use proper error types instead of using strings.Contains()

database/database.go

@@ -49,8 +49,8 @@ func InitDB(cfg *config.Config, clear bool) error {
 		return err
 	}
 
-	user, err := cfg.String("db.user")
-	if err != nil && !strings.Contains(err.Error(), "Required setting 'db.user' not set") {
+	user, err := cfg.StringOr("db.user", "")
+	if err != nil {
 		return err
 	}
 

routes/healthz/healthz_endpoint.go

@@ -24,7 +24,6 @@ package healthz
 import (
 	"log"
 	"net/http"
-	"strings"
 
 	"git.rwth-aachen.de/acs/public/villas/web-backend-go/configuration"
 	"git.rwth-aachen.de/acs/public/villas/web-backend-go/database"
@@ -55,8 +54,8 @@ func getHealth(c *gin.Context) {
 	}
 
 	// check if connection to AMQP broker is alive if backend was started with AMQP client
-	url, err := configuration.GlobalConfig.String("amqp.host")
-	if err != nil && strings.Contains(err.Error(), "Required setting 'amqp.host' not set") {
+	url, err := configuration.GlobalConfig.StringOr("amqp.host", "not-set")
+	if err != nil && url == "not-set" {
 		c.JSON(http.StatusOK, gin.H{})
 		return
 	} else if err != nil {

routes/infrastructure-component/ic_amqpclient.go

@@ -25,7 +25,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"log"
-	"strings"
 
 	"git.rwth-aachen.de/acs/public/villas/web-backend-go/helper"
 	"github.com/gin-gonic/gin"
@@ -197,7 +196,7 @@ func (s *InfrastructureComponent) updateExternalIC(payload ICUpdate, body []byte
 			if err != nil {
 				// if component could not be deleted there are still configurations using it in the DB
 				// continue with the update to save the new state of the component and get back to the deletion later
-				if strings.Contains(err.Error(), "postponed") {
+				if _, ok := err.(*DeletionPostponed); ok {
 					log.Println(err) // print log message
 				} else {
 					return err // return upon DB error

routes/infrastructure-component/ic_errors.go

@@ -0,0 +1,32 @@
+/** User package, methods.
+*
+* @author Sonja Happ <sonja.happ@eonerc.rwth-aachen.de>
+* @copyright 2014-2019, Institute for Automation of Complex Power Systems, EONERC
+* @license GNU General Public License (version 3)
+*
+* VILLASweb-backend-go
+*
+* This program is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*********************************************************************************/
+package infrastructure_component
+
+import "fmt"
+
+type DeletionPostponed struct {
+	References int
+}
+
+func (e *DeletionPostponed) Error() string {
+	return fmt.Sprintf("deletion of IC postponed, %d config(s) associated to it", e.References)
+}

routes/infrastructure-component/ic_methods.go

@@ -22,7 +22,6 @@
 package infrastructure_component
 
 import (
-	"fmt"
 	"git.rwth-aachen.de/acs/public/villas/web-backend-go/database"
 )
 
@@ -68,7 +67,7 @@ func (s *InfrastructureComponent) delete() error {
 	noConfigs := db.Model(s).Association("ComponentConfigurations").Count()
 
 	if noConfigs > 0 {
-		return fmt.Errorf("deletion of IC postponed, %v config(s) associated to it", noConfigs)
+		return &DeletionPostponed{References: noConfigs}
 	}
 
 	// delete InfrastructureComponent from DB (does NOT remain as dangling)

routes/user/user_endpoints.go

@@ -24,7 +24,6 @@ package user
 import (
 	"fmt"
 	"net/http"
-	"strings"
 
 	"git.rwth-aachen.de/acs/public/villas/web-backend-go/helper"
 
@@ -188,9 +187,9 @@ func updateUser(c *gin.Context) {
 	// case that the request updates the role of the old user)
 	updatedUser, err := req.updatedUser(callerID, callerRole, oldUser)
 	if err != nil {
-		if strings.Contains(err.Error(), "Admin") || strings.Contains(err.Error(), "pw not changed") {
+		if _, ok := err.(*ForbiddenError); ok {
 			helper.ForbiddenError(c, err.Error())
-		} else if strings.Contains(err.Error(), "Username") || strings.Contains(err.Error(), "old or admin password") {
+		} else if _, ok := err.(*UsernameAlreadyTaken); ok {
 			helper.BadRequestError(c, err.Error())
 		} else { // password encryption failed
 			helper.InternalServerError(c, err.Error())

routes/user/user_errors.go

@@ -0,0 +1,40 @@
+/** User package, methods.
+*
+* @author Sonja Happ <sonja.happ@eonerc.rwth-aachen.de>
+* @copyright 2014-2019, Institute for Automation of Complex Power Systems, EONERC
+* @license GNU General Public License (version 3)
+*
+* VILLASweb-backend-go
+*
+* This program is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*********************************************************************************/
+package user
+
+import "fmt"
+
+type UsernameAlreadyTaken struct {
+	Username string
+}
+
+func (e *UsernameAlreadyTaken) Error() string {
+	return fmt.Sprintf("username is already taken: %s", e.Username)
+}
+
+type ForbiddenError struct {
+	Reason string
+}
+
+func (e *ForbiddenError) Error() string {
+	return fmt.Sprintf("permission denied: %s", e.Reason)
+}

routes/user/user_methods.go

@@ -43,7 +43,7 @@ func NewUser(username, password, mail, role string, active bool) (User, error) {
 	// Check that the username is NOT taken
 	err := newUser.ByUsername(username)
 	if err == nil {
-		return newUser, fmt.Errorf("username is already taken")
+		return newUser, &UsernameAlreadyTaken{Username: username}
 	}
 
 	newUser.Username = username

routes/user/user_test.go

@@ -54,11 +54,11 @@ type UserRequest struct {
 func TestMain(m *testing.M) {
 	err := configuration.InitConfig()
 	if err != nil {
-		panic(m)
+		panic(err)
 	}
 	err = database.InitDB(configuration.GlobalConfig, true)
 	if err != nil {
-		panic(m)
+		panic(err)
 	}
 	defer database.DBpool.Close()
 
@@ -541,7 +541,7 @@ func TestModifyAddedUserAsUser(t *testing.T) {
 		fmt.Sprintf("/api/v2/users/%v", newUserID), "PUT",
 		helper.KeyModels{"user": modRequest})
 	assert.NoError(t, err)
-	assert.Equalf(t, 400, code, "Response body: \n%v\n", resp)
+	assert.Equalf(t, 403, code, "Response body: \n%v\n", resp)
 
 	// modify newUser's password with wring old password
 	modRequest = UserRequest{
@@ -725,7 +725,7 @@ func TestModifyAddedUserAsAdmin(t *testing.T) {
 		fmt.Sprintf("/api/v2/users/%v", newUserID), "PUT",
 		helper.KeyModels{"user": modRequest})
 	assert.NoError(t, err)
-	assert.Equalf(t, 400, code, "Response body: \n%v\n", resp)
+	assert.Equalf(t, 403, code, "Response body: \n%v\n", resp)
 
 	// modify newUser's password, requires admin password
 	modRequest = UserRequest{

routes/user/user_validators.go

@@ -82,7 +82,7 @@ func (r *updateUserRequest) updatedUser(callerID interface{}, role interface{},
 	// Only the Admin must be able to update user's role
 	if role != "Admin" && r.User.Role != "" {
 		if r.User.Role != u.Role {
-			return u, fmt.Errorf("only Admin can update user's Role")
+			return u, &ForbiddenError{Reason: "only Admin can update user's Role"}
 		}
 	} else if role == "Admin" && r.User.Role != "" {
 		u.Role = r.User.Role
@@ -91,7 +91,7 @@ func (r *updateUserRequest) updatedUser(callerID interface{}, role interface{},
 	// Only the Admin must be able to update users Active state
 	if (r.User.Active == "yes" && !u.Active) || (r.User.Active == "no" && u.Active) {
 		if role != "Admin" {
-			return u, fmt.Errorf("only Admin can update user's Active state")
+			return u, &ForbiddenError{Reason: "only Admin can update user's Active state"}
 		} else {
 			u.Active = !u.Active
 		}
@@ -100,7 +100,7 @@ func (r *updateUserRequest) updatedUser(callerID interface{}, role interface{},
 	// Update the username making sure it is NOT taken
 	var testUser User
 	if err := testUser.ByUsername(r.User.Username); err == nil {
-		return u, fmt.Errorf("username is already taken")
+		return u, &UsernameAlreadyTaken{Username: r.User.Username}
 	}
 
 	if r.User.Username != "" {
@@ -111,7 +111,7 @@ func (r *updateUserRequest) updatedUser(callerID interface{}, role interface{},
 	if r.User.Password != "" {
 
 		if r.User.OldPassword == "" { // admin or old password has to be present for pw change
-			return u, fmt.Errorf("old or admin password is missing in request")
+			return u, &ForbiddenError{Reason: "missing old or admin password"}
 		}
 
 		if role == "Admin" { // admin has to enter admin password
@@ -123,14 +123,14 @@ func (r *updateUserRequest) updatedUser(callerID interface{}, role interface{},
 
 			err = adminUser.validatePassword(r.User.OldPassword)
 			if err != nil {
-				return u, fmt.Errorf("admin password not correct, pw not changed")
+				return u, &ForbiddenError{Reason: "admin password not correct, pw not changed"}
 			}
 
 		} else { //normal or guest user has to enter old password
 
 			err := oldUser.validatePassword(r.User.OldPassword)
 			if err != nil {
-				return u, fmt.Errorf("previous password not correct, pw not changed")
+				return u, &ForbiddenError{Reason: "previous password not correct, pw not changed"}
 			}
 		}