Example of using R to build a working web API

README.md

Example R API

To use, clone this repository and then run:

Rscript api.R

Test using the following URLs:

• http://localhost:8088/echo
• http://localhost:8088/echo?msg=Hello%20there,%20BigCare%20People
• http://localhost:8088/plot

api.R

pr <- plumber::plumb("plumber.R")
pr$run(port=8088)

plumber.R

# plumber.R

#' Echo the parameter that was sent in
#' @param msg The message to echo back.
#' @get /echo
function(msg=""){
    print('Message endpoint called with message:')
    print(msg)
  list(msg = paste0("The message is: '", msg, "'"))
}

#' Plot out data from the iris dataset
#' @param spec If provided, filter the data to only this species (e.g. 'setosa')
#' @get /plot
#' @png
function(spec){
  myData <- iris
  title <- "All Species"
  print('Plot endpoint called:')

  # Filter if the species was specified
  if (!missing(spec)){
    title <- paste0("Only the '", spec, "' Species")
    myData <- subset(iris, Species == spec)
  }
  print(title)

  plot(myData$Sepal.Length, myData$Petal.Length,
       main=title, xlab="Sepal Length", ylab="Petal Length")
}