R/get_data_by_variable.R

In bdl: Interface and Tools for 'BDL' API

#' @title Get data by variable Id from BDL API
#' @description Retrieve data for a given variable for multiple units
#'  from BDL with specified format.
#' @details
#'   Data to retrieve from
#'   \href{https://bdl.stat.gov.pl}{The
#'   BDL Web Services} can be filtered with arguments. To get JSON data from specified
#'   directory with custom filters use \code{\link{get_request}} directly.
#'
#'   To use a proxy to connect, a \code{\link[httr]{use_proxy}} can be
#'   passed to \code{\link[httr]{GET}}. For example
#'   \code{get_request(id, filters,
#'   config = httr::use_proxy(url, port, username, password))}.
#'
#' @param varId A single variable Id or vector of multiple variable id's. If multiple id's are used, some columns
#'   are not available. Use \code{\link{search_variables}} or \code{\link{get_variables}} to find variable id code.
#' @param unitParentId A 12 character NUTS id code of parent unit. Use \code{\link{search_units}} or
#'   \code{\link{get_units}} to find unit id code. If \code{NULL} (default) and \code{unitLevel} not
#'   set up, returns all available units for variable.
#' @param unitLevel A number from 0 to 6, filters the returned unit by its level.
#'    If \code{NULL} (default) no level filters apply. Use \code{\link{get_levels}} to find more info.
#' @param aggregateId An aggregate id. Use \code{\link{get_aggregates}} for more info.
#' @param year A vector of years. If \code{NULL} (default) returns data for all available years.
#' @param lang  A language of returned data, "pl" (default), "en"
#' @param ... Other arguments passed on to \code{\link[httr]{GET}}. For example
#'   a proxy parameters, see details.
#'
#' @return A dataset as a tibble.
#' @export
#' @examples
#'    # get_data_by_variable(varId = "3643", unitParentId = "030200000000")
#'    # get_data_by_variable("420", year = "2000", unitLevel = 6)
#'    
#'    # Multi variable download
#'    # get_data_by_variable(varId =c("415","420"), unitParentId = "030210423000")
#' @keywords utilities database
get_data_by_variable <- function(varId, unitParentId = NULL, unitLevel = NULL,
                                year = NULL, aggregateId = NULL, lang = c("pl","en"), 
                                ...) {

  if(any(is.na(varId)) || any(nchar_length(varId) == 0)){
    stop("Variable id should be non-zero length string.")
  }
  
  if (!is.null(unitParentId) && nchar_length(unitParentId) != 12) {
    stop("Unit id should be 12 characters NUTS id code.")
  }

  dir <- "data/By-Variable"
  lang <- match.arg(lang)
  
  if (length(varId) ==  1) {
    filters <- list(year = year, "unit-Parent-Id" = unitParentId,
                    "unit-Level" = unitLevel, "aggregate-Id" = aggregateId, lang = lang)
    
    df <- page_download(dir, varId, filters, ...)
    df <- add_attribute_labels(df, lang)
    df <- add_measure_columns(varId, df, lang)
    
  } else {
    varId <- as.list(varId)
    
    helper <- function(x) {
      temp <- try(get_data_by_variable(x, unitParentId = unitParentId, year = year, unitLevel = unitLevel, 
                                   aggregateId = aggregateId, lang = lang), silent = T)
      if(is.error(temp)){
        warning(paste("Filters returned empty data for variable", x, "and it will be skipped."), call. = F)
        return(NULL)
      }
      # temp <- add_attribute_labels(temp, lang)
      
      colname <- paste0("attrId_", x, sep = "")
      names(temp)[names(temp) == "attrId"] <- colname
      
      colname <- paste0("measureUnitId_", x, sep = "")
      names(temp)[names(temp) == "measureUnitId"] <- colname
      
      colname <- paste0("measureName_", x, sep = "")
      names(temp)[names(temp) == "measureName"] <- colname
      
      colname <- paste0("attributeDescription_", x, sep = "")
      names(temp)[names(temp) == "attributeDescription"] <- colname
      
      colname <- paste0("val_", x, sep = "")
      names(temp)[names(temp) == "val"] <- colname
      temp
    }
    
    df <- lapply(varId, helper)
    df <- df[lengths(df) != 0]
    
    if(length(df) > 0){
      df <- df %>% 
        purrr::reduce(dplyr::full_join, by = c("id", "name", "year"))
        
    } else {
      stop("Filters returned empty set for every variable you provided.")
    }
    

  }
  

  df <- dplyr::select(df, dplyr::one_of("id", "name", "year"), dplyr::starts_with("val"), dplyr::starts_with("measure"), dplyr::everything())
  df <- tibble::as_tibble(df)
  class(df) <- c("bdl", class(df))
  df
}