Http routes as state machine

gistfile1.txt

The route state machine defined in pseudo code below is able to handle the following routes:

/Api/Products/ 
/Api/Products/1
/Api/Categories
/Api/Categories/1

/Api/Products/1/Categories
/Api/Products/1/Categories/2


Definition:

Api : StateMachineRoot
{
  constraint = "Api"
  allowedtransitions = { products, customers }
}

Products: RouteState
{
   constraint = "Products"
   target: { ProductsController  }
   allowedtransitions = { ProductId }
}

ProductId: SetIntParamRouteState
{
   constraint = "[0-9]"
   actions: {  (int value) => vars.ProductId = value };
   allowedtransitions: { Categories }
}

Categories: RouteState
{
   constraint = "Categories"
   target = { CategoriesController  }
   allowedtransitions = { CategoryId }
}

CategoryId: SetIntParamRouteState
{
   constraint = "[0-9]"
   actions: {  (int value) => vars.CategoryId = value };
}


Algorithm:

Take first route segement       -> ("Api")
Find matching StateMachineRoot  -> (Api)

#Process Segment

Undertake any actions present   -> N/A
Set any targets present         -> N/A
Take next route segment         -> ("Products")
Loop available transitions
   If none match the route segment
      If a target has been set, try to invoke method on it according to params and verb
      If no target - return 404
   If a match is found
      Repeat #Process Segment with remaining route segments