pybind11 VS Oat++

I'm investigating using C++ to build a REST server, and would love to know of people's experiences with Crow-- or whether they would recommend something else as a "medium-level" abstraction C++ web server. As background, I started off experimenting with Python/FastAPI, which is great, but there is too much friction to translate from pybind11-exported C++ objects to the format that FastAPI expects, and, of course, there are inherent performance limitations using Python, which could impact scaling up if the project were to be successful.

I have a C++ function computing a large tensor which I would like to return to Python as a NumPy array via pybind11.

This is based on the Google Ink Stroke Modeler C++ library, and using pybind11 to make it available on python.

pybind11 makes it easy to call C++ from Python if you want to mix.

If you've never used Pybind before these pybind tests[1] and this repo[2] have good examples you can crib to get started (in addition to the docs). Once you handle passing/returning/creating the main data types (list, tuple, dict, set, numpy array) the first time, then it's mostly smooth sailing.

Pybind offers a lot of functionality, but core "good parts" I've found useful are (a) use a numpy array in Python and pass it to a C++ method to work on, (b) pass your python data structure to pybind and then do work on it in C++ (some copy overhead), and (c) Make a class/struct in C++ and expose it to Python (so no copying overhead and you can create nice cache-aware structs, etc.).

[1] https://github.com/pybind/pybind11/blob/master/tests/test_py...

I have a python module for which the logic is written in C++ and I use pybind11 to expose the objects and functions to Python.

Reading from Python requires a wrapper, using pybind11 this is fairly done.

Also I can highly recommend starting using C++ to augment your Python code, i.e. find the parts that are slow or undoable in Python and write those in C++ then expose them as Python functions. You can use https://github.com/pybind/pybind11 to call C++ code from Python.

I looked at oatpp and drogon, which are both great, but feel too high-level for my purposes. I tried drogon and got something working, but it feels like too much for my requirements, as in particular I'd like to slot in my choice of Json and message-body handling. C.f. the simple approach in Crow, which I easily understand and build on.

With the right libraries, C++ could be a good fit for applications that want to expose a fast web API to things that need lots of compute (simulators, for instance) or I/O (interactive editing of large datasets). Projects like Oat++ and Crow give me hope that we might see such an ecosystem develop.

Lots of other options have been mentioned, but I'll throw Oat++ into the mix. I used it for this purpose and it was reasonably painless.

https://github.com/oatpp/oatpp +WASM ;)

cd "some/temp/path/for/repositories" git clone https://github.com/oatpp/oatpp.git cd oatpp mkdir build && cd build cmake .. (sudo) make install

Maybe use something like https://oatpp.io to create a REST API: C++ in the backend with this library to create a REST server, and the JavaScript/TypeScript frontend to ask for the information.

I've used OATPP ( https://github.com/oatpp/oatpp ) which worked nicely for setting up simple rest interfaces. Supports things like swagger & websockets out of the box. It's also on Conan which is nice if you use cmake. I can't speak to it's performance but it has about a 1mb binary size footprint.

As for your web problem, I have only used https://oatpp.io/ in the past but I'm sure there are more frameworks like that on the internet.