read-only static page (web 1.0) versus user-editable dynamic content (web 2.0)

I recently found a use case for user-editable dynamic web content, which is a significant shift from the previous use case of read-only static web pages. I've spent the day exploring how to enable user-editable dynamic content using Flask as a web framework.

I realized that d3js is a distractingly pretty interface for the static graph, but it doesn't move me towards EquationMap.com's intuitive interface. My Flask-based interface for dynamic content is driven by conventional form-based input. While this would accomplish the functionality, it's not as sexy as EquationMap.

There remains important work to be done with the static read-only content, namely a "zoom" interface which connects the concept map to specific derivations.


Update 20151207: a generated "overview" concept map showing the relations between derivations was created

SQLite on Mac and in Python

http://souptonuts.sourceforge.net/readme_sqlite_tutorial.html

https://www.sqlite.org/datatype3.html

http://zetcode.com/db/sqlitepythontutorial/

Python
http://sebastianraschka.com/Articles/2014_sqlite_in_python_tutorial.html

import sqlite3

Mac

sqlite3

sqlite3 test.db

moving from local terminal interface with CSV to web interface with a database backend

The existing Physics Derivation Graph is centered on command-line input with PNG output. Recently I've been exploring use of d3js as a web frontend.

I'm considering moving the Physics Derivation Graph to something which supports a web frontend connected to a hosted database backend. No command-line interaction or installation required.

I've been using CSV to store the data because it is the most common format. That works fine as long as the PDG is local and command-line driven. Now I want to move to a website, (ie openshift --
https://openshift.redhat.com/app/console/application_type/ )
I've set up a Django cartridge

I realized I don't need to sketch a design for the PDG web interface. Instead, I can start with determining minimum functionality:

• user login (don't want spammers writing to the database)
• user view existing content
• user add new content

I've used Flask previously, but I think the functionality I want is sufficiently complex that Flask wouldn't be enough.

I don't know whether I could continue to use the existing CSV as a backend storage. At this point I don't need scalability in terms of user latency or amount of data.


Vision: enable users of the PDG to interact with content in a web interface

Goal: use Django on Openshift to enable authentication, storage of content, and manipulating content

Path:

1. Flask local instance
• https://hplgit.github.io/web4sciapps/doc/pub/._web4sa_flask006.html
• http://code.tutsplus.com/tutorials/an-introduction-to-pythons-flask-framework--net-28822
2. Flask read values from database - CSV
3. convert PDG CSV to local SQL database
4. read from local SQL database
5. write to local SQL database - https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/sqlite3.1.html
6. Flask read values from database - SQL
7. Django local instance
8. Django local instance read values from database
9. Django local instance write values from database
10. Django on Openshift - http://physicsderivationgraph.blogspot.com/2015/11/django-and-openshift.html
11. Django on Openshift read values from database
12. Django on Openshift write values from database
13. Django on Openshift write values from database by authenticated user

Database choices

https://www.digitalocean.com/community/tutorials/sqlite-vs-mysql-vs-postgresql-a-comparison-of-relational-database-management-systems
https://www.digitalocean.com/community/tutorials/a-comparison-of-nosql-database-management-systems-and-models

CSV

SQLite

SQLite only supports a single writer at a time (meaning the execution of an individual transaction). SQLite locks the entire database when it needs a lock (either read or write) and only one writer can hold a write lock at a time.
SQLite 3.7.0 added a new journal mode called Write Ahead Locking that supports concurrent reading while writing.

django and openshift

created a django cartridge on openshift
physicsderivationgraph-beanno.rhcloud.com

physicsderivationgraph-beanno.rhcloud.com/admin

On my computer I ran
sudo pip install django

python wsgi/myproject/manage.py migrate

python wsgi/myproject/manage.py runserver

python wsgi/myproject/manage.py syncdb

--> prompted to create a superuser