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Diffstat (limited to 'docs/tutorials/wiki/basiclayout.rst')
| -rw-r--r-- | docs/tutorials/wiki/basiclayout.rst | 30 |
1 files changed, 17 insertions, 13 deletions
diff --git a/docs/tutorials/wiki/basiclayout.rst b/docs/tutorials/wiki/basiclayout.rst index 8e6e89e57..c0faf30de 100644 --- a/docs/tutorials/wiki/basiclayout.rst +++ b/docs/tutorials/wiki/basiclayout.rst @@ -2,10 +2,9 @@ Basic Layout ============ -The starter files generated by the ``pyramid_zodb`` template are basic, -but they provide a good orientation for the high-level patterns common -to most :term:`traversal` -based :app:`Pyramid` (and :term:`ZODB` -based) projects. +The starter files generated by the ``pyramid_zodb`` template are basic, but +they provide a good orientation for the high-level patterns common to most +:term:`traversal` -based :app:`Pyramid` (and :term:`ZODB` based) projects. The source code for this tutorial stage can be browsed via `http://github.com/Pylons/pyramid/tree/master/docs/tutorials/wiki/src/basiclayout/ @@ -21,7 +20,7 @@ well as to contain application configuration code. When you run the application using the ``paster`` command using the ``development.ini`` generated config file, the application configuration -points at an Setuptools *entry point* described as ``egg:tutorial``. In our +points at a Setuptools *entry point* described as ``egg:tutorial``. In our application, because the application's ``setup.py`` file says so, this entry point happens to be the ``main`` function within the file named ``__init__.py``: @@ -78,11 +77,10 @@ Resources and Models with ``models.py`` hierarchically in a :term:`resource tree`. This tree is consulted by :term:`traversal` to map URLs to code. In this application, the resource tree represents the site structure, but it *also* represents the -:term:`domain model` of the application, because eeach resource is a node +:term:`domain model` of the application, because each resource is a node stored persistently in a :term:`ZODB` database. The ``models.py`` file is where the ``pyramid_zodb`` Paster template put the classes that implement our -resource objects, each of which happens also to be a domain model -object. +resource objects, each of which happens also to be a domain model object. Here is the source for ``models.py``: @@ -171,7 +169,6 @@ The ``development.ini`` (in the tutorial :term:`project` directory, as opposed to the tutorial :term:`package` directory) looks like this: .. literalinclude:: src/views/development.ini - :linenos: :language: ini @@ -184,15 +181,22 @@ composed of :term:`middleware`. The ``egg:WebError#evalerror`` middleware is at the "top" of the pipeline. This is middleware which displays debuggable errors in the browser while -you're developing (not recommended for deployment). +you're developing (not recommended for a production system). The ``egg:repoze.zodbconn#closer`` middleware is in the middle of the pipeline. This is a piece of middleware which closes the ZODB connection opened by the ``PersistentApplicationFinder`` at the end of the request. -The ``egg:repoze.tm#tm`` middleware is the last piece of middleware in the -pipeline. This commits a transaction near the end of the request unless -there's an exception raised. +The ``egg:repoze.retry#retry`` middleware catches ``ConflictError`` +exceptions from ZODB and retries the request up to three times (ZODB is an +optimistic concurrency database that relies on application-level transaction +retries when a conflict occurs). + +The ``tm`` middleware is the last piece of middleware in the pipeline. This +commits a transaction near the end of the request unless there's an exception +raised or the HTTP response code is an error code. The ``tm`` refers to the +``[filter:tm]`` section beneath the pipeline declaration, which configures +the transaction manager. The final line in the ``[pipeline:main]`` section is ``tutorial``, which refers to the ``[app:tutorial]`` section above it. The ``[app:tutorial]`` |