We are controlling the sonos via a small IOT device. This device will be placed at the homes of our customers.
In our home automation system we need to know the playbackstate + volume of the players/groups.
At which polling rate can we ask these parameters ?
We cannot use a cloud server to handle the subscription events.
I tried to put a https webservice in the IOT device with a self signed certificate but this doesn't work.
After I have posted the subscription I get a request in my webservice but the cloud sonos server disconnects immediately.
Probably because of the certificate is self signed - Or can there be another reason ?
Is there another way to recieve status events ?
During discovery In the players Json object there is a key 'websocketUrl'.
The documentation says "The secure WebSocket URL for the device. See Connect for details".
But I cannot find more info about this.
Can this be used ?
At which polling rate can we ask these parameters?
Consider using subscriptions instead of polling. See this answer for more: https://stackoverflow.com/a/60893119/4902948
We cannot use a cloud server to handle the subscription events...
Or can there be another reason?
Is there another way to [receive] status events?
You must host a service that satisfies a set of requirements to receive events. See this answer for more: https://stackoverflow.com/a/57189717/4902948
Also see Details on API credentials and events in New features in versions 11.1, 11.2 (S1), & 12.0 (S2).
Can [the 'websocketUrl'] be used?
This is not publicly available for use.
It would be a lot easier to use the (undocumented but more useful) UPnP APIs. You could simply Subscribe to the UPnP RenderingControl endpoint, then you will get an event every time the volume changes. To find when the track changes, subscribe to AVTransport endpoint.
You can do this with a local server (this is how every Sonos app works after all) and no special cert requirements either.
UPnP events are described in the UPnP spec.
Your question doesn't provide details about the language you're using, but if the device is powerfull enough to run node, you have a good change with my sonos library.
You can just pull the required information from the device as often as you like. Or use the build-in event subscriptions. If you use the events, it will automatically setup an http listener and automatically subscribe to all the events you're listening for.
Events are instant (as in 50ms-100ms after the event took place on the device).
If you request information it is send directly to the device and the device will respond with the answer. Pulling multiple data points per second has never been a problem to me.
Warning as stated above, this uses the undocumented local UPNP api, but since their own app also uses it, I'm guessing that won't change soon.
Related
I am having an API locally hosted in one of the servers (LAN). What I am looking to understand if it is feasible to enable push notification from the server in case of a record entry. Every time a post request is made to the local server, Is it possible to push a notification to a certain mobile device? Please note, I am not considering push notification from web services such as google, Azure, Firebase etc.
It is feasible.
As Sushi said, you can use WebSockets or other Sockets to keep connect between Apps and Server. When client connected to your server, server will record which app is connecting.
By the way, you can custom notification's url between server and app.Use some special characters to distinguish between your various parameters, such as &/[ ]. You are free to set the header and body style of the message. Also, when your message needs to be encrypted, some encryption methods can be used.
Here is a similar discussion about Building an Android notification server can be refer .
For some security reasons that I can't have a public accessible server to receive data from slack.
So, this is what I'm planning to do:
Inbound message from slack: using RTM API
Outbound message to slack: using RTM API or Web API
Questions:
Any better alternatives?
Any restrictions? (AFAIK, buttons and drop downs can't work)
If Web API reach rate limit, can I use incoming webhook as a backup plan?
RTM only approach
Yes, that would work. With only the RTM API you are limited to:
receiving and responding to messages
Other RTM events.
You can't use any interactive functionality like:
Interactive components (buttons, menus, datepickers)
Dialogs
Rate limit on message posting
Using the webhook as "backup" to circumvent the rate limit is not an option, since the rate limit of posting max 1 message per second applies to all form of message posting.
From the documentation:
In general, apps may post no more than one message per second per
channel, whether a message is posted via chat.postMessage, an incoming
webhook, or one of the many other ways to send messages in to Slack.
Alternatives
You did not give any details about the reasons why your app can't expose an endpoint to the public Internet. But you might want to consider using a VPN tunnel like ngrok.
Yes! Socket Mode
There is a new alternative from slack, Socket Mode, which doesn't require a publicly accessible server.
Note: this is only for private apps.
With Socket Mode you have an API token and your server uses it to communicate with Slack's servers and create a two way socket connection. This means your Slack Bot's code can run on a machine behind a firewall and not require any inbound ports to be opened.
Slack message delivery requires an acknowledgement once you get the message, or else they may retry to deliver it.
Limitations
Socket Mode has two main limitations:
Apps using Socket Mode are not currently allowed in the public Slack App Directory.
Socket Mode is only available for apps using new, granular permissions. If you created your app on or after December of 2019, good news: your app already uses the new permissions. Otherwise, you may have to migrate your classic Slack app to use granular permissions before turning on Socket Mode.
I'm working on a PoC of a system where a mobile app client needs to be connected on a server with communications going both ways : either for updating the server or being updated by it. There is no client-to-client communications for the moment.
The client logs in the server via an HTTPS/POST method and gets back a token if the credentials are OK. This token is to be used by any further communication in order to authenticate the user. The reason why I'm using HTTPS for logging in is that there also is a web interface for other purposes.
I could not find a tutorial or documentation that explains how to implement this use case with channels based on websocket transport. All I found so far are either partial and focus on some specific aspects (eg authentication, setting SSL/TLS, etc) and assume the reader already knows the rest or are the over simplified implementations of the chat app. I'm sure I'm not looking at the right place...
My questions are:
What would be the list of callback to implement this use case on
either side
On the server: how does a process send notifications to the
client
NB: I'm using Elixir 1.5.1 and Phoenix 1.3
From the Phoenix guide:
Each Channel will implement one or more clauses of each of these four callback functions — join/3, terminate/2, handle_in/3, and handle_out/3.
The page I linked contains also an MCVE of sockets running on Phoenix. In the bottom there are examples of how the server-client communication is done.
The only thing to apply this to your use-case would be to use one of authentication libraries (e.g. Überauth that comes with great examples) to handle token on each subsequent connection request.
Firstly, here is state of my application:
I have a request coming in from a client (angularjs app) into my API (web api 2). This request is processed and a record is stored in a database. A response is then sent back to the client.
Currently, I have a windows service polling and processing this record(s).
Processing this record can be long running. As a side effect to processing this record, there might be notifications generated to be sent back to one or more clients.
My question is how do I architect this, such that I can utilise SignalR to be able to push the notifications back to the client.
My stumbling block:
I can register and store (in-memory backed by a db) the client's SignalR connectionid along with the application's own user identifier. This way I can match a generated notification with a signalr client.
At the moment, I'm hosting the SignalR hubs within the IIS process. So how do I get back from the Windows Service to IIS to notify the client when a notification is generated?
Furthermore, I should say I am already using SignalR elsewhere in the application and am using a SQL Server backplane.
The issue's with the current architecture:
Any processing is done in the same web request, and notifications are sent out via SignalR before a response to the client is returned. Luckily, the processing is minimal and very quick.
I think this is not very good in terms of performance or maintenance in the long run.
Potential solutions:
Remove SignalR hubs from IIS and host them somewhere else - windows service?
Expose an endpoint on the API to for the windows service to call to push the notification once a notification is generated?
Finally, to add more ingredients to the mix: Use a service bus to remove the polling component of the windows service, and move to a pub/sub architecture. Although this is more work than I want to chew off right now.
Any ideas/recommendations/constructive criticisms are welcome.
Thanks.
Take a look at this sample for starters
Another more advanced solution can be using a backplane to manage the communications between the front end and the backend...
HTH
I'm new to ServiceStack and want some validation on a pattern we're thinking about using.
We want to use ServiceStack with Xamarin and Message Queues. While I understand how REST works under the covers, I'm not sure how the Message Queues on ServiceStack work and if its appropriate for mobile devices.
Specifically we know that all mobile devices are essentially behind a NAT firewall setup by the Telco. Meaning Clients can talk to servers, but servers cant talk directly to clients, without the client talking first.
While the concept of a ServiceBus is designed specifically to handle this case, i'm not sure if its "mobile network friendly".
I would assume that the client side implementation, would need to work in one of two ways: polling, blocking get.
Polling would have the client side frequently runing a Http GET to ask the server if anything is available on a queue. A Blocking Get would, perform a Http GET but have the server return nothing until data is ready. Or is there another technique that i'm missing?
If it is a poll, is there any way to control the Poll frequencies in service stack. If its a blocking get how is this configured..
What happens when the app goes to the background, do we need to cancel the connections manually. etc.etc.
We tool an old version of the ServiceStack client library and ported them to xamarin. We now see that the latest ServiceStack client side library is Xamarin compatible.
So, basically my question is: Had anyone used Message Queues from a Xamarin Mobile to ServiceStack with RedisMQ or other server side message queue.