Serverless PDF Generator

This project implements a serverless function for form processing and PDF generation using AWS Lambda.

Features

• Process form submissions securely
• Generate offer letter PDFs on demand
• Stateless architecture with no persistent storage
• CORS-enabled API endpoints

AWS Console Setup Instructions

1. Create SNS Topic

1. Open the AWS Console and navigate to SNS
2. Click "Create topic"
3. Select "Standard" type
4. Name: JobApplicationNotifications
5. Click "Create topic"
6. Copy the Topic ARN for later use

2. Create Lambda Function

1. Navigate to AWS Lambda
2. Click "Create function"
3. Select "Author from scratch"
4. Name: formHandler
5. Runtime: Node.js 14.x
6. Architecture: x86_64
7. Click "Create function"

3. Configure Lambda Function

1. In the function page, scroll to "Code source"
2. Delete the default code in index.js
3. Copy and paste the code from our index.js file
4. Click "Deploy"

4. Add Dependencies

1. In the Lambda function page, click "Layers"
2. Click "Create layer"
3. Name: pdf-dependencies
4. Upload a ZIP file containing node_modules with pdfkit and aws-sdk

   npm install pdfkit aws-sdk
   zip -r layer.zip node_modules
   

5. Compatible runtimes: Select Node.js 14.x
6. Click "Create"
7. Go back to your function and add this layer

5. Configure Environment Variables

1. In the Lambda function page, click "Configuration"
2. Click "Environment variables"
3. Click "Edit"
4. Add key: SNS_TOPIC_ARN with value: [Your SNS Topic ARN]
5. Click "Save"

6. Configure IAM Permissions

1. In the Lambda function page, click "Configuration"
2. Click "Permissions"
3. Click the role name to open the IAM console
4. Click "Add permissions" > "Create inline policy"
5. Service: SNS
6. Actions: Publish
7. Resources: Add your SNS Topic ARN
8. Click "Review policy"
9. Name: SNSPublishPolicy
10. Click "Create policy"

7. Create API Gateway

1. Navigate to API Gateway
2. Click "Create API"
3. Select "REST API" and click "Build"
4. API name: FormProcessingAPI
5. Click "Create API"

8. Create Resources and Methods

1. Click "Create Resource"

2. Resource Name: process-form

3. Click "Create Resource"

4. With /process-form selected, click "Create Method"

5. Select POST and click the checkmark

6. Integration type: Lambda Function

7. Lambda Function: formHandler

8. Click "Save"

9. Click "Create Resource" again

10. Resource Name: generate-pdf

11. Click "Create Resource"

12. With /generate-pdf selected, click "Create Method"

13. Select POST and click the checkmark

14. Integration type: Lambda Function

15. Lambda Function: formHandler

16. Click "Save"

9. Enable CORS

1. For each resource (/process-form and /generate-pdf):
   • Select the resource
   • Click "Actions" > "Enable CORS"
   • Check "Access-Control-Allow-Origin" and enter *
   • Click "Enable CORS and replace existing CORS headers"

10. Deploy API

1. Click "Actions" > "Deploy API"
2. Deployment stage: [New Stage]
3. Stage name: dev
4. Click "Deploy"
5. Note the "Invoke URL" - this is your API endpoint

11. Update Frontend

1. Open frontend-example.html
2. Update the API_ENDPOINTS object with your API Gateway URLs:

   const API_ENDPOINTS = {
       processForm: 'https://your-api-id.execute-api.region.amazonaws.com/dev/process-form',
       generatePdf: 'https://your-api-id.execute-api.region.amazonaws.com/dev/generate-pdf'
   };

Testing

Local Testing

1. Install dependencies:

   npm install
   

2. Run the test script:

   node test.js
   

API Testing

1. Use the provided test JSON files with curl or Postman:

   curl -X POST -H "Content-Type: application/json" -d @test-form.json https://your-api-id.execute-api.region.amazonaws.com/dev/process-form
   

Deployment with Serverless Framework

If you prefer using the Serverless Framework instead of manual setup:

1. Install Serverless Framework:

   npm install -g serverless
   

2. Configure AWS credentials:

   serverless config credentials --provider aws --key YOUR_ACCESS_KEY --secret YOUR_SECRET_KEY
   

3. Deploy:

   ./deploy.sh
   

Security Considerations

• All functions are stateless
• No data is stored persistently
• API Gateway provides request validation
• IAM roles limit function permissions