doc/book/devweb/views/basetemplates.rst
changeset 10491 c67bcee93248
parent 10222 75d6096216d7
child 10495 5bd914ebf3ae
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc/book/devweb/views/basetemplates.rst	Thu Jan 08 22:11:06 2015 +0100
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+.. -*- coding: utf-8 -*-
+
+.. _templates:
+
+Templates
+=========
+
+Templates are the entry point for the |cubicweb| view system. As seen
+in :ref:`views_base_class`, there are two kinds of views: the
+templatable and non-templatable.
+
+
+Non-templatable views
+---------------------
+
+Non-templatable views are standalone. They are responsible for all the details
+such as setting a proper content type (or mime type), the proper document
+headers, namespaces, etc. Examples are pure xml views such as RSS or Semantic Web
+views (`SIOC`_, `DOAP`_, `FOAF`_, `Linked Data`_, etc.), and views which generate
+binary files (pdf, excel files, etc.)
+
+.. _`SIOC`: http://sioc-project.org/
+.. _`DOAP`: http://trac.usefulinc.com/doap
+.. _`FOAF`: http://www.foaf-project.org/
+.. _`Linked Data`: http://linkeddata.org/
+
+
+To notice that a view is not templatable, you just have to set the
+view's class attribute `templatable` to `False`. In this case, it
+should set the `content_type` class attribute to the correct MIME
+type. By default, it is text/xhtml. Additionally, if your view
+generate a binary file, you have to set the view's class attribute
+`binary` to `True` too.
+
+
+Templatable views
+-----------------
+
+Templatable views are not concerned with such pesky details. They
+leave it to the template. Conversely, the template's main job is to:
+
+* set up the proper document header and content type
+* define the general layout of a document
+* invoke adequate views in the various sections of the document
+
+
+Look at :mod:`cubicweb.web.views.basetemplates` and you will find the base
+templates used to generate (X)HTML for your application. The most important
+template there is :class:`~cubicweb.web.views.basetemplates.TheMainTemplate`.
+
+.. _the_main_template_layout:
+
+TheMainTemplate
+~~~~~~~~~~~~~~~
+
+.. _the_main_template_sections:
+
+Layout and sections
+```````````````````
+
+A page is composed as indicated on the schema below :
+
+.. image:: ../../images/main_template.png
+
+The sections dispatches specific views:
+
+* `header`: the rendering of the header is delegated to the
+  `htmlheader` view, whose default implementation can be found in
+  ``basetemplates.py`` and which does the following things:
+
+    * inject the favicon if there is one
+    * inject the global style sheets and javascript resources
+    * call and display a link to an rss component if there is one available
+
+  it also sets up the page title, and fills the actual
+  `header` section with top-level components, using the `header` view, which:
+
+    * tries to display a logo, the name of the application and the `breadcrumbs`
+    * provides a login status area
+    * provides a login box (hiden by default)
+
+* `left column`: this is filled with all selectable boxes matching the
+  `left` context (there is also a right column but nowadays it is
+  seldom used due to bad usability)
+
+* `contentcol`: this is the central column; it is filled with:
+
+    * the `rqlinput` view (hidden by default)
+    * the `applmessages` component
+    * the `contentheader` view which in turns dispatches all available
+      content navigation components having the `navtop` context (this
+      is used to navigate through entities implementing the IPrevNext
+      interface)
+    * the view that was given as input to the template's `call`
+      method, also dealing with pagination concerns
+    * the `contentfooter`
+
+* `footer`: adds all footer actions
+
+.. note::
+
+  How and why a view object is given to the main template is explained
+  in the :ref:`publisher` chapter.
+
+Configure the main template
+```````````````````````````
+
+You can overload some methods of the
+:class:`~cubicweb.web.views.basetemplates.TheMainTemplate`, in order to fulfil
+your needs. There are also some attributes and methods which can be defined on a
+view to modify the base template behaviour:
+
+* `paginable`: if the result set is bigger than a configurable size, your result
+  page will be paginated by default. You can set this attribute to `False` to
+  avoid this.
+
+* `binary`: boolean flag telling if the view generates some text or a binary
+  stream.  Default to False. When view generates text argument given to `self.w`
+  **must be a unicode string**, encoded string otherwise.
+
+* `content_type`, view's content type, default to 'text/xhtml'
+
+* `templatable`, boolean flag telling if the view's content should be returned
+  directly (when `False`) or included in the main template layout (including
+  header, boxes and so on).
+
+* `page_title()`, method that should return a title that will be set as page
+  title in the html headers.
+
+* `html_headers()`, method that should return a list of HTML headers to be
+  included the html headers.
+
+
+You can also modify certain aspects of the main template of a page
+when building a url or setting these parameters in the req.form:
+
+* `__notemplate`, if present (whatever the value assigned), only the content view
+  is returned
+
+* `__force_display`, if present and its value is not null, no pagination whatever
+  the number of entities to display (e.g. similar effect as view's `paginable`
+  attribute described above.
+
+* `__method`, if the result set to render contains only one entity and this
+  parameter is set, it refers to a method to call on the entity by passing it the
+  dictionary of the forms parameters, before going the classic way (through step
+  1 and 2 described juste above)
+
+* `vtitle`, a title to be set as <h1> of the content
+
+Other templates
+~~~~~~~~~~~~~~~
+
+There are also the following other standard templates:
+
+* :class:`cubicweb.web.views.basetemplates.LogInTemplate`
+* :class:`cubicweb.web.views.basetemplates.LogOutTemplate`
+* :class:`cubicweb.web.views.basetemplates.ErrorTemplate` specializes
+  :class:`~cubicweb.web.views.basetemplates.TheMainTemplate` to do
+  proper end-user output if an error occurs during the computation of
+  TheMainTemplate (it is a fallback view).