partial fix login error message

src/app/component/login/login.component.ts

@@ -37,6 +37,10 @@ export class LoginComponent implements OnInit {
 
   createNewUser(createUser: UserEntity) {
     console.log(createUser.username+" "+createUser.password);
+    if (createUser.username == '' || createUser.password == '') {
+      this.errorCreateUser = true;
+      return;
+    }
     this.userService.getUsers().subscribe(users => {
       this.users = users;
       for (let i = 0; i < this.users.length; i++) {
@@ -55,9 +59,14 @@ export class LoginComponent implements OnInit {
 
   loginFunction(username: string, password: string) {
     this.userService.getUser(username).subscribe(user => {
-      if (user.password == password) {
-        this.cookieService.setUsername(username);
-        this.router.navigate(['/home']);
+      console.log(user);
+      if (user !== null) {
+        if (user.password == password) {
+          this.cookieService.setUsername(username);
+          this.router.navigate(['/home']);
+        }else {
+          this.errorLogin = true;
+        }
       } else {
         this.errorLogin = true;
       }
@@ -73,6 +82,8 @@ export class LoginComponent implements OnInit {
   }
 
   switch() {
+    this.errorCreateUser = false;
+    this.errorLogin = false;
     if (this.login) {
       this.login = false;
     } else {

src/app/component/management/management.component.ts

@@ -49,9 +49,15 @@ export class ManagementComponent implements OnInit {
     this.translations = this.readTranslationJsonService.getManagementTranslations();
     this.username = this.cookieService.getUsername();
     this.userService.getUser(this.username).subscribe(user => {
-      if (user.admin == false) {
-        this.route.navigate(['/home']);
+      if (user !== null) {
+        if (user.admin == false) {
+          this.route.navigate(['/home']);
+        }
+      }else {
+        this.cookieService.deleteUsername();
+        this.route.navigate(['/login']);
       }
+
     });
     this.locationService.getLocations().subscribe(locations => {
       this.locations = locations;

src/app/service/http/user.service.ts

@@ -1,6 +1,7 @@
 import {Injectable} from "@angular/core";
 import {HttpClient} from "@angular/common/http";
 import {UserEntity} from "../../interface/UserEntity";
+import {catchError, of} from "rxjs";
 
 const BASE_URL = "progetto152";
 const USER = BASE_URL + "/user";
@@ -21,16 +22,27 @@ export class UserService {
     return this.http.get<UserEntity[]>(USER);
   }
 
+
   getUser(username: string) {
-    return this.http.get<UserEntity>(USER + "/" + username);
+    return this.http.get<UserEntity>(USER + "/" + username).pipe(
+      catchError(error => {
+        if (error.status === 404) {
+          return of(null);
+        } else {
+          throw error;
+        }
+      })
+    );
   }
 
+
+
   getUserById(id: number) {
     return this.http.get<UserEntity>(GET_USER_BY_ID + "/" + id);
   }
 
   createUser(user: UserEntity) {
-    console.log("create "+user);
+    console.log("create " + user);
     return this.http.post<UserEntity>(USER, user);
 
   }