implemented unlinking of oidc connection

frontend/src/routes/user/ConnectedServices.svelte

@@ -5,7 +5,7 @@
 
     let connections = $state([]);
 
-    onMount(async () => {
+    async function loadConnections(){
         let url = `${location.protocol}//${location.host.replace('5173','8080')}/api/user/oidc/connected`;
 
         let resp = await fetch(url,{credentials:'include'});
@@ -16,7 +16,23 @@
                 console.log(entry);
             }
         }
+    }
+
+    onMount(loadConnections);
+
+    async function unlink(connection){
+        const url = `${location.protocol}//${location.host.replace('5173','8080')}/api/user/oidc/connected`;
+        const resp = fetch(url,{
+            method: 'DELETE',
+            credentials: 'include',
+            body: JSON.stringify(connection)
         });
+        if (resp.ok){
+            alert('succeeded');
+        } else {
+            alert('failed');
+        }
+    }
 </script>
 
 {#if connections.length>0}
@@ -36,7 +52,7 @@
             <td>{connection.service_id}</td>
             <td>{connection.foreign_id}</td>
             <td>
-                <button>{t('user.unlink')}</button>
+                <button onclick={() => unlink(connection)}>{t('user.unlink')}</button>
             </td>
         </tr>
         {/each}

user/src/main/java/de/srsoftware/umbrella/user/UserModule.java

@@ -20,6 +20,7 @@ import static java.net.HttpURLConnection.*;
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static java.text.MessageFormat.format;
 import static java.time.temporal.ChronoUnit.DAYS;
+import static javax.security.auth.callback.ConfirmationCallback.OK;
 
 import com.sun.net.httpserver.HttpExchange;
 import de.srsoftware.tools.Path;
@@ -81,11 +82,59 @@ public class UserModule extends PathHandler {
 			headers.add("Access-Control-Allow-Origin", url);
 			headers.add("Access-Control-Allow-Headers", "Content-Type");
 			headers.add("Access-Control-Allow-Credentials", "true");
-			headers.add("Access-Control-Allow-Methods","GET, POST, PATCH");
+			headers.add("Access-Control-Allow-Methods","DELETE, GET, POST, PATCH");
 		}
 		return ex;
 	}
 
+	private boolean deleteOIDC(HttpExchange ex, UmbrellaUser user, Path path) throws IOException {
+		var head = path.pop();
+		return switch (head){
+			case CONNECTED -> deleteServiceConnection(ex,user);
+			case null, default -> super.doGet(path,ex);
+		};
+	}
+
+	private boolean deleteServiceConnection(HttpExchange ex, UmbrellaUser user) throws IOException {
+		if (user == null) return sendContent(ex,HTTP_SERVER_ERROR,"Expected user object to be of type DbUser");
+		JSONObject json;
+		try {
+			json = json(ex);
+		} catch (Exception e){
+			LOG.log(WARNING,"Request does not contain valid JSON",e);
+			return sendContent(ex,HTTP_FAILED_DEPENDENCY,"Request does not contain valid JSON");
+		}
+		if (!(json.has(FOREIGN_ID) && json.get(FOREIGN_ID) instanceof String foreignId && !foreignId.isBlank())) return sendContent(ex,HTTP_UNPROCESSABLE,format(ERROR_MISSING_FIELD,FOREIGN_ID));
+		if (!(json.has(SERVICE_ID) && json.get(SERVICE_ID) instanceof String serviceId && !serviceId.isBlank())) return sendContent(ex,HTTP_UNPROCESSABLE,format(ERROR_MISSING_FIELD,SERVICE_ID));
+
+
+		try {
+			logins.unlink(ForeignLogin.of(serviceId,foreignId,user.id()));
+			return sendEmptyResponse(OK,ex);
+		} catch (UmbrellaException e) {
+			return send(ex,e);
+		}
+
+	}
+
+	@Override
+	public boolean doDelete(Path path, HttpExchange ex) throws IOException {
+		UmbrellaUser user = null;
+		var sessionToken = SessionToken.from(ex).map(Token::of);
+		if (sessionToken.isPresent()) try {
+			user = users.load(users.load(sessionToken.get()));
+		} catch (UmbrellaException e) {
+			LOG.log(WARNING,e);
+		}
+		addCors(ex);
+		var head = path.pop();
+		switch (head) {
+			case OIDC: return deleteOIDC(ex,user,path);
+
+		};
+		return super.doDelete(path, ex);
+	}
+
 	@Override
 	public boolean doGet(Path path, HttpExchange ex) throws IOException {
 		UmbrellaUser user = null;