API Endpoints

Reference for all server endpoints.

Overview

The Express server (app.js) exposes the following endpoints:

Endpoint	Method	Description
/submit	POST	Submit code to Gradescope
/starter/:filename	GET	Get starter code template
/lti/launch	POST	Handle LTI 1.3 launch
/auth/status	GET	Check authentication status

POST /submit

Submit student code to Gradescope for grading.

Request

POST /submit
Content-Type: application/json

Body:

{
  "code": "print('Hello, World!')",
  "email": "student@school.edu",
  "stud_id": "900123456",
  "asg_id": "6617143",
  "file_name": "program.py"
}

Parameters

Field	Type	Required	Description
code	string	Yes	The Python code to submit
email	string	No	Student email address
stud_id	string	No	Student ID
asg_id	string	Yes	Gradescope assignment ID
file_name	string	No	Filename (default: program.py)

Response

Success (200):

{
  "success": true,
  "message": "Submission successful",
  "url": "https://www.gradescope.com/courses/1106756/assignments/6617143/submissions/123456"
}

Error (400):

{
  "success": false,
  "error": "Missing required field: asg_id"
}

Error (500):

{
  "success": false,
  "error": "Gradescope submission failed"
}

GET /starter/:filename

Retrieve starter code template for an assignment.

Request

GET /starter/lab1_starter.py

Response

Success (200):

{
  "code": "# Lab 1 Starter Code\n\ndef calculate_total(items):\n    pass"
}

Not Found (404):

{
  "error": "Starter file not found"
}

POST /lti/launch

Handle LTI 1.3 launch from D2L Brightspace.

Request

This endpoint receives an LTI 1.3 launch request from D2L. The request contains:

• JWT token with student information
• Course and assignment context
• Custom parameters

Response

On successful validation, redirects to the code editor with context:

302 Redirect → /codemirror-demo.html?email=...&asg_id=...

On failure:

{
  "error": "Invalid LTI launch"
}

GET /auth/status

Check if the current session has valid Gradescope credentials.

Request

GET /auth/status

Response

Authenticated:

{
  "authenticated": true,
  "email": "student@school.edu"
}

Not Authenticated:

{
  "authenticated": false
}

Static Files

The server also serves static files:

Path	File
/	codemirror-demo.html
/mockD2L.html	Mock D2L interface
/login.html	Gradescope login page
/styles/*	CSS files

Error Handling

All endpoints return consistent error responses:

{
  "success": false,
  "error": "Error message here"
}

HTTP Status Codes

Code	Meaning
200	Success
400	Bad request (missing/invalid parameters)
401	Unauthorized (no valid session)
404	Not found
500	Server error

Rate Limiting

Currently, there is no rate limiting implemented. For production, consider adding:

const rateLimit = require('express-rate-limit');

const limiter = rateLimit({
  windowMs: 60 * 1000, // 1 minute
  max: 10 // 10 requests per minute
});

app.use('/submit', limiter);