D2L Brightspace Integration

Connect the Gradescope Submitter to D2L Brightspace using LTI 1.3.

Prerequisites

• D2L Administrator access (or work with your admin)
• Your server running with HTTPS
• Server domain name

Step 1: Register LTI Tool in D2L

INFO

This requires D2L Administrator access. Contact your institution's D2L admin if needed.

1. In D2L, go to Admin Tools → Manage Extensibility
2. Click LTI Advantage → Register Tool
3. Enter the following configuration:

Field	Value
Name	Gradescope Code Submitter
Domain	your-server-domain.com
Redirect URLs	https://your-server-domain.com/lti/launch
Target Link URI	https://your-server-domain.com/codemirror-demo.html
OpenID Connect Login URL	https://your-server-domain.com/lti/login
Keyset URL	https://your-server-domain.com/.well-known/jwks.json

4. After registration, copy:
   • Client ID → Put in .env as LTI_CLIENT_ID
   • Deployment ID → Put in .env as LTI_DEPLOYMENT_ID

Step 2: Create LTI Link in Course

1. In your D2L course, go to Content
2. Create a new External Learning Tool link
3. Select your registered LTI tool
4. Add custom parameters for the assignment:

asg_id=YOUR_GRADESCOPE_ASSIGNMENT_ID
file_name=program.py

Step 3: Add to Quiz

Option A: Iframe Embed

1. Create or edit a Quiz in D2L
2. Add a Written Response question
3. In the question text, switch to HTML mode and add:

<iframe 
  src="https://your-server-domain.com/codemirror-demo.html?asg_id=ASSIGNMENT_ID&file_name=program.py" 
  width="100%" 
  height="600px" 
  frameborder="0"
  allow="clipboard-read; clipboard-write">
</iframe>

Replace:

• your-server-domain.com with your actual server URL
• ASSIGNMENT_ID with the Gradescope assignment ID

Option B: LTI Link

1. In the quiz, add an External Tool question type
2. Select your registered LTI tool
3. Configure custom parameters

LTI Data Flow

D2L Quiz → LTI Launch Request → /lti/launch endpoint
    ↓
Validate LTI payload (signature, claims)
    ↓
Extract student info (email, name, ID)
    ↓
Check for existing Gradescope session
    ↓
Redirect to code editor with context

Custom Parameters

Pass assignment-specific data via LTI custom parameters:

Parameter	Description
asg_id	Gradescope assignment ID
file_name	Submission filename (default: program.py)
starter	Starter code template file

Troubleshooting

"Invalid LTI launch"

• Verify LTI_CLIENT_ID and LTI_DEPLOYMENT_ID match D2L registration
• Check server logs for specific validation errors
• Ensure HTTPS is properly configured

Iframe not loading

• D2L requires HTTPS for iframe embedding
• Check X-Frame-Options headers on your server
• Verify D2L whitelist includes your domain

Student not recognized

• LTI passes student email from D2L
• Ensure student is enrolled in Gradescope course
• Check that emails match between systems

Security Considerations

1. LTI signatures — All launches are cryptographically signed
2. State tokens — Prevent CSRF attacks in auth flow
3. Session isolation — Each student has separate credentials
4. HTTPS required — All communication is encrypted

Next Steps

• Creating Assignments — Set up individual assignments
• HTTPS Configuration — Enable HTTPS for production