R/request_api_gauges.R

In SophiaDobko/assimReservoirs: This package assimilates reservoir volumes in Ceará, Northeast Brazil

#' Request rain data from FUNCEME api
#'
#' This function requests api rain data for selected rain gauges
#' @param requestDate latest date of interest, e.g. today(), default is as.Date("2018-03-15")
#' @param Ndays number of days to go back in time from requestDate, default = 5
#' @param gauges_catch output of ```rain_gauges_catch```
#' @return a dataframe with the precipitation available for the requested dates and gauges
#' @importFrom lubridate today
#' @importFrom dplyr bind_rows
#' @importFrom jsonlite fromJSON
#' @export

request_api_gauges <- function(requestDate = as.Date("2018-03-15") , Ndays = 5, gauges_catch) {

  api <- data.frame()
  for(c in 1:nrow(gauges_catch)){
    codigo = gauges_catch$codigo[c]

    rain_list <- list()
    for(i in seq(0, Ndays-1)){
      request=paste0('http://api.funceme.br/rest/pluvio/pluviometria-funceme-normalizada?codigo=',
                     codigo,
                     '&data.date=',
                     format(requestDate-i, tz="America/Fortaleza", format="%Y-%m-%d"))
      resp=jsonlite::fromJSON(request)
      value=resp$list$valor

      if(is.null(value)) {
        warning(paste0("No values for codigo ", codigo, " recorded after requested date ", requestDate))
        value=NA
      }
      dt=strptime(resp$list$data$date,format="%Y-%m-%d %H:%M:%S",tz="America/Fortaleza")
      if(length(dt)==0) {
        dt=NA
      }
      rainOut=data.frame(returnedDate=as.Date(dt), requestDate=requestDate, value=value, codigo=codigo)

      rain_list[[i+1]] <- rainOut
    }
    rain <- dplyr::bind_rows(rain_list)
    api <- rbind(api, rain)
  }
return(api)
}