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tiramisu · ‎08-01-2024

@TY14 , I think your problem is that you're answering the request in an synchronous way blocking the provider. So the provider can't send keepalives back to the broker/client. When a client gets no keepalive or answer after 3 seconds it will asume that the request is dead and return a timeout. A solution is to do it in an asynchronous way: Have a worker thread for doing the "hard" work. In the on...-Method forward the request to the worker thread and return without calling the callback In the worker thread do the work and after finishing call the callback with the result. So the provider thread is not blocked and can send keepalives back to the client/webserver. You as a implementer of a provider can modify the timeout values:

tiramisu · ‎02-24-2023

Multithreading behaviour (for example: does the system/client/provider/node etc. have to be deleted in the same thread as where it was created?) The api is threadsafe. So you can call any interface function from any thread. For example: If you use a client you can make requests from any thread. How do the asynch callbacks work? Where are they called from? Each client/provider you create has a own thread. If you do a request, this request is forwarded to the client thread and processed there. If there is an answer, the callback will be called in context of this client thread (asynch case). The syncronous method call simply waits for this callback and returns. Same for a provider. All onRead()/on...() methods are called from the provider thread. So there is a linearization of all requests. It's also allowed to forward the callback if your on...() method to a worker thread and call it there. So its possible to anser it in an asynchronous way. This you should use if you don't want to block your provider if the answer of the request will take a long time. The provider detects that the callback was not called and keeps the request alive this a configurable timeout.

tiramisu · ‎07-15-2022

Normaly runtime type information is not necessary in good code. When you have to use dynamic cast in your code it seams that there is something wrong with your design. So, why do you need dynamic casts? Could it be that there is a better soloution to avoid it?

tiramisu · ‎04-29-2022

Soon. In "near" Future it will be possible to read whole structures from PLC with one read operation. So, stay tuned.

tiramisu · ‎03-08-2022

Hello, Our motivation for not documenting the comunication layerout is not about obfuscation, but hiding complexity and maintaining compatibility. Anyhow, a few words about how the data layer communication works: Communication is encrypted by curveMQ. The public key of communication to the server is available in datalayer/curvemq/publickey (read per HTTPS) For authentication a token is obtained per HTTPS and sent with each request. But please understand that don't want to make the internal message structure public. This has the following reasons: The libraray provides a stable interface we can not guarantee on telegram level. This is for you a better option to build your application on a stable API instead of using the message level which might be extended or exchanged by something else, which would make your application incompatable. In addition that are certain semantics and required behavioiurs (eg. keepalive, dead connection detection, ...) which also makes it hard to implement and support directly from other programming languages. As I understand you want to have a portable python application between linux and windows. The Data Layer library is available for linux and windows. So perhaps we can find a convinient way to use these library in the different OS. Please can you elaborate what is the problem with python and datalayer SDK in windows, so that we can help you better? regards tiramisu

About tiramisu

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