feat(cli): download examples via npm

Author: bajtos

packages/cli/generators/example/clone-example.js

@@ -0,0 +1,16 @@
+// Copyright IBM Corp. 2018. All Rights Reserved.
+// Node module: @loopback/cli
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+'use strict';
+
+const path = require('path');
+const pacote = require('pacote');
+
+module.exports = function downloadAndExtractExample(exampleName, cwd) {
+  const packageSpec = `@loopback/example-${exampleName}`;
+  const outDir = path.join(cwd, `loopback4-example-${exampleName}`);
+  await pacote.extract(packageSpec, outDir);
+  return outDir;
+};

packages/cli/generators/example/downloader.js

@@ -7,7 +7,7 @@
 
 const BaseGenerator = require('../../lib/base-generator');
 const chalk = require('chalk');
-const cloneExampleFromGitHub = require('./clone-example');
+const downloadAndExtractExample = require('./downloader');
 const path = require('path');
 const utils = require('../../lib/utils');
 
@@ -84,12 +84,11 @@ module.exports = class extends BaseGenerator {
     );
   }
 
-  cloneExampleFromGitHub() {
+  downloadAndExtract() {
     if (this.shouldExit()) return false;
     const cwd = process.cwd();
-    return cloneExampleFromGitHub(this.exampleName, cwd).then(o => {
-      this.outDir = path.relative(cwd, o);
-    });
+    const absOutDir = await downloadAndExtractExample(this.exampleName, cwd);
+    this.outDir = path.relative(cwd, absOutDir);
   }
 
   end() {

packages/cli/generators/example/index.js

@@ -44,13 +44,11 @@
     "change-case": "^3.0.2",
     "debug": "^3.1.0",
     "gulp-rename": "^1.2.2",
-    "gunzip-maybe": "^1.4.1",
     "lodash": "^4.17.5",
     "minimist": "^1.2.0",
+    "pacote": "^8.1.1",
     "regenerate": "^1.3.3",
-    "request": "^2.85.0",
     "semver": "^5.5.0",
-    "tar-fs": "^1.16.0",
     "unicode-10.0.0": "^0.7.4",
     "validate-npm-package-name": "^3.0.0",
     "yeoman-generator": "^2.0.3"

packages/cli/package.json

@@ -7,7 +7,7 @@
 
 const promisify = require('util').promisify;
 
-const cloneExampleFromGitHub = require('../../../generators/example/clone-example');
+const downloadAndExtractExample = require('../../../generators/example/downloader');
 const expect = require('@loopback/testlab').expect;
 const fs = require('fs');
 const TestSandbox = require('@loopback/testlab').TestSandbox;
@@ -26,7 +26,7 @@ describe('cloneExampleFromGitHub (SLOW)', function() {
   beforeEach('reset sandbox', () => sandbox.reset());
 
   it('extracts project files', async () => {
-    const outDir = await cloneExampleFromGitHub(VALID_EXAMPLE, SANDBOX_PATH);
+    const outDir = await downloadAndExtractExample(VALID_EXAMPLE, SANDBOX_PATH);
     const actualFiles = await glob('**', {
       cwd: outDir,
       ignore: 'node_modules/**',