== Web2Py ==
 * http://mdp.cti.depaul.edu/examples/static/cookbook.pdf
 * http://mdp.cti.depaul.edu/examples/static/web2py_cheatsheet.pdf

This is an MVC environment (like Rails).

=== Model ===
Defines databases in: {{{/models/module.py}}}   (equivalent of inst/mysql-dbcreate.sql)

=== Controller ===
Python functions in /controllers/module.py
e.g.
{{{
   def list_records():
       list=t2.itemize(table)
       return dict (list=list)
}}}    

=== View ===
HTML/Javascript templates in /views/module/function.html
   - these are normal HTML/JS files with the ability to add in Python code (e.g. variables) surrounded by brackets: {{ interpreted python here }}
   - there should be an .html file available for each function in the module (name normally being the same as the function)
   - if there is no view defined then a default view will be displayed, which will show the values of all the data it can see, but not be formatted nicely

   CSS/Javascript files are stored in /static      (equivalent of www/res)

Python:
 -  Slow start
  - http://openbookproject.net/thinkcs/python/english2e/
 - Quick start
  - http://diveintopython.org/
 - v.Quick start!
  - Indentation matters (use 4 spaces instead of Tabs)
  - OOP - everything is an object

T2 is used for AAA & simplified CRUD (inc Conflict Detection)
http://mdp.cti.depaul.edu/examples/static/t2.pdf
We extend the T2 class in modules/sahana.py

CRUD
Create Record:
  Controller
{{{
   def add_record():
       form=t2.create(db.table)
       return dict(form=form)
}}}
  View
    views/module/add_record.html
{{{
     {{=form}}
}}}
Display Record:
  Controller
{{{
   def display_record():
       item=t2.display(db.table)
       return dict(item=item)
}}}
  View
    views/module/display_record.html
{{{
     {{=item}}
}}}
Update Record:
  Controller
{{{
   def display_record():
       form=t2.update(db.table)
       return dict(form=form)
}}}
  View
    views/module/add_record.html
{{{
     {{=form}}
}}}
Delete Record:
  Controller
{{{
   def delete_record():
   db(db.table.id==t2.id).delete()
   response.confirmation=T("Record deleted")
   response.view="module/list_records.html"
}}}
  View
    normally not used (reuse existing list_records view)


Populate the side navigation Menus by adding this to each controller:
{{{
module='module'
# Current Module (for sidebar title)
module_name=db(db.module.name==module).select()[0].name_nice
# List Modules (from which to build Menu of Modules)
modules=db(db.module.enabled=='Yes').select(db.module.ALL,orderby=db.module.menu_priority)
# List Options (from which to build Menu for this Module)
options=db(db['%s_menu_option' % module].enabled=='Yes').select(db['%s_menu_option' % module].ALL,orderby=db['%s_menu_option' % module].priority)
}}}

Each function needs to return these values to the view:
  return dict(module_name=module_name,modules=modules,options=options)

List output can be made more functional by adding this to your table definitions in models/db.py:
   {{{db.table.represent=lambda table: A(table.display_field,_href=t2.action('display_table',table.id))}}}
Form labels can be set in a translatable manner using:
   {{{db.table.field.label=T("label")}}}
Form field can be made to use a TEXTAREA by marking the field as being type 'text':
   {{{SQLField('field','text'),}}}
Form field can be made to use a SELECT dropdown by setting the field as a lookup to another table:
   {{{SQLField('field',db.othertable),}}}
Set this to use a different field than 'id' in the views (e.g. 'name') using:
   {{{db.table.field.requires=IS_NULL_OR(IS_IN_DB(db,'othertable.id','othertable.name'))}}}
Form field being required can be marked using:
   {{{db.table.field.comment=SPAN("*",_class="req")}}}
Help for a form field can be set using:
   {{{A(SPAN("[Help]"),_class="popupLink",_id="tooltip",_title=T("Help|This is what this field is for."))}}}


Conflict Detection:
Add this field to each table which needs protecting (in models/db.py):
SQLField('modified_on','datetime'), # Used by T2 to do edit conflict-detection

AAA
 Controller
  Each controller which incldues protected functions needs this:
{{{
   def login():
       response.view='login.html'
	   return dict(form=t2.login())
   def logout(): t2.logout(next='login')
   def register():
	   response.view='register.html'
	   return dict(form=t2.register())
  Each protected function needs this:
   @t2.requires_login('login')
   def function():
}}}

How to add a new module?
- copy existing & edit!
  Model
   Add module to db.module:
    http://127.0.0.1:8000/sahana/appadmin/select/db?query=db.module.id%3E0
   Create a table to store the module's menu options to /models/module.py
    db.module_menu_option
   Add tables to /models/module.py
    db.module_table
  Controller
   Add CRUD functions for these tables to /views/module.py
  View
   Add HTML templates for these functions: /views/module/function.html

How to do Options fields?
Sahana2 has a generic 'field_options' table for storing Options fields/.
Sahana3 uses a separate table for each lookup list

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