R/gladstone_ports.R

In msandifo/reproscir: Tools for suppoting @reprosci -= aka reproducible science

#' Title
#'
#' @param year
#' @param month
#' @param fuel
#' @param country
#'
#' @return
#' @export
#'
#' @examples
#'
read_gladstone_ports<- function(year=NULL,
                                month=NULL,
                                fuel="Liquefied Natural Gas",
                                country="Total"){
  #args <- as.list(match.call()) #

  # set some defaults
  if (is.null(year)) year <- lubridate::year(Sys.Date())
  if (is.null(month)) {
    current.month <- lubridate::month(Sys.Date())
    #note that the GPA does not usiually post prvious month until second week of current month.

    if (current.month>1 ) month <- current.month- 1  else  {
      month=12  #set previous month for year skip
      year<-year-1
    }
  }
  if (month>= 10) yearmonth= paste(year,month, sep="") else
    yearmonth= paste(year,month, sep="0") #profix months<10 with "0"
  message(paste(fuel,  month.abb[month], year))
  url<-paste0("http://content1.gpcl.com.au/viewcontent/CargoComparisonsSelection/CargoOriginDestination.aspx?View=C&Durat=M&Key=",yearmonth)
  wg <- rvest::html_session(url )
  batches <- xml2::read_html(wg) %>%
    rvest::html_nodes("#MainContent_pnlResults")   #class(batches)
  table <- batches %>%
    rvest::html_nodes("td") %>%
    rvest::html_text()
  lng.ind <- which( table==fuel)
  t.ind <-which(stringr::str_detect(table,country))
  total.ind <-which(stringr::str_detect(table,"Total"))
  #print(t.ind)
  t.lng.ind  <- t.ind[t.ind>lng.ind][1]
  total.lng.ind  <- total.ind[total.ind>lng.ind][1]
 # print(lng.ind)
 # print(t.lng.ind)
  if (t.lng.ind > total.lng.ind) value=0 else
  value <- table[t.lng.ind+1] %>% stringr::str_replace_all(",","") %>%as.numeric()
  mdays <- lubridate::days_in_month(lubridate::ymd(paste(year,month, "01", sep="-")))
  if(country=="Total"){
    ships <- table[t.lng.ind+2] %>% stringr::str_replace_all(",","") %>%as.numeric()
    return(data.frame(year=year,
                      month=month,
                      date=lubridate::ymd(paste(year,month, "15", sep="-")),
                      tonnes=value,
                      shipments=ships,
                      mdays=mdays))
  } else
    return(data.frame(year=year,
                      month=month,
                      date=lubridate::ymd(paste(year,month, "15", sep="-")),
                      tonnes=value,
                      mdays=mdays))
}

# requires purrr
#reads a sequence of gladstone port authority tables
#' Title
#'
#' @param years
#' @param fuel
#' @param country
#'
#' @return
#' @export
#'
#' @examples
read_gladstone_year <- function(years=2015:lubridate::year(Sys.Date()),
                                fuel="Liquefied Natural Gas",
                                country="Total"){
  y= rep(years, each=12)
  m= rep(1:12,  length(years))   #l  <- list(y=2016:2017,m=1:2 )
  my_fun <- function(y,m, fuel="Liquefied Natural Gas", country="Total") {
    read_gladstone_ports(year=y, month=m, fuel=fuel,country = country )
  }
  purrr::map2_df(y,m, my_fun,  fuel=fuel, country=country)
}


#' Title
#'
#' @param local.path
#' @param years
#'
#' @return
#' @export
#'
#' @examples
update_gladstone <- function(local.path=NULL,
                             years=2015:lubridate::year(Sys.Date()),
                             update=T ){
  local.path=validate_directory(local.path, folder="gladstone")
  gladstone.file = paste0(local.path, "/", "lng.Rdata")
  if (!file.exists(gladstone.file)) {
    read_gladstone_year(years=years ) -> lng
    save(lng, file=gladstone.file )} else load(gladstone.file)
 lng<- lng %>%  subset( !is.na(tonnes))

day.dif = 100 #????
  if (update) {
    last.month <- lng$month
    last.year <-  lng$year
    next.year<- last.year
    while (day.dif >15+30+6) {  #note that GPA  Cargo sttas are usuall not posted until at least 5 days into follwoing month
      next.month<-  (last.month+1)
      if (next.month==13) {next.month<- 1; next.year<- next.year+1}
      day.dif<- day.dif-zoo::as.yearmon("2007-12") %>% lubridate::days_in_month()
      lng <-rbind(lng, read_gladstone_ports(year=next.year, month=next.month, fuel="Liquefied Natural Gas", country="Total" ) )
      save(lng, file=gladstone.file )}
  }
 lng
}