Counter Examples

In this project we are going to implement a counter with various front-ends and back-ends.

The simpler version of the counter script handles a single counter. Every time we run the counter it will fetch the latest value from the "back-end", increment it by one, display the new value, and save the new value back to the "back-end". An interaction might look like this:

$ count
  1
$ count
  2
$ count
  3

The slightly more complex version will receive a string as an input and for each string it will maintain a separate counter. So an interaction might look like this:

$ count foo
  foo: 1
$ count foo
  foo: 2
$ count bar
  bar: 1
$ count foo
  foo: 3

The front-end can be command line, or web, or maybe some other GUI.

The back-end is some kind of a "database". It can be a plain text file, some data serialization format, a relational database, a NoSQL database and who knows what else.

This is going to be a long project, but it might help understand various techniques for data serialization.

• A command-line counter script that uses a plain file called counter.txt for a single counter.

• On-load counter with JavaScript and local storage

• Multiple command line counters with plain TSV text file back-end

• A command line counter with database back-end using DBIx::Class

• Command line counter with JSON backend

• Counter with Dancer session

• In-memory counter using AngularJS

• Automatic counter using AngularJS

• Several counters in MongoDB client

• Command line counter with MongoDB as storage

• Command-line counter in Python for a single counter.

• Counter with Mojolicious Lite

• Command line counter with Memcached

• increasing numbers in a text file

Front-end

• command line
• web based:
• plain CGI
• CGI with Ajax
• plain PSGI
• PSGI with Ajax
• Dancer
• Mojolicious

Back-end

• several counters each one in its own file
• several counters in a .txt file in CSV format
• several counters in a yaml/json file
• 1 counter in SQLite
• several counters in SQLite
• 1 counter in MySQL
• several counters in MySQL
• ? PostgreSQL
• 1 counter in MongoDB
• several counters in MongoDB