R/cityweather.R

In nahfa911/weatherforecas: OpenWeatherMap API client package

#' cityweather
#'
#' This object can connect to the openweathermap API and get the 24 hours
#' forecasting of the desired city. For more information about this API
#' see the link bellow :
#' \url{https://openweathermap.org/}
#'
#' @field cityname A character shows the city name.
#' @field content A list contains the content of API response.
#' @field status_code An integer that shows the status code of API response.
#' @field has_error A boolean that shows TRUE if there is an error.
#'
#' @import methods
#' @exportClass cityweather
#' @export cityweather


cityweather <- setRefClass('cityweather',
                           fields = list(cityname = "character",
                                         content = "list",
                                         status_code = "integer",
                                         has_error = "logical"),
                           methods = list(
                             initialize = function(cityname, key = '3c656bd3014279a8f41b90522c014977') {
                               "Getting the data from API"
                               resp <- httr::GET(paste0('http://api.openweathermap.org/data/2.5/forecast?q=',
                                                        cityname, '&cnt=9&units=metric&appid=', key))

                               if(httr::status_code(resp) == 404) {
                                 stop("This city does not exist!")
                               }
                               if(httr::http_type(resp) != 'application/json') {
                                 stop('Response is not in json format!', call. = FALSE)
                               }
                               if(httr::http_error(resp)){
                                 stop(sprintf('The server responded with this error:\n[%s]\n%s\n<%s>',
                                              httr::status_code(resp),
                                              httr::content(resp)$message,
                                              httr::content(resp)$documentation_url),
                                      call. = FALSE)
                               }

                               content <<- jsonlite::fromJSON(httr::content(resp,'text'))
                               cityname <<- cityname
                               status_code <<- httr::status_code(resp)
                               has_error <<- httr::http_error(resp)
                            },

                            print = function() {
                              "Print out the structure of response content"
                              cat('The structure of response content:\n')
                              str(content)
                            }
                          )
)

#' @importFrom httr GET
#' @importFrom httr content
#' @importFrom httr status_code
#' @importFrom httr http_error
#' @importFrom httr http_type
#' @importFrom jsonlite fromJSON
NULL