Add ability to redirect all prints

[ShaharHD]

Added output (which defaults to std::cout) and error (which defaults to std::cerr) to allow easier redirect of all prints.

Useful when used in a daemon for example or when using a more complex system like spdlog

[FlorianReimold]

This looks really good. Awesome technique to just pass a stream. I always thought about the best technique for redirectable log output and this may be it.
I will take a deeper look after the holidays and merge this PR 👍

[FlorianReimold]

port should not be const, as it is passed by value (will give warnings otherwise)

[ShaharHD]

I have no issue reverting it, but I never saw an issue with a const for any C or C++ int types when by-value is used (by-ref might be an issue)
(I try to use const on every param method to avoid typos or incorrect assignment)

[ShaharHD]

Can you give an example of where you might think it will fail?

[ShaharHD]

This looks really good. Awesome technique to just pass a stream. I always thought about the best technique for redirectable log output and this may be it. I will take a deeper look after the holidays and merge this PR 👍

Thank you :) but you did 99.9% of the work with this awesome library 🥇

I see it it failing on some windows builds in the CI/CD and pushed a fix - please trigger the workflow again.

[ShaharHD]

@FlorianReimold I've used CMake FetchContent_Declare with PATCH_COMMAND to test this in my code base - hence the commits to of fixing some additional issues.

Let me know if you prefer I squash those

Also, can you please run clang-tidy and push?
I've tried to match your code style, but I'm more of a clang-format guy ...

[FlorianReimold]

I let clang tidy check the code. There were no additional warnings, except from the consts. I fixed them.

I am currently looking at the Constructor API. For instance, the following call is technically fine:

FtpServer("127.0.0.1", my_stream);

However, this only sets the "normal" log stream, not the error stream, creating the following situation:

• normal messages are directed to my_steam
• error messages are directed to std::cerr by default

I don't really like that, I think any user who passes only 1 stream would expect both the normal output and error-output would end up in that stream. I suggest the following:

• Only passing 1 stream should make both outputs be redirected into that stream
  or
• The API should force the user to also set the error stream, if they set the normal output stream

What do you think?

[ShaharHD]

I let clang tidy check the code. There were no additional warnings, except from the consts. I fixed them.

Still curious as to why you got that error.
I'm using clang-17 and I see no error with that const

I am currently looking at the Constructor API. For instance, the following call is technically fine:

FtpServer("127.0.0.1", my_stream);

However, this only sets the "normal" log stream, not the error stream, creating the following situation:

• normal messages are directed to my_steam
• error messages are directed to std::cerr by default

I don't really like that, I think any user who passes only 1 stream would expect both the normal output and error-output would end up in that stream. I suggest the following:

• Only passing 1 stream should make both outputs be redirected into that stream
  or
• The API should force the user to also set the error stream, if they set the normal output stream

What do you think?

Added constructor methods to inforce both or none.