R/api_source_hls.R

In e-sensing/sits: Satellite Image Time Series Analysis for Earth Observation Data Cubes

#' @title Create an items object in an HLS cube
#' @keywords internal
#' @noRd
#' @description \code{.source_items_new()} this function is called to create
#' an items object. In case of Web services, this function is responsible for
#' making the Web requests to the server.
#' @param source     Name of the STAC provider.
#' @param ...        Other parameters to be passed for specific types.
#' @param collection Collection to be searched in the data source.
#' @param stac_query Query that follows the STAC protocol
#' @param tiles      Selected tiles (optional)
#' @return An object referring the images of a sits cube.
#' @export
.source_items_new.hls_cube <- function(source, ...,
                                       collection,
                                       stac_query,
                                       tiles = NULL) {
    if (!is.null(tiles)) {
        stop(paste("HLS cubes do not support searching for tiles, use",
            "'roi' parameter instead.",
            call. = FALSE
        ))
    }
    # NASA EarthData requires a login/password combination
    netrc_path <- "~/.netrc"
    if (.Platform$OS.type == "windows") {
        netrc_path <- "%HOME%\\_netrc"
    }
    if (!file.exists(netrc_path)) {
        stop(paste(
            "could not find .netrc file", "\n",
            "Have you configured your access to NASA EarthData?"
        ))
    }

    # Convert roi to bbox
    lon <- stac_query$params$intersects$coordinates[, , 1]
    lat <- stac_query$params$intersects$coordinates[, , 2]
    stac_query$params$intersects <- NULL
    stac_query$params$bbox <- c(min(lon), min(lat), max(lon), max(lat))
    # making the request
    items_info <- rstac::post_request(q = stac_query, ...)
    .check_stac_items(items_info)
    # if more than 2 times items pagination are found the progress bar
    # is displayed
    progress <- rstac::items_matched(items_info) > 2 *
        .conf("rstac_pagination_limit")
    # check documentation mode
    progress <- .check_documentation(progress)
    # fetching all the metadata and updating to upper case instruments
    items_info <- rstac::items_fetch(items = items_info, progress = progress)
    # checks if the items returned any items
    .check_that(
        x = rstac::items_length(items_info) != 0,
        msg = paste(
            "the provided search returned 0 items. Please, verify",
            "the provided parameters."
        )
    )
    return(items_info)
}
#' @title Organizes items by tiles for HLS collections
#' @param source     Name of the STAC provider.
#' @param ...        Other parameters to be passed for specific types.
#' @param items      \code{STACItemcollection} object from rstac package.
#' @param collection Collection to be searched in the data source.
#' @return A list of items.
#' @keywords internal
#' @noRd
#' @export
.source_items_tile.hls_cube <- function(source, ...,
                                        items,
                                        collection = NULL) {
    tiles <- strsplit(rstac::items_reap(items, field = "id"), "\\.")
    tiles <- purrr::map_chr(tiles, function(x) x[[3]])
    substr(tiles, 2, 6)
}
#' @noRd
#' @title Configure access.
#' @param source  Data source
#' @param collection Image collection
#' @return Called for side effects
.source_configure_access.hls_cube <- function(source, collection = NULL) {
    netrc_file <- "~/.netrc"
    if (.Platform$OS.type == "windows")
        netrc_file <- "%HOME%_netrc"
    # does the file exist
    if (!file.exists(netrc_file))
        stop(paste("Missing HLS access configuration.",
                    "Please see instructions in Chapter 4 of on-line book"))
    else{
        conf_hls <- utils::read.delim(netrc_file)
        if (!(.conf("HLS_ACCESS_URL") %in% names(conf_hls)))
            stop(paste("Missing HLS access configuration.",
                       "Please see instructions in Chapter 4 of on-line book"))
    }
    return(invisible(source))
}