wiki:DeveloperGuidelinesS3

Version 3 (modified by Dominic König, 11 years ago) ( diff )

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DeveloperGuidelines | S3

S3 Framework Extensions for Web2py

All S3 framework extensions for web2py reside as a Python package in modules/s3:

ModuleFunctionality
s3aaaAuthentication, Authorization, Accouting
s3cfgDeployment Settings
s3gisGIS Module
s3msgMessaging API
s3test
s3toolsTools
s3utilsUtilities
s3validatorsCustom Validators
s3vitaPerson Finder Toolkit (VITA)
s3widgetsCustom UI Widgets
s3xrcExtensible Resource Controller (S3XRC)
s3restRESTful API (S3XRC)
s3crudRESTful CRUD Methods (S3XRC)
s3searchRESTful Search Methods
s3exportResource Export Toolkit (S3XRC)
s3importResource Import Toolkit (S3XRC)
s3modelData Model Extensions (S3XRC)
s3xmlXML Toolkit (S3XML)

The s3base Namespace

The names of the S3 package (=classes, functions, constants) are defined in modules/s3/__init__.py - all names which are imported in this file are available under the s3base namespace.

This namespace is imported in models/000_1st_run.py, thus it is available to all models and controllers - you don't need to import any S3 names separately, and neither do you need to think under which namespace a S3 class or function is available: always simply use the s3base prefix:

gis = s3base.GIS(...)
resource = s3base.S3Resource(...)

For convenience, the names of s3utils, s3widgets and s3validators are also imported into the global namespace, so you do not need a namesace prefix to access them:

mytable.myfield.requires = IS_UTC_DATETIME()
mywidget = S3CheckboxWidget.widget()

Extending S3

If you're going to add things to S3, please do it at the right place:

  • Utility functions which are meant to be globally available belong into modules/s3/s3utils.py
  • All other utility functions should either be class methods or should not be globally available
  • New classes should be added to the respective modules
  • New modules should be added as separate files

To make a class, function or constant available in the s3base namespace, you should import it in modules/s3/__init__.py:

from s3xrc import S3ResourceController

Note that you need to use the from s3xxx import yyy notation (relative import).

Importing Modules

Any submodule in modules/s3 can import names from any other submodule in modules/s3 by simply from s3xxx import yyy, by relative import:

from s3xrc import S3ResourceController

If you use the wildcard:

from s3xxx import *

then you have to ensure that the name you want to import is listed in the __all__ variable inside the respective s3xxx submodule:

__all__ = ["MyClass", "MyOtherClass"]

If __all___ is not declared inside a submodule, then all names are imported - but this should be avoided.

You can also import names from other modules in the modules directory, by relative import:

from ..pyparsing import ParseBaseException

Note the .. before the module path.

Coding Conventions

Please consider our coding conventions when coding S3 extensions:

  • names of top-level functions must be prefixed by s3_, must be all lowercase (no CamelCase!), with words separated by underscores, e.g. s3_my_function
  • names of genuine S3 classes (even if based on web2py classes) must be prefixed by S3, and use CamelCase, e.g. S3ResourceController
  • names of customized web2py classes (which are meant to be used instead of the native web2py class) are suffixed with S3, e.g. AuthS3
  • constants must be prefixed by S3, all uppercase, with words separated by underscores, e.g. S3_MY_CONSTANT
  • functions inside of classes can be named arbitrarily, however, their names should somehow indicate what they do
  • all modules must have a docstring describing the module, the module author(s), the copyright and license
  • the copyright statement must declare the SSF as copyright holder, and the license must be MIT
  • dependencies can be declared with the @requires: statement
""" Utilities

    @requires: U{B{I{gluon}} <http://web2py.com>}

    @author: Fran Boon <fran[at]aidiq.com>
    @author: Michael Howden <michael[at]aidiq.com>
    @author: Pradnya Kulkarni

    @copyright: (c) 2010 Sahana Software Foundation
    @license: MIT

    Permission is hereby granted, free of charge, to any person
    obtaining a copy of this software and associated documentation
    files (the "Software"), to deal in the Software without
    restriction, including without limitation the rights to use,
    copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following
    conditions:

    The above copyright notice and this permission notice shall be
    included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
    OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
    HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
    WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
    OTHER DEALINGS IN THE SOFTWARE.

"""

  • all functions - in classes or top-level - must have docstrings explaining what they are supposed to do
  • the docstring should contain an @author: tag if the author differs from the module author
  • you should add your email address, if you want others to contact you with questions or suggestions
def shn_split_multi_value(value):
    """
    @author: Michael Howden <michael[at]aidiq.com>

    Converts a series of numbers delimited by |, or already in a string into a list

    If value = None, returns []

    """

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