apps may define :term:`exception views ` which can handle any raised exceptions that escape from your code while processing -a request. By default, an unhandled exception will be caught by the `EXCVIEW` -:term:`tween` which will then lookup an exception view that can handle the +a request. By default an unhandled exception will be caught by the ``EXCVIEW`` +:term:`tween`, which will then lookup an exception view that can handle the exception type, generating an appropriate error response. In :app:`Pyramid` 1.7 the :meth:`pyramid.request.Request.invoke_exception_view` -was introduced which allows a user to invoke an exception view while manually +was introduced, allowing a user to invoke an exception view while manually handling an exception. This can be useful in a few different circumstances: -- Manually handling an exception losing the current call stack / flow. +- Manually handling an exception losing the current call stack or flow. -- Handling exceptions outside of the context of the `EXCVIEW` tween. The - tween only covers certain parts of the request processing pipeline - (See :ref:`router_chapter`) and there are some corner cases where an - exception can be raised which will still bubble up to middleware and possibly - to the web server where a generic ``500 Internal Server Error`` will be +- Handling exceptions outside of the context of the ``EXCVIEW`` tween. The + tween only covers certain parts of the request processing pipeline (See + :ref:`router_chapter`). There are also some corner cases where an exception + can be raised that will still bubble up to middleware, and possibly to the + web server in which case a generic ``500 Internal Server Error`` will be returned to the client. Below is an example usage of @@ -323,5 +327,5 @@ Below is an example usage of # re-raise and let someone else handle it raise -Please note that in most cases you do not need to write code like this an may -rely on the `EXCVIEW` tween to handle this for you. +Please note that in most cases you do not need to write code like this, and you +may rely on the ``EXCVIEW`` tween to handle this for you. -- cgit v1.2.3