Add arbitrary URL handlers

[jcheng5]

Similar to addResourcePath, but instead of a directory path, take a Rook function.

https://groups.google.com/forum/#!topic/shiny-discuss/J7kGarNBjBQ

And also @daattali and @hadley have asked for something similar.

This would not be anything close to our vision for what an enterprise-ready HTTP API server could look like, but for people who have Shiny apps that need callbacks (SNS is one, OAuth is another), this would be an open door to all sorts of opportunities.

[Tutuchan]

Hello,
Are there any news on this issue ?
Thanks in advance,
Pierre

[JohnCoene]

This is the way I go about it (to expose Prometheus metrics) but since 1.6 will export httpResponse we're halfway there it seems 🎉

res <- getFromNamespace("httpResponse", "shiny")
handlerManager <- getFromNamespace("handlerManager", "shiny")

handler <- function(req){
  if(!req$PATH_INFO == "/metrics")
    return()

  res(200L, "text/plain", "Hello world!")
}

handlerManager$addHandler(handler, "/metrics")