🐛 [Bug]: cache middleware: runtime error: index out of range [0] with length 0 (#3075)

Resolves #3072

Signed-off-by: brunodmartins <bdm2943@icloud.com>

middleware/cache/cache.go

@@ -117,46 +117,49 @@ func New(config ...Config) fiber.Handler {
 		// Get timestamp
 		ts := atomic.LoadUint64(&timestamp)
 
-		// Invalidate cache if requested
-		if cfg.CacheInvalidator != nil && cfg.CacheInvalidator(c) && e != nil {
-			e.exp = ts - 1
-		}
-
-		// Check if entry is expired
-		if e.exp != 0 && ts >= e.exp {
-			deleteKey(key)
-			if cfg.MaxBytes > 0 {
-				_, size := heap.remove(e.heapidx)
-				storedBytes -= size
-			}
-		} else if e.exp != 0 && !hasRequestDirective(c, noCache) {
-			// Separate body value to avoid msgp serialization
-			// We can store raw bytes with Storage 👍
-			if cfg.Storage != nil {
-				e.body = manager.getRaw(key + "_body")
-			}
-			// Set response headers from cache
-			c.Response().SetBodyRaw(e.body)
-			c.Response().SetStatusCode(e.status)
-			c.Response().Header.SetContentTypeBytes(e.ctype)
-			if len(e.cencoding) > 0 {
-				c.Response().Header.SetBytesV(fiber.HeaderContentEncoding, e.cencoding)
-			}
-			for k, v := range e.headers {
-				c.Response().Header.SetBytesV(k, v)
-			}
-			// Set Cache-Control header if enabled
-			if cfg.CacheControl {
-				maxAge := strconv.FormatUint(e.exp-ts, 10)
-				c.Set(fiber.HeaderCacheControl, "public, max-age="+maxAge)
+		// Cache Entry not found
+		if e != nil {
+			// Invalidate cache if requested
+			if cfg.CacheInvalidator != nil && cfg.CacheInvalidator(c) {
+				e.exp = ts - 1
 			}
 
-			c.Set(cfg.CacheHeader, cacheHit)
+			// Check if entry is expired
+			if e.exp != 0 && ts >= e.exp {
+				deleteKey(key)
+				if cfg.MaxBytes > 0 {
+					_, size := heap.remove(e.heapidx)
+					storedBytes -= size
+				}
+			} else if e.exp != 0 && !hasRequestDirective(c, noCache) {
+				// Separate body value to avoid msgp serialization
+				// We can store raw bytes with Storage 👍
+				if cfg.Storage != nil {
+					e.body = manager.getRaw(key + "_body")
+				}
+				// Set response headers from cache
+				c.Response().SetBodyRaw(e.body)
+				c.Response().SetStatusCode(e.status)
+				c.Response().Header.SetContentTypeBytes(e.ctype)
+				if len(e.cencoding) > 0 {
+					c.Response().Header.SetBytesV(fiber.HeaderContentEncoding, e.cencoding)
+				}
+				for k, v := range e.headers {
+					c.Response().Header.SetBytesV(k, v)
+				}
+				// Set Cache-Control header if enabled
+				if cfg.CacheControl {
+					maxAge := strconv.FormatUint(e.exp-ts, 10)
+					c.Set(fiber.HeaderCacheControl, "public, max-age="+maxAge)
+				}
 
-			mux.Unlock()
+				c.Set(cfg.CacheHeader, cacheHit)
 
-			// Return response
-			return nil
+				mux.Unlock()
+
+				// Return response
+				return nil
+			}
 		}
 
 		// make sure we're not blocking concurrent requests - do unlock
@@ -193,6 +196,7 @@ func New(config ...Config) fiber.Handler {
 			}
 		}
 
+		e = manager.acquire()
 		// Cache response
 		e.body = utils.CopyBytes(c.Response().Body())
 		e.status = c.Response().StatusCode()

middleware/cache/cache_test.go

@@ -47,9 +47,10 @@ func Test_Cache_Expired(t *testing.T) {
 	t.Parallel()
 	app := fiber.New()
 	app.Use(New(Config{Expiration: 2 * time.Second}))
-
+	count := 0
 	app.Get("/", func(c fiber.Ctx) error {
-		return c.SendString(strconv.FormatInt(time.Now().UnixNano(), 10))
+		count++
+		return c.SendString(strconv.Itoa(count))
 	})
 
 	resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
@@ -86,9 +87,10 @@ func Test_Cache(t *testing.T) {
 	app := fiber.New()
 	app.Use(New())
 
+	count := 0
 	app.Get("/", func(c fiber.Ctx) error {
-		now := strconv.FormatInt(time.Now().UnixNano(), 10)
-		return c.SendString(now)
+		count++
+		return c.SendString(strconv.Itoa(count))
 	})
 
 	req := httptest.NewRequest(fiber.MethodGet, "/", nil)
@@ -305,9 +307,10 @@ func Test_Cache_Invalid_Expiration(t *testing.T) {
 	cache := New(Config{Expiration: 0 * time.Second})
 	app.Use(cache)
 
+	count := 0
 	app.Get("/", func(c fiber.Ctx) error {
-		now := strconv.FormatInt(time.Now().UnixNano(), 10)
-		return c.SendString(now)
+		count++
+		return c.SendString(strconv.Itoa(count))
 	})
 
 	req := httptest.NewRequest(fiber.MethodGet, "/", nil)
@@ -414,8 +417,10 @@ func Test_Cache_NothingToCache(t *testing.T) {
 
 	app.Use(New(Config{Expiration: -(time.Second * 1)}))
 
+	count := 0
 	app.Get("/", func(c fiber.Ctx) error {
-		return c.SendString(time.Now().String())
+		count++
+		return c.SendString(strconv.Itoa(count))
 	})
 
 	resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
@@ -447,12 +452,16 @@ func Test_Cache_CustomNext(t *testing.T) {
 		CacheControl: true,
 	}))
 
+	count := 0
 	app.Get("/", func(c fiber.Ctx) error {
-		return c.SendString(time.Now().String())
+		count++
+		return c.SendString(strconv.Itoa(count))
 	})
 
+	errorCount := 0
 	app.Get("/error", func(c fiber.Ctx) error {
-		return c.Status(fiber.StatusInternalServerError).SendString(time.Now().String())
+		errorCount++
+		return c.Status(fiber.StatusInternalServerError).SendString(strconv.Itoa(errorCount))
 	})
 
 	resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
@@ -508,9 +517,11 @@ func Test_CustomExpiration(t *testing.T) {
 		return time.Second * time.Duration(newCacheTime)
 	}}))
 
+	count := 0
 	app.Get("/", func(c fiber.Ctx) error {
+		count++
 		c.Response().Header.Add("Cache-Time", "1")
-		return c.SendString(strconv.FormatInt(time.Now().UnixNano(), 10))
+		return c.SendString(strconv.Itoa(count))
 	})
 
 	resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
@@ -588,8 +599,11 @@ func Test_CacheHeader(t *testing.T) {
 		return c.SendString(fiber.Query[string](c, "cache"))
 	})
 
+	count := 0
 	app.Get("/error", func(c fiber.Ctx) error {
-		return c.Status(fiber.StatusInternalServerError).SendString(time.Now().String())
+		count++
+		c.Response().Header.Add("Cache-Time", "1")
+		return c.Status(fiber.StatusInternalServerError).SendString(strconv.Itoa(count))
 	})
 
 	resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
@@ -615,10 +629,13 @@ func Test_Cache_WithHead(t *testing.T) {
 	app := fiber.New()
 	app.Use(New())
 
+	count := 0
 	handler := func(c fiber.Ctx) error {
-		now := strconv.FormatInt(time.Now().UnixNano(), 10)
-		return c.SendString(now)
+		count++
+		c.Response().Header.Add("Cache-Time", "1")
+		return c.SendString(strconv.Itoa(count))
 	}
+
 	app.Route("/").Get(handler).Head(handler)
 
 	req := httptest.NewRequest(fiber.MethodHead, "/", nil)
@@ -708,8 +725,10 @@ func Test_CacheInvalidation(t *testing.T) {
 		},
 	}))
 
+	count := 0
 	app.Get("/", func(c fiber.Ctx) error {
-		return c.SendString(time.Now().String())
+		count++
+		return c.SendString(strconv.Itoa(count))
 	})
 
 	resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
@@ -731,6 +750,93 @@ func Test_CacheInvalidation(t *testing.T) {
 	require.NotEqual(t, body, bodyInvalidate)
 }
 
+func Test_CacheInvalidation_noCacheEntry(t *testing.T) {
+	t.Parallel()
+	t.Run("Cache Invalidator should not be called if no cache entry exist ", func(t *testing.T) {
+		t.Parallel()
+		app := fiber.New()
+		cacheInvalidatorExecuted := false
+		app.Use(New(Config{
+			CacheControl: true,
+			CacheInvalidator: func(c fiber.Ctx) bool {
+				cacheInvalidatorExecuted = true
+				return fiber.Query[bool](c, "invalidate")
+			},
+			MaxBytes: 10 * 1024 * 1024,
+		}))
+		_, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/?invalidate=true", nil))
+		require.NoError(t, err)
+		require.False(t, cacheInvalidatorExecuted)
+	})
+}
+
+func Test_CacheInvalidation_removeFromHeap(t *testing.T) {
+	t.Parallel()
+	t.Run("Invalidate and remove from the heap", func(t *testing.T) {
+		t.Parallel()
+		app := fiber.New()
+		app.Use(New(Config{
+			CacheControl: true,
+			CacheInvalidator: func(c fiber.Ctx) bool {
+				return fiber.Query[bool](c, "invalidate")
+			},
+			MaxBytes: 10 * 1024 * 1024,
+		}))
+
+		count := 0
+		app.Get("/", func(c fiber.Ctx) error {
+			count++
+			return c.SendString(strconv.Itoa(count))
+		})
+
+		resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
+		require.NoError(t, err)
+		body, err := io.ReadAll(resp.Body)
+		require.NoError(t, err)
+
+		respCached, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
+		require.NoError(t, err)
+		bodyCached, err := io.ReadAll(respCached.Body)
+		require.NoError(t, err)
+		require.True(t, bytes.Equal(body, bodyCached))
+		require.NotEmpty(t, respCached.Header.Get(fiber.HeaderCacheControl))
+
+		respInvalidate, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/?invalidate=true", nil))
+		require.NoError(t, err)
+		bodyInvalidate, err := io.ReadAll(respInvalidate.Body)
+		require.NoError(t, err)
+		require.NotEqual(t, body, bodyInvalidate)
+	})
+}
+
+func Test_CacheStorage_CustomHeaders(t *testing.T) {
+	t.Parallel()
+	app := fiber.New()
+	app.Use(New(Config{
+		CacheControl: true,
+		Storage:      memory.New(),
+		MaxBytes:     10 * 1024 * 1024,
+	}))
+
+	app.Get("/", func(c fiber.Ctx) error {
+		c.Response().Header.Set("Content-Type", "text/xml")
+		c.Response().Header.Set("Content-Encoding", "utf8")
+		return c.Send([]byte("<xml><value>Test</value></xml>"))
+	})
+
+	resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
+	require.NoError(t, err)
+	body, err := io.ReadAll(resp.Body)
+	require.NoError(t, err)
+
+	respCached, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
+	require.NoError(t, err)
+	bodyCached, err := io.ReadAll(respCached.Body)
+	require.NoError(t, err)
+	require.True(t, bytes.Equal(body, bodyCached))
+	require.NotEmpty(t, respCached.Header.Get(fiber.HeaderCacheControl))
+}
+
 // Because time points are updated once every X milliseconds, entries in tests can often have
 // equal expiration times and thus be in an random order. This closure hands out increasing
 // time intervals to maintain strong ascending order of expiration

middleware/cache/heap.go

@@ -15,7 +15,7 @@ type heapEntry struct {
 // elements in constant time. It does so by handing out special indices
 // and tracking entry movement.
 //
-// indexdedHeap is used for quickly finding entries with the lowest
+// indexedHeap is used for quickly finding entries with the lowest
 // expiration timestamp and deleting arbitrary entries.
 type indexedHeap struct {
 	// Slice the heap is built on

middleware/cache/manager.go

@@ -83,8 +83,7 @@ func (m *manager) get(key string) *item {
 		return it
 	}
 	if it, _ = m.memory.Get(key).(*item); it == nil { //nolint:errcheck // We store nothing else in the pool
-		it = m.acquire()
-		return it
+		return nil
 	}
 	return it
 }

middleware/cache/manager_test.go

@@ -0,0 +1,26 @@
+package cache
+
+import (
+	"testing"
+	"time"
+
+	"github.com/gofiber/utils/v2"
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_manager_get(t *testing.T) {
+	t.Parallel()
+	cacheManager := newManager(nil)
+	t.Run("Item not found in cache", func(t *testing.T) {
+		t.Parallel()
+		assert.Nil(t, cacheManager.get(utils.UUID()))
+	})
+	t.Run("Item found in cache", func(t *testing.T) {
+		t.Parallel()
+		id := utils.UUID()
+		cacheItem := cacheManager.acquire()
+		cacheItem.body = []byte("test-body")
+		cacheManager.set(id, cacheItem, 10*time.Second)
+		assert.NotNil(t, cacheManager.get(id))
+	})
+}