140 lines
6.6 KiB
ReStructuredText
140 lines
6.6 KiB
ReStructuredText
.. _rest:
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REST Controller
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===============
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If you need to write controllers to interact with objects, using the
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``RestController`` may help speed things up. It follows the Representational
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State Transfer Protocol, also known as REST, by routing the standard HTTP
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verbs of GET, POST, PUT, and DELETE to individual methods::
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from pecan import expose
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from pecan.rest import RestController
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from mymodel import Book
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class BooksController(RestController):
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@expose()
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def get(self, id):
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book = Book.get(id)
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if not book:
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abort(404)
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return book.title
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URL Mapping
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-----------
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By default, the ``RestController`` routes as follows:
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+-----------------+--------------------------------------------------------------+--------------------------------------------+
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| Method | Description | Example Method(s) / URL(s) |
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+=================+==============================================================+============================================+
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| get_one | Display one record. | GET /books/1 |
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+-----------------+--------------------------------------------------------------+--------------------------------------------+
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| get_all | Display all records in a resource. | GET /books/ |
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+-----------------+--------------------------------------------------------------+--------------------------------------------+
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| get | A combo of get_one and get_all. | GET /books/ |
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| | +--------------------------------------------+
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| | | GET /books/1 |
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+-----------------+--------------------------------------------------------------+--------------------------------------------+
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| new | Display a page to create a new resource. | GET /books/new |
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+-----------------+--------------------------------------------------------------+--------------------------------------------+
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| edit | Display a page to edit an existing resource. | GET /books/1/edit |
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+-----------------+--------------------------------------------------------------+--------------------------------------------+
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| post | Create a new record. | POST /books/ |
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+-----------------+--------------------------------------------------------------+--------------------------------------------+
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| put | Update an existing record. | POST /books/1?_method=put |
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| | +--------------------------------------------+
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| | | PUT /books/1 |
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+-----------------+--------------------------------------------------------------+--------------------------------------------+
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| get_delete | Display a delete confirmation page. | GET /books/1/delete |
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+-----------------+--------------------------------------------------------------+--------------------------------------------+
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| delete | Delete an existing record. | POST /books/1?_method=delete |
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| | +--------------------------------------------+
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| | | DELETE /books/1 |
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+-----------------+--------------------------------------------------------------+--------------------------------------------+
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Pecan's ``RestController`` uses the de-facto standard ``?_method=`` query
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string hack to work around the lack of PUT/DELETE support in current browsers.
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The ``RestController`` still supports the ``index``, ``_default``, and
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``_lookup`` routing overrides. If you need to override ``_route``, however,
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make sure to call ``RestController._route`` at the end of your custom
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``_route`` method so that the REST routing described above still occurs.
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Nesting
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-------
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``RestController`` instances can be nested so that child resources get the
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parameters necessary to look up parent resources. For example::
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from pecan import expose
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from pecan.rest import RestController
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from mymodel import Author, Book
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class BooksController(RestController):
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@expose()
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def get(self, author_id, id):
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author = Author.get(author_id)
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if not author_id:
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abort(404)
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book = author.get_book(id)
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if not book:
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abort(404)
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return book.title
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class AuthorsController(RestController):
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books = BooksController()
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@expose()
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def get(self, id):
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author = Author.get(id)
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if not author:
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abort(404)
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return author.name
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class RootController(object):
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authors = AuthorsController()
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Accessing ``/authors/1/books/2`` would call ``BooksController.get`` with an
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``author_id`` of 1 and ``id`` of 2.
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To determine which arguments are associated with the parent resource, Pecan
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looks at the ``get_one`` or ``get`` method signatures, in that order, in the
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parent controller. If the parent resource takes a variable number of arguments,
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Pecan will hand it everything up to the child resource controller name (e.g.,
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``books`` in the above example).
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Custom Actions
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--------------
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In addition to the default methods defined above, you can add additional
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behaviors to a ``RestController`` by defining a special ``_custom_actions``
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dictionary. For example::
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from pecan import expose
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from pecan.rest import RestController
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from mymodel import Book
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class BooksController(RestController):
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_custom_actions = {
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'checkout': ['POST']
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}
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@expose()
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def checkout(self, id):
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book = Book.get(id)
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if not book:
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abort(404)
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book.checkout()
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Additional method names are the keys in the dictionary. The values are lists
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of valid HTTP verbs for those custom actions, including PUT and DELETE.
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