routing

routing is an R port of pillarjs/router, the routing mechanism that underpins Express.js. It gives R web frameworks a syntax that mimics how Express.js applications are written, so the same patterns that make Express.js applications easy to read and reason about are now available in R.

Installation

pak::pak("JulioCollazos64/routing")

Let’s look at an example:

library(routing)
router <- Router$new()
router$use(function(req,res){
  print(req)
})
router$get("/hello", function(req,res){
  res$send("Hello world!")
})

Even if we knew nothing about web development, we can clearly see the things that matter from this code snippet:

• Router - We create an object called router that holds all the rules for how incoming requests should be handled.
• Middleware - router$use() appends a piece of code that runs on every requests, regardless of path or method.
• Route definition
  • HTTP verb - get means this route only responds to HTTP GET requests
  • PATH - /hello is the URL path this route matches

Moreover, the routing mechanism happens in the same order you write your code so you can read how your request goes from top to bottom.

How it differs from Express.js

1. We use forward() instead of next() to pass control to the next handler.
2. You don’t need to declare forward as an argument to your handler to call it inside.
3. If your handler doesn’t return a response or call forward(), one is called on your behalf.