> On 10 Dec 2015, at 20:22, Matthew Davies via swift-users
> <swift-users@swift.org> wrote:
>
> I'm building a URL router in which I'd like to pass a controller and a
> method. I don't want to instantiate all the controllers up front and pass the
> methods in as closures, nor do I want old controller instances still kept
> around. If there's a better way, I'm definitely open to any suggestions. I'm
> still learning the "Swift" way to do things.
The way I would do this is to define my controller interface with a protocol
and then have a dictionary of the following type:
[String: (Request) throws -> Controller]
where Controller is the protocol and Request is the HTTP request.
So you have a dictionary of URLs to functions (or closures) that create
instances that conform to the Controller protocol. The closure takes a
parameter of the HTTP request so it has the option of choosing the returned
instance based on the method or headers or parameters in the request.
In my implementation, I took the path part of the URL and if it was in the
dictionary it would use the returned closure to create the controller. If it
wasn’t there, I chopped off the last path part and tried again and so on until
I was left with “/“ which always maps to a controller.
The closure is allowed to throw so I could put something like this in for a path
{ _ in throw HTTPError(404) }
which would be handled further up the call chain by generating a 404 response.
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