feat(subscribe): add short token generation and validation logic

pkg/tool/string.go

@@ -0,0 +1,38 @@
+package tool
+
+import (
+	"crypto/sha256"
+	"encoding/binary"
+	"errors"
+	"math/rand"
+)
+
+func FixedUniqueString(s string, length int, alphabet string) (string, error) {
+	if alphabet == "" {
+		alphabet = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	}
+	if length <= 0 {
+		return "", errors.New("length must be > 0")
+	}
+	if length > len(alphabet) {
+		return "", errors.New("length greater than available unique characters")
+	}
+
+	// Generate deterministic seed from SHA256
+	hash := sha256.Sum256([]byte(s))
+	seed := int64(binary.LittleEndian.Uint64(hash[:8])) // 前 8 字节
+
+	r := rand.New(rand.NewSource(seed))
+
+	// Copy alphabet to mutable array
+	data := []rune(alphabet)
+
+	// Deterministic shuffle (Fisher–Yates)
+	for i := len(data) - 1; i > 0; i-- {
+		j := r.Intn(i + 1)
+		data[i], data[j] = data[j], data[i]
+	}
+
+	// Take first N characters
+	return string(data[:length]), nil
+}

pkg/tool/string_test.go

@@ -0,0 +1,27 @@
+package tool
+
+import (
+	"testing"
+)
+
+func TestFixedUniqueString(t *testing.T) {
+	a := "example"
+	b := "example1"
+	c := "example"
+
+	strA1, err := FixedUniqueString(a, 8, "")
+	strB1, err := FixedUniqueString(b, 8, "")
+	strC1, err := FixedUniqueString(c, 8, "")
+	if err != nil {
+		t.Logf("Error: %v", err.Error())
+		return
+	}
+	if strA1 != strC1 {
+		t.Errorf("Expected strA1 and strC1 to be equal, got %s and %s", strA1, strC1)
+	}
+	if strA1 == strB1 {
+		t.Errorf("Expected strA1 and strB1 to be different, got %s and %s", strA1, strB1)
+	}
+	t.Logf("strA1 and strB1 are not equal, strA1: %s, strB1: %s", strA1, strB1)
+	t.Logf("strA1 and strC1 are equal,strA1: %s, strC1: %s", strA1, strC1)
+}