This module implements the perspective submission service for VoxPop, allowing users to submit perspectives on issues with rate limiting and security measures for unverified users.

Design

The system is built around the following components:

PerspectiveService: Handles the business logic for perspective submissions
PerspectiveHandler: Exposes the HTTP API endpoint
Rate Limiting: Uses Redis for tracking submission counts

API Endpoints

Submit Perspective

Endpoint: POST /submit-perspective

Request Body:

{
  "issueId": "issue-12345",
  "text": "This is my perspective on the issue.",
  "fileURL": "http://example.com/document.pdf",
  "userAddress": "0x1234567890abcdef",
  "isVerified": false,
  "captchaToken": "valid-token"
}

Response:

{
  "success": true,
  "hash": "QmHash123issu"
}

Features

Text Validation

Maximum text length: 1000 characters
Sanitizes input to prevent injection attacks

File Validation

Maximum file size: 5MB
Currently mocked in the implementation

Unverified Users

Limited to 5 submissions per day
Must provide a valid CAPTCHA token

Error response if rate limit exceeded:

{
  "success": false,
  "error": "Rate limit exceeded. Maximum 5 submissions per day for unverified users."
}

IPFS Storage

Uploads content to IPFS via Pinata (currently mocked)
Returns an IPFS hash for the content

Configuration

The service requires Redis for rate limiting:

REDIS_ADDR: Redis server address (default: "localhost:6379")
REDIS_PASSWORD: Redis password (default: "")
REDIS_DB: Redis database number (default: 0)

Example Usage

Verified User

// Request
{
  "issueId": "issue-12345",
  "text": "This is my perspective on the issue.",
  "fileURL": "http://example.com/document.pdf",
  "userAddress": "0x1234567890abcdef",
  "isVerified": true
}

// Response
{
  "success": true,
  "hash": "QmHash123issu"
}

Unverified User (with CAPTCHA)

// Request
{
  "issueId": "issue-12345",
  "text": "This is my perspective on the issue.",
  "userAddress": "0x1234567890abcdef",
  "isVerified": false,
  "captchaToken": "valid-token"
}

// Response
{
  "success": true,
  "hash": "QmHash123issu"
}

Rate Limit Exceeded

// Response (HTTP 429)
{
  "success": false,
  "error": "Rate limit exceeded. Maximum 5 submissions per day for unverified users."
}

Testing

Run the tests with:

go test ./perspective