GoogleChromeLabs · addyosmani · Aug 27, 2019 · Aug 14, 2019 · Aug 22, 2019 · Aug 22, 2019
diff --git a/cra-network-aware-only-if-cached-loading/.gitignore b/cra-network-aware-only-if-cached-loading/.gitignore
@@ -0,0 +1,23 @@
+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+/node_modules
+/.pnp
+.pnp.js
+
+# testing
+/coverage
+
+# production
+/build
+
+# misc
+.DS_Store
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
diff --git a/cra-network-aware-only-if-cached-loading/README.md b/cra-network-aware-only-if-cached-loading/README.md
@@ -0,0 +1,15 @@
+
+# Demo: Network-aware force-cache based resource loading in React
+
+A demo showing how to use network-aware resource loading in React using force-cache mode in fetch request.
+
+This project was bootstrapped with [Create React App](https://github.com/facebookincubator/create-react-app).
+
+## Installation
+```
+git clone https://github.com/GoogleChromeLabs/environment-aware-components
+cd cra-network-aware-force-cache-loading
+npm install
+npm start
+npm run build
+```
diff --git a/cra-network-aware-only-if-cached-loading/package-lock.json b/cra-network-aware-only-if-cached-loading/package-lock.json
diff --git a/cra-network-aware-only-if-cached-loading/package.json b/cra-network-aware-only-if-cached-loading/package.json
@@ -0,0 +1,34 @@
+{
+  "name": "cra-network-aware-force-cache-loading",
+  "version": "0.1.0",
+  "homepage": ".",
+  "private": true,
+  "dependencies": {
+    "fetch-intercept": "^2.3.1",
+    "react": "^16.8.6",
+    "react-dom": "^16.8.6",
+    "react-scripts": "3.0.1"
+  },
+  "scripts": {
+    "start": "react-scripts start",
+    "build": "react-scripts build",
+    "test": "react-scripts test",
+    "eject": "react-scripts eject"
+  },
+  "eslintConfig": {
+    "extends": "react-app"
+  },
+  "browserslist": {
+    "production": [
+      ">0.2%",
+      "not dead",
+      "not op_mini all"
+    ],
+    "development": [
+      "last 1 chrome version",
+      "last 1 firefox version",
+      "last 1 safari version"
+    ]
+  },
+  "license": "Apache-2.0"
+}
diff --git a/...k-aware-only-if-cached-loading/public/assets/responsive-media/image-max-res.jpg b/...k-aware-only-if-cached-loading/public/assets/responsive-media/image-max-res.jpg
diff --git a/...ware-only-if-cached-loading/public/assets/responsive-media/image-medium-res.jpg b/...ware-only-if-cached-loading/public/assets/responsive-media/image-medium-res.jpg
diff --git a/...k-aware-only-if-cached-loading/public/assets/responsive-media/image-min-res.jpg b/...k-aware-only-if-cached-loading/public/assets/responsive-media/image-min-res.jpg
diff --git a/cra-network-aware-only-if-cached-loading/public/assets/responsive-media/video-hd-res.mp4 b/cra-network-aware-only-if-cached-loading/public/assets/responsive-media/video-hd-res.mp4
diff --git a/cra-network-aware-only-if-cached-loading/public/favicon.ico b/cra-network-aware-only-if-cached-loading/public/favicon.ico
diff --git a/cra-network-aware-only-if-cached-loading/public/index.html b/cra-network-aware-only-if-cached-loading/public/index.html
@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <meta name="theme-color" content="#000000" />
+    <!--
+      manifest.json provides metadata used when your web app is installed on a
+      user's mobile device or desktop. See https://developers.google.com/web/fundamentals/web-app-manifest/
+    -->
+    <link rel="manifest" href="%PUBLIC_URL%/manifest.json" />
+    <!--
+      Notice the use of %PUBLIC_URL% in the tags above.
+      It will be replaced with the URL of the `public` folder during the build.
+      Only files inside the `public` folder can be referenced from the HTML.
+
+      Unlike "/favicon.ico" or "favicon.ico", "%PUBLIC_URL%/favicon.ico" will
+      work correctly both with client-side routing and a non-root public URL.
+      Learn how to configure a non-root public URL by running `npm run build`.
+    -->
+    <title>Network Aware Component</title>
+  </head>
+  <body>
+    <noscript>You need to enable JavaScript to run this app.</noscript>
+    <div id="root"></div>
+    <!--
+      This HTML file is a template.
+      If you open it directly in the browser, you will see an empty page.
+
+      You can add webfonts, meta tags, or analytics to this file.
+      The build step will place the bundled scripts into the <body> tag.
+
+      To begin the development, run `npm start` or `yarn start`.
+      To create a production bundle, use `npm run build` or `yarn build`.
+    -->
+  </body>
+</html>
diff --git a/cra-network-aware-only-if-cached-loading/public/manifest.json b/cra-network-aware-only-if-cached-loading/public/manifest.json
@@ -0,0 +1,15 @@
+{
+  "short_name": "React App",
+  "name": "Create React App Sample",
+  "icons": [
+    {
+      "src": "favicon.ico",
+      "sizes": "64x64 32x32 24x24 16x16",
+      "type": "image/x-icon"
+    }
+  ],
+  "start_url": ".",
+  "display": "standalone",
+  "theme_color": "#000000",
+  "background_color": "#ffffff"
+}
diff --git a/cra-network-aware-only-if-cached-loading/src/App.css b/cra-network-aware-only-if-cached-loading/src/App.css
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2019 Google LLC
+ *
+ * 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
+ *
+ *     https://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.
+ */
+
+.App {
+  text-align: center;
+}
+
+.App-logo {
+  animation: App-logo-spin infinite 20s linear;
+  height: 40vmin;
+  pointer-events: none;
+}
+
+.App-header {
+  background-color: #282c34;
+  min-height: 100vh;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  font-size: calc(10px + 2vmin);
+  color: white;
+}
+
+.App-link {
+  color: #61dafb;
+}
+
+@keyframes App-logo-spin {
+  from {
+    transform: rotate(0deg);
+  }
+  to {
+    transform: rotate(360deg);
+  }
+}
diff --git a/cra-network-aware-only-if-cached-loading/src/App.js b/cra-network-aware-only-if-cached-loading/src/App.js
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2019 Google LLC
+ *
+ * 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
+ *
+ *     https://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.
+ */
+
+import React from 'react';
+
+import ConnectionAwareMedia from './components/ConnectionAwareMedia';
+import './App.css';
+
+const App = () => {
+  return (
+    <div className="App">
+      <header className="App-header">
+        <ConnectionAwareMedia />
+      </header>
+    </div>
+  );
+};
+
+export default App;
diff --git a/cra-network-aware-only-if-cached-loading/src/App.test.js b/cra-network-aware-only-if-cached-loading/src/App.test.js
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2019 Google LLC
+ *
+ * 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
+ *
+ *     https://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.
+ */
+
+import React from 'react';
+import ReactDOM from 'react-dom';
+import App from './App';
+
+it('renders without crashing', () => {
+  const div = document.createElement('div');
+  ReactDOM.render(<App />, div);
+  ReactDOM.unmountComponentAtNode(div);
+});
diff --git a/cra-network-aware-only-if-cached-loading/src/assets/images/max-res.jpg b/cra-network-aware-only-if-cached-loading/src/assets/images/max-res.jpg
diff --git a/cra-network-aware-only-if-cached-loading/src/assets/images/medium-res.jpg b/cra-network-aware-only-if-cached-loading/src/assets/images/medium-res.jpg
diff --git a/cra-network-aware-only-if-cached-loading/src/assets/images/min-res.jpg b/cra-network-aware-only-if-cached-loading/src/assets/images/min-res.jpg
diff --git a/...work-aware-only-if-cached-loading/src/assets/responsive-media/image-max-res.jpg b/...work-aware-only-if-cached-loading/src/assets/responsive-media/image-max-res.jpg
diff --git a/...k-aware-only-if-cached-loading/src/assets/responsive-media/image-medium-res.jpg b/...k-aware-only-if-cached-loading/src/assets/responsive-media/image-medium-res.jpg
diff --git a/...work-aware-only-if-cached-loading/src/assets/responsive-media/image-min-res.jpg b/...work-aware-only-if-cached-loading/src/assets/responsive-media/image-min-res.jpg
diff --git a/cra-network-aware-only-if-cached-loading/src/assets/responsive-media/video-hd-res.mp4 b/cra-network-aware-only-if-cached-loading/src/assets/responsive-media/video-hd-res.mp4
diff --git a/cra-network-aware-only-if-cached-loading/src/assets/videos/4g-video.mp4 b/cra-network-aware-only-if-cached-loading/src/assets/videos/4g-video.mp4
diff --git a/...are-only-if-cached-loading/src/components/ConnectionAwareMedia/connection-aware-media.css b/...are-only-if-cached-loading/src/components/ConnectionAwareMedia/connection-aware-media.css
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2019 Google LLC
+ *
+ * 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
+ *
+ *     https://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.
+ */
+
+.root-frame {
+  width: 90%;
+}
+
+.responsive {
+  width: 100%;
+  height: auto;
+}
diff --git a/cra-network-aware-only-if-cached-loading/src/components/ConnectionAwareMedia/index.js b/cra-network-aware-only-if-cached-loading/src/components/ConnectionAwareMedia/index.js
@@ -0,0 +1,127 @@
+/*
+ * Copyright 2019 Google LLC
+ *
+ * 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
+ *
+ *     https://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.
+ */
+
+import React, { useEffect, useState } from 'react';
+
+import { useEffectiveConnectionType } from '../../utils/hooks';
+import './connection-aware-media.css';
+
+const MEDIA_TYPE = {
+  VIDEO: 'video',
+  IMAGE: 'image'
+};
+
+const ResponsiveMedia = ({mediaType, objectURL}) => {
+  let responsiveMedia = null;
+
+  if (mediaType === MEDIA_TYPE.VIDEO) {
+    responsiveMedia = <video className='responsive' src={objectURL} controls />;
+  } else if (mediaType === MEDIA_TYPE.IMAGE) {
+    responsiveMedia = <img className='responsive' src={objectURL} alt='resolution based on effective connection type' />;
+  }
+
+  return responsiveMedia;
+};
+
+const requestMedia = async ect => {
+  let baseURL;
+  switch (ect) {
+    case 'slow-2g':
+      baseURL = '/assets/responsive-media/image-min-res.jpg';
+      break;
+    case '2g':
+      baseURL = '/assets/responsive-media/image-medium-res.jpg';
+      break;
+    case '3g':
+      baseURL = '/assets/responsive-media/image-max-res.jpg';
+      break;
+    case '4g':
+      baseURL = '/assets/responsive-media/video-hd-res.mp4';
+      break;
+    default:
+      baseURL = '/assets/responsive-media/video-hd-res.mp4';
+      break;
+  }
+
+  const imageQualities = ['max-res', 'medium-res', 'min-res'];
+  const videoQualities = ['hd-res'];
+
+  let qualities;
+  let mediaType;
+  if (baseURL.includes(MEDIA_TYPE.VIDEO)) {
+    mediaType = MEDIA_TYPE.VIDEO;
+    qualities = videoQualities;
+  } else if (baseURL.includes(MEDIA_TYPE.IMAGE)) {
+    mediaType = MEDIA_TYPE.IMAGE;
+    qualities = imageQualities;
+  }
+
+  if (!mediaType) return null;
+
+  for (const quality of qualities) {
+    const regexFromQualities = new RegExp(qualities.join("|"));
+    const url = baseURL.replace(regexFromQualities, quality);
+    try {
+      const response = await fetch(url, {
+        cache: 'only-if-cached',
+        // only-if-cached will only work for same-origin requests.
+        mode: 'same-origin'
+      });
+      if (response.ok) {
+        const blob = await response.blob();
+        const objectURL = URL.createObjectURL(blob);
+        console.log('only-if-cached feeding url => ', url);
+        return <ResponsiveMedia mediaType={mediaType} objectURL={objectURL} />;
+      }
+    } catch(error) {
+      console.log('[ConnectionAwareMedia requestImage only-if-cached] error => ', error);
+    }
+  }
+
+  // If we get this far, there's no match in the HTTP cache.
+  // Make a network request:
+  try {
+    const blob = await fetch(baseURL).then(response => response.blob());
+    const objectURL = URL.createObjectURL(blob);
+    console.log('network request feeding url => ', baseURL);
+    return <ResponsiveMedia mediaType={mediaType} objectURL={objectURL} />;
+  } catch(error) {
+    console.log('[ConnectionAwareMedia requestImage default] error => ', error);
+  }
+
+  return null;
+};
+
+const ConnectionAwareMedia = () => {
+  const { effectiveConnectionType } = useEffectiveConnectionType();
+  const [responsiveMedia, setResponsiveMedia] = useState(null);
+
+  console.log('[ConnectionAwareMedia] effectiveConnectionType => ', effectiveConnectionType);
+
+  useEffect(() => {
+    requestMedia(effectiveConnectionType).then(media => {
+      setResponsiveMedia(media);
+    });
+  }, [effectiveConnectionType]);
+
+  return (
+    <div className='root-frame'>
+      {responsiveMedia}
+    </div>
+  );
+};
+
+export default ConnectionAwareMedia;