fix(mobile): ios random logout

[alextran1502]

fix #8146

The issue is in the method _isEndpointAvailable

  Future<bool> _isEndpointAvailable(String serverUrl) async {
    final Client client = Client();

    if (!serverUrl.endsWith('/api')) {
      serverUrl += '/api';
    }

    try {
      final response = await client
          .get(
            Uri.parse(serverUrl),
          )
          .timeout(const Duration(seconds: 5));

+      if (response.statusCode == 502) {
+        _log.severe(
+          "Server Gateway Error: ${response.body} - Cannot communicate to the server",
+        );
+        return false;
+      }
    } on TimeoutException catch (_) {
      return false;
    } on SocketException catch (_) {
      return false;
    }
    return true;
  }

Even when the server is down, the get request can return a response with HTTP status code 502, which should be checked and handled similarly to TimoutException or SocketException to enter the offline mode.

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[mmomjian]

LGTM. Hopefully at a minimum the increased logging will help provide info.

Do we know why the 502 is getting hit / server is unreachable? From my external monitoring tools (which checks for both page content and HTTP return code) Immich Web and API endpoints are rock solid.

[alextran1502]

Do we know why the 502 is getting hit / server is unreachable? From my external monitoring tools (which checks for both page content and HTTP return code) Immich Web and API endpoints are rock solid.

@mmomjian We don't. My guess is the internal timeout mechanism of the HTTP client. During my testing, I saw it returns 502 sometimes when the server is up and solid during the login process. I submitted the build for TestFlight, and we should be able to test this mechanism on your phones before merging it

[jrasm91]

You should probably do the opposite actually. If it isn't a 200, log the error and return false.

[alextran1502]

Done; it never hit a valid GET endpoint, so it returned 404 or 512. I modify to use GET /server-info/ping to get a valid HTTP 200 when possible

[mmomjian]

Will $serverUrl contain the /api suffix even if not provided on the login screen? I know it works without it currently but im not sure where that gets added/checked.

[alextran1502]

@mmomjian it gets added if it is not included