R/blob_utils.R

In Rielbe/aztools: Implementation of several functions for interacting with Azure storage accounts.

#' Download all files from a directory in an Azure Storage Account's container
#'
#' This function downloads all the files located at the given az_path recursively
#' and saves them in the directory specified by local_path.
#'
#' @param az_path String. Path to the directory that will be downloaded. If provided, it must end with "/".
#' @param local_path String. Local directory where the files will be stored.
#' @param account_name String. Storage account name.
#' @param container_name String. Container name.
#' @param sas_token String. SAS token with the required permissions to download the files.
#' @return The output of the download process.
#' @export
Download_Batch <- function(az_path = "", local_path = ".", account_name, container_name,
                           sas_token) {

  download_query <- paste0("az storage copy -s ",
                           "'https://", account_name, ".blob.core.windows.net/",
                           container_name, "/", az_path, sas_token, "'",
                           " -d ", local_path, " --recursive")

  result <- system(download_query, intern = T)

  if (!is.null(attributes(result))) stop("Error al descargar los blobs.")

  result
}

#' Upload all files from a local directory to an Azure Storage Account's container
#'
#' This function uploads all files located at the given local_path recursively
#' and saves them in the directory specified by az_path.
#'
#' @param az_path String. Path to the directory where files will be uploaded. If provided, it must end with "/".
#' @param local_path String. Local directory where the files to upload are located.
#' @param account_name String. Storage account name.
#' @param container_name String. Container name.
#' @param sas_token String. SAS token with the required permissions to upload the files.
#' @return The output of the upload process.
#' @export
Upload_Batch <- function(az_path = "", local_path = ".", account_name, container_name,
                         sas_token) {

  upload_query <- paste0("az storage copy -d ",
                         "'https://", account_name, ".blob.core.windows.net/",
                         container_name, "/", az_path, sas_token, "'",
                         " -s ", local_path, " --recursive")

  result <- system(upload_query, intern = T)

  if (!is.null(attributes(result))) stop("Error al subir los blobs.")

  result
}


#' List all the blobs inside a directory
#'
#' This function list all blobs inside a directory
#' @param az_path String. Path to the directory inside the blob container.
#' @param account_name String. Storage account name.
#' @param container_name String. Container name.
#' @param sas_token String. SAS token with the requiered permissions to list the files.
#' @return List of all blobs inside the directory
#' @export
List_Blobs <- function(az_path, account_name, container_name, sas_token) {

  list_query <- paste0("az storage blob list -c ", container_name,
                        " --account-name ", account_name, " --prefix ",
                        az_path, " --sas-token '", sas_token, "'")
  raw_result <- system(list_query, intern = T)

  if(!is.null(attributes(raw_result))) stop("Error al listar el directorio.")

  raw_result <- noquote(noquote(paste(raw_result, collapse = "")))

  parsed_list <- rjson::fromJSON(json_str = raw_result, simplify = T)

  names_vector <- c()

  for (element in parsed_list) {
    names_vector <- c(names_vector, element$name)
  }

  names_vector
}

#' Download a specific blob
#'
#' This function downloads the blob specified at the az_blob param
#' @param az_blob String. Path to the blob.
#' @param local_file String. Path to the file where the blob will be downloded.
#' @param account_name String. Storage account name.
#' @param container_name String. Container name.
#' @param sas_token String. SAS token with the requiered permissions to download.
#' @export
Download_Blob <- function(az_blob, local_file = "./az_download.file",
                          account_name, container_name, sas_token) {

  download_query <- paste0("az storage blob download --name ", az_blob,
                           " --file ", local_file, " -c ", container_name,
                           " --account-name ", account_name, " --sas-token '",
                           sas_token, "'")

  result <- system(download_query, intern = T)

  if (!is.null(attributes(result))) stop("Error al descargar el blob")
}


#' Upload a specific blob
#'
#' This function uploads the blob specified at the local_file param
#' @param local_file String. Path to the file that will be uploaded
#' @param az_blob String. Path to the blob.
#' @param account_name String. Storage account name.
#' @param container_name String. Container name.
#' @param sas_token String. SAS token with the requiered permissions to upload.
#' @export
Upload_Blob <- function(local_file, az_blob,
                          account_name, container_name, sas_token) {

  download_query <- paste0("az storage blob upload --name ", az_blob,
                           " --file ", local_file, " -c ", container_name,
                           " --account-name ", account_name, " --sas-token '",
                           sas_token, "'")

  result <- system(download_query, intern = T)

  if (!is.null(attributes(result))) stop("Error al descargar el blob")
}


#' Check if a blob exists in certain directory
#'
#' This function checks if a blob exists in certain directory
#' @param blob_name String. Name of the blob.
#' @param directory String. Path where the blob will be searched.
#' @param account_name String. Storage account name.
#' @param container_name String. Container name.
#' @param sas_token String. SAS token with the requiered permissions to upload.
#' @return TRUE if the blob exists, FALSE if not.
#' @export
Blob_Exists <- function(blob_name, directory, account_name, container_name,
                       sas_token) {

  listed_dir <- List_Blobs(directory, account_name, container_name, sas_token)

  for (file in listed_dir) {
    splitted <- strsplit(file, split = "/")
    file_name <- splitted[[1]][length(splitted[[1]])]

    if (blob_name == file_name) return(TRUE)
  }

  FALSE
}