Add tf.util.fetch.

.gitignore

@@ -13,4 +13,3 @@ bazel-out/
 yalc.lock
 .rpt2_cache/
 package/
-integration_tests/benchmarks/ui/bundle.js

package.json

@@ -22,6 +22,7 @@
     "@bazel/typescript": "^0.27.8",
     "@types/jasmine": "~2.5.53",
     "@types/node": "~9.6.0",
+    "@types/node-fetch": "^2.1.2",
     "browserify": "~16.2.3",
     "clang-format": "~1.2.4",
     "jasmine": "~3.1.0",
@@ -65,6 +66,7 @@
     "@types/seedrandom": "2.4.27",
     "@types/webgl-ext": "0.0.30",
     "@types/webgl2": "0.0.4",
-    "seedrandom": "2.4.3"
+    "seedrandom": "2.4.3",
+    "node-fetch": "~2.1.2"
   }
 }

rollup.config.js

@@ -49,7 +49,7 @@ function config({plugins = [], output = {}, external = []}) {
       node(),
       // Polyfill require() from dependencies.
       commonjs({
-        ignore: ['crypto'],
+        ignore: ['crypto', 'node-fetch'],
         include: 'node_modules/**',
         namedExports: {
           './node_modules/seedrandom/index.js': ['alea'],

src/io/browser_http.ts

@@ -21,8 +21,7 @@
  * Uses [`fetch`](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API).
  */
 
-import {ENV} from '../environment';
-import {assert} from '../util';
+import {assert, fetch as systemFetch} from '../util';
 import {concatenateArrayBuffers, getModelArtifactsInfoForJSON} from './io_utils';
 import {IORouter, IORouterRegistry} from './router_registry';
 import {IOHandler, LoadOptions, ModelArtifacts, ModelJSON, OnProgressCallback, SaveResult, WeightsManifestConfig, WeightsManifestEntry} from './types';
@@ -34,7 +33,7 @@ export class BrowserHTTPRequest implements IOHandler {
   protected readonly path: string;
   protected readonly requestInit: RequestInit;
 
-  private readonly fetchFunc: (path: string, init?: RequestInit) => Response;
+  private readonly fetchFunc: Function;
 
   readonly DEFAULT_METHOD = 'POST';
 
@@ -50,31 +49,17 @@ export class BrowserHTTPRequest implements IOHandler {
     this.weightPathPrefix = loadOptions.weightPathPrefix;
     this.onProgress = loadOptions.onProgress;
 
-    if (loadOptions.fetchFunc == null) {
-      const systemFetch = ENV.global.fetch;
-      if (typeof systemFetch === 'undefined') {
-        throw new Error(
-            'browserHTTPRequest is not supported outside the web browser ' +
-            'without a fetch polyfill.');
-      }
-      // Make sure fetch is always bound to global object (the
-      // original object) when available.
-      loadOptions.fetchFunc = systemFetch.bind(ENV.global);
-    } else {
+    if (loadOptions.fetchFunc != null) {
       assert(
           typeof loadOptions.fetchFunc === 'function',
           () => 'Must pass a function that matches the signature of ' +
               '`fetch` (see ' +
               'https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API)');
+      this.fetchFunc = loadOptions.fetchFunc;
+    } else {
+      this.fetchFunc = systemFetch;
     }
 
-    this.fetchFunc = (path: string, requestInits: RequestInit) => {
-      // tslint:disable-next-line:no-any
-      return loadOptions.fetchFunc(path, requestInits).catch((error: any) => {
-        throw new Error(`Request for ${path} failed due to error: ${error}`);
-      });
-    };
-
     assert(
         path != null && path.length > 0,
         () =>

src/io/browser_http_test.ts

@@ -162,9 +162,7 @@ describeWithFlags('browserHTTPRequest-load fetch', NODE_ENVS, () => {
     try {
       tf.io.browserHTTPRequest('./model.json');
     } catch (err) {
-      expect(err.message)
-          .toMatch(
-              /not supported outside the web browser without a fetch polyfill/);
+      expect(err.message).toMatch(/Unable to find fetch polyfill./);
     }
   });
 });

src/io/weights_loader.ts

@@ -40,7 +40,7 @@ export async function loadWeightsAsArrayBuffer(
   }
 
   const fetchFunc =
-      loadOptions.fetchFunc == null ? fetch : loadOptions.fetchFunc;
+      loadOptions.fetchFunc == null ? util.fetch : loadOptions.fetchFunc;
 
   // Create the requests for all of the weights in parallel.
   const requests =

src/util.ts

@@ -15,6 +15,7 @@
  * =============================================================================
  */
 
+import {ENV} from './environment';
 import {DataType, DataTypeMap, FlatVector, NumericDataType, RecursiveArray, TensorLike, TypedArray} from './types';
 
 /**
@@ -664,3 +665,43 @@ export function assertNonNegativeIntegerDimensions(shape: number[]) {
             `shape [${shape}].`);
   });
 }
+
+let systemFetch: Function;
+const getSystemFetch = () => {
+  let fetchFunc: Function;
+
+  if (ENV.global.fetch != null) {
+    fetchFunc = ENV.global.fetch;
+  } else {
+    if (ENV.get('IS_NODE')) {
+      // tslint:disable-next-line:no-require-imports
+      fetchFunc = require('node-fetch');
+    } else {
+      throw new Error(`Unable to find fetch polyfill.`);
+    }
+  }
+  return fetchFunc;
+};
+
+/**
+ * Returns a platform-specific implementation of
+ * [`fetch`](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API).
+ *
+ * If `fetch` is defined on the global object (`window`, `process`, etc.),
+ * `tf.util.fetch` returns that function.
+ *
+ * If not, `tf.util.fetch` returns a platform-specific solution.
+ *
+ * ```js
+ * tf.util.fetch('path/to/resource')
+ *  .then(response => {}) // handle response
+ * ```
+ */
+/** @doc {heading: 'Util'} */
+export function fetch(path: string, requestInits?: RequestInit) {
+  console.log('calling fetch util');
+  if (systemFetch == null) {
+    systemFetch = getSystemFetch();
+  }
+  return systemFetch(path, requestInits);
+}

src/util_test.ts

@@ -15,6 +15,7 @@
  * =============================================================================
  */
 
+import {ENV} from './environment';
 import {scalar, tensor2d} from './ops/ops';
 import {inferShape} from './tensor_util_env';
 import * as util from './util';
@@ -495,3 +496,14 @@ describe('util.toNestedArray', () => {
     expect(util.toNestedArray([1, 0, 2], a)).toEqual([]);
   });
 });
+
+describe('util.fetch', () => {
+  it('should allow overriding global fetch', () => {
+    console.log('in fetch test');
+    console.log(ENV.global);
+    spyOn(ENV.global, 'fetch').and.callFake(() => {});
+
+    util.fetch('');
+    expect(ENV.global.fetch).toHaveBeenCalled();
+  });
+});

yarn.lock

@@ -46,6 +46,13 @@
   resolved "https://registry.yarnpkg.com/@types/jasmine/-/jasmine-2.5.54.tgz#a6b5f2ae2afb6e0307774e8c7c608e037d491c63"
   integrity sha512-B9YofFbUljs19g5gBKUYeLIulsh31U5AK70F41BImQRHEZQGm4GcN922UvnYwkduMqbC/NH+9fruWa/zrqvHIg==
 
+"@types/node-fetch@^2.1.2":
+  version "2.1.7"
+  resolved "https://registry.yarnpkg.com/@types/node-fetch/-/node-fetch-2.1.7.tgz#0231559340f6e3f3a0608692077d744c87b5b367"
+  integrity sha512-TZozHCDVrs0Aj1B9ZR5F4Q9MknDNcVd+hO5lxXOCzz07ELBey6s1gMUSZHUYHlPfRFKJFXiTnNuD7ePiI6S4/g==
+  dependencies:
+    "@types/node" "*"
+
 "@types/node@*":
   version "10.12.18"
   resolved "https://registry.yarnpkg.com/@types/node/-/node-10.12.18.tgz#1d3ca764718915584fcd9f6344621b7672665c67"
@@ -2988,6 +2995,11 @@ nice-try@^1.0.4:
   resolved "https://registry.yarnpkg.com/nice-try/-/nice-try-1.0.5.tgz#a3378a7696ce7d223e88fc9b764bd7ef1089e366"
   integrity sha512-1nh45deeb5olNY7eX82BkPO7SSxR5SSYJiPTrTdFUVYwAl8CKMA5N9PjTYkHiRjisVcxcQ1HXdLhx2qxxJzLNQ==
 
+node-fetch@~2.1.2:
+  version "2.1.2"
+  resolved "https://registry.yarnpkg.com/node-fetch/-/node-fetch-2.1.2.tgz#ab884e8e7e57e38a944753cec706f788d1768bb5"
+  integrity sha1-q4hOjn5X44qUR1POxwb3iNF2i7U=
+
 node-pre-gyp@^0.10.0:
   version "0.10.3"
   resolved "https://registry.yarnpkg.com/node-pre-gyp/-/node-pre-gyp-0.10.3.tgz#3070040716afdc778747b61b6887bf78880b80fc"