bfs_get_data.R

#' Get BFS data in a given language
#'
#' Get a dataset using the PXWEB API v1.
#' You should choose either the BFS number (FSO number) of the BFS offical url
#' of a given dataset. You can query particulary variables using the `query` argument.
#'
#' @param number_bfs The BFS number (FSO number) of a dataset.
#' @param language Language of the dataset to be translated if exists, i.e. "de", "fr", "it" or "en".
#' @param query A list with named values, a json query file or json query string using \code{pxweb::pxweb_query()}.
#' @param column_name_type Column name type as "text" or as "code".
#' @param variable_value_type Variable value type as "text" or as "code".
#' @param clean_names Clean column names using \code{janitor::clean_names()}.
#' @param delay Integer Number of seconds to wait before query using \code{Sys.sleep()}.
#'
#' @importFrom magrittr %>%
#'
#' @seealso \code{\link{bfs_get_data_comments}}
#'
#' @return A tbl_df (a type of data frame; see tibble or
#' dplyr packages). Returns NULL if no connection.
#'
#' @export
bfs_get_data <- function(number_bfs, language = "de", query = NULL, column_name_type = "text", variable_value_type = "text", clean_names = FALSE, delay = NULL) {
  language <- match.arg(arg = language, choices = c("de", "fr", "it", "en"))
  # fail gracefully if no internet connection
  if (!curl::has_internet()) {
    message("No internet connection")
    return(NULL)
  }
  pxweb_api_url <- paste0("https://www.pxweb.bfs.admin.ch/api/v1/", language, "/", number_bfs, "/", number_bfs, ".px")
  # if too many requests HTTP 429
  df_json <- httr2::request("https://www.pxweb.bfs.admin.ch/api/v1") %>%
    httr2::req_url_path_append(paste0(language, "/", number_bfs, "/", number_bfs, ".px")) %>%
    httr2::req_retry(max_tries = 2, max_seconds = 10) %>%
    httr2::req_perform() %>%
    httr2::resp_body_json(simplifyVector = TRUE)
  if(!is.null(delay)) {
    Sys.sleep(delay) # waiting time in seconds before query
  }
  if (is.null(query)) {
    variables <- df_json$variables$code
    values <- df_json$variables$values
    df <- rbind(rep("*", length(values)))
    names(df) <- variables
    dims <- as.list(df)
    pxq <- pxweb::pxweb_query(dims)
  } else {
    if (!is.list(query)) {
      variables <- paste(df_json$variables$code, collapse = ", ")
      stop(paste0("`query` should be a list using the variables: ", variables, "."), call. = FALSE)
    }
    dims <- query
    pxq <- pxweb::pxweb_query(dims)
  }
  df_pxweb <- pxweb::pxweb_get_data(url = pxweb_api_url, query = pxq, column.name.type = column_name_type, variable.value.type = variable_value_type)
  tbl <- tibble::as_tibble(df_pxweb, .name_repair = "minimal")
  if (clean_names) {
    tbl <- janitor::clean_names(tbl)
  }
  return(tbl)
}