How to detect a lost connection via chrome.hid API? - google-chrome-app

I don't see a way to register a callback when a connection is lost in the chrome.hid API. E.g. an onConnectionLost method.
How am I supposed to detect a user accidentally pulling the cable in the middle of a process? Are we expected to poll, somehow?

You should star this issue: https://code.google.com/p/chromium/issues/detail?id=349473. When it's implemented you'll be able to do what you want.

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Problem using signalr for chat application flutter

I had made a whole chat application using signalr as a socket with the online and offline facility. I am facing a few problems,
Signalr connection is always time out after some time, to overcome that I had condition if hubconnection is not connected then create new hubconnection (onResume app), but still it get hubconnection._callback got increased when sending message and not moving to server side socket. Again need to refresh whole app.
Can someone tell me whether this is problem because there are lot of operations going on and so signalr loses its connection as flutter is single thread and it cannot handle much? or should I use Isolate or inherit widget.
Summary problem:
I cannot send message in chat after sometime. It stores all message in hubconnection._callback and not going for server.
Is anything better solution to keep alive in both Android+iOS.
I had used https://pub.dev/packages/signalr_netcore package.
Please do not mention about firebase.
Any other logic suggestion is appreciable.
Thank you.
I've been using a different package, https://pub.dev/packages/signalr_core, which works fine without any particular issues what I have observed at the moment.
I'm only running about 10 listeners simultaneously, not sure if that is more or less than you. In the package I'm running you can establish connection with automatic reconnect. It looks like this:
HubConnectionBuilder().withAutomaticReconnect().withUrl(....)
It seems like your package have the same functionality... Have you tried that?

How to receive data from an api without any user interaction

I'm trying to receive some data from an API call and do some task based on the received data.
Let's say I have my flutter app opened and in that opened state without any click or any interaction I get some data or do any function when I send something through the API.
I used Firebase FCM to do such task - When I send something through the API the firebase notification captures that data and doing the tasks I want on the flutter app.
But I want to do without Firebase. How can I do that. Any solution/suggestions would be great. Thanks!
At first, let's put Flutter aside. Your problem is to pull data from API and do a specific task OR your API should notify the app through API.
For the first problem, a simple data polling should work: when the app is opened, you just start some kind of timer and periodically pull data from the API and do something. However, this method is not perfect, it drains the battery and in general, there are better ways to achieve the same thing, for instance using sockets or push notifications (as some of the answers already state that).
For your second problem - "or do any function when I send something through the API" - you need some kind of mechanism to notify your app for it to react and process the data. This one could be handled using the same mechanism as for the first problem.
So, probably you need to use some kind of push notification service (for instance OneSignal or Pusher, or any other similar service) or web sockets (https://flutter.dev/docs/cookbook/networking/web-sockets).
Your question is little bit unclear. Whatever if you want to do some network call even without any interaction by user you can call network in your onInit method. This method runs at the very beginning for individual screen. Then do your task based on the response
You need stream API for this,look into socket programming
You can use webs socket or pusher for this. When web socket is connected with your server that time you received some data and you can do your task.

how to add progress message in google home dialogflow

In my conversation dialogflow, I would like to add some progress messages like hang in with me, I'm looking up for that data or similar in the conversation. Is there any guidance or best practice to do this?
Unfortunately, there is no good way to do this at this time. If your webhook takes longer than about 5 seconds, Dialogflow will return one of the default responses it is set with. If you're not using Dialogflow, the Action SDK will say your webhook isn't responding and will close the conversation.
There is currently no way to send a reply, and then send another reply without the user saying something first.
One workaround might be to have the default response be something like "I'm looking that information up. Ask me again in a few seconds." When your lookup finally completes, cache the information so when/if the user asks the question again, you can return it more quickly.
Depending how long it takes, you may also wish to register a dynamic reprompt. This will send an event to your webhook if the user doesn't say anything. In a situation like this, they may say nothing for a few seconds, but that may be long enough for you to have computed the reply. So after a few seconds of silence you can suddenly announce "I've figured it out, the answer you were looking for is..." or something similar. This has some limitations - you can only reprompt twice like this before Google sends you a final reprompt and closes the conversation.
Although the platform does support notifications, these are still in developer preview and don't work with all devices. They also don't quite continue the conversation (it doesn't just start talking) - they just send a notification to a phone that there is a message and that they can restart the conversation. Depending on your use case, this may be useful combined with the above.
Update
The Media Response includes a feature that we can take advantage of to handle this. Similar to the dynamic reprompt method above, you'll get a call automatically when the media you're playing ends. So you can play a short "hold music" and your webhook will be called when it is finished. You can then either give the result or say you're still working on it and play more hold music.

Handle timeout of GNotifications in Gnome?

My program needs to react to the user not taking any action on a GNotification.
More specificially, a piece of data is written to the database only if the user does not press the "undo" button on the notification sent after the data's creation. My target deployment scenario does have notifications enabled and a real timeout value.
To be precise: Moving the notification "away" / deleting it should also count as such a timeout.
1) Is there a built-in way to 'listen' to notification timeouts?
2) If not, how could I still implement similar behavior?
I would use the D-Bus org.freedesktop.Notifications interface. Although it is still a draft specification, it does appear stable. My experience accessing the D-Bus interface using Vala has been that it is easier to use and gives the full feature set of the specification. GNotification doesn't seem to be as feature complete.
From the draft specification you will see there is an expire_timeout argument of the org.freedesktop.Notifications.Notify method. That should fit your time out requirement, although I've not used it personally. There is also a org.freedesktop.Notifications.NotificationClosed signal that will allow your program to be notified when the notification is closed, including because of a time out or if it was dismissed by the user.
This post about the screen lock re-design for GNOME Shell 3.10 might give some indication of what notifications are capable of. The post includes some screenshots of notifications appearing in the lock screen.

How does the Notice Area on Facebook works?

How does the notification area on Facebook works?
I'm taking about the automatically red box that appears.
If I have a message/something new on my wall.
I believe it is also in Stack Exchange, is that a Javascript interval?
Please see this thread
How does one do realtime updates of a web page?
Not sure about this, but I'd wager that both Facebook and SO use an implementation of Comet. Basically, you make a request to the server which is designed to be kept open a really long time, and the server only responds when it has something to say. When the request times out (or receives data back) you simply start up another one. This way you get as close to real-time data as you can without wasting a ton of bandwidth on empty requests.