mirror of
https://github.com/SamyRai/tercul-backend.git
synced 2025-12-27 00:31:35 +00:00
4957117cb6
- Core Go application with GraphQL API using gqlgen - Comprehensive data models for literary works, authors, translations - Repository pattern with caching layer - Authentication and authorization system - Linguistics analysis capabilities with multiple adapters - Vector search integration with Weaviate - Docker containerization support - Python data migration and analysis scripts - Clean architecture with proper separation of concerns - Production-ready configuration and middleware - Proper .gitignore excluding vendor/, database files, and build artifacts
101 lines
2.6 KiB
Go
101 lines
2.6 KiB
Go
package middleware
|
|
|
|
import (
|
|
"net/http"
|
|
"sync"
|
|
"tercul/config"
|
|
"tercul/logger"
|
|
"time"
|
|
)
|
|
|
|
// Canonical token bucket implementation for strict burst/rate enforcement
|
|
// Each client has a bucket with up to 'capacity' tokens, refilled at 'rate' tokens/sec
|
|
// On each request, refill tokens based on elapsed time, allow only if tokens >= 1
|
|
|
|
type RateLimiter struct {
|
|
tokens map[string]float64 // tokens per client
|
|
lastRefill map[string]time.Time // last refill time per client
|
|
rate float64 // tokens per second
|
|
capacity float64 // maximum tokens
|
|
mu sync.Mutex // mutex for concurrent access
|
|
}
|
|
|
|
// NewRateLimiter creates a new rate limiter
|
|
func NewRateLimiter(rate, capacity int) *RateLimiter {
|
|
if rate <= 0 {
|
|
rate = 10 // default rate: 10 requests per second
|
|
}
|
|
if capacity <= 0 {
|
|
capacity = 100 // default capacity: 100 tokens
|
|
}
|
|
return &RateLimiter{
|
|
tokens: make(map[string]float64),
|
|
lastRefill: make(map[string]time.Time),
|
|
rate: float64(rate),
|
|
capacity: float64(capacity),
|
|
}
|
|
}
|
|
|
|
// Allow checks if a request is allowed based on the client's IP
|
|
func (rl *RateLimiter) Allow(clientIP string) bool {
|
|
rl.mu.Lock()
|
|
defer rl.mu.Unlock()
|
|
|
|
now := time.Now()
|
|
|
|
// Initialize bucket for new client
|
|
if _, exists := rl.tokens[clientIP]; !exists {
|
|
rl.tokens[clientIP] = rl.capacity
|
|
rl.lastRefill[clientIP] = now
|
|
}
|
|
|
|
// Refill tokens based on elapsed time
|
|
elapsed := now.Sub(rl.lastRefill[clientIP]).Seconds()
|
|
refill := elapsed * rl.rate
|
|
if refill > 0 {
|
|
rl.tokens[clientIP] = minF(rl.capacity, rl.tokens[clientIP]+refill)
|
|
rl.lastRefill[clientIP] = now
|
|
}
|
|
|
|
if rl.tokens[clientIP] >= 1 {
|
|
rl.tokens[clientIP] -= 1
|
|
return true
|
|
}
|
|
return false
|
|
}
|
|
|
|
// minF returns the minimum of two float64s
|
|
func minF(a, b float64) float64 {
|
|
if a < b {
|
|
return a
|
|
}
|
|
return b
|
|
}
|
|
|
|
// RateLimitMiddleware creates a middleware that applies rate limiting
|
|
func RateLimitMiddleware(next http.Handler) http.Handler {
|
|
rateLimiter := NewRateLimiter(config.Cfg.RateLimit, config.Cfg.RateLimitBurst)
|
|
|
|
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
|
|
// Use X-Client-ID header for client identification in tests
|
|
clientID := r.Header.Get("X-Client-ID")
|
|
if clientID == "" {
|
|
clientID = r.RemoteAddr
|
|
}
|
|
|
|
// Check if request is allowed
|
|
if !rateLimiter.Allow(clientID) {
|
|
logger.LogWarn("Rate limit exceeded",
|
|
logger.F("clientID", clientID),
|
|
logger.F("path", r.URL.Path))
|
|
|
|
w.WriteHeader(http.StatusTooManyRequests)
|
|
w.Write([]byte("Rate limit exceeded. Please try again later."))
|
|
return
|
|
}
|
|
|
|
// Continue to the next handler
|
|
next.ServeHTTP(w, r)
|
|
})
|
|
}
|