[Blocks] Scaffolding react-fetch + first pass at node implementation (#18863)

* First pass at scaffolding out the Node implementation of react-data.

While incomplete, this patch contains some changes to the react-data
package in order to start adding support for Node.

The first part of this change accounts for splitting react-data/fetch
into two discrete entries, adding (and defaulting to) the Node
implementation.

The second part is sketching out a rough approximation of `fetch` for
Node. This implementation is not complete by any means, but provides a
starting point.

* Remove NodeFetch module and put it directly into ReactDataFetchNode.

* Replaced react-data with react-fetch.

This patch shuffles around some of the scaffolding that was in
react-data in favor of react-fetch. It also removes the additional
"fetch" package in favor of something flatter.

* Tweak package organization

* Simplify and add a test

Co-authored-by: Dan Abramov <dan.abramov@me.com>

fixtures/blocks/src/server/Comments.js

@@ -7,7 +7,7 @@
 /* eslint-disable import/first */
 
 import * as React from 'react';
-import {fetch} from 'react-data/fetch';
+import {fetch} from 'react-fetch';
 
 // TODO: Replace with asset reference.
 import Link from '../client/Link';

fixtures/blocks/src/server/Feed.js

@@ -7,7 +7,7 @@
 /* eslint-disable import/first */
 
 import * as React from 'react';
-import {fetch} from 'react-data/fetch';
+import {fetch} from 'react-fetch';
 import PostList from './PostList';
 
 export default function Feed() {

fixtures/blocks/src/server/PostList.js

@@ -8,7 +8,7 @@
 
 import * as React from 'react';
 import {Suspense, unstable_SuspenseList as SuspenseList} from 'react';
-import {preload} from 'react-data/fetch';
+import {preload} from 'react-fetch';
 import PostGlimmer from './PostGlimmer';
 import Post from './Post';
 

fixtures/blocks/src/server/ProfileBio.js

@@ -7,7 +7,7 @@
 /* eslint-disable import/first */
 
 import * as React from 'react';
-import {fetch} from 'react-data/fetch';
+import {fetch} from 'react-fetch';
 
 export default function ProfileBio({userId}) {
   const user = fetch(`/users/${userId}`).json();

fixtures/blocks/src/server/ProfilePage.js

@@ -7,7 +7,7 @@
 
 import * as React from 'react';
 import {Suspense} from 'react';
-import {fetch} from 'react-data/fetch';
+import {fetch} from 'react-fetch';
 import {matchRoute} from './ServerRouter';
 import ProfileTimeline from './ProfileTimeline';
 import ProfileBio from './ProfileBio';

fixtures/blocks/src/server/ProfileTimeline.js

@@ -7,7 +7,7 @@
 /* eslint-disable import/first */
 
 import * as React from 'react';
-import {fetch} from 'react-data/fetch';
+import {fetch} from 'react-fetch';
 import PostList from './PostList';
 
 export default function ProfileTimeline({userId}) {

packages/react-data/npm/fetch.js

@@ -1,7 +0,0 @@
-'use strict';
-
-if (process.env.NODE_ENV === 'production') {
-  module.exports = require('./cjs/react-data-fetch.production.min.js');
-} else {
-  module.exports = require('./cjs/react-data-fetch.development.js');
-}

packages/react-data/npm/index.js

@@ -1,7 +0,0 @@
-'use strict';
-
-if (process.env.NODE_ENV === 'production') {
-  module.exports = require('./cjs/react-data.production.min.js');
-} else {
-  module.exports = require('./cjs/react-data.development.js');
-}

packages/react-data/src/__tests__/ReactDataFetch-test.js

@@ -1,23 +0,0 @@
-/**
- * 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.
- *
- * @emails react-core
- */
-
-'use strict';
-
-describe('ReactDataFetch', () => {
-  let ReactDataFetch;
-
-  beforeEach(() => {
-    ReactDataFetch = require('react-data/fetch');
-  });
-
-  // TODO: test something useful.
-  it('exports something', () => {
-    expect(ReactDataFetch.fetch).not.toBe(undefined);
-  });
-});

packages/react-fetch/README.md

@@ -1,4 +1,4 @@
-# react-data
+# react-fetch
 
 This package is meant to be used alongside yet-to-be-released, experimental React features. It's unlikely to be useful in any other context.
 

packages/react-fetch/index.browser.js

@@ -9,4 +9,4 @@
 
 'use strict';
 
-export * from './src/fetch/ReactDataFetch';
+export * from './src/ReactFetchBrowser';

packages/react-fetch/index.js

@@ -9,4 +9,4 @@
 
 'use strict';
 
-export * from './src/ReactData';
+export * from './index.node';

packages/react-fetch/index.node.js

@@ -7,6 +7,6 @@
  * @flow
  */
 
-export function createResource(): any {
+'use strict';
-  // TODO
+
-}
+export * from './src/ReactFetchNode';

packages/react-fetch/npm/index.browser.js

@@ -0,0 +1,7 @@
+'use strict';
+
+if (process.env.NODE_ENV === 'production') {
+  module.exports = require('./cjs/react-fetch.browser.production.min.js');
+} else {
+  module.exports = require('./cjs/react-fetch.browser.development.js');
+}

packages/react-fetch/npm/index.js

@@ -0,0 +1,3 @@
+'use strict';
+
+module.exports = require('./index.node');

packages/react-fetch/npm/index.node.js

@@ -0,0 +1,7 @@
+'use strict';
+
+if (process.env.NODE_ENV === 'production') {
+  module.exports = require('./cjs/react-fetch.node.production.min.js');
+} else {
+  module.exports = require('./cjs/react-fetch.node.development.js');
+}

packages/react-fetch/package.json

@@ -1,22 +1,26 @@
 {
   "private": true,
-  "name": "react-data",
+  "name": "react-fetch",
   "description": "Helpers for creating React data sources",
   "version": "0.0.0",
   "repository": {
     "type" : "git",
     "url" : "https://github.com/facebook/react.git",
-    "directory": "packages/react-data"
+    "directory": "packages/react-fetch"
   },
   "files": [
     "LICENSE",
     "README.md",
     "build-info.json",
     "index.js",
-    "fetch.js",
+    "index.node.js",
+    "index.browser.js",
     "cjs/"
   ],
   "peerDependencies": {
     "react": "^16.13.1"
+  },
+  "browser": {
+    "./index.js": "./index.browser.js"
   }
 }

packages/react-fetch/src/ReactFetchNode.js

@@ -0,0 +1,229 @@
+/**
+ * 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.
+ *
+ * @flow
+ */
+
+import type {Wakeable} from 'shared/ReactTypes';
+
+import * as http from 'http';
+import * as https from 'https';
+
+import {readCache} from 'react/unstable-cache';
+
+type FetchResponse = {|
+  // Properties
+  headers: any,
+  ok: boolean,
+  redirected: boolean,
+  status: number,
+  statusText: string,
+  type: 'basic',
+  url: string,
+  // Methods
+  arrayBuffer(): ArrayBuffer,
+  blob(): any,
+  json(): any,
+  text(): string,
+|};
+
+function nodeFetch(
+  url: string,
+  options: mixed,
+  onResolve: any => void,
+  onReject: any => void,
+): void {
+  const {hostname, pathname, search, port, protocol} = new URL(url);
+  const nodeOptions = {
+    hostname,
+    port,
+    path: pathname + search,
+    // TODO: cherry-pick supported user-passed options.
+  };
+  const nodeImpl = protocol === 'https:' ? https : http;
+  const request = nodeImpl.request(nodeOptions, response => {
+    // TODO: support redirects.
+    onResolve(new Response(response));
+  });
+  request.on('error', error => {
+    onReject(error);
+  });
+  request.end();
+}
+
+const Pending = 0;
+const Resolved = 1;
+const Rejected = 2;
+
+type PendingResult = {|
+  status: 0,
+  value: Wakeable,
+|};
+
+type ResolvedResult<V> = {|
+  status: 1,
+  value: V,
+|};
+
+type RejectedResult = {|
+  status: 2,
+  value: mixed,
+|};
+
+type Result<V> = PendingResult | ResolvedResult<V> | RejectedResult;
+
+const fetchKey = {};
+
+function readResultMap(): Map<string, Result<FetchResponse>> {
+  const resources = readCache().resources;
+  let map = resources.get(fetchKey);
+  if (map === undefined) {
+    map = new Map();
+    resources.set(fetchKey, map);
+  }
+  return map;
+}
+
+function readResult<T>(result: Result<T>): T {
+  if (result.status === Resolved) {
+    return result.value;
+  } else {
+    throw result.value;
+  }
+}
+
+function Response(nativeResponse) {
+  this.headers = nativeResponse.headers;
+  this.ok = nativeResponse.statusCode >= 200 && nativeResponse.statusCode < 300;
+  this.redirected = false; // TODO
+  this.status = nativeResponse.statusCode;
+  this.statusText = nativeResponse.statusMessage;
+  this.type = 'basic';
+  this.url = nativeResponse.url;
+
+  this._response = nativeResponse;
+  this._blob = null;
+  this._json = null;
+  this._text = null;
+
+  const callbacks = [];
+  function wake() {
+    // This assumes they won't throw.
+    while (callbacks.length > 0) {
+      const cb = callbacks.pop();
+      cb();
+    }
+  }
+  const result: PendingResult = (this._result = {
+    status: Pending,
+    value: {
+      then(cb) {
+        callbacks.push(cb);
+      },
+    },
+  });
+  const data = [];
+  nativeResponse.on('data', chunk => data.push(chunk));
+  nativeResponse.on('end', () => {
+    if (result.status === Pending) {
+      const resolvedResult = ((result: any): ResolvedResult<Buffer>);
+      resolvedResult.status = Resolved;
+      resolvedResult.value = Buffer.concat(data);
+      wake();
+    }
+  });
+  nativeResponse.on('error', err => {
+    if (result.status === Pending) {
+      const rejectedResult = ((result: any): RejectedResult);
+      rejectedResult.status = Rejected;
+      rejectedResult.value = err;
+      wake();
+    }
+  });
+}
+
+Response.prototype = {
+  constructor: Response,
+  arrayBuffer() {
+    const buffer = readResult(this._result);
+    return buffer;
+  },
+  blob() {
+    // TODO: Is this needed?
+    throw new Error('Not implemented.');
+  },
+  json() {
+    const buffer = readResult(this._result);
+    return JSON.parse(buffer.toString());
+  },
+  text() {
+    const buffer = readResult(this._result);
+    return buffer.toString();
+  },
+};
+
+function preloadResult(url: string, options: mixed): Result<FetchResponse> {
+  const map = readResultMap();
+  let entry = map.get(url);
+  if (!entry) {
+    if (options) {
+      if (options.method || options.body || options.signal) {
+        // TODO: wire up our own cancellation mechanism.
+        // TODO: figure out what to do with POST.
+        throw Error('Unsupported option');
+      }
+    }
+    const callbacks = [];
+    const wakeable = {
+      then(cb) {
+        callbacks.push(cb);
+      },
+    };
+    const wake = () => {
+      // This assumes they won't throw.
+      while (callbacks.length > 0) {
+        const cb = callbacks.pop();
+        cb();
+      }
+    };
+    const result: Result<FetchResponse> = (entry = {
+      status: Pending,
+      value: wakeable,
+    });
+    nodeFetch(
+      url,
+      options,
+      response => {
+        if (result.status === Pending) {
+          const resolvedResult = ((result: any): ResolvedResult<FetchResponse>);
+          resolvedResult.status = Resolved;
+          resolvedResult.value = response;
+          wake();
+        }
+      },
+      err => {
+        if (result.status === Pending) {
+          const rejectedResult = ((result: any): RejectedResult);
+          rejectedResult.status = Rejected;
+          rejectedResult.value = err;
+          wake();
+        }
+      },
+    );
+    map.set(url, entry);
+  }
+  return entry;
+}
+
+export function preload(url: string, options: mixed): void {
+  preloadResult(url, options);
+  // Don't return anything.
+}
+
+export function fetch(url: string, options: mixed): FetchResponse {
+  const result = preloadResult(url, options);
+  return readResult(result);
+}

packages/react-fetch/src/__tests__/ReactFetchBrowser-test.js

@@ -9,15 +9,15 @@
 
 'use strict';
 
-describe('ReactData', () => {
+describe('ReactFetchBrowser', () => {
-  let ReactData;
+  let ReactFetchBrowser;
 
   beforeEach(() => {
-    ReactData = require('react-data');
+    ReactFetchBrowser = require('react-fetch');
   });
 
   // TODO: test something useful.
   it('exports something', () => {
-    expect(ReactData.createResource).not.toBe(undefined);
+    expect(ReactFetchBrowser.fetch).not.toBe(undefined);
   });
 });

packages/react-fetch/src/__tests__/ReactFetchNode-test.js

@@ -0,0 +1,92 @@
+/**
+ * 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.
+ *
+ * @emails react-core
+ */
+
+'use strict';
+
+describe('ReactFetchNode', () => {
+  let ReactCache;
+  let ReactFetchNode;
+  let http;
+  let fetch;
+  let server;
+  let serverEndpoint;
+  let serverImpl;
+
+  beforeEach(done => {
+    jest.resetModules();
+    ReactCache = require('react/unstable-cache');
+    ReactFetchNode = require('react-fetch');
+    http = require('http');
+    fetch = ReactFetchNode.fetch;
+
+    server = http.createServer((req, res) => {
+      serverImpl(req, res);
+    });
+    server.listen(done);
+    serverEndpoint = `http://localhost:${server.address().port}/`;
+
+    // TODO: A way to pass load context.
+    ReactCache.CacheProvider._context._currentValue = ReactCache.createCache();
+  });
+
+  afterEach(done => {
+    server.close(done);
+    server = null;
+  });
+
+  async function waitForSuspense(fn) {
+    while (true) {
+      try {
+        return fn();
+      } catch (promise) {
+        if (typeof promise.then === 'function') {
+          await promise;
+        } else {
+          throw promise;
+        }
+      }
+    }
+  }
+
+  it('can read text', async () => {
+    serverImpl = (req, res) => {
+      res.write('ok');
+      res.end();
+    };
+    await waitForSuspense(() => {
+      const response = fetch(serverEndpoint);
+      expect(response.status).toBe(200);
+      expect(response.statusText).toBe('OK');
+      expect(response.ok).toBe(true);
+      expect(response.text()).toEqual('ok');
+      // Can read again:
+      expect(response.text()).toEqual('ok');
+    });
+  });
+
+  it('can read json', async () => {
+    serverImpl = (req, res) => {
+      res.write(JSON.stringify({name: 'Sema'}));
+      res.end();
+    };
+    await waitForSuspense(() => {
+      const response = fetch(serverEndpoint);
+      expect(response.status).toBe(200);
+      expect(response.statusText).toBe('OK');
+      expect(response.ok).toBe(true);
+      expect(response.json()).toEqual({
+        name: 'Sema',
+      });
+      // Can read again:
+      expect(response.json()).toEqual({
+        name: 'Sema',
+      });
+    });
+  });
+});

scripts/rollup/build.js

@@ -260,7 +260,7 @@ function getFormat(bundleType) {
 
 function getFilename(name, globalName, bundleType) {
   // we do this to replace / to -, for react-dom/server
-  name = name.replace('/', '-');
+  name = name.replace('/index.', '.').replace('/', '-');
   switch (bundleType) {
     case UMD_DEV:
       return `${name}.development.js`;

scripts/rollup/bundles.js

@@ -115,16 +115,7 @@ const bundles = [
     externals: ['react'],
   },
 
-  /******* React Data (experimental, new) *******/
+  /******* React Fetch Browser (experimental, new) *******/
-  {
-    bundleTypes: [NODE_DEV, NODE_PROD, NODE_PROFILING],
-    moduleType: ISOMORPHIC,
-    entry: 'react-data',
-    global: 'ReactData',
-    externals: ['react'],
-  },
-
-  /******* React Data Fetch (experimental, new) *******/
   {
     bundleTypes: [
       NODE_DEV,
@@ -135,9 +126,18 @@ const bundles = [
       FB_WWW_PROFILING,
     ],
     moduleType: ISOMORPHIC,
-    entry: 'react-data/fetch',
+    entry: 'react-fetch/index.browser',
-    global: 'ReactDataFetch',
+    global: 'ReactFetch',
-    externals: ['react', 'react-data'],
+    externals: ['react'],
+  },
+
+  /******* React Fetch Node (experimental, new) *******/
+  {
+    bundleTypes: [NODE_DEV, NODE_PROD],
+    moduleType: ISOMORPHIC,
+    entry: 'react-fetch/index.node',
+    global: 'ReactFetch',
+    externals: ['react', 'http', 'https'],
   },
 
   /******* React DOM *******/

scripts/rollup/modules.js

@@ -15,6 +15,7 @@ const importSideEffects = Object.freeze({
   'scheduler/tracing': HAS_NO_SIDE_EFFECTS_ON_IMPORT,
   'react-dom/server': HAS_NO_SIDE_EFFECTS_ON_IMPORT,
   'react/jsx-dev-runtime': HAS_NO_SIDE_EFFECTS_ON_IMPORT,
+  'react-fetch/node': HAS_NO_SIDE_EFFECTS_ON_IMPORT,
 });
 
 // Bundles exporting globals that other modules rely on.