R/install_wget.R

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

#' @title Download and install wget.
#' @description This function download and install standalone version of
#'  [GNU Wget](https://eternallybored.org/misc/wget) for Windows.
#' @param wget_dir (optional) Path where wget executable will be installed
#'  (default: the package path).
#' @param force (optional) Logical: if TRUE, install even if it is already 
#'  installed (default is FALSE).
#' @return The path of wget
#'
#' @author Luigi Ranghetti, phD (2018) \email{ranghetti.l@@irea.cnr.it}
#' @note License: GPL 3.0
#' @export
#' @examples \dontrun{
#' install_wget()
#' }

install_wget <- function(wget_dir = system.file(package = "theia2r"), force = FALSE) {
    
    # define the versions to download (for Windows)
    wget_ver <- package_version("1.19.4")
    
    # run only on Windows
    if (Sys.info()["sysname"] != "Windows") {
        print_message(type = "warning", "This function is only for Windows.")
        return(invisible(NULL))
    }
    
    # check if it is already installed
    binpaths <- load_binpaths()
    if (force != TRUE & !is.null(binpaths$wget)) {
        wget_bin <- binpaths$wget
        if (file.exists(wget_bin)) {
            print_message(type = "message", "wget is already installed; to overwrite, set force = TRUE.")
            return(invisible(NULL))
        }
    }
    
    # Download wget
    wget_url <- paste0("https://eternallybored.org/misc/wget/releases/wget-", wget_ver, if (Sys.info()["machine"] == "x86-64") {
        "-win64"
    } else {
        "-win32"
    }, ".zip")
    wget_zip <- normalize_path(file.path(wget_dir, "wget.zip"), mustWork = FALSE)
    wget_path <- normalize_path(file.path(wget_dir, "wget.exe"), mustWork = FALSE)
    download.file(wget_url, wget_zip)
    if (file.exists(wget_zip)) {
        unzip(zipfile = wget_zip, files = basename(wget_path), exdir = dirname(wget_path), unzip = "internal")
        unlink(wget_zip)
    }
    if (file.exists(wget_path)) {
        binpaths$wget <- wget_path
        writeLines(jsonlite::toJSON(binpaths, pretty = TRUE), attr(binpaths, "path"))
    }
    # # add to the path system(paste0('setx PATH '',binpaths$wget,'''), intern=TRUE)
    
    wget_path
    
}