Add simple server

[guenhter]

The functionality for starting a simple server is added. It is not possible yet with to also add nodes. Only a empty server is started which can be connected to.

[sgoll]

Wow, thank you! 🚀

Can you fix the CI errors? They mainly deal with missing docs and some minor nitpicking from clippy. You should be able to reproduce most of these with cargo clippy.

[sgoll]

Can you fix the remaining errors before we merge this?

[guenhter]

:) feels like more errors than added lines of code. Yes, I'll look into it. Thx

[uklotzde]

:) feels like more errors than added lines of code. Yes, I'll look into it. Thx

We have agreed on applying aggressive linting rules regarding both code and documentation. Rust gives us the tools and we are using them. Should hopefully pay off in the long term 😅

[guenhter]

Totally agree. The first time is always some hard but after getting used to it, I guess it is no big deal any more.

[uklotzde]

Totally agree. The first time is always some hard but after getting used to it, I guess it is no big deal any more.

Installing and running pre-commit locally will reduce the feedback times.

Our .justfile contains the required commands in the setup and pre-commit recipes. Not yet mentioned in the README 🙈

[guenhter]

I've pushed a few more things to this to make the simple server be a little bit more useful.

Note, that I'm not the advanced Rust dev yet, so chances are high, that I do things wrong here from a Rust point of view or that I did something which is not how you intended to be done.

[guenhter]

What is the idea behind the package Client and ua::Client? I did the same with the server but at this point, I'm keen to remove the ua::Server and pack everything just into the Server. Any remarks on that?

[sgoll]

What is the idea behind the package Client and ua::Client? I did the same with the server but at this point, I'm keen to remove the ua::Server and pack everything just into the Server. Any remarks on that?

The idea is that the types in the ua module are thin wrappers around the underlying structures from open62541-sys, with names and methods mostly intact and following the same principles as the underlying library. They should add only what is necessary to make their interface safe (or explicitly marked unsafe, but that should be restricted to crate-local methods), but no additional business logic.

On the other hand, the non-ua client API is allowed to deviate from the open62541 naming and methods, adding a more Rust-idiomatic interface (which is still pretty much in flow at this point and far from being set in stone).

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That being said, the distinction is not as clear as it should be: some of the methods or rather free helper functions from async_client.rs could be moved to ua/client.rs, e.g. service_request() → ua::Client::async_service().

[sgoll]

Thank you for all the improvements! 🎉