I try to use txt-records to share information between multiple devices. Therefore I am using bonjour/avahi. The server-side works fine as wireshark proofs. Information is added to the txt-record and sent out using MDNS.
The problem occurs on the client side, where the daemon/service does not seem to get the information change all the time. It is stuck with information that is already outdated and does not automatically update it when I try to resolve the service again.
On the client side I am using DNSServiceResolve in combination with a callback function where I call TXTRecordContainsKey and TXTRecordGetValuePtr to make sure the data is available before use. This all works fine except that, as already mentioned, the information is not always updated.
Am I missing something, or are there any additional API-function calls that I can use to force the daemon to update its record except DNSServiceResolve?
Thank you in advance.
Solved, always make sure you deaktivate your firewall when dealing with such strange problems...
This completely solved my issue.
Related
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?
I need a little advice with deploying Triton inference server with explicit model control. From the looks of it, this mode gives the user the most control to which model goes live. But the problem I’m not able to solve is how to load models in case the server goes down in production which triggers a new instance to spawn up.
The only solution I can think of is to have a service poll the server at regular time intervals, constantly check if my live models are actually live and if not, load them. But this seems like quite a complicated process.
I would like to know how others have solved this problem.
Thanks in advance
I have built and started an OPC UA embedded Openmodelica server with the BouncingBall model like so:
$ omc +s path/to/model
$ ./BouncingBall -embeddedServer=opc-ua -rt=1
Now I'm trying to interact with it using an OPCUA client. However, I don't understand how I'm supposed to interact with the server properly. As far as I know this is undocumented.
The most promising approach seems to be to set enableStopTime to false and run to true. Then the simulation seems to run indefinitely and the values seem to make sense. It seems I'm only able to extract the values in real time however. While running, when I set run to false it seems that the server enters an erroneous state and it refuses to give any values back.
If I restart the executable and instead set step to true nothing seems to change and after trying to set step to true a second time the server becomes unresponsive. The -rt=1 option doesn't seem to matter. Seems like it enters the same state as above (1).
(After restart) If I leave enableStopTime to be true and set run to true the simulation runs to stop and then the server quits with message The simulation finished successfully. Maybe this is intended. Kind of seems odd. Would make sense to be able to restart the simulation or trigger it with new options.
What I would hope to be able to do: Start and stop simulation as well as rewind to a certain point to check the value at that point. It seems to me that the API "affords" this functionality and it could probably be provided by hackingly wrapping the executable and API. Are the above bugs or intended? What is the intended way to interact with an OPC UA server in these cases?
The OpenModelica compiler version is 1.16.0~1-g84b4a71
Please try the latest nightly build
It includes the following commit.
That might solve it. I believe things worked without subscriptions before, since I could never reproduce this without them.
(By the way, do people go on our git commit feed and try to reproduce bugs fixed in the last 24 hours; we quite often get questions that were just recently fixed)
I need help, I'm desperate
During two weeks I have been working in my project, this uses serial port communication (a PIC serial board). I got to set the connection up, but I can not get data from the COM port. I've read some forums and the cause of the problem seems to be the incomplete implementation of System.IO.Ports class.
When I try to get data of the COM port, the event SerialDataReceivedEventHandler (represents the method that will handle the DataReceived event of a SerialPort object.) is not called or activated. I tried to resolve it but I don't find a definitive solution. I thought to prove a external DLL, but a friend told me that the problem will go on, in fact I did it and got the same problem: SerialDataReceivedEventHandler does not work. Also, someone recommended me using a secondary thread, although I don´t understand how to do it at all.
I wrote a program in visual C# and everything works fine. I'm intrigued.
I need to find a solution, some idea or good documentation. If there's someone knows something about it, help me please.
I need to understand the cause of this to continue.
Unity is based on Mono, and Mono doesn't implement completely the Serial class, in particular there are no notifications implemented (such as SerialDataReceivedEvent).
That's why it works in Visual Studio, and not in Unity.
Here are the differences between the Mono and complete .NET implementation of the Serial class :
Extract from http://www.mono-project.com/archived/howtosystemioports/#limitations
"Limitations
At the time of this writing, there are a a few limitations that one must take note:
1) There is no event notification for received serial data. If you want to receive data, one must set a timeout and watch for received data by polling ReadByte() when you think there might be data.
2) One must Read data in byte[] format only – there is no char[] support. You must do your own reading of bytes and translate that into your encoding.
3) DiscardNull, ParityReplace, ReceivedBytesThreshold are not implemented."
I think it happens because the Unity is based on Mono instead of .Net, and a pretty old version of it. You couldn't use Linq on iOS devices for a long time because of AOT bugs, and the localisation implementation is buggy (or at least it was in the previous versions of Unity I tried to work with). I wasn't even able to find the source of System.IO.Ports in the source of Unity's Mono fork, so it's surprising it compiles at all.
I am a little confused on how to go about and do this....
On each page of my app i connect to PHP file to drag in data from my server. I have about 10 pages. Now if there is no connection to the internet then of course now data can be received.
Often the app crashes and we are putting this down to not having the data due to a change in connection or wifi whatever.
Now i have setup the reachability thing and that works, but i dont know how to link this in with the PHP calls. Should i check the reachability and if no connection then dont run the call. If so, what about all the variables, they will still be null and cause an error then?
I dont really know what is the best solution.
Hope you can help
Alex
Are the php calls just to receive data from a database without using a built in DB framework such as SQLite? If so, I went the same route to avoid the headache at first, but running SQLite in your app is a better solution overall, and reduces multiple dependencies (such as internet connection).
Now if the php calls that give you data back are receiving this information from yet another source and then feeding it into its own DB.....
Should i check the reachability and if no connection then dont run the call
Yes you should. This is done in multiple apps already. What variables would be null in this case? Pop the code that makes the call in an "if" block below this check, and only run it if true. Error handling other variables that might be null because the php call isn't setting them is up to you. You can do this is multiple ways.
You should certainly cache the data so the App doesn't HAVE to connect to the internet to display something, other than that I would make sure to use asynchronous requests and the timeout feature of NSURLRequest to control your attempts to request data in the background. If you don't get the data, just keep using what you have cached.