WebAuthenticator not working with Mozilla Firefox

Hi,

I am using your WebAuthenticator for authenticating a MAUI windows app. The authenticator works correctly with edge and chrome browsers. But when I set Mozilla as default browser, the browser opens, accepts login credentials, brings the app in the foreground but the control is never returned to the MAUI app.

On Debugging the WebAuthenticator.cs I found this:-

   // WebAuthenticator.cs
    tasks.Add(taskId, tcs);
    var uri = await tcs.Task.ConfigureAwait(false);

Here, the control never returns to the last line after the second last is executed.

Using with Windows 11 and Firefox 111.0.1 (64-bit).

[RobinS-S]

@dotMorten @shv07 @oliverholliday I’ve tested it out a bit, and found out it is indeed a Firefox problem. Fixing this in your code would be nice to get something working fast, but I agree they should fix it. Reported it at Bugzilla.

[benny-ayote]

I experienced the same issue. The quotation marks expected in the JSON string value of the state parameter are being removed by Firefox. This did not occur in Chrome.

Firefox: https://[URL]/auth?redirect=myapp://&state={appInstanceId:",signinId:6fc43c2c-7df7-443d-ba11-4e37e4aa9a4b}

Chrome: https://[URL]/auth?redirect=myapp://&state={"appInstanceId":"","signinId":"2739798f-d690-4426-abcf-4f1a9dce3ea6"}

As a result, the call to JsonObject.Parse(state) throws an exception due to the improperly formed JSON.

// WebAuthenticator.cs
var jsonObject = System.Text.Json.Nodes.JsonObject.Parse(state) as JsonObject;
if (jsonObject is not null)
...

I was able to resolve by changing this:

query["state"] = stateJson.ToJsonString();

to this:

query["state"] = Uri.EscapeDataString(stateJson.ToJsonString());