Added len validations at CreateIdOf (#11)

* Fix: Invalid len of CUID2

* Updated: Moved validation to Init() function | Change in Tests | Updated README Accordingly

README.md

@@ -23,12 +23,12 @@ import (
 )
 
 func main() {
-	id := cuid2.CreateId()
+	id, err := cuid2.CreateId()
 	fmt.Println(id)
 	// to create default length id
 	// us1hfvvf2uyzmh031bav6skw
 
-	idWithLength := cuid2.CreateIdOf(10)
+	idWithLength, err := cuid2.CreateIdOf(10)
 	// zev57ezp7c
 
 	createId := cuid2.Init(customRandomFunction, customCounterFunction, length, customFingerprintString)

cuid2.go

@@ -1,6 +1,7 @@
 package cuid2
 
 import (
+	"errors"
 	"golang.org/x/crypto/sha3"
 	"math"
 	"math/big"
@@ -17,7 +18,7 @@ var (
 	DefaultRandom      = rand.Float64
 	DefaultCounter     func() int64
 	DefaultFingerprint string
-	defaultInit        func() string
+	defaultInit        func() (string, error)
 	envVariableKeys    string
 	cuidRegex          = regexp.MustCompile("^[a-z][0-9a-z]+$")
 )
@@ -91,8 +92,16 @@ func createEntropy(length int, random func() float64) string {
 	return entropy.String()
 }
 
-func Init(random func() float64, counter func() int64, length int, fingerprint string) func() string {
-	return func() string {
+func Init(random func() float64, counter func() int64, length int, fingerprint string) func() (string, error) {
+	return func() (string, error) {
+		minLength := 2
+		maxLength := bigLength
+
+		// Ensure length is between 2 and 32
+		if length < minLength || length > maxLength {
+			return "", errors.New("len should be between 2 and 32")
+		}
+
 		firstLetter := randomLetter(random)
 
 		// If we're lucky, the base 36 conversion calls may reduce hashing rounds
@@ -108,15 +117,15 @@ func Init(random func() float64, counter func() int64, length int, fingerprint s
 		hash := hash(hashInput)
 
 		cuid2 := firstLetter + hash[1:length]
-		return cuid2
+		return cuid2, nil
 	}
 }
 
-func CreateId() string {
+func CreateId() (string, error) {
 	return defaultInit()
 }
 
-func CreateIdOf(len int) string {
+func CreateIdOf(len int) (string, error) {
 	return Init(DefaultRandom, DefaultCounter, len, DefaultFingerprint)()
 }
 

cuid2_collision_test.go

@@ -66,8 +66,8 @@ func createIdPool(t *testing.T, max int, poolId int, idPoolResponseChan chan *Id
 	defer wg.Done()
 	set := make(map[string]struct{}, max)
 	for i := 0; i < max; i++ {
-		id := CreateId()
-		if !IsCuid(id) {
+		id, err := CreateId()
+		if !IsCuid(id) && err != nil {
 			t.Errorf("The id %s is not a CUID", id)
 			break
 		}

cuid2_test.go

@@ -7,8 +7,8 @@ import (
 )
 
 func create(t *testing.T) string {
-	id := CreateId()
-	if id == "" {
+	id, err := CreateId()
+	if id == "" || err != nil {
 		t.Fatalf("Cuid not generated")
 	}
 	if len(id) != 24 {
@@ -42,8 +42,18 @@ func TestFirstCharFromAtoZ(t *testing.T) {
 func TestIsCuidFalse(t *testing.T) {
 	tests := []string{
 		"", "1", "1", "asdf98923jhf90283jh02983hjf02983fh", "afasd as dfas ", "1asdfasdf", "   ",
-		CreateId() + CreateId() + CreateId(),
 	}
+
+	combinationOfCuids := ""
+	for i := 0; i < 3; i++ {
+		id, err := CreateId()
+		if err != nil {
+			t.Fatalf("Failed to create CUID: %v", err)
+		}
+		combinationOfCuids += id
+	}
+	tests = append(tests, combinationOfCuids)
+
 	for _, tt := range tests {
 		t.Run(tt, func(t *testing.T) {
 			isCuid := IsCuid(tt)
@@ -77,7 +87,11 @@ func TestIsCuidWithValidIds(t *testing.T) {
 func FuzzTestRandom(f *testing.F) {
 	noOfIdsToGenerate := 1000
 	for range noOfIdsToGenerate {
-		f.Add(CreateId())
+		id, err := CreateId()
+		if err != nil {
+			f.Fatalf("Failed to create CUID: %v", err)
+		}
+		f.Add(id)
 	}
 
 	f.Fuzz(func(t *testing.T, id string) {
@@ -93,8 +107,8 @@ func TestConfigurability(t *testing.T) {
 	length := 3
 	fingerprint := "abc"
 	fn := Init(random, counter, length, fingerprint)
-	id := fn()
-	if id == "" {
+	id, err := fn()
+	if id == "" || err != nil {
 		t.Errorf("Custom function didn't return proper id")
 	}
 	if len(id) != 3 {
@@ -108,9 +122,9 @@ func TestLengthWithFullCustomization(t *testing.T) {
 	for tt := minLen; tt <= maxLen; tt++ {
 		t.Run(fmt.Sprintf("with length %d", tt), func(t *testing.T) {
 			createId := Init(DefaultRandom, DefaultCounter, tt, DefaultFingerprint)
-			id := createId()
+			id, err := createId()
 			fmt.Printf("Created id %q\n", id)
-			if len(id) != tt {
+			if len(id) != tt || err != nil {
 				t.Errorf("Expected id of len %d. Got %d\n", tt, len(id))
 			}
 		})
@@ -122,11 +136,23 @@ func TestLengthOnlyCustomization(t *testing.T) {
 	maxLen := 32
 	for tt := minLen; tt <= maxLen; tt++ {
 		t.Run(fmt.Sprintf("with length %d", tt), func(t *testing.T) {
-			id := CreateIdOf(tt)
+			id, err := CreateIdOf(tt)
 			fmt.Printf("Created id %q\n", id)
-			if len(id) != tt {
+			if len(id) != tt || err != nil {
 				t.Errorf("Expected id of len %d. Got %d\n", tt, len(id))
 			}
 		})
 	}
 }
+
+func TestInvalidLength(t *testing.T) {
+	tests := []int{1, 33, 0, -1}
+	for _, tt := range tests {
+		t.Run(fmt.Sprintf("with length %d", tt), func(t *testing.T) {
+			id, err := CreateIdOf(tt)
+			if id != "" || err.Error() != "len should be between 2 and 32" {
+				t.Errorf("Expected error 'len should be between 2 and 32' and Empty ID but got %s with ID=%s\n", err.Error(), id)
+			}
+		})
+	}
+}