Add file.download to Conduit

Summary:
This is required to make "arc patch" and "arc export" support binary changes.

Test Plan:
Called from web console and "arc".

Reviewed By: aran
Reviewers: tuomaspelkonen, jungejason, aran
CC: aran, epriestley
Differential Revision: 326

src/__phutil_library_map__.php

@@ -96,6 +96,7 @@ phutil_register_library_map(array(
     'ConduitAPI_differential_updatetaskrevisionassoc_Method' => 'applications/conduit/method/differential/updatetaskrevisionassoc',
     'ConduitAPI_diffusion_getcommits_Method' => 'applications/conduit/method/diffusion/getcommits',
     'ConduitAPI_diffusion_getrecentcommitsbypath_Method' => 'applications/conduit/method/diffusion/getrecentcommitsbypath',
+    'ConduitAPI_file_download_Method' => 'applications/conduit/method/file/download',
     'ConduitAPI_file_upload_Method' => 'applications/conduit/method/file/upload',
     'ConduitAPI_path_getowners_Method' => 'applications/conduit/method/path/getowners',
     'ConduitAPI_user_find_Method' => 'applications/conduit/method/user/find',
@@ -593,6 +594,7 @@ phutil_register_library_map(array(
     'ConduitAPI_differential_updatetaskrevisionassoc_Method' => 'ConduitAPIMethod',
     'ConduitAPI_diffusion_getcommits_Method' => 'ConduitAPIMethod',
     'ConduitAPI_diffusion_getrecentcommitsbypath_Method' => 'ConduitAPIMethod',
+    'ConduitAPI_file_download_Method' => 'ConduitAPIMethod',
     'ConduitAPI_file_upload_Method' => 'ConduitAPIMethod',
     'ConduitAPI_path_getowners_Method' => 'ConduitAPIMethod',
     'ConduitAPI_user_find_Method' => 'ConduitAPIMethod',

src/applications/conduit/method/file/download/ConduitAPI_file_download_Method.php

@@ -0,0 +1,54 @@
+<?php
+
+/*
+ * Copyright 2011 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+class ConduitAPI_file_download_Method extends ConduitAPIMethod {
+
+  public function getMethodDescription() {
+    return "Download a file from the server.";
+  }
+
+  public function defineParamTypes() {
+    return array(
+      'phid' => 'required phid',
+    );
+  }
+
+  public function defineReturnType() {
+    return 'nonempty base64-bytes';
+  }
+
+  public function defineErrorTypes() {
+    return array(
+      'ERR-BAD-PHID' => 'No such file exists.',
+    );
+  }
+
+  protected function execute(ConduitAPIRequest $request) {
+    $phid = $request->getValue('phid');
+
+    $file = id(new PhabricatorFile())->loadOneWhere(
+      'phid = %s',
+      $phid);
+    if (!$file) {
+      throw new ConduitException('ERR-BAD-PHID');
+    }
+
+    return base64_encode($file->loadFileData());
+  }
+
+}

src/applications/conduit/method/file/download/__init__.php

@@ -0,0 +1,16 @@
+<?php
+/**
+ * This file is automatically generated. Lint this module to rebuild it.
+ * @generated
+ */
+
+
+
+phutil_require_module('phabricator', 'applications/conduit/method/base');
+phutil_require_module('phabricator', 'applications/conduit/protocol/exception');
+phutil_require_module('phabricator', 'applications/files/storage/file');
+
+phutil_require_module('phutil', 'utils');
+
+
+phutil_require_source('ConduitAPI_file_download_Method.php');