Add HTTPStatusMessageFunc to allow users to override status messages (a…

…ppleboy#96)

Add HTTPStatusMessageFunc to allow users to override HTTP status messages triggered by the middleware

auth_jwt.go

@@ -74,8 +74,53 @@ type GinJWTMiddleware struct {
 
 	// TimeFunc provides the current time. You can override it to use another time value. This is useful for testing or if your server uses a different time zone than your tokens.
 	TimeFunc func() time.Time
+
+	// HTTP Status messages for when something in the JWT middleware fails.
+	// Check error (e) to determine the appropriate error message.
+	HTTPStatusMessageFunc func(e error, c *gin.Context) string
 }
 
+var (
+	// ErrMissingRealm indicates Realm name is required
+	ErrMissingRealm = errors.New("realm is missing")
+
+	// ErrMissingSecretKey indicates Secret key is required
+	ErrMissingSecretKey = errors.New("secret key is required")
+
+	// ErrForbidden when HTTP status 403 is given
+	ErrForbidden = errors.New("you don't have permission to access this resource")
+
+	// ErrMissingAuthenticatorFunc indicates Authenticator is required
+	ErrMissingAuthenticatorFunc = errors.New("ginJWTMiddleware.Authenticator func is undefined")
+
+	// ErrMissingLoginValues indicates a user tried to authenticate without username or password
+	ErrMissingLoginValues = errors.New("missing Username or Password")
+
+	// ErrFailedAuthentication indicates authentication failed, could be faulty username or password
+	ErrFailedAuthentication = errors.New("incorrect Username or Password")
+
+	// ErrFailedTokenCreation indicates JWT Token failed to create, reason unknown
+	ErrFailedTokenCreation = errors.New("failed to create JWT Token")
+
+	// ErrExpiredToken indicates JWT token has expired. Can't refresh.
+	ErrExpiredToken = errors.New("token is expired")
+
+	// ErrEmptyAuthHeader can be thrown if authing with a HTTP header, the Auth header needs to be set
+	ErrEmptyAuthHeader = errors.New("auth header is empty")
+
+	// ErrInvalidAuthHeader indicates auth header is invalid, could for example have the wrong Realm name
+	ErrInvalidAuthHeader = errors.New("auth header is invalid")
+
+	// ErrEmptyQueryToken can be thrown if authing with URL Query, the query token variable is empty
+	ErrEmptyQueryToken = errors.New("query token is empty")
+
+	// ErrEmptyCookieToken can be thrown if authing with a cookie, the token cokie is empty
+	ErrEmptyCookieToken = errors.New("cookie token is empty")
+
+	// ErrInvalidSigningAlgorithm indicates signing algorithm is invalid, needs to be HS256, HS384, or HS512
+	ErrInvalidSigningAlgorithm = errors.New("invalid signing algorithm")
+)
+
 // Login form structure.
 type Login struct {
 	Username string `form:"username" json:"username" binding:"required"`
@@ -127,12 +172,18 @@ func (mw *GinJWTMiddleware) MiddlewareInit() error {
 		}
 	}
 
+	if mw.HTTPStatusMessageFunc == nil {
+		mw.HTTPStatusMessageFunc = func(e error, c *gin.Context) string {
+			return e.Error()
+		}
+	}
+
 	if mw.Realm == "" {
-		return errors.New("realm is required")
+		return ErrMissingRealm
 	}
 
 	if mw.Key == nil {
-		return errors.New("secret key is required")
+		return ErrMissingSecretKey
 	}
 
 	return nil
@@ -142,7 +193,7 @@ func (mw *GinJWTMiddleware) MiddlewareInit() error {
 func (mw *GinJWTMiddleware) MiddlewareFunc() gin.HandlerFunc {
 	if err := mw.MiddlewareInit(); err != nil {
 		return func(c *gin.Context) {
-			mw.unauthorized(c, http.StatusInternalServerError, err.Error())
+			mw.unauthorized(c, http.StatusInternalServerError, mw.HTTPStatusMessageFunc(err, nil))
 			return
 		}
 	}
@@ -157,7 +208,7 @@ func (mw *GinJWTMiddleware) middlewareImpl(c *gin.Context) {
 	token, err := mw.parseToken(c)
 
 	if err != nil {
-		mw.unauthorized(c, http.StatusUnauthorized, err.Error())
+		mw.unauthorized(c, http.StatusUnauthorized, mw.HTTPStatusMessageFunc(err, c))
 		return
 	}
 
@@ -168,7 +219,7 @@ func (mw *GinJWTMiddleware) middlewareImpl(c *gin.Context) {
 	c.Set("userID", id)
 
 	if !mw.Authorizator(id, c) {
-		mw.unauthorized(c, http.StatusForbidden, "You don't have permission to access.")
+		mw.unauthorized(c, http.StatusForbidden, mw.HTTPStatusMessageFunc(ErrForbidden, c))
 		return
 	}
 
@@ -186,19 +237,19 @@ func (mw *GinJWTMiddleware) LoginHandler(c *gin.Context) {
 	var loginVals Login
 
 	if c.ShouldBindWith(&loginVals, binding.JSON) != nil {
-		mw.unauthorized(c, http.StatusBadRequest, "Missing Username or Password")
+		mw.unauthorized(c, http.StatusBadRequest, mw.HTTPStatusMessageFunc(ErrMissingLoginValues, c))
 		return
 	}
 
 	if mw.Authenticator == nil {
-		mw.unauthorized(c, http.StatusInternalServerError, "Missing define authenticator func")
+		mw.unauthorized(c, http.StatusInternalServerError, mw.HTTPStatusMessageFunc(ErrMissingAuthenticatorFunc, c))
 		return
 	}
 
 	userID, ok := mw.Authenticator(loginVals.Username, loginVals.Password, c)
 
 	if !ok {
-		mw.unauthorized(c, http.StatusUnauthorized, "Incorrect Username / Password")
+		mw.unauthorized(c, http.StatusUnauthorized, mw.HTTPStatusMessageFunc(ErrFailedAuthentication, c))
 		return
 	}
 
@@ -224,7 +275,7 @@ func (mw *GinJWTMiddleware) LoginHandler(c *gin.Context) {
 	tokenString, err := token.SignedString(mw.Key)
 
 	if err != nil {
-		mw.unauthorized(c, http.StatusUnauthorized, "Create JWT Token faild")
+		mw.unauthorized(c, http.StatusUnauthorized, mw.HTTPStatusMessageFunc(ErrFailedTokenCreation, c))
 		return
 	}
 
@@ -244,7 +295,7 @@ func (mw *GinJWTMiddleware) RefreshHandler(c *gin.Context) {
 	origIat := int64(claims["orig_iat"].(float64))
 
 	if origIat < mw.TimeFunc().Add(-mw.MaxRefresh).Unix() {
-		mw.unauthorized(c, http.StatusUnauthorized, "Token is expired.")
+		mw.unauthorized(c, http.StatusUnauthorized, mw.HTTPStatusMessageFunc(ErrExpiredToken, c))
 		return
 	}
 
@@ -264,7 +315,7 @@ func (mw *GinJWTMiddleware) RefreshHandler(c *gin.Context) {
 	tokenString, err := newToken.SignedString(mw.Key)
 
 	if err != nil {
-		mw.unauthorized(c, http.StatusUnauthorized, "Create JWT Token faild")
+		mw.unauthorized(c, http.StatusUnauthorized, mw.HTTPStatusMessageFunc(ErrFailedTokenCreation, c))
 		return
 	}
 
@@ -316,12 +367,12 @@ func (mw *GinJWTMiddleware) jwtFromHeader(c *gin.Context, key string) (string, e
 	authHeader := c.Request.Header.Get(key)
 
 	if authHeader == "" {
-		return "", errors.New("auth header empty")
+		return "", ErrEmptyAuthHeader
 	}
 
 	parts := strings.SplitN(authHeader, " ", 2)
 	if !(len(parts) == 2 && parts[0] == mw.TokenHeadName) {
-		return "", errors.New("invalid auth header")
+		return "", ErrInvalidAuthHeader
 	}
 
 	return parts[1], nil
@@ -331,7 +382,7 @@ func (mw *GinJWTMiddleware) jwtFromQuery(c *gin.Context, key string) (string, er
 	token := c.Query(key)
 
 	if token == "" {
-		return "", errors.New("Query token empty")
+		return "", ErrEmptyQueryToken
 	}
 
 	return token, nil
@@ -341,7 +392,7 @@ func (mw *GinJWTMiddleware) jwtFromCookie(c *gin.Context, key string) (string, e
 	cookie, _ := c.Cookie(key)
 
 	if cookie == "" {
-		return "", errors.New("Cookie token empty")
+		return "", ErrEmptyCookieToken
 	}
 
 	return cookie, nil
@@ -367,7 +418,7 @@ func (mw *GinJWTMiddleware) parseToken(c *gin.Context) (*jwt.Token, error) {
 
 	return jwt.Parse(token, func(token *jwt.Token) (interface{}, error) {
 		if jwt.GetSigningMethod(mw.SigningAlgorithm) != token.Method {
-			return nil, errors.New("invalid signing algorithm")
+			return nil, ErrInvalidSigningAlgorithm
 		}
 
 		return mw.Key, nil

auth_jwt_test.go

@@ -1,6 +1,7 @@
 package jwt
 
 import (
+	"errors"
 	"net/http"
 	"net/http/httptest"
 	"testing"
@@ -51,7 +52,7 @@ func TestMissingRealm(t *testing.T) {
 	err := authMiddleware.MiddlewareInit()
 
 	assert.Error(t, err)
-	assert.Equal(t, "realm is required", err.Error())
+	assert.Equal(t, ErrMissingRealm, err)
 }
 
 func TestMissingKey(t *testing.T) {
@@ -72,7 +73,7 @@ func TestMissingKey(t *testing.T) {
 	err := authMiddleware.MiddlewareInit()
 
 	assert.Error(t, err)
-	assert.Equal(t, "secret key is required", err.Error())
+	assert.Equal(t, ErrMissingSecretKey, err)
 }
 
 func TestMissingTimeOut(t *testing.T) {
@@ -149,7 +150,7 @@ func TestInternalServerError(t *testing.T) {
 
 			message, _ := jsonparser.GetString(data, "message")
 
-			assert.Equal(t, "realm is required", message)
+			assert.Equal(t, ErrMissingRealm.Error(), message)
 			assert.Equal(t, http.StatusInternalServerError, r.Code)
 		})
 }
@@ -175,7 +176,7 @@ func TestMissingAuthenticatorForLoginHandler(t *testing.T) {
 			data := []byte(r.Body.String())
 			message, _ := jsonparser.GetString(data, "message")
 
-			assert.Equal(t, "Missing define authenticator func", message)
+			assert.Equal(t, ErrMissingAuthenticatorFunc.Error(), message)
 			assert.Equal(t, http.StatusInternalServerError, r.Code)
 		})
 }
@@ -215,7 +216,7 @@ func TestLoginHandler(t *testing.T) {
 
 			message, _ := jsonparser.GetString(data, "message")
 
-			assert.Equal(t, "Missing Username or Password", message)
+			assert.Equal(t, ErrMissingLoginValues.Error(), message)
 			assert.Equal(t, http.StatusBadRequest, r.Code)
 			assert.Equal(t, "application/json; charset=utf-8", r.HeaderMap.Get("Content-Type"))
 		})
@@ -230,7 +231,7 @@ func TestLoginHandler(t *testing.T) {
 
 			message, _ := jsonparser.GetString(data, "message")
 
-			assert.Equal(t, "Incorrect Username / Password", message)
+			assert.Equal(t, ErrFailedAuthentication.Error(), message)
 			assert.Equal(t, http.StatusUnauthorized, r.Code)
 		})
 
@@ -755,3 +756,36 @@ func TestDefineTokenHeadName(t *testing.T) {
 			assert.Equal(t, http.StatusOK, r.Code)
 		})
 }
+
+func TestHTTPStatusMessageFunc(t *testing.T) {
+	var successError = errors.New("Successful test error")
+	var failedError = errors.New("Failed test error")
+	var successMessage = "Overwrite error message."
+
+	authMiddleware := &GinJWTMiddleware{
+		Key:        key,
+		Timeout:    time.Hour,
+		MaxRefresh: time.Hour * 24,
+		Authenticator: func(userId string, password string, c *gin.Context) (string, bool) {
+			if userId == "admin" && password == "admin" {
+				return "", true
+			}
+
+			return "", false
+		},
+
+		HTTPStatusMessageFunc: func(e error, c *gin.Context) string {
+			if e == successError {
+				return successMessage
+			}
+
+			return e.Error()
+		},
+	}
+
+	successString := authMiddleware.HTTPStatusMessageFunc(successError, nil)
+	failedString := authMiddleware.HTTPStatusMessageFunc(failedError, nil)
+
+	assert.Equal(t, successMessage, successString)
+	assert.NotEqual(t, successMessage, failedString)
+}