Add download file API

Summary: Changelog: Expose "downloadFile" API to Flipper plugins. Allow them to download files form the web to Flipper Server.

Reviewed By: mweststrate

Differential Revision: D32950685

fbshipit-source-id: 7b7f666e165ff7bf209230cdc96078272ede3616

desktop/flipper-common/src/index.tsx

@@ -20,6 +20,7 @@ export * from './server-types';
 export {sleep} from './utils/sleep';
 export {timeout} from './utils/timeout';
 export {isTest} from './utils/isTest';
+export {assertNever} from './utils/assertNever';
 export {
   logPlatformSuccessRate,
   reportPlatformFailures,

desktop/flipper-common/src/server-types.tsx

@@ -121,6 +121,7 @@ export type FlipperServerEvents = {
     id: string;
     message: string;
   };
+  'download-file-update': DownloadFileUpdate;
 };
 
 export type IOSDeviceParams = {
@@ -151,6 +152,11 @@ export type FlipperServerCommands = {
     command: string,
     options?: ExecOptions & {encoding?: BufferEncoding},
   ) => Promise<ExecOut<string>>;
+  'download-file-start': (
+    url: string,
+    dest: string,
+    options?: DownloadFileStartOptions,
+  ) => Promise<DownloadFileStartResponse>;
   'get-config': () => Promise<FlipperServerConfig>;
   'get-changelog': () => Promise<string>;
   'device-list': () => Promise<DeviceDescription[]>;
@@ -326,6 +332,54 @@ export interface MkdirOptions {
   mode?: string | number;
 }
 
+export interface DownloadFileStartOptions {
+  method?: 'GET' | 'POST';
+  timeout?: number;
+  maxRedirects?: number;
+  headers?: Record<string, string>;
+  overwrite?: boolean;
+}
+
+export type DownloadFileUpdate = {
+  id: string;
+  downloaded: number;
+  /**
+   * Set to 0 if unknown
+   */
+  totalSize: number;
+} & (
+  | {
+      status: 'downloading';
+    }
+  | {
+      status: 'success';
+    }
+  | {status: 'error'; message: string; stack?: string}
+);
+
+export interface DownloadFileStartResponse {
+  /**
+   * Download ID
+   */
+  id: string;
+  /**
+   * Response status
+   */
+  status: number;
+  /**
+   * Response status text
+   */
+  statusText: string;
+  /**
+   * Response headers
+   */
+  headers: Record<string, string>;
+  /**
+   * Size of the file, being downloaded, in bytes. Inferred from the "Content-Length" header. Set to 0 if unknown.
+   */
+  totalSize: number;
+}
+
 export type FlipperServerConfig = {
   gatekeepers: Record<string, boolean>;
   env: Partial<Record<ENVIRONMENT_VARIABLES, string>>;

desktop/flipper-common/src/utils/assertNever.tsx

@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+export const assertNever: (val: never) => asserts val = (val) => {
+  if (val) {
+    throw new Error(`Assert never failed. Received ${val}`);
+  }
+};