11 `````````````````````````````````````

    11 ````````````````````````````````````````

    55 

    55 [FROM-LAX-BOOK]

    56 

    57 Tip: when modifying views, you do not need to restart the local 

    58 server. Just save the file in your editor and reload the page in your

    59 browser to see the changes.

    60 

    61 With `LAX`, views are defined by Python classes. A view includes :

    62 

    63 - an identifier (all objects in `LAX` are entered in a registry

    64   and this identifier will be used as a key)

    65   

    66 - a filter to select the resulsets it can be applied to

    67 

    68 `LAX` provides a lot of standard views, for a complete list, you

    69 will have to read the code in directory ``ginco/web/views/`` (XXX

    70 improve doc).

    71 

    72 For example, the view named ``primary`` is the one used to display

    73 a single entity.

    74 

    75 If you want to change the way a ``BlogEntry`` is displayed, just

    76 override the view ``primary`` in ``BlogDemo/views.py`` ::

    77 

    78   01. from ginco.web.views import baseviews

    79   02.

    80   03. class BlogEntryPrimaryView(baseviews.PrimaryView):

    81   04.

    82   05.     accepts = ('BlogEntry',)

    83   06.

    84   07.     def cell_call(self, row, col):

    85   08.         entity = self.entity(row, col)

    86   09.         self.w(u'<h1>%s</h1>' % entity.title)

    87   10.         self.w(u'<p>published on %s in category %s</p>' % \

    88   11.                (entity.publish_date.strftime('%Y-%m-%d'), entity.category))

    89   12.         self.w(u'<p>%s</p>' % entity.text)

    90 

    91 The above source code defines a new primary view (`line 03`) for

    92 ``BlogEntry`` (`line 05`). 

    93 

    94 Since views are applied to resultsets and resulsets can be tables of

    95 data, it is needed to recover the entity from its (row,col)

    96 coordinates (`line 08`). We will get to this in more detail later.

    97 

    98 The view has a ``self.w()`` method that is used to output data. Here `lines

    99 09-12` output HTML tags and values of the entity's attributes.

   100 

   101 When displaying same blog entry as before, you will notice that the

   102 page is now looking much nicer.

   103 

   104 .. image:: ../images/lax-book.09-new-view-blogentry.en.png

   105    :alt: blog entries now look much nicer

   106 

   107 Let us now improve the primary view of a blog ::

   108 

   109   01. class BlogPrimaryView(baseviews.PrimaryView):

   110   02. 

   111   03.     accepts = ('Blog',)

   112   04.

   113   05.     def cell_call(self, row, col):

   114   06.         entity = self.entity(row, col)

   115   07.         self.w(u'<h1>%s</h1>' % entity.title)

   116   08.         self.w(u'<p>%s</p>' % entity.description)

   117   09.         rset = self.req.execute('Any E WHERE E entry_of B, B eid "%s"' % entity.eid)

   118   10.         self.wview('primary', rset)

   119 

   120 In the above source code, `lines 01-08` are similar to the previous

   121 view we defined.

   122 

   123 At `line 09`, a simple request in made to build a resultset with all

   124 the entities linked to the current ``Blog`` entity by the relationship

   125 ``entry_of``. The part of the framework handling the request knows

   126 about the schema and infer that such entities have to be of the

   127 ``BlogEntry`` kind and retrieves them.

   128 

   129 The request returns a selection of data called a resultset. At 

   130 `line 10` the view 'primary' is applied to this resultset to output

   131 HTML. 

   132 

   133 **This is to be compared to interfaces and protocols in object-oriented

   134 languages. Applying a given view to all the entities of a resultset only

   135 requires the availability, for each entity of this resultset, of a

   136 view with that name that can accepts the entity.**

   137 

   138 Assuming we added entries to the blog titled `MyLife`, displaying it

   139 now allows to read its description and all its entries.

   140 

   141 .. image:: ../images/lax-book.10-blog-with-two-entries.en.png

   142    :alt: a blog and all its entries

   143 

   144 **Before we move forward, remember that the selection/view principle is

   145 at the core of `LAX`. Everywhere in the engine, data is requested

   146 using the RQL language, then HTML/XML/text/PNG is output by applying a

   147 view to the resultset returned by the query. That is where most of the

   148 flexibility comes from.**

   149 

   150 [WRITE ME]

   151 

   152 * implementing interfaces, calendar for blog entries

   153 * show that a calendar view can export data to ical

   154 

   155 We will implement the ginco.interfaces.ICalendarable interfaces on

   156 entities.BloEntry and apply the OneMonthCalendar and iCalendar views

   157 to resultsets like "Any E WHERE E is BlogEntry"

   158 

   159 * create view "blogentry table" with title, publish_date, category

   160 

   161 We will show that by default the view that displays 

   162 "Any E,D,C WHERE E publish_date D, E category C" is the table view.

   163 Of course, the same can be obtained by calling

   164 self.wview('table',rset)

   165 

   166 * in view blog, select blogentries and apply view "blogentry table"

   167 * demo ajax by filtering blogentry table on category

   168 

   169 we did the same with 'primary', but with tables we can turn on filters

   170 and show that ajax comes for free.

    80 --------------------------------------------------------------------------------

   195 -----------------------------------------------------------------------------------

    85 .. image:: images/main_template_layout.png

   200 .. image:: ../images/main_template_layout.png