ghc participant training

Sahana Eden:Emergency

Development Environment

30 September 2010, Grace Hopper Celebration

Fran Boon

fran@sahanafoundation.org

Agenda

• Stack Overview

• Getting Set up

• Model View Controller– Filesystem Layout

• Build a New Module– S3 REST Controller

Stack OverviewServer

Sahana Eden (S3)

Web2Py

Python

HTML

JavaScript

CSS

Client Browser

Eclipse Firebug

Installation: Virtual Machine

Simplest way to start:http://eden.sahanafoundation.org/wiki/InstallationGuidelinesVirtualMachine

Full Developer Environment:•Eclipse•Codebase (Web2Py/Sahana Eden)

Launch Eclipse to get started…

Model-View-Controller

web2py/applications/eden/

•controllers

•models

•views

Model-View-Controller• Models

– Define Tables in the Database

• Controllers– Workflow, Logic

• Views– HTML / JS Templates parsed server-side– JS functions then run client-side in browser

Model-View-Controller

• Static– no server-side processing– Images– CSS– JavaScript

• Modules– Python libraries

Modules• Sahana concept

– Logical grouping of user-facing functionality– Not to be confused with Python modules

• i.e. not web2py/applications/eden/modules

• Consist of:– Model(s)– Controller– Views

Sahana Modules

• Organisation Registry: org

• Person Finder: pr, mpr, dvi

• Request Management: rms

• Inventory: inv

• Shelter Registry: cr

• Mapping: gis

• Messaging: msg

LaunchPad

Merge proposal

Branches

Trunk

Local Branch

Your Branch

bzr merge

bzr push

Request processing

1. Web2Py environment setup

2. All Models executed (alphabetical order)

3. Controller executed

4. Controller Function executed

5. View parsed (explicit variable passing)

6. HTML/JS returned to browser

Emergency• We have to build a module before bed!

Software Development Cycle

Incident Reporting SystemData:• Location• Date• Reporter• Details

Screens:• Report Incident• View Incidents• Update Incident

Define Data

models/inc.py

table = db.define_table("inc_incident",

location_id(),

Field("date", "date"),

person_id(),

comments()

)

Forms for CRUD

controllers/inc.py

def incident():

return shn_rest_controller("inc",

"incident")

We’re done!

http://127.0.0.1:8000/eden/inc/incident

1.Create an incident.

2.View in different formats:– .json, .xml, .xls, .pdf

http://127.0.0.1:8000/eden/inc/incident/1.json

Views: Custom REST

views/inc/incident_list_create.html

{{extend "layout.html"}}

<p>A Normal HTML Paragraph</p>

{{rheader="A Paragraph inserted inside the page"}}

{{include "_list_create.html"}}

{{include "gis/location_autocomplete.js"}}

•Python code inside {{ }} is parsed server-side•Views can extend (one) & include (many) other views•Extend ‘layout’ for overall look/feel•Variables only visible to views if:

– explicitly passed in return dict()– stored in global variables: request, response, session

SQL constraints / Validators

models/inc.py

table = db.define_table("inc_incident",

Field("code", unique=True),

…

)

DAL supports Live Migrations

Field Types models/inc.py

table = db.define_table ("inc_incident",

…

Field("date", "date"),

…

)

Default Values

models/inc.py

table = db.define_table("inc_incident",

…

Field("date_date", "date", default=request.utcnow),

…

)

Labels models/inc.py

table.person_id.label = "Reporter"

Internationalisation models/inc.py

table.person_id.label = T("Reporter“)

Comments models/inc.py

table.code.comment = SPAN("*", _class="req")

Requires

models/03_gis.py

db.gis_location.comment = …

db.gis_location.requires = IS_ONE_OF(…)

Represent

models/03_gis.py

db.gis_location.represent = shn_location_represent

Exploring: Web2Py shell• Python is great for interactive exploring!

– Web2Py allows this too

w2p

python web2py.py –S eden –M

• Explore objects with tabdb.

gis.

DALTry these in the shell: w2p

db.define_table("person", Field("name"))

id = db.person.insert(name="max")query = (db.person.id == id)

db(query).count()

db(query).update(name="Max")

rows = db(query).select(orderby=db.person.name)for row in rows:

print row.name

db(query).delete()

End

Enable Module models/000_config.py

deployment_settings.modules = Storage(

…

#irs = Storage(

inc = Storage(

name_nice = "Incident Reporting System", description = "Report Incidents",

module_type = 3

),

…

)

Index page controllers/inc.py

module = request.controller

def index():

"Custom View"

module_name = \ deployment_settings.modules[module].name_nice

return dict(module_name=module_name)

View

views/inc/index.html

{{extend "layout.html"}}

{{=H2(module_name)}}

<p>This module allows users to track their vehicles</p>

{{=LI(A("List Vehicles", _href=URL(r=request, f="vehicle")))}}

Controller: Menu controllers/inc.py

response.menu_options = [

[T("Incidents"), False, URL(r=request, f="incident"),[[T("List"), False, URL(r=request, f="incident")],[T("Add"), False, URL(r=request, f="incident",

args="create")] ]]]

Joined Resources

• So far:– Resource = Single Table

• Reality:– Resource spread out over multiple Tables

Joined Resources: Model

• Link Vehicle to Location– vts_presence

Joined Resources: Model

models/vts.pymodule = "vts"

resource = "presence"

tablename = "%s_%s" % (module, resource)

table = db.define_table(tablename,

Field("vehicle_id"),

Field("location_id"),

)

Joined Resources: Model

models/vts.py

table = db.define_table(tablename,

Field("vehicle_id", db.vts_vehicle),

Field("location_id", db.gis_location),

)

Joined Resources: Model

models/vts.py

table = db.define_table(tablename,

Field("vehicle_id", db.vts_vehicle),

location_id(),

)

Joined Resources: Controller controllers/vts.py

def presence():

resource = request.function

return shn_rest_controller(module, resource)

http://127.0.0.1:8000/eden/vts/presence

Joined Resources: Model

models/vts.py

table = db.define_table(tablename,

Field("vehicle_id", db.vts_vehicle),

location_id(),

)

table.vehicle_id.requires = IS_ONE_OF(db,

"vts_vehicle.id",

"vts_vehicle.registration")

Joined Resources: Model

models/vts.py

table = db.define_table(tablename,

Field("vehicle_id", db.vts_vehicle),

location_id(),

Field("timestmp", "datetime"),

)

table.vehicle_id.requires = IS_ONE_OF(db, "vts_vehicle.id", "vts_vehicle.registration")

table.timestmp.requires = IS_DATETIME()

Represent

table.vehicle_id.represent = lambda id: function

DAL: Optimised SQL queries

“Find the vehicle with this ID”:

db(db.vts_vehicle.id == id).select()

db(db.vts_vehicle.id == id).select().first()

“Return the Registration”:

db(db.vts_vehicle.id == id).select().first().registration

db(db.vts_vehicle.id == id).\

select(limitby=(0,1)).first().registration

db(db.vts_vehicle.id == id).\

select(db.vts_vehicle.registration,

limitby=(0,1)).first().registration

JR: Represent models/vts.py

table.vehicle_id.represent = lambda id: db(db.vts_vehicle.id == id).\ select(db.vts_vehicle.registration, limitby=(0,1)).first().registration

Components models/vts.py

# Presence as component of vehicle

s3xrc.model.add_component(module,

resource,

multiple=True,

joinby=dict(vts_vehicle="vehicle_id"),

deletable=True,

editable=True)

http://127.0.0.1:8000/eden/vts/vehicle/1/presence

RHeader controllers/vts.pydef shn_vts_rheader(r, tabs=[]):

if r.representation == "html":

rheader_tabs = shn_rheader_tabs(r, tabs)

vehicle = r.record

rheader = DIV(TABLE(

TR(TH(T("Vehicle: ")), vehicle.registration)

),

rheader_tabs

)

return rheader

return None

RHeader Tabs controllers/vts.pydef vehicle():

…

output = shn_rest_controller(module, "vehicle",

rheader=lambda r: shn_vts_rheader(r,

tabs = [(T("Basic Details"), None),

(T("Presence"), "presence")

]))

return output

http://127.0.0.1:8000/eden/vts/vehicle/1/presence

RHeader Tabs

S3 is built on Web2Py

REST

CRUD

SQLFORM

FORM

Form submission

• Use Firebug’s Net Panel to look at a form submission.

• Each field has an entry in form.vars

• Can add additional vars to the form in a custom View

• Can process these within our Controller– onvalidation: Before DB I/O– onaccept: After DB I/O

Documentation

• Examples from other modules

• Developer Guidelines on Wiki:http://eden.sahanafoundation.org/wiki/DeveloperGuidelines

• But the best…?

Use the Source, Luke!Many resources and tricks on the Internet find you will, but the ultimate answers only in the source lie