| commit | author | age | ||
| b731b5 | 1 | .. _qtut_routing: |
| PE | 2 | |
| b1b922 | 3 | ========================================== |
| PE | 4 | 11: Dispatching URLs To Views With Routing |
| 5 | ========================================== | |
| 6 | ||
| 72c219 | 7 | Routing matches incoming URL patterns to view code. Pyramid's routing has a |
| SP | 8 | number of useful features. |
| 9 | ||
| b1b922 | 10 | |
| PE | 11 | Background |
| 12 | ========== | |
| 13 | ||
| 72c219 | 14 | Writing web applications usually means sophisticated URL design. We just saw |
| SP | 15 | some Pyramid machinery for requests and views. Let's look at features that help |
| 16 | in routing. | |
| b1b922 | 17 | |
| 4caf31 | 18 | Previously we saw the basics of routing URLs to views in Pyramid. |
| b1b922 | 19 | |
| 72c219 | 20 | - Your project's "setup" code registers a route name to be used when matching |
| SP | 21 | part of the URL |
| b1b922 | 22 | |
| 72c219 | 23 | - Elsewhere a view is configured to be called for that route name. |
| b1b922 | 24 | |
| PE | 25 | .. note:: |
| 26 | ||
| 6c36d7 | 27 | Why do this twice? Other Python web frameworks let you create a route and |
| SP | 28 | associate it with a view in one step. As illustrated in |
| 29 | :ref:`routes_need_ordering`, multiple routes might match the same URL | |
| 30 | pattern. Rather than provide ways to help guess, Pyramid lets you be | |
| 31 | explicit in ordering. Pyramid also gives facilities to avoid the problem. | |
| 32 | It's relatively easy to build a system that uses implicit route ordering | |
| 33 | with Pyramid too. See `The Groundhog series of screencasts | |
| 34 | <http://static.repoze.org/casts/videotags.html>`_ if you're interested in | |
| b1b922 | 35 | doing so. |
| PE | 36 | |
| 72c219 | 37 | |
| b1b922 | 38 | Objectives |
| PE | 39 | ========== |
| 40 | ||
| 72c219 | 41 | - Define a route that extracts part of the URL into a Python dictionary. |
| b1b922 | 42 | |
| 72c219 | 43 | - Use that dictionary data in a view. |
| SP | 44 | |
| b1b922 | 45 | |
| PE | 46 | Steps |
| 47 | ===== | |
| 48 | ||
| 49 | #. First we copy the results of the ``view_classes`` step: | |
| 50 | ||
| 51 | .. code-block:: bash | |
| 52 | ||
| 187104 | 53 | $ cd ..; cp -r view_classes routing; cd routing |
| e612f1 | 54 | $ $VENV/bin/pip install -e . |
| b1b922 | 55 | |
| PE | 56 | #. Our ``routing/tutorial/__init__.py`` needs a route with a replacement |
| 57 | pattern: | |
| 58 | ||
| 59 | .. literalinclude:: routing/tutorial/__init__.py | |
| 60 | :linenos: | |
| 61 | ||
| 62 | #. We just need one view in ``routing/tutorial/views.py``: | |
| 63 | ||
| 64 | .. literalinclude:: routing/tutorial/views.py | |
| 65 | :linenos: | |
| 66 | ||
| 67 | #. We just need one view in ``routing/tutorial/home.pt``: | |
| 68 | ||
| 69 | .. literalinclude:: routing/tutorial/home.pt | |
| 70 | :language: html | |
| 71 | :linenos: | |
| 72 | ||
| 73 | #. Update ``routing/tutorial/tests.py``: | |
| 74 | ||
| 75 | .. literalinclude:: routing/tutorial/tests.py | |
| 76 | :linenos: | |
| 77 | ||
| 78 | #. Now run the tests: | |
| 79 | ||
| 80 | .. code-block:: bash | |
| 81 | ||
| 251ddd | 82 | $ $VENV/bin/py.test tutorial/tests.py -q |
| 72c219 | 83 | .. |
| SP | 84 | 2 passed in 0.39 seconds |
| b1b922 | 85 | |
| PE | 86 | #. Run your Pyramid application with: |
| 87 | ||
| 88 | .. code-block:: bash | |
| 89 | ||
| 187104 | 90 | $ $VENV/bin/pserve development.ini --reload |
| b1b922 | 91 | |
| d749bf | 92 | #. Open http://localhost:6543/howdy/amy/smith in your browser. |
| 72c219 | 93 | |
| b1b922 | 94 | |
| PE | 95 | Analysis |
| 96 | ======== | |
| 97 | ||
| 98 | In ``__init__.py`` we see an important change in our route declaration: | |
| 99 | ||
| 100 | .. code-block:: python | |
| 101 | ||
| 102 | config.add_route('hello', '/howdy/{first}/{last}') | |
| 103 | ||
| 72c219 | 104 | With this we tell the :term:`configurator` that our URL has a "replacement |
| SP | 105 | pattern". With this, URLs such as ``/howdy/amy/smith`` will assign ``amy`` to |
| 106 | ``first`` and ``smith`` to ``last``. We can then use this data in our view: | |
| b1b922 | 107 | |
| PE | 108 | .. code-block:: python |
| 109 | ||
| 110 | self.request.matchdict['first'] | |
| 111 | self.request.matchdict['last'] | |
| 112 | ||
| 72c219 | 113 | ``request.matchdict`` contains values from the URL that match the "replacement |
| SP | 114 | patterns" (the curly braces) in the route declaration. This information can |
| 115 | then be used anywhere in Pyramid that has access to the request. | |
| b1b922 | 116 | |
| 72c219 | 117 | Extra credit |
| b1b922 | 118 | ============ |
| PE | 119 | |
| 72c219 | 120 | #. What happens if you to go the URL http://localhost:6543/howdy? Is this the |
| SP | 121 | result that you expected? |
| b1b922 | 122 | |
| 72c219 | 123 | .. seealso:: `Weird Stuff You Can Do With URL Dispatch |
| SP | 124 | <http://www.plope.com/weird_pyramid_urldispatch>`_ |
