swift-openapi-vapor + `TaskLocal`s to pass the `Request` to the OpenAPI handler

vapor+openapi+tasklocals.swift

/// PREREQUISITES:
/// Add https://github.com/pointfreeco/swift-dependencies as a dependency of your target, currently it looks like so:
/// `.package(url: "https://github.com/pointfreeco/swift-dependencies", from: "1.0.0"),`

// MARK: '+DependencyValues.swift'

import Vapor
import Dependencies

extension DependencyValues {
    /// The request available in the context. This will cause a crash if you don't access it in a `Request` context.
    /// It will not ever crash if you use it like in this example in the routes, but you can also make it 
    /// an optional property if you want to.
    var request: Request {
        get { self[RequiredGenericKey.self] }
        set { self[RequiredGenericKey.self] = newValue }
    }

    /// A generic `DependencyKey` that requires a value to be present, or crashes.
    private enum RequiredGenericKey<Value>: DependencyKey {
        static var liveValue: Value {
            fatalError("Value of type \(Value.self) is not registered in this context")
        }
    }
}

// MARK: 'OpenAPIMiddleware.swift'

import Vapor
import Dependencies

/// A middleware to inject the request to the context.
/// You might need to use this middleware as the last registered middleware on the app.
struct OpenAPIMiddleware: AsyncMiddleware {
    func respond(
        to request: Request,
        chainingTo responder: AsyncResponder
    ) async throws -> Response {
        /// Inject the request to the context.
        try await withDependencies {
            $0.request = request
        } operation: {
            try await responder.respond(to: request)
        }
    }
}

// MARK: 'MyAPIProtocol.swift'

import OpenAPIVapor
import Dependencies

struct MyAPI: APIProtocol {
    @Dependency(\.request) var request

    func myOpenAPIEndpointFunction() async throws -> Operations.myOperation.Output {
        /// Use `request` as if this is a normal Vapor endpoint function
    }
}