Adding upstream version 2.52.6.

Signed-off-by: Daniel Baumann <daniel@debian.org>

middleware/limiter/limiter_fixed.go

@@ -0,0 +1,106 @@
+package limiter
+
+import (
+	"strconv"
+	"sync"
+	"sync/atomic"
+
+	"github.com/gofiber/fiber/v2"
+	"github.com/gofiber/fiber/v2/utils"
+)
+
+type FixedWindow struct{}
+
+// New creates a new fixed window middleware handler
+func (FixedWindow) New(cfg Config) fiber.Handler {
+	var (
+		// Limiter variables
+		mux        = &sync.RWMutex{}
+		max        = strconv.Itoa(cfg.Max)
+		expiration = uint64(cfg.Expiration.Seconds())
+	)
+
+	// Create manager to simplify storage operations ( see manager.go )
+	manager := newManager(cfg.Storage)
+
+	// Update timestamp every second
+	utils.StartTimeStampUpdater()
+
+	// Return new handler
+	return func(c *fiber.Ctx) error {
+		// Don't execute middleware if Next returns true
+		if cfg.Next != nil && cfg.Next(c) {
+			return c.Next()
+		}
+
+		// Get key from request
+		key := cfg.KeyGenerator(c)
+
+		// Lock entry
+		mux.Lock()
+
+		// Get entry from pool and release when finished
+		e := manager.get(key)
+
+		// Get timestamp
+		ts := uint64(atomic.LoadUint32(&utils.Timestamp))
+
+		// Set expiration if entry does not exist
+		if e.exp == 0 {
+			e.exp = ts + expiration
+		} else if ts >= e.exp {
+			// Check if entry is expired
+			e.currHits = 0
+			e.exp = ts + expiration
+		}
+
+		// Increment hits
+		e.currHits++
+
+		// Calculate when it resets in seconds
+		resetInSec := e.exp - ts
+
+		// Set how many hits we have left
+		remaining := cfg.Max - e.currHits
+
+		// Update storage
+		manager.set(key, e, cfg.Expiration)
+
+		// Unlock entry
+		mux.Unlock()
+
+		// Check if hits exceed the cfg.Max
+		if remaining < 0 {
+			// Return response with Retry-After header
+			// https://tools.ietf.org/html/rfc6584
+			c.Set(fiber.HeaderRetryAfter, strconv.FormatUint(resetInSec, 10))
+
+			// Call LimitReached handler
+			return cfg.LimitReached(c)
+		}
+
+		// Continue stack for reaching c.Response().StatusCode()
+		// Store err for returning
+		err := c.Next()
+
+		// Check for SkipFailedRequests and SkipSuccessfulRequests
+		if (cfg.SkipSuccessfulRequests && c.Response().StatusCode() < fiber.StatusBadRequest) ||
+			(cfg.SkipFailedRequests && c.Response().StatusCode() >= fiber.StatusBadRequest) {
+			// Lock entry
+			mux.Lock()
+			e = manager.get(key)
+			e.currHits--
+			remaining++
+			manager.set(key, e, cfg.Expiration)
+			// Unlock entry
+			mux.Unlock()
+		}
+
+		// We can continue, update RateLimit headers
+		c.Set(xRateLimitLimit, max)
+		c.Set(xRateLimitRemaining, strconv.Itoa(remaining))
+		c.Set(xRateLimitReset, strconv.FormatUint(resetInSec, 10))
+
+		return err
+	}
+}