FrontEnd Bug Fix

anwendung/src/components/InputForm.jsx

@@ -43,8 +43,14 @@ export default function InputForm(p) {
         let url = "http://localhost:8080/users/all?sessionid=" + sessionid;
 
 
+        try {
             await fetch(url).then(response => response.json()).then(user => setUsers(user));
         }
+        catch(e)
+        {
+            router.push("/")
+        }
+    }
 
     useEffect(() => {
 
@@ -213,7 +219,7 @@ export default function InputForm(p) {
                                 }}><input type="checkbox" onChange={(e) => {
                                     onCheckBoxClicked(user, e);
                                 }}/></div></td>
-                                <td style={{}}>{user.firstName + " " + user.lastName}</td>
+                                <td style={{textAlign: "center"}}>{user.firstName + " " + user.lastName}</td>
                                 <select id={"userSelect"} name={"userSelect"} className={"box-shadow selector"}
                                         multiple={false} style={{
                                     maxHeight: 80,

anwendung/src/components/Logout.jsx

@@ -0,0 +1,24 @@
+import Button from "@/components/Button";
+import {useRouter} from "next/router";
+
+export default function Logout()
+{
+    const router = useRouter()
+
+    async function logout()
+    {
+        let url = "http://localhost:8080/users/logout?sessionid=" + localStorage.getItem("sessionid");
+        await fetch(url)
+        await router.push("/")
+    }
+
+    return (
+        <div style={{
+            position: "absolute",
+            left: 20,
+            top: 20
+        }}>
+            <Button onClick={() => logout()} text={"Logout"} color={"#77932b"} width={100} height={40}/>
+        </div>
+    )
+}

anwendung/src/pages/createSemester.js

@@ -1,13 +1,27 @@
 import InputForm from "@/components/InputForm";
 import {useRouter} from "next/router";
+import Logout from "@/components/Logout";
+import {useEffect} from "react";
 
 export default function CreateSemester()
 {
     const router = useRouter();
     let {courseName, startDate, endDate} = router.query;
 
+    useEffect(() => {
+        let checkURL = "http://localhost:8080/users/check?sessionid=" + localStorage.getItem("sessionid");
+        try {
+            fetch(checkURL).then(r => console.log(r))
+        }
+        catch(e)
+        {
+            router.push("/")
+        }
+    }, []);
+
     return (
         <div className={"normal-centered"}>
+            <Logout/>
             <InputForm startDate={startDate} endDate={endDate} courseName={courseName}/>
         </div>
     )

anwendung/src/pages/semesteroverview.js

@@ -5,6 +5,7 @@ import InputForm from "@/components/InputForm";
 import {useRouter} from "next/router";
 import PopUp from "@/components/PopUp";
 import Background from "@/components/Background";
+import Logout from "@/components/Logout";
 
 export default function SemesterOverview(p)
 {
@@ -12,9 +13,14 @@ export default function SemesterOverview(p)
     {
         let urlTest = "http://localhost:8080/semester/all?sessionid=" + localStorage.getItem("sessionid");
 
+        try {
             await fetch(urlTest).then(response => response.json()).then(s => {
                 setEntries(s)
             })
+        } catch(e)
+        {
+            router.push("/")
+        }
     }
 
     function onClickSemester(e, m)
@@ -83,8 +89,17 @@ export default function SemesterOverview(p)
 
     useEffect(() => {
         getSemesters();
+        let checkURL = "http://localhost:8080/users/check?sessionid=" + localStorage.getItem("sessionid");
+        try {
+            fetch(checkURL).then(r => console.log(r))
+        }
+        catch(e)
+        {
+            router.push("/")
+        }
     }, [])
 
+
     const [entries, setEntries] = useState([])
     const [modalDisplay, setModalDisplay] = useState("none");
     const [modalHint, setModalHint] = useState("");
@@ -92,6 +107,7 @@ export default function SemesterOverview(p)
 
     return (
         <div className={"semester-overview"}>
+            <Logout/>
             <Background/>
             {
                 entries.map(e => (<SemesterTile text={e.name} onClick={(f) => onClickSemester(e, f)} onButtonDeleteClick={() => {

backend/src/main/java/com/example/backend/anwprj/controller/UserController.java

@@ -140,6 +140,20 @@ public class UserController {
         return new ResponseEntity<>(HttpStatus.FORBIDDEN);
     }
 
+    @CrossOrigin
+    @GetMapping("/users/check")
+    public ResponseEntity<User> checkLogin(@RequestParam(name="sessionid") String sessionid)
+    {
+        User u = UserSessionIDHandler.getUserBySessionID(sessionid);
+
+        if(u != null)
+        {
+            return new ResponseEntity<>(db.getUser(u.getId()), HttpStatus.OK);
+        }
+
+        return new ResponseEntity<>(HttpStatus.NOT_FOUND);
+    }
+
     @CrossOrigin
     @DeleteMapping("/users")
     public ResponseEntity<Boolean> deleteUser(@RequestParam(name = "sessionid") String sessionID, @RequestParam(name = "mail") String mail) {