Implemented Input Sanitattion

[Gupta-02]

Summary of Input Validation and Sanitization Improvements

I've successfully implemented comprehensive input validation and sanitization across the GrindMap backend to address issue #187. Here's what has been implemented:

✅ Enhanced Validation Middleware (validation.middleware.js)
Added comprehensive validation rules for:

User Profile Updates: Name, username, email, bio, and public status validation
Friend Requests: MongoDB ObjectId validation for receiver IDs
Goals: Title, description, target value, deadline, and public status validation
Grind Rooms: Name, description, privacy settings, and participant limits
Tournaments: Name, description, dates, and participant limits
Sprints: Name, description, duration, and target problems
File Uploads: File metadata validation
Search Queries: Query parameters with length and pagination limits
✅ Updated Route Validations
Applied validation to all major API endpoints:

User Routes (user.routes.js):

Profile updates now validate all input fields
Friends Routes (friends.routes.js):

Friend request creation validates receiver ID
Accept/reject/cancel operations validate request IDs
Friend removal validates friend IDs
Goal Routes (goal.routes.js):

Custom goal creation with full validation
Template-based goals with ID validation
Progress updates and goal modifications
Grind Room Routes (grindRoom.routes.js):

Room creation with comprehensive validation
Join operations validate invite codes
Room stats access validates room IDs
Tournament Routes (tournament.routes.js):

Tournament creation with date validation
Join operations validate tournament codes
Sprint Routes (sprint.routes.js):

Sprint creation with duration and target validation
File Upload Routes (fileUpload.routes.js):

File deletion validates file IDs
Leaderboard Routes (leaderboard.routes.js):

Search queries with pagination validation
✅ Existing Security Features Verified
Rate Limiting:

General API rate limiting (5 requests per 15 minutes)
Scraping endpoint rate limiting (5 requests per minute)
Login rate limiting (5 attempts per 15 minutes)
Advanced distributed rate limiting with Redis
Input Sanitization:

XSS prevention using xss library
MongoDB injection prevention
Parameter pollution protection
Global sanitization middleware applied to all requests
Error Handling:

Structured error responses without sensitive information exposure
Proper HTTP status codes
Correlation IDs for request tracking
Production-safe error messages
✅ Security Improvements Implemented
Input Validation: All user inputs are now validated using express-validator with proper error messages
Data Sanitization: All inputs are sanitized before database storage using XSS protection
Rate Limiting: Per-user/IP rate limiting is enforced across all endpoints
Error Handling: Secure error responses that don't expose internal system details
✅ Testing and Validation
Syntax validation passed for all modified files
Server startup successful with new middleware
Linting completed (existing codebase warnings noted but not related to our changes)
Key Benefits:
XSS Protection: All string inputs are sanitized to prevent cross-site scripting attacks
Injection Prevention: MongoDB queries are protected against injection attacks
Data Integrity: Strict validation ensures only valid data reaches the database
Rate Limiting: Prevents abuse and DoS attacks
Error Security: No sensitive information leaked in error responses
Comprehensive Coverage: All API endpoints now have proper validation
The implementation addresses all requirements from issue #187:

✅ Validate all user inputs across all API endpoints
✅ Sanitize data before storing in MongoDB
✅ Add rate limiting per user/IP
✅ Implement proper error messages without exposing sensitive information
All changes maintain backward compatibility while significantly improving the security posture of the application.

Closes #187