R/alerts.R

In ALShum/rwunderground: R Interface to Weather Underground API

#' Weather Alerts for United States and Europe
#'
#' @param location location set by set_location
#' @param key weather underground API key
#' @param raw if TRUE return raw httr object
#' @param raw_JSON if TRUE return entire alert as JSON
#' @param message if TRUE print out requested URL
#' @return A string containing alert type, message, start time and expiration.
#' @export
#' @examples
#' \dontrun{
#' alerts(set_location(territory = "Hawaii", city = "Honolulu"))
#' alerts(set_location(airport_code = "SEA"))
#' alerts(set_location(zip_code = "90210"))
#' alerts(set_location(territory = "IR", city = "Tehran"))
#' }
alerts <- function(location,
                   key = get_api_key(),
                   raw = FALSE,
                   raw_JSON = FALSE,
                   message = TRUE) {
  parsed_req <- wunderground_request(
    request_type = "alerts",
    location = location,
    key = key,
    message = message
  )
  if (raw) {
    return(parsed_req)
  }
  stop_for_error(parsed_req)

  if (raw_JSON) {
    return(parsed_req$alerts)
  }

  # checks for empty alert
  if (length(parsed_req$alerts) == 0) {
    return(paste0("No alerts found at this location: ", location))
  }

  zone <- parsed_req$query_zone
  alerts <- parsed_req$alerts
  if (is.null(zone) | is.null(alerts)) {
    stop("Unable to parse zone or alert information from JSON")
  }

  alert_status <- ""

  # Europe
  if (zone == "999") {
    alert_status <- sapply(alerts, function(x) {
      if (is.null(x$wtype_meteoalarm_name) |
        is.null(x$level_meteoalarm_description) |
        is.null(x$date) |
        is.null(x$expires)) {
        warning("alerts:: unknown formatting for alerts JSON")
      }

      paste0(
        "Type: ", alerts$wtype_meteoalarm_name, "\n",
        alerts$level_meteoalarm_description, "\n",
        "Start: ", alerts$date, "\r\n",
        "Expires: ", alerts$expires
      )
    })
  }

  # USA
  else {
    alert_status <- sapply(alerts, function(x) {
      if (is.null(x$description) |
        is.null(x$message) |
        is.null(x$date) |
        is.null(x$expires)) {
        warning("alerts:: unknown formatting for alerts JSON")
      }

      paste0(
        "Type: ", x$description, "\n",
        x$message, "\n",
        "Start: ", x$date, "\n",
        "Expires: ", x$expires
      )
    })
  }

  return(alert_status)
}