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| author | Paul Everitt <paul@agendaless.com> | 2008-07-24 17:14:16 +0000 |
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| committer | Paul Everitt <paul@agendaless.com> | 2008-07-24 17:14:16 +0000 |
| commit | 1a7b14de4bc89ef0fd162ef8e62d01926e42b54e (patch) | |
| tree | 8d9ccc8187ac29eb80ac310c6f82c17d548cdf54 /docs/tutorials/lxmlgraph/step04.rst | |
| parent | c1a6ef6f751a16b7a352bc3fdad13d4b5b73f212 (diff) | |
| download | pyramid-1a7b14de4bc89ef0fd162ef8e62d01926e42b54e.tar.gz pyramid-1a7b14de4bc89ef0fd162ef8e62d01926e42b54e.tar.bz2 pyramid-1a7b14de4bc89ef0fd162ef8e62d01926e42b54e.zip | |
Add tutorial sections
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| -rw-r--r-- | docs/tutorials/lxmlgraph/step04.rst | 98 |
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diff --git a/docs/tutorials/lxmlgraph/step04.rst b/docs/tutorials/lxmlgraph/step04.rst new file mode 100644 index 000000000..8112610a2 --- /dev/null +++ b/docs/tutorials/lxmlgraph/step04.rst @@ -0,0 +1,98 @@ +================================================ +Step 04: Hierarchical Rendering With XSLT +================================================ + +Now that we have basic templating for our XML graph in place, let's +start doing some fun stuff with it. As we walk through use cases and +build out patterns for implementing them, we'll get to leverage some +features available in XML processors. For better or worse. [wink] + +In this step we take a look at the following: + +- Build a nested, folder-like website + +- Render the HTML common to all pages, then render the part specific + to a certain page + +- Show contents of a folder when sitting on a folder, and content of a + document when sitting on a document + + +Pre-Flight Cleanup +==================== + +In the last example, we had a default template that used ZPT. We're +shifting the rest of the steps over to XSLT. Thus, our +``myapp/configure.zcml`` is now simpler: + +.. literalinclude:: step04/myapp/configure.zcml + :linenos: + :language: xml + +We also remove the ZPT view function from ``views.py``, as we'll see +in a moment. + +Design Change: Trees and Context IDs +======================================== + +In ``repoze.bfg``, the ``context`` variable that is passed into our +view function equates to the Python object that was grabbed on the +current hop in the URL. For ``repoze.lxmlgraph``, that "context" +object is a node in the XML document, found by traversing node +children. + +For the XSLT in Step 03, we passed in the context node. From the +XSLT's perpective, the universe started at the context node. It could +only see information in that node and the children beneath it. + +If we could see the entire tree, however, we could put the other +information to use: showing the name of the site in a header, listing +the breadcrumbs to reach the document, and other portal-style boxes. + +To enable this, we need the following: + +#. A way to pass in the entire XML document tree. + +#. A way to uniquely point at the item in the XML that we are + currently sitting on, with the fastest performance possible. + +We will thus make the following changes in our approach: + +#. The XML document will support an ``xml:id`` attribute on each node + that has a ``name`` attribute. The ``xml:id`` uniquely identifies + the resource within the document. Moreover, it leverages built-in + support for high-speed lookups in XPath. + +#. We change the view function to pass in the root of the tree, + instead of the context node. + +#. We also pass in, via an XSLT parameter, the ``xml:id`` of the + context node. + +#. The XSLT will start at the top of the tree, generate the site-wide + look and feel, then render the context node. + +That's the big picture. Each of these changes will be explained in +detail below. + + +File ``myapp/samplemodel.xml`` +================================ + +The XML document with the information for our website has quite a +number of changes: + +.. literalinclude:: step04/myapp/samplemodel.xml + :linenos: + :language: xml + +#. Line 3 shows that our ``<site>`` now gets a ``<title>``. + +#. On Line 4 we make an index document at the root that contains a + document-wide unique value for its ``@xml:id``. + +#. In lines 5-11, our ``<document>`` gets some extra information: a + ``<title>``, plus some HTML-namespaced markup content inside a + ``<body>``. + +#. |