added model downloader R wrapper (microsoft#356)

src/codegen/src/main/scala/WrapperGenerator.scala

@@ -235,6 +235,18 @@ class SparklyRWrapperGenerator extends WrapperGenerator {
                 |import(sparklyr)
                 |
                 |export(sdf_transform)
+                |export(smd_model_downloader)
+                |export(smd_download_by_name)
+                |export(smd_local_models)
+                |export(smd_remote_models)
+                |export(smd_get_model_name)
+                |export(smd_get_model_uri)
+                |export(smd_get_model_type)
+                |export(smd_get_model_hash)
+                |export(smd_get_model_size)
+                |export(smd_get_model_input_node)
+                |export(smd_get_model_num_layers)
+                |export(smd_get_model_layer_names)
                 |""".stripMargin)
 
   def formatWrapperName(name: String): String =

src/downloader/src/main/R/model_downloader.R

@@ -0,0 +1,157 @@
+# Copyright (C) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See LICENSE in project root for information.
+
+DEFAULT_URL = "https://mmlspark.azureedge.net/datasets/CNTKModels/"
+
+#' A class for downloading CNTK pretrained models in R. To download all models use the downloadModels
+#' function. To browse models from the microsoft server please use remoteModels.
+#'
+#' Creates the ModelDownloader.
+#'
+#' @param sc A spark context for interfacing between python and java
+#' @param localPath The folder to save models to
+#' @param serverURL The location of the model Server, beware this default can change!
+#' @param ... Optional arguments; currently unused.
+#'
+#' @family Model downloader
+#'
+#' @export
+smd_model_downloader <- function(sc, localPath, serverURL=DEFAULT_URL, ...) {
+    session <- spark_session(sc)
+    env <- new.env(parent = emptyenv())
+    env$model <- "com.microsoft.ml.spark.ModelDownloader"
+    downloader <- invoke_new(sc, env$model, session, localPath, serverURL)
+}
+
+#' Downloads the model by given name
+#'
+#' @param smd_model_downloader The model downloader
+#' @param name The name of the model
+#' @param ... Optional arguments; currently unused.
+#'
+#' @family Model downloader
+#'
+#' @export
+smd_download_by_name <- function(model_downloader, name, ...) {
+    model <- invoke(model_downloader, "downloadByName", name)
+}
+
+#' Downloads models stored locally on the filesystem
+#'
+#' @param smd_model_downloader The model downloader
+#' @param ... Optional arguments; currently unused.
+#'
+#' @family Model downloader
+#'
+#' @export
+smd_local_models <- function(model_downloader, ...) {
+    model <- invoke(model_downloader, "localModels")
+}
+
+#' Downloads models stored remotely.
+#'
+#' @param smd_model_downloader The model downloader
+#' @param ... Optional arguments; currently unused.
+#'
+#' @family Model downloader
+#'
+#' @export
+smd_remote_models <- function(model_downloader, ...) {
+    model <- invoke(model_downloader, "remoteModels")
+}
+
+#' Gets the name of the downloaded model
+#'
+#' @param model The downloaded model
+#' @param ... Optional arguments; currently unused.
+#'
+#' @family Model downloader
+#'
+#' @export
+smd_get_model_name <- function(model, ...) {
+    name <- invoke(model, "name")
+}
+
+#' Gets the location of the model's bytes
+#'
+#' @param model The downloaded model
+#' @param ... Optional arguments; currently unused.
+#'
+#' @family Model downloader
+#'
+#' @export
+smd_get_model_uri <- function(model, ...) {
+    uri <- invoke(invoke(model, "uri"), "toString")
+}
+
+#' Gets the domain that the model operates on
+#'
+#' @param model The downloaded model
+#' @param ... Optional arguments; currently unused.
+#'
+#' @family Model downloader
+#'
+#' @export
+smd_get_model_type <- function(model, ...) {
+    name <- invoke(model, "modelType")
+}
+
+#' Gets the sha256 hash of the models bytes
+#'
+#' @param model The downloaded model
+#' @param ... Optional arguments; currently unused.
+#'
+#' @family Model downloader
+#'
+#' @export
+smd_get_model_hash <- function(model, ...) {
+    name <- invoke(model, "hash")
+}
+
+#' Gets the size of the model in bytes
+#'
+#' @param model The downloaded model
+#' @param ... Optional arguments; currently unused.
+#'
+#' @family Model downloader
+#'
+#' @export
+smd_get_model_size <- function(model, ...) {
+    name <- invoke(model, "size")
+}
+
+#' Gets the node which represents the input
+#'
+#' @param model The downloaded model
+#' @param ... Optional arguments; currently unused.
+#'
+#' @family Model downloader
+#'
+#' @export
+smd_get_model_input_node <- function(model, ...) {
+    name <- invoke(model, "inputNode")
+}
+
+#' Gets the number of layers of the model
+#'
+#' @param model The downloaded model
+#' @param ... Optional arguments; currently unused.
+#'
+#' @family Model downloader
+#'
+#' @export
+smd_get_model_num_layers <- function(model, ...) {
+    name <- invoke(model, "numLayers")
+}
+
+#' Gets the names of nodes that represent layers in the network
+#'
+#' @param model The downloaded model
+#' @param ... Optional arguments; currently unused.
+#'
+#' @family Model downloader
+#'
+#' @export
+smd_get_model_layer_names <- function(model, ...) {
+    name <- invoke(model, "layerNames")
+}