= Developer Guidelines - Basics = 
[[TOC]]
Here are some helpful hints to get started developing in Sahana Eden.

* [wiki:DeveloperGuidelinesSahana2Migration Help for Developers Migrating from Sahana PHP]
* [wiki:DeveloperGuidelinesDjangoMigration Help for Developers Migrating from Django]

== Running Sahana Eden ==
{{{
cd .. # the web2py main directory
python web2py.py
}}}
Or if you don't want to have to enter a password (or have issues launching the Web2Py GUI).
{{{
python web2py.py -a 1234
}}}

== Wiping the Database ==
Out of the box Sahana Eden is set to use the SQLite database. If you want to wipe all the data, simply delete the {{{databases/}}} directory, along with the {{{sessions/}}} directory (this contains details about your login - which will be invalid as you'll be deleting the user account). The next time you run Sahana Eden, it will recreate the database tables.

== Pre-Populating Data ==
Sahana Eden is able to "[DeveloperGuidelines/PrePopulate Pre-Populate]" data so you can explore/test/develop the application with different types of data. Pre-Populate options are associated with the [DeveloperGuidelines/Templates Templates], but they can be set in {{{models/000_config.py}}}.

{{{IFRC_Train}}} is a good set of pre-populate to use (See: https://github.com/flavour/eden/tree/master/private/templates/IFRC_Train). It also has an admin user account: admin@example.com password: testing. To use it edit {{{models/000_config.py}}}:

After:
{{{
# =============================================================================
# Over-rides to the Template may be done here
}}}
Add (or un-comment):
{{{
settings.base.prepopulate = ["IFRC_Train"]
}}}

Pre-populate data will only be created if the database is empty, so you may need to wipe the database first. It may take a few minutes to load the data.

== Debug Mode ==
In {{{models/000_config.py}}} uncomment this line:
{{{
settings.base.debug = True
}}}
to:
* Use the non-minified CSS & JS
* See changes in {{{modules/s3db}}} files without restarting Web2Py

== Running a Sahana Eden Python Shell ==
To open a Python Shell in the Sahana Eden Environment, where you can inspect Web2Py and Sahana Eden variables as well as access the data:
{{{
cd web2py
python web2py.py -S eden -M
}}}
To have database changes be persistent (e.g. to see via Web UI), you will need to commit the transactions: {{{db.commit()}}}.

== Python ==
Indentation matters (use 4 spaces instead of Tabs)
* http://diveintopython.net
* http://openbookproject.net/thinkcs/python/english2e/
* http://software-carpentry.org
* Python v2 documentation: http://docs.python.org/ (We are currently using v2.7.)

== Web2Py ==
This is an [http://en.wikipedia.org/wiki/Model-view-controller MVC] environment (like [http://web2py.com/AlterEgo/default/show/103 Rails] & [http://web2py.com/AlterEgo/default/show/101 Django]. [http://vimeo.com/6507384 Django polls tutorial conversion course]).

Web2Py can work at several different levels of abstraction.[[BR]]
The Sahana Eden framework (S3) is built on Web2Py's !Auth/Crud classes in {{{tools.py}}} (with some remnants of the older T2), however sometimes we need more control therefore need to drop down a level or two.

Can execute a controller to be able to access its functions using:
{{{
execfile("applications/eden/controllers/mycontroller.py", globals())
}}}

Web2Py can be extended through [http://www.web2py.com/plugins Plugins] & also has a [http://web2pyslices.com recipes site].

* [http://web2py.com/book Web2py Book]

== Javascript ==
 * W3Schools' basic JS: http://www.w3schools.com/js/

 * jQuery is used for client-side business logic (hiding fields, opening up tabs, etc):
  * Tutorial 1: http://docs.jquery.com/Tutorials:How_jQuery_Works
  * Tutorial 2: http://docs.jquery.com/Tutorials:Getting_Started_with_jQuery
  * Main reference: http://docs.jquery.com
  * We use some plugins: http://plugins.jquery.com
  * & some Widgets: http://jqueryui.com

 * ExtJS is used for some advanced widgets:
  * http://www.sencha.com
  * http://dev.sencha.com/deploy/ext-4.0.0/examples/
  * API: http://www.extjs.com/deploy/dev/docs/

 * S3 includes a cross-browser debug utility (only shows up when ?debug=1):
{{{
s3_debug('message', value);
}}}

All global variables should be in the S3 namespace:
 * http://yuiblog.com/blog/2006/06/01/global-domination/

Private variables should be protected, e.g. using the Module Pattern:
 * http://yuiblog.com/blog/2007/06/12/module-pattern/
 * http://www.adequatelygood.com/2010/3/JavaScript-Module-Pattern-In-Depth

Can test out the performance of different options to achieve a task using:
 * http://jsperf.com

Can check quality using JSLint:
 * http://www.javascriptlint.com/online_lint.php

== XSLT ==
To transform XML (and CSV) files for importing and exporting data.
* [wiki:XsltTemplates Sahana Eden XSLT Documentation]
* XPath: http://www.w3schools.com/xpath/default.asp
* XSLT: http://www.w3schools.com/xsl/default.asp
* [http://codespeak.net/lxml/tutorial.html lxml Tutorial]