R/zzz.R

In ecmwfr: Interface to 'ECMWF' and 'CDS' Data Web Services

# Returns server URL
#
# Returns the url of the data servers for downloading
# public ECMWF data sets or data sets for the Copernicus CDS.
#
# @param id string, id of the request.
# @details The handling of CDS requests is slightly different from
# the one of ECMWF public data sets. To be able to get the status
# of a request for CDS data sets we do have to check the status
# by calling the 'task' urls. If an \code{id} is given the
# corresponding 'task' url will be returned. Used in
# \code{\link[ecmwfr]{cds_request} and \code{\link[ecmwfr]{cds_transfer}}
# (to be more explicit: in \code{\link[ecmwfr]{wf_transfer} if
# \code{type == "cds"}).
#
# @author Koen Kufkens
wf_server <- function(id, service = "cds") {

  # set base urls
  cds_url <- "https://cds.climate.copernicus.eu/api"
  ads_url <- "https://ads.atmosphere.copernicus.eu/api"
  cems_url <- "https://ewds.climate.copernicus.eu/api"

  # return url depending on service or id
  switch(
    service,
    "cds" = if (missing(id)) {
      return(cds_url)
    } else {
      return(paste0(cds_url,"/retrieve/v1/", "jobs/", id))
    },
  "ads" = if (missing(id)) {
        return(ads_url)
      } else {
        return(paste0(ads_url,"/retrieve/v1/", "jobs/", id))
      },
  "cems" = if (missing(id)) {
      return(cems_url)
    } else {
      return(paste0(cems_url,"/retrieve/v1/", "jobs/", id))
    }
  )

  stop("No server for the service found")
}

# Simple progress spinner
#
# Shows a spinner while waiting for a request to be processed.
#
# @param seconds integer, seconds to sleep
#
# @details Shows a spinner while waiting for a request to be processed.
# If \code{id} (character) is set, the request id will be shown in addition.
#
# @author Koen Kufkens, Reto Stauffer
spinner <- function(seconds) {
  # set start time, counter
  start_time <- Sys.time()
  spinner_count <- 1

  while (Sys.time() <= start_time + seconds) {
    # slow down while loop
    Sys.sleep(0.2)

    # update spinner message
    message(paste0(c("-", "\\", "|", "/")[spinner_count],
                   " polling server ... \r"),
            appendLF = FALSE)

    # update spinner count
    spinner_count <- ifelse(spinner_count < 4, spinner_count + 1, 1)
  }
}

# Startup message when attaching the package.
.onAttach <-
  function(libname = find.package("ecmwfr"),
           pkgname = "ecmwfr") {

    # startup messages
    vers <- as.character(utils::packageVersion("ecmwfr"))
    txt <- paste(
      "\n     This is 'ecmwfr' version ",
      vers,
      ". Please respect the terms of use:\n",
      "     - https://www.ecmwf.int/en/terms-use\n"
    )
    if (interactive())
      packageStartupMessage(txt)

    # force http/2 for all products
    httr::set_config(httr::config(http_version = 2))
  }

# check if server is reachable
# returns bolean TRUE if so
ecmwf_running <- function(url) {
  ct <- try(httr::GET(url))

  # trap time-out, httr should exit clean but doesn't
  # it seems
  if (inherits(ct, "try-error")) {
    return(FALSE)
  }

  # trap 400 errors
  if (ct$status_code >= 404) {
    return(FALSE)
  } else {
    return(TRUE)
  }
}

# gets url where to get API key
wf_key_page <- function(service) {
  "https://cds-beta.climate.copernicus.eu/profile"
}

# checks credentials, disabled until
# v2 API clarification
# wf_check_login <- function(user, key, service) {
#
#   # CDS service
#   url <- paste0(wf_server(service = "cds"), "/tasks/")
#   ct <- httr::GET(url, httr::authenticate(user, key))
#   return(httr::status_code(ct) < 400)
#
#   # CDS-beta service
#   if (service == "cds_beta") {
#     # url <- paste0(wf_server(service = "cds_beta"), "/processes/")
#     # ct <- httr::GET(
#     #   url,
#     #   httr::add_headers(
#     #     'PRIVATE-TOKEN' = key
#     #   )
#     # )
#     # return(httr::status_code(ct) < 400)
#     message("CDS-beta login validation is non-functional!")
#     return(TRUE)
#   }
# }

# build an archetype from arguments and body (either list or expression)
new_archetype <- function(args, body) {
  if (is.list(body)) {
    body_exp <- rlang::expr(list())
    body_exp[names(body)] <- body
    body <- body_exp
  }
  f <- rlang::new_function(args, body)
  class(f) <- c("ecmwfr_archetype", class(f))
  f
}

# Creates a script to then run as a job
make_script <- function(call, name) {
  script <- tempfile()

  call$job_name <- NULL

  lines <-
    writeLines(paste0(
      "library(ecmwfr)\n",
      name,
      " <- ",
      paste0(deparse(call), collapse = "")
    ), script)
  return(script)
}

# Downloads only the header information
# retrieve_header <- function(url, headers) {
#   h <- curl::new_handle()
#   curl::handle_setheaders(h, .list = headers)
#   con <- curl::curl(url, handle = h)
#
#   open(con, "rf")
#   head <- curl::handle_data(h)
#   close(con)
#
#   head$headers <- curl::parse_headers_list(head$headers)
#   return(head)
# }

# Encapsulates errors are warnings logic.
warn_or_error <- function(..., error = FALSE) {
  if (error) {
    stop(...)
  } else {
    warning(...)
  }
}

# Guesses the username and service from request
guess_service <- function(request, user = NULL) {

  if (missing(user) || is.null(user)) {
    user <- keyring::key_list(keyring = "ecmwfr")[["username"]][1]
  }

  # checks user login, the request layout and
  # returns the service to use if successful
  # TODO LOGIN CHECK
  wf_check <- try(wf_check_request(request), silent = TRUE)

  if (nrow(wf_check) <= 0 || is.null(wf_check) || inherits(wf_check, "try-error") ) {
    stop(
      sprintf(
" Data identifier %s is not found in Web API, CDS, CDS-beta or ADS datasets.
 Or your login credentials do not match your request.",
        request$dataset_short_name
      ),
      call. = FALSE
    )
  }

  return(list(user = user,
              service = wf_check$service,
              url = wf_check$url))
}

exit_message <- function(url, path, file, service) {

  intro <- paste(
    "Even after exiting your request is still beeing processed!\n\n"
  )

  options <- paste(
    "- Retry downloading as soon as completed! \n\n",
    "  If you close your session use the following code: \n\n",
    "  wf_transfer(\n   url = '",
    url,
    "',\n   path = '",
    path,
    "',\n   filename = '",
    file,
    "'\n  )\n\n",
    "- Delete the job upon completion using:\n",
    "  wf_delete(\n   url ='", url,"'\n  )\n\n",
    "  If your session stays open you can donwload or delete requests using: \n\n",
    "  file$download() and file$delete() *\n\n",
    " [* with file from: file <- wf_request(request)] \n\n",
    sep = ""
  )

  # combine all messages
  exit_msg <- paste(intro, options, sep = "")
  message(sprintf(
    "- Your request has been submitted as a %s request.\n\n  %s",
    toupper(service),
    exit_msg
  ))
}