~~NOTOC~~

====== Project 0 ======

====== Summary ======
Create a webapp to enable a group of people to collaborate online on authoring a simple document. The goal is to expose the challenges that underlie building such a webapp without a framework and, to that end, it will be implemented with CGI using a scripting language (Perl).


====== Perl Resources ======
[[http://www.perl.org/|Authoritative page]]
[[http://www.comp.leeds.ac.uk/Perl/start.html|Tutorial]]
[[http://www.cse.yorku.ca/~roumani/perl/|My page]]

====== Base Requirement ======
Whenever a user visits the URL of your webapp, a screen similar to the following is displayed:

{{:proj0.jpg|}}

The webapp allows several users to concurrently create a list of countries. The user enters a country name and then clicks the "add" button. The above screen shows that 4 countries have been entered so far (by all users) and 2 of them were created by this user in this session (the other 2 may have been created by other users or by this user in a prior session). The master list is displayed beneath as shown. 

**Validation** \\

  * If the entry made by the user is already present in the master list then it is rejected. In that case, the same screen is re-served (with its information updated to reflect any changes made by others in the master list) but with a line added at the top containing, in red colour, the message: "This country has already been added". Furthermore, the text box must be filled with whatever the user entered; i.e. the entry is echoed back. 

  * If the entry is empty or contains only whitespace then it is also rejected, and the form is re-served, as above, with the message: "Country name cannot be blank!". 

In all other cases, the country is added, the form re-served, and no message appears at the top.

====== Possible Variations ======

  * Country name must be made up of letters and possibly a hyphen in the middle.
  * The master list should be displayed sorted.

  * Don't send the master list if the client is iPhone or Blackberry.
  * If a user remained idle while others are adding countries, the counter on the screen would not remain correct. Fix this.

  * Map your app's URL to a directory.
  * Add logging to your webapp.

  * Add authentication to your webapp.
  * Add confidentiality to your webapp.

  * Trigger an event if a user successfully added more than 5 counties per session.
  * Compress your webapp's response.

  * Keep track of the counties entered by the user in the session, not just the count, and enable the user to view them.
  * Enable richer content. Rather than just a country name, the user may also enter the capital and possibly the population.

The following two variations require CSS and JavaScript:

  * Rather than serve the list every time, change the UI to a sidebar and two links "Add a Country" and  "Show Master List"
  * To improve responsiveness, and to place less demand on the network, have the client do some validation. Server validation should remain unchanged (why?).