Middleware

You can also employ middleware with use: these are run first at every request. Note that unlike other methods (e.g.: get) those may return a response but do not have to.

note

See request and response documentation to see how to add and retrieve data from them.

Existing Middlewares

List of existing middleswares. See the documentation for more details.

• druid Logger
• alesia Minifier
• eburones Sessions
• agris Security
• scilis Cookies
• titan Prometheus middleware
• surf CSRF protection
• signaculum favicon
• pugger Pug engine
• jader Jade engine
• slighe Pattern matching

Feel free to make a PR to add to the list.

Creating middlewares

Below we add a middleware that simply print the time at which the request is recevied.

library(ambiorix)

app <- Ambiorix$new()

app$use(\(req, res){
  print(Sys.time())
})

app$get("/", \(req, res){
  res$send("Using {ambiorix}!")
})

app$get("/about", \(req, res){
  res$text("About")
})

app$start()

Multiple middleware can also be used. These can be used to modify add parameters to the request.

library(ambiorix)

app <- Ambiorix$new()

app$use(\(req, res){
  req$x <- 1 # set x to 1
})

app$use(\(req, res){
  print(req$x)
})

app$get("/", \(req, res){
  res$sendf("x set to %s", req$x)
})

app$start()

Common Pattern

Existing middlewares tend to use function factories, which is useful if you want to package of write reusable middleware.

middleware <- \(prefix){
  \(req, res){
    cat(PREFIX, "-log\n")
  }
}

app$use(middleware("PREFIX"))