R/s2_download.R

In pobsteta/theia2r: An R toolbox to find, download and preprocess Sentinel-2 data

#' @title Download S2 products.
#' @description The function downloads a single S2 product.
#'  Input filename must be an element obtained with
#'  [s2_list] function
#'  (the content must be a URL, and the name the product name).
#' @param s2_prodlist List of the products to be downloaded
#'  (this must be the output of [s2_list] function).
#' @param downloader Executable to use to download products
#'  (default: 'wget').
#' @param apihub Path of the 'apihub.txt' file containing credentials
#'  of scihub account. If NA (default) the default credentials
#'  (username 'user', password 'user') will be used.
#' @param tile Single Sentinel-2 Tile string (5-length character)
#' @param outdir (optional) Full name of the existing output directory
#'  where the files should be created (default: current directory).
#' @return NULL
#'
#' @author Luigi Ranghetti, phD (2017) \email{ranghetti.l@@irea.cnr.it}
#' @note License: GPL 3.0
#' @importFrom reticulate r_to_py
#' @export
#'
#' @examples \dontrun{
#' single_s2 <- paste0('https://scihub.copernicus.eu/apihub/odata/v1/',
#'   'Products(\'c7142722-42bf-4f93-b8c5-59fd1792c430\')/\\$value')
#' names(single_s2) <- 'S2A_MSIL1C_20170613T101031_N0205_R022_T32TQQ_20170613T101608.SAFE'
#' # (this is equivalent to:
#' # single_s2 <- example_s2_list[1]
#' # where example_s2_list is the output of the example of the
#' # s2_list() function)
#'
#' # Download the whole product
#' s2_download(single_s2, outdir=tempdir())
#'
#' # Download a specific tile
#' s2_download(single_s2, tile='32TQQ', outdir=tempdir())
#' # (for products with compact names, the two above commands produce equivalent
#' # results: the first one downloads a SAFE archive, while the second one
#' # downloads single product files)
#'
#' # Download a serie of products
#' pos <- st_sfc(st_point(c(12.0, 44.8)), crs=st_crs(4326))
#' time_window <- as.Date(c('2017-05-01','2017-07-30'))
#' example_s2_list <- s2_list(spatial_extent=pos, tile='32TQQ', time_interval=time_window)
#' s2_download(example_s2_list, outdir=tempdir())
#' }

s2_download <- function(s2_prodlist = NULL, downloader = "wget", apihub = NA, tile = NULL, outdir = ".") {
    
    # convert input NA arguments in NULL
    for (a in c("s2_prodlist", "tile", "apihub")) {
        if (suppressWarnings(all(is.na(get(a))))) {
            assign(a, NULL)
        }
    }
    
    # import s2download
    s2download <- import_s2download(convert = FALSE)
    
    # check downloader
    if (!downloader %in% c("wget", "aria2")) {
        print_message(type = "warning", "Downloader \"", downloader, "\" not recognised ", "(wget will be used)")
        downloader <- "wget"
    }
    
    # read the path of the downloader
    binpaths <- load_binpaths(downloader)
    
    # TODO add checks on the format of filename (one element output of s2_list)
    
    # link to apihub
    if (is.null(apihub)) {
        apihub <- file.path(s2download$inst_path, "apihub.txt")
    }
    if (!file.exists(apihub)) {
        print_message(type = "error", "File apihub.txt with the SciHub credentials is missing.")  # TODO build it
    }
    
    for (i in seq_len(length(s2_prodlist))) {
        
        link <- s2_prodlist[i]
        filename <- names(s2_prodlist[i])
        # download archive for compactname products and for oldname on Windows, untile #107 will be solved
        if (safe_getMetadata(filename, "nameinfo")$version == "compact" | Sys.info()["sysname"] == "Windows") {
            py_tile <- r_to_py(NULL)
            unzip_tile <- TRUE
        } else {
            py_tile <- r_to_py(tile)
            unzip_tile <- FALSE
        }
        
        print_message(type = "message", date = TRUE, "Checking product ", i, " of ", length(s2_prodlist), " (", filename, ")...")
        
        trace_function(s2download$download_s2product, filename = filename, link = link, downloader = downloader, apihub = apihub, tile = py_tile, no_download = FALSE, 
            write_dir = outdir, file_list = NULL, downloader_path = dirname(binpaths[[if (downloader == "aria2") {
                "aria2c"
            } else {
                "wget"
            }]]), trace_funname = "s2download", trace_files = file.path(outdir, c(filename, paste0(filename, ".zip"))))
        # s2download$download_s2product( filename = filename, link = link, downloader = downloader, apihub = apihub, tile = py_tile, no_download = FALSE, write_dir = outdir,
        # file_list = NULL, downloader_path = dirname(binpaths[[if (downloader=='aria2') {'aria2c'} else {'wget'}]]) )
        
    }
    
    return(invisible(NULL))
    
}