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).

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

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.

• 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?).