init commit

internal/util/util.go

@@ -0,0 +1,73 @@
+package util
+
+import (
+	"crypto/rand"
+	"math/big"
+	"net/mail"
+	"strconv"
+	"strings"
+
+	"github.com/google/uuid"
+)
+
+// ConvertStringToInt32 converts a string to int32.
+func ConvertStringToInt32(src string) (int32, error) {
+	parsed, err := strconv.ParseInt(src, 10, 32)
+	if err != nil {
+		return 0, err
+	}
+	return int32(parsed), nil
+}
+
+// HasPrefixes returns true if the string s has any of the given prefixes.
+func HasPrefixes(src string, prefixes ...string) bool {
+	for _, prefix := range prefixes {
+		if strings.HasPrefix(src, prefix) {
+			return true
+		}
+	}
+	return false
+}
+
+// ValidateEmail validates the email.
+func ValidateEmail(email string) bool {
+	if _, err := mail.ParseAddress(email); err != nil {
+		return false
+	}
+	return true
+}
+
+func GenUUID() string {
+	return uuid.New().String()
+}
+
+var letters = []rune("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+
+// RandomString returns a random string with length n.
+func RandomString(n int) (string, error) {
+	var sb strings.Builder
+	sb.Grow(n)
+	for i := 0; i < n; i++ {
+		// The reason for using crypto/rand instead of math/rand is that
+		// the former relies on hardware to generate random numbers and
+		// thus has a stronger source of random numbers.
+		randNum, err := rand.Int(rand.Reader, big.NewInt(int64(len(letters))))
+		if err != nil {
+			return "", err
+		}
+		if _, err := sb.WriteRune(letters[randNum.Uint64()]); err != nil {
+			return "", err
+		}
+	}
+	return sb.String(), nil
+}
+
+// ReplaceString replaces all occurrences of old in slice with new.
+func ReplaceString(slice []string, old, new string) []string {
+	for i, s := range slice {
+		if s == old {
+			slice[i] = new
+		}
+	}
+	return slice
+}

internal/util/util_test.go

@@ -0,0 +1,31 @@
+package util
+
+import (
+	"testing"
+)
+
+func TestValidateEmail(t *testing.T) {
+	tests := []struct {
+		email string
+		want  bool
+	}{
+		{
+			email: "t@gmail.com",
+			want:  true,
+		},
+		{
+			email: "@usememos.com",
+			want:  false,
+		},
+		{
+			email: "1@gmail",
+			want:  true,
+		},
+	}
+	for _, test := range tests {
+		result := ValidateEmail(test.email)
+		if result != test.want {
+			t.Errorf("Validate Email %s: got result %v, want %v.", test.email, result, test.want)
+		}
+	}
+}