Add scan and keys functions to get objects and keys matching key pattern

CONTRIBUTORS

@@ -7,3 +7,4 @@ Dustin Sallings <dustin@spy.net>
 Jason Mooberry <jasonmoo@me.com>
 Sergey Shepelev <temotor@gmail.com>
 Alex Edwards <ajmedwards@gmail.com>
+Minudika Malshan <minudika.dev@gmail.com>

cache.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"os"
 	"runtime"
+	"strings"
 	"sync"
 	"time"
 )
@@ -165,6 +166,43 @@ func (c *cache) GetWithExpiration(k string) (interface{}, time.Time, bool) {
 	return item.Object, time.Time{}, true
 }
 
+// Keys retrieves all non-expired keys in the cache that contain the given substring pattern.
+// It returns a slice of keys matching the pattern.
+func (c *cache) Keys(pattern string) []interface{} {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	var matchedKeys []interface{}
+	for k, i := range c.items {
+		if strings.Contains(k, pattern) {
+			if i.Expiration <= 0 || time.Now().UnixNano() < i.Expiration {
+				matchedKeys = append(matchedKeys, k)
+			}
+		}
+	}
+
+	return matchedKeys
+}
+
+// Scan searches for and retrieves all non-expired cached items associated with keys that
+// contain the given substring pattern.
+// It returns a slice of matching cached items.
+func (c *cache) Scan(pattern string) []interface{} {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	var matchedObjects []interface{}
+	for k, i := range c.items {
+		if strings.Contains(k, pattern) {
+			if i.Expiration <= 0 || time.Now().UnixNano() < i.Expiration {
+				matchedObjects = append(matchedObjects, i.Object)
+			}
+		}
+	}
+
+	return matchedObjects
+}
+
 func (c *cache) get(k string) (interface{}, bool) {
 	item, found := c.items[k]
 	if !found {

cache_test.go

@@ -1769,3 +1769,50 @@ func TestGetWithExpiration(t *testing.T) {
 		t.Error("expiration for e is in the past")
 	}
 }
+
+func TestKeys(t *testing.T) {
+	tc := New(DefaultExpiration, 0)
+
+	tc.Set("jane_001", "admin", 50*time.Millisecond)   // Will expire after 50 milliseconds
+	tc.Set("john_002", "user", NoExpiration)           // Never expires
+	tc.Set("alice_003", "editor", 10*time.Millisecond) // Expires immediately due to DefaultExpiration = 0
+
+	keys := tc.Keys("jane")
+	if len(keys) != 1 || keys[0] != "jane_001" {
+		t.Error("Expected to find 'jane_001' but got:", keys)
+	}
+
+	keys = tc.Keys("002")
+	if len(keys) != 1 || keys[0] != "john_002" {
+		t.Error("Expected to find 'john_002' but got:", keys)
+	}
+
+	keys = tc.Keys("003")
+	if len(keys) != 0 {
+		t.Error("Expected no keys for 'alice_003' as it should have expired, but got:", keys)
+	}
+}
+
+func TestScan(t *testing.T) {
+	tc := New(DefaultExpiration, 0)
+
+	tc.Set("jane_001", "admin", 50*time.Millisecond)   // Will expire after 50 milliseconds
+	tc.Set("john_002", "user", NoExpiration)           // Never expires
+	tc.Set("alice_003", "editor", 10*time.Millisecond) // Expires immediately due to DefaultExpiration = 0
+
+	roles := tc.Scan("jane")
+	if len(roles) != 1 || roles[0].(string) != "admin" {
+		t.Error("Expected to find role 'admin' for 'jane_001' but got:", roles)
+	}
+
+	roles = tc.Scan("002")
+	if len(roles) != 1 || roles[0].(string) != "user" {
+		t.Error("Expected to find role 'user' for 'john_002' but got:", roles)
+	}
+
+	<-time.After(25 * time.Millisecond)
+	roles = tc.Scan("003")
+	if len(roles) != 0 {
+		t.Error("Expected no roles for 'alice_003' as it should have expired, but got:", roles)
+	}
+}