Assignment 2: Bid points

Due: 5pm, Friday, February 10. Value: 40 pts. You may work with one other student on this assignment if you wish. Submit to Sauron.

In this assignment, you'll develop a front end (as described under Front end below) for allowing students to bid for courses. We'll suppose that each student enrolling in the course has 10 points to allocate between courses that the student would like to take; whenever the student wishes to enroll in the course, a bid of at least one must be placed onto the course.

Back end

I have already created a back end using an SQLite database. This includes two files to be executed using Node.js (with the nodejs command). There should be no reason for you to modify either of these two files, linked below.

bids-init.js	Creates the initial database, deleting old database if necessary.
bids-server.js	Runs the HTTP server to serve files and respond to requests

The initial database as configured by bids-init.js has a set of 15 courses (as it happens, those offered for Maymester 2012), along with bids for three students (named bugs, daffy, and elmer).

For most requests coming from the browser, the HTTP server bids-server.js assumes that the path requested represents a filename, and it looks in the current directory to find the data it should send in response. However, there are two special paths that the server treats specially: /fetch and /set_bid.

/fetch

This should be sent as a GET request, with a parameter named user (technically optional). The server returns a JSON object containing a success property that is true or false. If success is false, then the JSON object has a message property whose value is a string denoting the problem with the request. If success is true, then the JSON object has a results property whose value is an array of objects representing each course in the database. Each of these course objects has the following properties (all with string values):

course	The course identifier (e.g., CSCI 135)
title	The course title (e.g., Robotics Explorations Studio)
instructor	The instructor (e.g., Ferrer)
enroll	The number of students who have bid for the course.
bid	The number of points bid by the indicated user. (This is omitted if the GET request omits a user parameter).

/set_bid

This should be sent as a POST request, with three parameters: user specifying the student's user ID, course specifying the course ID (e.g., CSCI 135), and bid specifying the requested bid that the indicated user wishes to place on the requested course. The server returns a JSON object containing a success property whose value is true or false. If success is false, then the JSON object has a message property whose value is a string denoting the problem with the request. Some potential problems are a user ID with nonalphanumeric characters, a user ID whose length is not between 1 and 40, an unrecognized course ID, a bid that is identical to the current bid in the database, or a bid that will push the user's total bids over 10.

Front end

In addition to the two back-end files displayed above, you'll also want to download the jQuery JavaScript library, which will be served as part of the front end alongside the JavaScript file that you write.

jquery-1.7.1.js

jQuery library

The front end should work as follows: The page will initially display a log in form consisting of a blank requesting the user ID and a button for logging in. The page should send a /fetch request to the server; if successful, the log-in form should disappear, replaced with the information sent by /fetch in a table such as the following.

ARTS 130	Digital Art I	Payne	0	—	Change
ARTS 290	Beginning Bookbinding	Jensen	0	—	Change
CLAS 255	Medical Etymology	Resinski	0	—	Change
CSCI 135	Robotics Explorations Studio	Ferrer	2	1	Change
DANC 205	Intro to Asian Music and Dance	Griebling/Rogers	0	—	Change
ENGC 390	Non-Contemporary Poetry	Jaeger	1	2	Change
ENGL 272	Crime Literature and Film	West	1	—	Change
PHIL 200	Ethics and Pornography	Campolo	2	—	Change
PHYS 100	Physics of Superheroes	Wright	3	4	Change
PHYS 160	Astronomy	Wright	1	—	Change
POLI 365	Law and Legal Reasoning	Maslin-Wicks	1	—	Change
PSYC 180	Illusions and the Brain	Puri	0	—	Change
PSYC 185	Sleep and Dreaming	Peszka	0	—	Change
PSYC 190	Social Psychology in Film	Zorwick	2	3	Change

From here, entering an integer into any blank and clicking the Change button should result in a /set_bid request being sent to the server for the corresponding course. Upon the completion of the /set_bid request, if success is false, the message should be displayed for the user to see; and if success is true, the page should refresh the table to reflect the updated value.

After logging in, the page should also include a link for refreshing the table (which would get updated information in case another user has registered for a course since the current information was entered) and a link for logging out (which would return the screen to its initial login state).

While the above description describes the basic behavior of your Web page fairly thoroughly, there is quite a bit of flexibility about how exactly it is presented. You should strive to make your page as usable as possible. As always, feel free to talk with me regarding any questions about how to do something specific.

Submit the files containing your HTML, CSS, and JavaScript (but not the distributed files) to Sauron.