wiki:DeveloperGuidelines/Basics

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Developer Guidelines - Basics

Here are some helpful hints to get started developing in Sahana Eden.

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 "Pre-Populate" data so you can explore/test/develop the application with different types of data. Pre-Populate options are associated with the 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)

Web2Py

This is an MVC environment (like Rails & Django. Django polls tutorial conversion course).

Web2Py can work at several different levels of abstraction.
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 Plugins & also has a recipes site.

Javascript

  • 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:

Private variables should be protected, e.g. using the Module Pattern:

Can test out the performance of different options to achieve a task using:

Can check quality using JSLint:

XSLT

To transform XML (and CSV) files for importing and exporting data.

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