R/get_series.R

In jcizel/ecbapi: API to the ECB's Statistical Data Warehouse (SDW)

##' Download an ECB dataset
##'
##' This function downloads an ECB dataset, specified by the user. The available
##' datasets can be viewed by using the `get_datasets` function.
##' 
##' @param dataset Name of the dataset to download. 
##' @return A data.table containing the requested data.
##' @author Janko Cizel
get_series <- function(
  dataset = 'AME',
  series_id = "......ZUTN"
  ){

    sdw.root <- getOption('sdw.roots')[[getOption('sdw.loc')]]
    message(sprintf("Note: The current setting is to access the '%s' version of the SDW. If you wish to switch the version (the two possiblities are 'internal' and 'external'), please specify the desired option via:\n\noptions(sdw.loc = 'internal/external')\n\nThe internal option gives access to a broader set of datasets but is available only from within the ECB network.",
                    getOption('sdw.loc')))    

    sprintf('%s/service/data/%s/%s',
            sdw.root,
            dataset,
            series_id) ->
        url
  
    ## download_file <- getURL(url,ssl.verifypeer = FALSE)
    ## test url: url = "https://sdw-wsrest.ecb.europa.eu/service/data/AME"
    ## download_file <- getURL(url,ssl.verifypeer = FALSE)
    set_config(config(ssl_verifypeer = 0L))
    GET(url,accept_xml()) %>>%
        content(as = 'text',
                encoding = 'UTF-8') ->
        download_file
    
    
  doc <- xml2::read_xml(download_file)
  ns <- xml_ns(doc)
  
  doc %>>% xml_find_all('.//generic:Series',ns = ns) ->
    nodes
  
  nodes %>>% 
    list.map({
      message(sprintf('Processed node %s out of %s',.i, length(nodes)))
      
      . %>>%
        xml_find_all('./generic:Attributes/generic:Value',ns = ns) %>>%
        xml_attrs %>>% as.list %>>%
        list.map({
          l <- .
          o <- l[[2L]]
          names(o) <- l[[1L]]    
          o 
        }) %>>% do.call(what = 'c') %>>%
        as.list %>>% as.data.table ->
        part1
      
      . %>>%
        xml_find_all('./generic:SeriesKey/generic:Value',ns = ns) %>>%
        xml_attrs %>>% as.list %>>%
        list.map({
          l <- .
          o <- l[[2L]]
          names(o) <- l[[1L]]    
          o 
        }) %>>% do.call(what = 'c') %>>%
        as.list %>>% as.data.table ->
        part2
      
      . %>>%
        xml_find_all('./generic:Obs/generic:ObsDimension',ns = ns) %>>%
        xml_attrs %>>% as.list %>>%
        list.map(value) %>>%
        unlist ->
        part3
      
      . %>>%
        xml_find_all('./generic:Obs/generic:ObsValue',ns = ns) %>>%
        xml_attrs %>>% as.list %>>%
        list.map(value) %>>%
        unlist ->
        part4         
      
      cbind(part1, part2, date = part3, value = part4)
    }) %>>% rbindlist(fill = TRUE) ->
    result
  
  return(result)
}


## get_series_ameco <- function(concept_id = "ZUTN"){
##   get_series(
##     dataset = 'AME',
##     series_id = sprintf("......%s",concept_id)
##   )
## }


# get_series_ameco()