Turnin Webapp

Written By Jonathan Clark 2011 For 11-711 at Carnegie Mellon University

Overview

A tool for instructors that allows students to submit .tgz files using a web interface.

Features:

• Dead simple web-interface
• Minimal configuration
• Built-in cryptographic receipt system to verify student turn-in claims (in case there is a discrepancy between the file on-disk and a file the student claims to have submitted)
• Tracks multiple submissions

The most recent version of files submitted are kept in data/uploads. The entire history of files submitted by students is kept in data/uploads/all. All generated receipts are logged to data/receipts.log.

Building and Running the WebApp

This app is built ontop of Scalatra https://github.com/scalatra/scalatra

You'll need Scala 2.9.1+ installed. You probably want to run this as a special user with very few permissions.

./build.sh
./run.sh

Now have a look at your turnin server running at http://localhost:8081

Configuration

Edit data/turnin.conf

You can configure which files should be expected in the submission by editing data/manifest.txt

You can change the logo by replacing webapps/turnin/logo.png

Working with Receipts

Generating an Encryption Key for Turnin Receipts

You'll need to generate a unique secret key, which will be used to generate recepts. Make sure to keep this secret from the people who you will be giving receipts to.

./keygen.sh key.bin

Verifying the Time and MD5 Checksum of a Submission

Given the receipt (e.g. a362b2bf7cd6dc646e7fabc478208752), you can verify the time of submission. If the student also provides the file they claim to have submitted, you can also verify the file's contents.

./view.sh key.bin a362b2bf7cd6dc646e7fabc478208752
md5sum file_student_claims_submitted.tar.gz

Checking for Stolen Receipts

If a student claims the receipt of another student, you can verify this by grepping through the file "receipts.log", which records all issued receipts.

Manually Generating a Receipt

You should never need to do this manually since the webapp does this for you. But just in case:

./generate.sh data/key.bin start.jar

Future Features

• Protection against bots

References

http://wiki.eclipse.org/Jetty/Reference/Dependencies http://wiki.eclipse.org/Jetty/Feature/WebAppDeployer http://www.enavigo.com/2008/08/29/deploying-a-web-application-to-jetty/ http://scalate.fusesource.org/documentation/user-guide.html