R/explore_file.R

In tgver: Turing Geovisualization Engine R package

#' A function to explore a spatial csv or geojson file
#'
#' Current version can only read geojson/csv files using the given `file.uri`.
#'
#' @param file.uri character path of file to explore
#' @param background Boolean to run the process in the background,
#' defaults to `FALSE`
#' @return no value returned, depending on `background` either a or not
#' blocking `plumber` instance is started. A message is displayed with
#' instance details.
#'
#' @export
#' @examples {
#' fp = file.path(tempdir(), "test.geojson")
#' gj = c(
#' '[
#'       {"type":"Point","coordinates":[0,0]},
#'       {"type":"LineString","coordinates":[[-1,-1],[1,1]]},
#'         {
#'       "type": "FeatureCollection",
#'       "features": [
#'       {
#'         "type": "Feature",
#'         "properties": {"id":1},
#'         "geometry": {"type": "Point", "coordinates": [100.0, 0.0]}
#'       }
#'     ]
#'   }
#'     ]'
#' )
#' write(gj, fp)
#' ps = tgver::explore_file(fp, background = TRUE)
#' ps$kill()
#' unlink(fp, recursive = TRUE)
#' }
explore_file = function(file.uri, background = FALSE) {
  stopifnotonecharacter(file.uri,
                        "explore_file takes only one character parameter.")

  stopifnotvalidfile(file.uri)

  # only geojson || csv
  if(!any(grepl("json|csv", basename(file.uri)))) {
    stop("explore_file can only read .geojson and .csv files.")
  }

  geojson = NULL

  if(grepl("geojson", basename(file.uri))) {
    geojson = paste(readLines(file.uri), collapse = "")
  } else {
    # TODO: convert csv to geojson (via sf?)

  }

  # prepare back-end
  endpoint = "/explore_file"
  explore_geojson(endpoint, geojson, background)
}