Example of creating a plumber endpoint with multiple data types

api.R

#
# This is a Plumber API. You can run the API by clicking
# the 'Run API' button above.
#
# Find out more about building APIs with Plumber here:
#
#    https://www.rplumber.io/
#

library(plumber)
library(tibble)

work <- function(seed) {
  if (!is.null(seed)) {
    set.seed(as.integer(seed))
  }
  
  tibble(val = rlnorm(100))
}

#* @param seed
#* @serializer unboxedJSON
#* @get /data
function(seed) {
  
  work(seed)
  
}


#* @param seed
#* @get /data/<type>
function(res, type, seed) {
  
  type <- tolower(type)
  
  if (!type %in% c("json", "rds")) {
    stop(type, " is an invalid endpoint. Valid endpoints are 'json' and 'rds'", 
         call. = FALSE)
  }
  x <- work(seed)
  
  if (type == "rds") {
    res$setHeader("content-type", "application/rds")
    tmp <- tempfile()
    saveRDS(x, file = tmp)
    res$body <- readBin(tmp, "raw", n = file.info(tmp)$size)
    return(res)
  }
  
  # default to JSON
  res$setHeader("content-type", "application/json")
  res$body <- jsonlite::toJSON(x, auto_unbox = TRUE)
  return(res)
}

stand_up_api.R

api <- plumber::plumb("api.R")


api$run(port = 8000)