Merge pull request #18 from inbo/16-new-function-download-file-from-g…

…oogledrive

16 new function download file from googledrive

DESCRIPTION

@@ -12,5 +12,8 @@ Roxygen: list(markdown = TRUE)
 RoxygenNote: 7.3.1
 Imports: 
     dplyr (>= 1.1.4),
+    googledrive (>= 2.1.1),
     magrittr (>= 2.0.3),
-    rlang (>= 1.1.3)
+    rlang (>= 1.1.3),
+    svDialogs (>= 1.1.0),
+    utils (>= 4.3.2)

NAMESPACE

@@ -2,4 +2,5 @@
 
 export(check)
 export(colcompare)
+export(download_gdrive_if_missing)
 importFrom(magrittr,"%>%")

R/download_gdrive_if_missing.R

@@ -0,0 +1,103 @@
+#' Download gdrive if missing
+#'
+#' @author Sander Devisscher
+#'
+#' @description This function downloads the specified file from google drive if the destination
+#' file does not exist. If it does exist the user will be prompted to download
+#' it again.
+#'
+#' @param gfileID character google file token
+#' @param destfile character destination filename with extention
+#' @param update_always optional boolean to trigger a download everytime the
+#' function is run. default is FALSE.
+#' @param email optional character specifying the users email used to access the
+#' googledrive file.
+#'
+#' @details
+#' Its best practice to provide the email in encrypted form. This can be easily
+#' achieved by adding email as an item in a .renviron file or even beter by using
+#' more robust encryption methods.
+#'
+#' @returns If the destination file was missing it is now downloaded from the
+#' googledrive.
+#'
+#' @examples
+#' \dontrun{
+#' # download newest version of the team charter
+#' download_gdrive_if_missing(gfileID = "1gtqcZojPnbLhEgpul3r9sy2zK3UyyCVG",
+#'                            destfile = "../../Teamcharters/Teamcharter_FIS.pdf",
+#'                            email = Sys.getenv("email"),
+#'                            update_always = TRUE)
+#' }
+#' \dontrun{
+#' # download newest DRG Agouti export
+#' download_gdrive_if_missing(gfileID = "1FX8DDyREKMH1M3iW9ijWjVjO_tBH8PXi",
+#'                            destfile = "../fis-projecten/Grofwild/Drongengoed/Input/Agouti/drongengoed_240502.zip",
+#'                            email = Sys.getenv("email"),
+#'                            update_always = TRUE)
+#' }
+
+#' @export
+
+download_gdrive_if_missing <- function(gfileID,
+                                       destfile,
+                                       update_always = FALSE,
+                                       email){
+  # Authentication ####
+  ## email uit system variables
+  if (check(email) == 0) {
+    email <- Sys.getenv("email")
+    print("extracting email from System variables")
+  }
+
+  ## email dmv popup
+  if (email == "") {
+    email <- svDialogs::dlg_input("je email adres:")
+    email <- email$res
+  }
+
+  ## Authenticate
+  googledrive::drive_auth(email)
+
+  # Check whether file exists locally ####
+  ## Check whether destpath exists locally ####
+  destpath <- dirname(destfile)
+
+  if(!dir.exists(destpath)){
+    # destpath doesn't exist => create ?
+    q_create_dir <- utils::askYesNo(msg = paste0(destpath, " aanmaken?"))
+
+    if(q_create_dir == TRUE | update_always == TRUE){
+      dir.create(destpath,
+                 recursive = TRUE)
+    }
+  }
+
+  if(update_always == FALSE){
+    # update only when file doesn't exist or when user asks for it
+    if(file.exists(destfile)){
+      # destfile bestaat => update ?
+      q_update_destfile <- utils::askYesNo(paste0("update ", gsub(pattern = destpath,
+                                                           replacement = "",
+                                                           destfile), "?"))
+      if(q_update_destfile == TRUE){
+        download <- TRUE
+      }else{
+        download <- FALSE
+      }
+    }else{
+      # destfile bestaat niet => download!
+      download <- TRUE
+    }
+  }else{
+    # update everytime
+    download <- TRUE
+  }
+
+  # Download ####
+  if(download == TRUE){
+    googledrive::drive_download(googledrive::as_id(gfileID),
+                                path = destfile,
+                                overwrite = TRUE)
+  }
+}