diff -r 9ecd54ea0634 -r 4b66ad23fbd1 doc/book/en/20-04-develop-views.en.txt --- a/doc/book/en/20-04-develop-views.en.txt Thu Nov 20 20:36:03 2008 +0100 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,128 +0,0 @@ -.. -*- coding: utf-8 -*- - - -Developing the user interface with Views -======================================== - -XXXFIXME MERGE THIS WITH 05-define-views.en.txt - -Before moving to this section, make sure you read the `Essentials` -section in the Introduction. - -Tip: when modifying views, you do not need to restart the local -server. Just save the file in your editor and reload the page in your -browser to see the changes. - -The selection/view principle ----------------------------- - -With `LAX`, views are defined by Python classes. A view includes: - -- an identifier (all objects in `LAX` are entered in a registry - and this identifier will be used as a key) - -- a filter to select the resulsets it can be applied to - -`LAX` provides a lot of standard views, for a complete list, you -will have to read the code in directory ``ginco/web/views/`` (XXX -improve doc). - -For example, the view named ``primary`` is the one used to display -a single entity. - -If you want to change the way a ``BlogEntry`` is displayed, just -override the view ``primary`` in ``BlogDemo/views.py`` :: - - 01. from ginco.web.views import baseviews - 02. - 03. class BlogEntryPrimaryView(baseviews.PrimaryView): - 04. - 05. accepts = ('BlogEntry',) - 06. - 07. def cell_call(self, row, col): - 08. entity = self.entity(row, col) - 09. self.w(u'
published on %s in category %s
' % \ - 11. (entity.publish_date.strftime('%Y-%m-%d'), entity.category)) - 12. self.w(u'%s
' % entity.text) - -The above source code defines a new primary view (`line 03`) for -``BlogEntry`` (`line 05`). - -Since views are applied to resultsets and resulsets can be tables of -data, it is needed to recover the entity from its (row,col) -coordinates (`line 08`). We will get to this in more detail later. - -The view has a ``self.w()`` method that is used to output data. Here `lines -09-12` output HTML tags and values of the entity's attributes. - -When displaying same blog entries as before, you will notice that the -page is now looking much nicer. - -.. image:: images/lax-book.09-new-view-blogentry.en.png - :alt: blog entries now look much nicer - -Let us now improve the primary view of a blog :: - - 01. class BlogPrimaryView(baseviews.PrimaryView): - 02. - 03. accepts = ('Blog',) - 04. - 05. def cell_call(self, row, col): - 06. entity = self.entity(row, col) - 07. self.w(u'%s
' % entity.description) - 09. rset = self.req.execute('Any E WHERE E entry_of B, B eid "%s"' % entity.eid) - 10. self.wview('primary', rset) - -In the above source code, `lines 01-08` are similar to the previous -view we defined. - -At `line 09`, a simple request in made to build a resultset with all -the entities linked to the current ``Blog`` entity by the relationship -``entry_of``. The part of the framework handling the request knows -about the schema and infer that such entities have to be of the -``BlogEntry`` kind and retrieves them. - -The request returns a selection of data called a resultset. At -`line 10` the view 'primary' is applied to this resultset to output -HTML. - -**This is to be compared to interfaces and protocols in object-oriented -languages. Applying a given view to all the entities of a resultset only -requires the availability, for each entity of this resultset, of a -view with that name that can accepts the entity.** - -Assuming we added entries to the blog titled `MyLife`, displaying it -now allows to read its description and all its entries. - -.. image:: images/lax-book.10-blog-with-two-entries.en.png - :alt: a blog and all its entries - -**Before we move forward, remember that the selection/view principle is -at the core of `LAX`. Everywhere in the engine, data is requested -using the RQL language, then HTML/XML/text/PNG is output by applying a -view to the resultset returned by the query. That is where most of the -flexibility comes from.** - -[WRITE ME] - -* implementing interfaces, calendar for blog entries -* show that a calendar view can export data to ical - -We will implement the ginco.interfaces.ICalendarable interfaces on -entities.BloEntry and apply the OneMonthCalendar and iCalendar views -to resultsets like "Any E WHERE E is BlogEntry" - -* create view "blogentry table" with title, publish_date, category - -We will show that by default the view that displays -"Any E,D,C WHERE E publish_date D, E category C" is the table view. -Of course, the same can be obtained by calling -self.wview('table',rset) - -* in view blog, select blogentries and apply view "blogentry table" -* demo ajax by filtering blogentry table on category - -we did the same with 'primary', but with tables we can turn on filters -and show that ajax comes for free.