Generic app constructor

[dranikpg]

The crow app currently has only a default constructor. This is quite unhandy for initializing middleware, as all of them have to be default-construtible and have to be initialized manually by extracting them out of the app one by one.

Instead, users should be able to provide already constructed middleware. Ideally this should work without listing all middleware, but only by specifying the required ones.

What works now:

// no default or copy constructor required, it supports move-only
struct D {
  D() = delete;
  D(const D&) = delete;
};

// Any subset can be specified
// in any order
crow::App<A, B, C, D> app(D{args...}, A{args...});

What it looked like before:

crow::App<A, B, C, D> app;
app.get_middleware<A>() = A{args...};
app.get_middleware<D>() = D{args...};

Note: this has to be merged after blueprint middleware, as it has some conflicts. Just puttin' it on the waiting list 😃

[The-EDev]

I'm guessing this is ready for review? @dranikpg

[dranikpg]

It is. I've just been waiting for the CI build to finish 👀 It did so for amd64, so it'll most likely for the other targets

[The-EDev]

seems like the test was blocked for ARM64, might be a one off bug..

[The-EDev]

Everything seems to be alright. Thanks a lot for your work and patience @dranikpg

[The-EDev]

Note to self: It might be worth documenting this feature either in guides or examples.