Dynamic Web Programming:python pg and cgi modulesMansi M. KasliwalCarnegie Institution for ScienceCalifornia Institute of Technology

Database

• Logical tables to organize large amounts of data• Easy-to-manage: add/subtract/modify• Structure facilitating super-fast complex queries

• Python “pg” module• connect• query, insert, delete, update

(Note: psycopg2 module for cursor handling in large databases, copy command etc.)

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An Example Database Schemacreatedb tutorial

psql –d tutorial CREATE SEQUENCE people_id_seq;

CREATE TABLE people ( id bigint NOT NULL default nextval(‘people_id_seq’),firstname text, lastname text );

CREATE TABLE education ( people_id bigint, subject text, degree text, college text,

year int );

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Example pg commandsimport pg

#Connect to Databasedb = pg.connect(dbname=‘tutorial’, host=‘localhost’, user=‘mmk’)

#Add Entriesdb.insert(people, [firstname=‘mansi’, lastname=‘kasliwal’])delete(table, [d,] [key = val, ...])update(table, [d,] [key = val, ...])

#Example Query Joining Two Tablesresult = db.query(“SELECT * from people, education WHERE people.id = education.people_id AND subject=‘astronomy’;”)

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Dynamic Web Programming• Generate nimble webpages on-the-fly that push and pull

data to and fro a database• Python “cgi” module is easy-to-use• URL: GET method

• e.g. tutorial.cgi?firstname=‘mansi’&lastname=‘kasliwal’• FORM: POST method

• Radio buttons or check boxes• Drop down menu• File upload/download• Blank Text Area

• Retrieving cookies• e.g. os.environ['REMOTE_USER']

(Note: wsgi is more portable than cgi since it unifies the application programming interface; wsgi = Web Server Gateway Interface)

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Example Form

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#!/usr/bin/python # Import modules for CGI handling import cgi, cgitb

# Create instance of FieldStorage form =cgi.FieldStorage()

# Put up a form<form action="/cgi-bin/tutorial.cgi" method="post"> First Name: <input type="text" name="firstname"> <br /> Last Name: <input type="text" name="lastname" /><input type="submit" value="Submit" /> </form>

# Get data from fields first_name = form.getvalue('firstname') last_name = form.getvalue('lastname')

#Insert entry into databasedb.insert(people, [firstname=‘%s’, lastname=‘%s’] %(first_name, last_name))

Check box / Dropdown Menu

<form action="/cgi-bin/checkbox.cgi" method="POST" target="_blank"> <input type="checkbox" name="maths" value="on" /> Maths <input type="checkbox" name="physics" value="on" /> Physics <input type="submit" value="Select Subject" /> </form>

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<form action="/cgi-bin/dropdown.cgi" method="post" target="_blank"> <select name="dropdown"> <option value="Maths" selected>Maths</option> <option value="Physics">Physics</option> </select> <input type="submit" value="Submit"/> </form>

Applications in Time Domain

1. A Treasures Portal2. Follow-up Marshals

a. Extragalactic Transientsb. Milky Way Variablesc. Solar Systemd. Target-of-opportunity

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iPTF Treasures Portal

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Developers: MMK, Yi Cao

The iPTF Treasure Chest

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A versatile portal with query derivatives:1. ROBOTIC treasurer2. SYSTEMATIC daily monitoring 3. YOUNG supernovae4. GAP transients in the local universe 5. SLOWLY rising supernovae6. LARGE amplitude stars7. Fermi/Icecube target of opportunity fields triggers8. M31/M33 transients and variables9. FAST Transients10. NUCLEAR Transients

Developers: MMK, Yi Cao, Iair Arcavi

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Developers: Robert Quimby, MMK, Iair Arcavi

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Light Curves: Key to Variable Stars

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Developers: David Levitan

Automatically match with SDSS, WISE, SimbadLinks to NED, CRTS, LINEAR, etc. Periods

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Period search

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Movement: Key to Asteroids

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Developer: Adam Waszczak

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Questions?

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