Refactor code by using switch instead of if-else (#318)

Author: alexandear

cmd/jwt/main.go

@@ -60,13 +60,14 @@ func main() {
 
 // Figure out which thing to do and then do that
 func start() error {
-	if *flagSign != "" {
+	switch {
+	case *flagSign != "":
 		return signToken()
-	} else if *flagVerify != "" {
+	case *flagVerify != "":
 		return verifyToken()
-	} else if *flagShow != "" {
+	case *flagShow != "":
 		return showToken()
-	} else {
+	default:
 		flag.Usage()
 		return fmt.Errorf("none of the required flags are present.  What do you want me to do?")
 	}
@@ -79,17 +80,18 @@ func loadData(p string) ([]byte, error) {
 	}
 
 	var rdr io.Reader
-	if p == "-" {
+	switch p {
+	case "-":
 		rdr = os.Stdin
-	} else if p == "+" {
+	case "+":
 		return []byte("{}"), nil
-	} else {
-		if f, err := os.Open(p); err == nil {
-			rdr = f
-			defer f.Close()
-		} else {
+	default:
+		f, err := os.Open(p)
+		if err != nil {
 			return nil, err
 		}
+		rdr = f
+		defer f.Close()
 	}
 	return io.ReadAll(rdr)
 }
@@ -136,14 +138,16 @@ func verifyToken() error {
 		if err != nil {
 			return nil, err
 		}
-		if isEs() {
+		switch {
+		case isEs():
 			return jwt.ParseECPublicKeyFromPEM(data)
-		} else if isRs() {
+		case isRs():
 			return jwt.ParseRSAPublicKeyFromPEM(data)
-		} else if isEd() {
+		case isEd():
 			return jwt.ParseEdPublicKeyFromPEM(data)
+		default:
+			return data, nil
 		}
-		return data, nil
 	})
 
 	// Print some debug data
@@ -221,40 +225,41 @@ func signToken() error {
 		}
 	}
 
-	if isEs() {
-		if k, ok := key.([]byte); !ok {
+	switch {
+	case isEs():
+		k, ok := key.([]byte)
+		if !ok {
 			return fmt.Errorf("couldn't convert key data to key")
-		} else {
-			key, err = jwt.ParseECPrivateKeyFromPEM(k)
-			if err != nil {
-				return err
-			}
 		}
-	} else if isRs() {
-		if k, ok := key.([]byte); !ok {
+		key, err = jwt.ParseECPrivateKeyFromPEM(k)
+		if err != nil {
+			return err
+		}
+	case isRs():
+		k, ok := key.([]byte)
+		if !ok {
 			return fmt.Errorf("couldn't convert key data to key")
-		} else {
-			key, err = jwt.ParseRSAPrivateKeyFromPEM(k)
-			if err != nil {
-				return err
-			}
 		}
-	} else if isEd() {
-		if k, ok := key.([]byte); !ok {
+		key, err = jwt.ParseRSAPrivateKeyFromPEM(k)
+		if err != nil {
+			return err
+		}
+	case isEd():
+		k, ok := key.([]byte)
+		if !ok {
 			return fmt.Errorf("couldn't convert key data to key")
-		} else {
-			key, err = jwt.ParseEdPrivateKeyFromPEM(k)
-			if err != nil {
-				return err
-			}
+		}
+		key, err = jwt.ParseEdPrivateKeyFromPEM(k)
+		if err != nil {
+			return err
 		}
 	}
 
-	if out, err := token.SignedString(key); err == nil {
-		fmt.Println(out)
-	} else {
+	out, err := token.SignedString(key)
+	if err != nil {
 		return fmt.Errorf("error signing token: %w", err)
 	}
+	fmt.Println(out)
 
 	return nil
 }

example_test.go

@@ -163,17 +163,18 @@ func ExampleParse_errorChecking() {
 		return []byte("AllYourBase"), nil
 	})
 
-	if token.Valid {
+	switch {
+	case token.Valid:
 		fmt.Println("You look nice today")
-	} else if errors.Is(err, jwt.ErrTokenMalformed) {
+	case errors.Is(err, jwt.ErrTokenMalformed):
 		fmt.Println("That's not even a token")
-	} else if errors.Is(err, jwt.ErrTokenSignatureInvalid) {
+	case errors.Is(err, jwt.ErrTokenSignatureInvalid):
 		// Invalid signature
 		fmt.Println("Invalid signature")
-	} else if errors.Is(err, jwt.ErrTokenExpired) || errors.Is(err, jwt.ErrTokenNotValidYet) {
+	case errors.Is(err, jwt.ErrTokenExpired) || errors.Is(err, jwt.ErrTokenNotValidYet):
 		// Token is either expired or not active yet
 		fmt.Println("Timing is everything")
-	} else {
+	default:
 		fmt.Println("Couldn't handle this token:", err)
 	}
 

hmac_test.go

@@ -66,16 +66,17 @@ func TestHMACVerify(t *testing.T) {
 
 func TestHMACSign(t *testing.T) {
 	for _, data := range hmacTestData {
-		if data.valid {
-			parts := strings.Split(data.tokenString, ".")
-			method := jwt.GetSigningMethod(data.alg)
-			sig, err := method.Sign(strings.Join(parts[0:2], "."), hmacTestKey)
-			if err != nil {
-				t.Errorf("[%v] Error signing token: %v", data.name, err)
-			}
-			if !reflect.DeepEqual(sig, decodeSegment(t, parts[2])) {
-				t.Errorf("[%v] Incorrect signature.\nwas:\n%v\nexpecting:\n%v", data.name, sig, parts[2])
-			}
+		if !data.valid {
+			continue
+		}
+		parts := strings.Split(data.tokenString, ".")
+		method := jwt.GetSigningMethod(data.alg)
+		sig, err := method.Sign(strings.Join(parts[0:2], "."), hmacTestKey)
+		if err != nil {
+			t.Errorf("[%v] Error signing token: %v", data.name, err)
+		}
+		if !reflect.DeepEqual(sig, decodeSegment(t, parts[2])) {
+			t.Errorf("[%v] Incorrect signature.\nwas:\n%v\nexpecting:\n%v", data.name, sig, parts[2])
 		}
 	}
 }

none_test.go

@@ -59,16 +59,17 @@ func TestNoneVerify(t *testing.T) {
 
 func TestNoneSign(t *testing.T) {
 	for _, data := range noneTestData {
-		if data.valid {
-			parts := strings.Split(data.tokenString, ".")
-			method := jwt.GetSigningMethod(data.alg)
-			sig, err := method.Sign(strings.Join(parts[0:2], "."), data.key)
-			if err != nil {
-				t.Errorf("[%v] Error signing token: %v", data.name, err)
-			}
-			if !reflect.DeepEqual(sig, decodeSegment(t, parts[2])) {
-				t.Errorf("[%v] Incorrect signature.\nwas:\n%v\nexpecting:\n%v", data.name, sig, parts[2])
-			}
+		if !data.valid {
+			continue
+		}
+		parts := strings.Split(data.tokenString, ".")
+		method := jwt.GetSigningMethod(data.alg)
+		sig, err := method.Sign(strings.Join(parts[0:2], "."), data.key)
+		if err != nil {
+			t.Errorf("[%v] Error signing token: %v", data.name, err)
+		}
+		if !reflect.DeepEqual(sig, decodeSegment(t, parts[2])) {
+			t.Errorf("[%v] Incorrect signature.\nwas:\n%v\nexpecting:\n%v", data.name, sig, parts[2])
 		}
 	}
 }

rsa_pss_test.go

@@ -84,18 +84,19 @@ func TestRSAPSSSign(t *testing.T) {
 	}
 
 	for _, data := range rsaPSSTestData {
-		if data.valid {
-			parts := strings.Split(data.tokenString, ".")
-			method := jwt.GetSigningMethod(data.alg)
-			sig, err := method.Sign(strings.Join(parts[0:2], "."), rsaPSSKey)
-			if err != nil {
-				t.Errorf("[%v] Error signing token: %v", data.name, err)
-			}
-
-			ssig := encodeSegment(sig)
-			if ssig == parts[2] {
-				t.Errorf("[%v] Signatures shouldn't match\nnew:\n%v\noriginal:\n%v", data.name, ssig, parts[2])
-			}
+		if !data.valid {
+			continue
+		}
+		parts := strings.Split(data.tokenString, ".")
+		method := jwt.GetSigningMethod(data.alg)
+		sig, err := method.Sign(strings.Join(parts[0:2], "."), rsaPSSKey)
+		if err != nil {
+			t.Errorf("[%v] Error signing token: %v", data.name, err)
+		}
+
+		ssig := encodeSegment(sig)
+		if ssig == parts[2] {
+			t.Errorf("[%v] Signatures shouldn't match\nnew:\n%v\noriginal:\n%v", data.name, ssig, parts[2])
 		}
 	}
 }