R/getAQDMrequest.R

In ebailey78/raqdm: Access data from U.S. EPA's Air Quality Data Mart in R

#'getAQDMrequest
#'
#'Retrieve a data.frame requested with \code{getAQDMdata(synchronous = FALSE)}
#'
#'@param request an object of the type \code{AQDMrequest} produced by \code{\link{getAQDMdata}}.
#'@param \dots Additional arguments to be passed to \code{\link{read.table}}.
#'
#'@return
#'  A data.frame containing the data requested by \code{\link{getAQDMdata}}.
#'  
#'@examples
#'\dontrun{
#'  # Send a request to AQDM
#'  x <- getAQDMdata(user = "me@@email.com", pw = "abc123", param = "44201",
#'                   state = 18, county = 89, bdate = "20140101",
#'                   edate = "20141231")
#'                   
#'  # Once you get an email for EPA saying the data is ready:
#'  df <- getAQDMrequest(x)
#'}
#'@export
getAQDMrequest <- function(request, ...) {
  
  if(class(request) != "AQDMrequest") {
    stop("You must provide an 'AQDMrequest' object.")
  }
  
  URL <- paste0(baseURL, "retrieve?id=", request$requestID)
  
  tf <- tempfile()
  if(class(try(download.file(URL, tf, quiet = TRUE), silent = TRUE)) != "try-error") {
  
    return(readFile(tf, request$format))
    
  } else {
    warning("Data not available yet. Try again shortly, or wait for an email from aqdmrs@epa.gov.")
    return(invisible(FALSE))
  }
  
}