Bot can handle request from Skype desktop app, but not from Skype store app

3
votes

I have written a small chat bot using the MS bot framework. I added the Skype and Web channels, and host the bot on Azure with the smallest pay-as-you-go plan. The bot itself is working nicely, both through the web chat and in Skype conversations, both directly (1on1 chat) as well as in groups, when I'm using the Skype desktop app.

Unfortunately, when using the Skype app installed from the Microsoft store, nothing works anymore... Sending a message to the bot (in direct chats and groups) always produces HTTP 500 responses from my bot. Digging into it a bit releaved a simple NullReferenceException being thrown, apparently in the very first line in my dialog handler (see below): The call stack pointed at this line, but the error happened later, see below:

namespace MyBot.Dialogs {
    [Serializable]
    public class RootDialog: IDialog<IMessageActivity> {
        public Task StartAsync(IDialogContext context) {
            context.Wait(MessageReceivedAsync);
            return Task.CompletedTask;
        }

        private async Task MessageReceivedAsync(IDialogContext context, IAwaitable<IMessageActivity> result) {
            // call stack pointed to next line
            Activity activity = await result as Activity;

            //... some unproblematic stuff

            string username = activity.From.Name;
            // the next line was the actual problem:
            if(username.Contains(" "))
                //...
        }
    }
}

This part of the code, as well as the full MessagesController are taken without changed from the bot framework examples, and as mentioned before, the bot is working fine from web chat and the "regular" Skype desktop app. Even in a group chat with some users on the desktop app and some on the store app, the users with the desktop app can interact with the bot as expected, while the store app users only trigger errors.

The obvious questions here are of course: how (and why) do the two Skype apps differ from a bot perspective, and how can I handle this?

Edit: As it turns out, the Skype desktop app sets the activity.From.Name property to the user's name, while the Skype store app does not. The mean part is, the channelid's for both are the same ("skype", obviously).

1
c#botframeworkskypeskypedeveloperskype-bots
Two things to try: - what happens if you remove the <IMessageActivity> from the IDialog inheritance. I suspect nothing will change - what happens if you do var activity = await result;? – Ezequiel Jadib
Definitely a strange issue. Have you debugged locally, to see what is different between the messages? blog.botframework.com/2017/10/19/… – Eric Dahlvang
@EzequielJadib I could not notice any difference when doing either of these things, unfortunately. – Ralf Stauder
@EricDahlvang Thanks for the link and hint, I found the problem. As it turned out, the error did not happen in the line mentioned in the call stack (the "await result"), but several lines further. Editing the actual question for future reference now... – Ralf Stauder

1 Answers

1
votes

Thanks to the comment of @EricDahlvang, I noticed that the error was not the line mentioned above at first, despite the call stack specifically giving this line number. The error happened later, when I tried to work with "activity.From.Name". As it turns out, the regular Skype sets this property to match the users display name, while the Skype store app does not, and returns null.