simplified code across the app and consolidated duplicated helpers

lib/api/marianumcloud/app_password/delete_app_password.dart

@@ -18,13 +18,7 @@ class DeleteAppPassword {
       NextcloudOcs.uri('core/apppassword'),
       // An explicit header may belong to an inactive account, so the active
       // session's headers must not be required then.
-      headers: authorizationHeader == null
-          ? NextcloudOcs.headers()
-          : {
-              'Accept': 'application/json',
-              'OCS-APIRequest': 'true',
-              'Authorization': authorizationHeader,
-            },
+      headers: NextcloudOcs.headers(authorization: authorizationHeader),
     );
   }
 }

lib/api/marianumcloud/app_password/get_app_password.dart

@@ -28,23 +28,17 @@ class GetAppPassword {
       label,
       () => _client.get(
         NextcloudOcs.uri('core/getapppassword'),
-        headers: {
-          ...NextcloudOcs.headers(),
-          // Deliberately NOT the shared Authorization value: that one prefers
-          // the app password, but an app password cannot mint another one —
-          // this endpoint requires the real password.
-          'Authorization': SessionManager()
+        // Deliberately NOT the shared Authorization value: that one prefers
+        // the app password, but an app password cannot mint another one —
+        // this endpoint requires the real password.
+        headers: NextcloudOcs.headers(
+          authorization: SessionManager()
               .requireNextcloud()
               .realPasswordBasicAuthHeader,
-        },
+        ),
       ),
     ))!;
-    if (response.statusCode < 200 || response.statusCode >= 300) {
-      throwForStatus(
-        response.statusCode,
-        httpErrorDetail(label, response.body, response.statusCode),
-      );
-    }
+    ensureSuccess(label, response);
     final json = jsonDecode(utf8.decode(response.bodyBytes));
     final data = (json as Map)['ocs']?['data'];
     final appPassword = data is Map ? data['apppassword'] as String? : null;

lib/api/marianumcloud/cloud_users/cloud_users_actions.dart

@@ -1,4 +1,3 @@
-import 'dart:convert';
 import 'dart:developer';
 import 'dart:typed_data';
 
@@ -96,9 +95,8 @@ class GetUserInfo {
       uri,
     );
     try {
-      final root = jsonDecode(response.body) as Map<String, dynamic>;
       final data =
-          (root['ocs'] as Map<String, dynamic>)['data'] as Map<String, dynamic>;
+          NextcloudOcs.decode(response.body)['data'] as Map<String, dynamic>;
       return CloudUserInfo(
         userId: data['id'] as String,
         displayName: (data['displayname'] as String?) ?? '',

lib/api/marianumcloud/login_flow/login_flow_api.dart

@@ -29,12 +29,7 @@ class LoginFlowApi {
         headers: {'Accept': 'application/json', 'User-Agent': userAgent},
       ),
     ))!;
-    if (response.statusCode < 200 || response.statusCode >= 300) {
-      throwForStatus(
-        response.statusCode,
-        httpErrorDetail(label, response.body, response.statusCode),
-      );
-    }
+    ensureSuccess(label, response);
     return LoginFlowInit.fromJson(
       jsonDecode(utf8.decode(response.bodyBytes)) as Map<String, dynamic>,
     );
@@ -53,12 +48,7 @@ class LoginFlowApi {
       ),
     ))!;
     if (response.statusCode == 404) return null;
-    if (response.statusCode < 200 || response.statusCode >= 300) {
-      throwForStatus(
-        response.statusCode,
-        httpErrorDetail(label, response.body, response.statusCode),
-      );
-    }
+    ensureSuccess(label, response);
     return LoginFlowCredentials.fromJson(
       jsonDecode(utf8.decode(response.bodyBytes)) as Map<String, dynamic>,
     );

lib/api/marianumcloud/nextcloud_ocs.dart

@@ -13,10 +13,13 @@ class NextcloudOcs {
   static Map<String, dynamic> decode(String raw) =>
       (jsonDecode(raw) as Map<String, dynamic>)['ocs'] as Map<String, dynamic>;
 
-  static Map<String, String> headers() => {
+  /// [authorization] overrides the active session's credentials, which are
+  /// then not required.
+  static Map<String, String> headers({String? authorization}) => {
     'Accept': 'application/json',
     'OCS-APIRequest': 'true',
-    'Authorization': SessionManager().requireNextcloud().basicAuthHeader,
+    'Authorization':
+        authorization ?? SessionManager().requireNextcloud().basicAuthHeader,
   };
 
   static Uri uri(String pathSuffix, {Map<String, dynamic>? queryParameters}) {

lib/api/marianumcloud/talk/chat/fetch_chat_page.dart

@@ -0,0 +1,46 @@
+import 'package:flutter/foundation.dart';
+import 'package:http/http.dart' as http;
+
+import '../../../errors/server_exception.dart';
+import '../../../http_errors.dart';
+import '../../nextcloud_ocs.dart';
+import 'get_chat_params.dart';
+import 'get_chat_response.dart';
+
+/// GETs a chat page outside [TalkApi], which treats non-2xx as errors: here
+/// HTTP 304 (nothing new / no older messages) is a normal outcome and yields
+/// `null`.
+Future<GetChatResponse?> fetchChatPage({
+  required String label,
+  required String chatToken,
+  required GetChatParams params,
+  Duration? timeout,
+  bool parseOffIsolate = false,
+}) async {
+  final uri = NextcloudOcs.uri(
+    'apps/spreed/api/v1/chat/$chatToken',
+    queryParameters: params.toJson(),
+  );
+  final headers = NextcloudOcs.headers();
+
+  final response = (await sendGuarded('$label $uri', () {
+    final request = http.get(uri, headers: headers);
+    return timeout == null ? request : request.timeout(timeout);
+  }))!;
+
+  final status = response.statusCode;
+  if (status == 304) return null;
+  if (status >= 200 && status < 300) {
+    final parsed = parseOffIsolate
+        ? await compute(_parseChatResponse, response.body)
+        : _parseChatResponse(response.body);
+    return parsed..headers = response.headers;
+  }
+  throw ServerException(
+    statusCode: status,
+    technicalDetails: '$label $uri: HTTP $status',
+  );
+}
+
+GetChatResponse _parseChatResponse(String body) =>
+    GetChatResponse.fromJson(NextcloudOcs.decode(body));

lib/api/marianumcloud/talk/chat/get_chat.dart

@@ -1,6 +1,3 @@
-import 'package:http/http.dart' as http;
-import 'package:http/http.dart';
-
 import '../../nextcloud_ocs.dart';
 import '../talk_api.dart';
 import 'get_chat_params.dart';
@@ -16,11 +13,4 @@ class GetChat extends TalkApi<GetChatResponse> {
   @override
   GetChatResponse assemble(String raw) =>
       GetChatResponse.fromJson(NextcloudOcs.decode(raw));
-
-  @override
-  Future<Response> request(
-    Uri uri,
-    Object? body,
-    Map<String, String>? headers,
-  ) => http.get(uri, headers: headers);
 }

lib/api/marianumcloud/talk/chat/get_chat_history.dart

@@ -1,17 +1,12 @@
-import 'package:flutter/foundation.dart';
-import 'package:http/http.dart' as http;
-
-import '../../../errors/server_exception.dart';
-import '../../../http_errors.dart';
-import '../../nextcloud_ocs.dart';
+import 'fetch_chat_page.dart';
 import 'get_chat_params.dart';
 import 'get_chat_response.dart';
 
 /// Backwards-paging variant of GetChat (`lookIntoFuture=0` + `lastKnownMessageId`)
-/// that fetches the page of messages *older* than a given id. Bypasses [TalkApi]
-/// because that layer treats non-2xx as errors, and the server answers HTTP 304
-/// when there are no older messages left — a normal "start of chat" outcome here.
-/// `setReadMarker=off` so paging into history never moves the read cursor.
+/// that fetches the page of messages *older* than a given id. The server
+/// answers HTTP 304 when there are no older messages left — a normal "start of
+/// chat" outcome (see [fetchChatPage]). `setReadMarker=off` so paging into
+/// history never moves the read cursor.
 class GetChatHistory {
   final String chatToken;
   final int lastKnownMessageId;
@@ -24,39 +19,18 @@ class GetChatHistory {
   });
 
   /// Returns the older page, or `null` on HTTP 304 (no older messages).
-  Future<GetChatResponse?> run() async {
-    final params = GetChatParams(
+  Future<GetChatResponse?> run() => fetchChatPage(
+    label: 'GetChatHistory',
+    chatToken: chatToken,
+    params: GetChatParams(
       lookIntoFuture: GetChatParamsSwitch.off,
       lastKnownMessageId: lastKnownMessageId,
       includeLastKnown: GetChatParamsSwitch.off,
       setReadMarker: GetChatParamsSwitch.off,
       limit: limit,
-    );
-    final uri = NextcloudOcs.uri(
-      'apps/spreed/api/v1/chat/$chatToken',
-      queryParameters: params.toJson(),
-    );
-    final headers = NextcloudOcs.headers();
-
-    final response = (await sendGuarded(
-      'GetChatHistory $uri',
-      () => http.get(uri, headers: headers),
-    ))!;
-
-    final status = response.statusCode;
-    if (status == 304) return null;
-    if (status >= 200 && status < 300) {
-      // A page holds up to 200 messages and lands while the user is scrolling;
-      // decoding it on the UI isolate stalls the fling.
-      final parsed = await compute(_parseChatResponse, response.body);
-      return parsed..headers = response.headers;
-    }
-    throw ServerException(
-      statusCode: status,
-      technicalDetails: 'GetChatHistory $uri: HTTP $status',
-    );
-  }
+    ),
+    // A page holds up to 200 messages and lands while the user is scrolling;
+    // decoding it on the UI isolate stalls the fling.
+    parseOffIsolate: true,
+  );
 }
-
-GetChatResponse _parseChatResponse(String body) =>
-    GetChatResponse.fromJson(NextcloudOcs.decode(body));

lib/api/marianumcloud/talk/chat/long_poll_chat.dart

@@ -1,15 +1,10 @@
-import 'package:http/http.dart' as http;
-
-import '../../../errors/server_exception.dart';
-import '../../../http_errors.dart';
-import '../../nextcloud_ocs.dart';
+import 'fetch_chat_page.dart';
 import 'get_chat_params.dart';
 import 'get_chat_response.dart';
 
-/// Long-poll variant of GetChat (`lookIntoFuture=1`). Bypasses [TalkApi]
-/// because that layer treats non-2xx as errors, and we need 304 to be a
-/// normal "no new messages" outcome. `setReadMarker=on` lets the server
-/// move the read cursor whenever the call returns messages.
+/// Long-poll variant of GetChat (`lookIntoFuture=1`); HTTP 304 is the normal
+/// "no new messages" outcome (see [fetchChatPage]). `setReadMarker=on` lets
+/// the server move the read cursor whenever the call returns messages.
 class LongPollChat {
   final String chatToken;
   final int lastKnownMessageId;
@@ -22,37 +17,17 @@ class LongPollChat {
   });
 
   /// Returns the response, or `null` on HTTP 304 (server timeout, nothing new).
-  Future<GetChatResponse?> run() async {
-    final params = GetChatParams(
+  Future<GetChatResponse?> run() => fetchChatPage(
+    label: 'LongPollChat',
+    chatToken: chatToken,
+    params: GetChatParams(
       lookIntoFuture: GetChatParamsSwitch.on,
       timeout: timeoutSeconds,
       lastKnownMessageId: lastKnownMessageId,
       includeLastKnown: GetChatParamsSwitch.off,
       setReadMarker: GetChatParamsSwitch.on,
       limit: 100,
-    );
-    final uri = NextcloudOcs.uri(
-      'apps/spreed/api/v1/chat/$chatToken',
-      queryParameters: params.toJson(),
-    );
-    final headers = NextcloudOcs.headers();
-
-    final response = (await sendGuarded(
-      'LongPollChat $uri',
-      () => http
-          .get(uri, headers: headers)
-          .timeout(Duration(seconds: timeoutSeconds + 15)),
-    ))!;
-
-    final status = response.statusCode;
-    if (status == 304) return null;
-    if (status >= 200 && status < 300) {
-      return GetChatResponse.fromJson(NextcloudOcs.decode(response.body))
-        ..headers = response.headers;
-    }
-    throw ServerException(
-      statusCode: status,
-      technicalDetails: 'LongPollChat $uri: HTTP $status',
-    );
-  }
+    ),
+    timeout: Duration(seconds: timeoutSeconds + 15),
+  );
 }

lib/api/marianumcloud/talk/get_participants/get_participants.dart

@@ -1,5 +1,3 @@
-import 'package:http/http.dart' as http;
-
 import '../../nextcloud_ocs.dart';
 import '../talk_api.dart';
 import 'get_participants_response.dart';
@@ -11,11 +9,4 @@ class GetParticipants extends TalkApi<GetParticipantsResponse> {
   @override
   GetParticipantsResponse assemble(String raw) =>
       GetParticipantsResponse.fromJson(NextcloudOcs.decode(raw));
-
-  @override
-  Future<http.Response> request(
-    Uri uri,
-    Object? body,
-    Map<String, String>? headers,
-  ) => http.get(uri, headers: headers);
 }

lib/api/marianumcloud/talk/get_poll/get_poll_state.dart

@@ -1,5 +1,3 @@
-import 'package:http/http.dart' as http;
-
 import '../../nextcloud_ocs.dart';
 import '../talk_api.dart';
 import 'get_poll_state_response.dart';
@@ -13,11 +11,4 @@ class GetPollState extends TalkApi<GetPollStateResponse> {
   @override
   GetPollStateResponse assemble(String raw) =>
       GetPollStateResponse.fromJson(NextcloudOcs.decode(raw));
-
-  @override
-  Future<http.Response> request(
-    Uri uri,
-    Object? body,
-    Map<String, String>? headers,
-  ) => http.get(uri, headers: headers);
 }

lib/api/marianumcloud/talk/get_reactions/get_reactions.dart

@@ -1,7 +1,3 @@
-import 'package:http/http.dart' as http;
-import 'package:http/http.dart';
-
-import '../../../api_params.dart';
 import '../../nextcloud_ocs.dart';
 import '../talk_api.dart';
 import 'get_reactions_response.dart';
@@ -15,11 +11,4 @@ class GetReactions extends TalkApi<GetReactionsResponse> {
   @override
   GetReactionsResponse assemble(String raw) =>
       GetReactionsResponse.fromJson(NextcloudOcs.decode(raw));
-
-  @override
-  Future<Response>? request(
-    Uri uri,
-    ApiParams? body,
-    Map<String, String>? headers,
-  ) => http.get(uri, headers: headers);
 }

lib/api/marianumcloud/talk/get_shared_items/get_shared_items.dart

@@ -1,5 +1,3 @@
-import 'package:http/http.dart' as http;
-
 import '../../nextcloud_ocs.dart';
 import '../talk_api.dart';
 import 'get_shared_items_response.dart';
@@ -30,11 +28,4 @@ class GetSharedItems extends TalkApi<GetSharedItemsResponse> {
   @override
   GetSharedItemsResponse assemble(String raw) =>
       GetSharedItemsResponse.fromOcs(NextcloudOcs.decode(raw));
-
-  @override
-  Future<http.Response> request(
-    Uri uri,
-    Object? body,
-    Map<String, String>? headers,
-  ) => http.get(uri, headers: headers);
 }

lib/api/marianumcloud/talk/get_shared_items/get_shared_items_overview.dart

@@ -1,5 +1,3 @@
-import 'package:http/http.dart' as http;
-
 import '../../nextcloud_ocs.dart';
 import '../talk_api.dart';
 import 'get_shared_items_overview_response.dart';
@@ -18,11 +16,4 @@ class GetSharedItemsOverview extends TalkApi<GetSharedItemsOverviewResponse> {
   @override
   GetSharedItemsOverviewResponse assemble(String raw) =>
       GetSharedItemsOverviewResponse.fromOcs(NextcloudOcs.decode(raw));
-
-  @override
-  Future<http.Response> request(
-    Uri uri,
-    Object? body,
-    Map<String, String>? headers,
-  ) => http.get(uri, headers: headers);
 }

lib/api/marianumcloud/talk/room/get_room.dart

@@ -1,5 +1,4 @@
 import 'package:flutter/foundation.dart';
-import 'package:http/http.dart' as http;
 
 import '../../nextcloud_ocs.dart';
 import '../talk_api.dart';
@@ -17,13 +16,6 @@ class GetRoom extends TalkApi<GetRoomResponse> {
   @override
   Future<GetRoomResponse> assembleAsync(String raw) =>
       compute(_parseRooms, raw);
-
-  @override
-  Future<http.Response> request(
-    Uri uri,
-    Object? body,
-    Map<String, String>? headers,
-  ) => http.get(uri, headers: headers);
 }
 
 GetRoomResponse _parseRooms(String raw) =>

lib/api/marianumcloud/talk/talk_api.dart

@@ -23,11 +23,12 @@ abstract class TalkApi<T extends ApiResponse?> {
 
   TalkApi(this.path, this.body, {this.headers, this.getParameters});
 
+  /// Defaults to a plain GET; endpoints with a body or another verb override it.
   Future<http.Response>? request(
     Uri uri,
     ApiParams? body,
     Map<String, String>? headers,
-  );
+  ) => http.get(uri, headers: headers);
   T assemble(String raw);
 
   /// Override to parse large payloads off the UI isolate (e.g. via `compute`