CLI command added for "lb4 cache --config"

docs/site/Cache-generator.md

@@ -0,0 +1,62 @@
+---
+lang: en
+title: 'Cache generator'
+keywords: LoopBack 4.0, LoopBack 4, Node.js, TypeScript, OpenAPI, CLI
+sidebar: lb4_sidebar
+permalink: /doc/en/lb4/Cache-generator.html
+---
+
+{% include content/generator-create-app.html lang=page.lang %}
+
+### Synopsis
+
+Add cache to LoopBack4 application using Redis datasource.
+
+```sh
+lb4 [cache] [options]
+```
+
+### Options
+
+`--datasource` : Valid Redis datasource name.
+
+{% include_relative includes/CLI-std-options.md %}
+
+### Interactive Prompts
+
+The tool will prompt you for:
+
+- **Name of the datasource.** If the datasource had been supplied from the
+  command line, the prompt is skipped and the datasource from command-line
+  argument is used.
+
+### Output
+
+Following files are generated as result of this command:
+
+```text
+.
+├── src/
+|   ├── models/
+|   |   └── cache.model.ts
+|   ├── providers/
+|   |   └── cache-strategy.provider.ts
+|   ├── repositories/
+|   |   └── cache.repository.ts
+```
+
+`cache.model.ts` is a model that cache repository uses to read and write data
+into datasource.
+
+`cache-strategy.provider.ts` provides the implementation of caching logic. You
+can modify this file to extend caching capabilities.
+
+`cache.repository.ts` is a repository that connects to Redis datasource and
+reads and writes values from datasource.
+
+The command also modifies `applications.ts` to include `CacheComponent`.
+
+```
+this.component(CacheComponent);
+this.bind(CacheBindings.CACHE_STRATEGY).toProvider(CacheStrategyProvider);
+```

docs/site/sidebars/lb4_sidebar.yml

@@ -879,6 +879,10 @@ children:
       url: Copyright-generator.html
       output: 'web, pdf'
 
+    - title: 'Cache generator'
+      url: Cache-generator.html
+      output: 'web, pdf'
+
   - title: 'Connectors reference'
     url: Connectors-reference.html
     output: 'web'

packages/cli/.yo-rc.json

@@ -1692,6 +1692,77 @@
       },
       "arguments": [],
       "name": "copyright"
+    },
+    "cache": {
+      "options": {
+        "help": {
+          "name": "help",
+          "type": "Boolean",
+          "alias": "h",
+          "description": "Print the generator's options and usage"
+        },
+        "skip-cache": {
+          "name": "skip-cache",
+          "type": "Boolean",
+          "description": "Do not remember prompt answers",
+          "default": false
+        },
+        "skip-install": {
+          "name": "skip-install",
+          "type": "Boolean",
+          "description": "Do not automatically install dependencies",
+          "default": false
+        },
+        "force-install": {
+          "name": "force-install",
+          "type": "Boolean",
+          "description": "Fail on install dependencies error",
+          "default": false
+        },
+        "ask-answered": {
+          "type": "Boolean",
+          "description": "Show prompts for already configured options",
+          "default": false,
+          "name": "ask-answered",
+          "hide": false
+        },
+        "datasource": {
+          "type": "String",
+          "required": false,
+          "description": "A valid redis datasource",
+          "name": "datasource",
+          "hide": false
+        },
+        "config": {
+          "type": "String",
+          "alias": "c",
+          "description": "JSON file name or value to configure options",
+          "name": "config",
+          "hide": false
+        },
+        "yes": {
+          "type": "Boolean",
+          "alias": "y",
+          "description": "Skip all confirmation prompts with default or provided value",
+          "name": "yes",
+          "hide": false
+        },
+        "format": {
+          "type": "Boolean",
+          "description": "Format generated code using npm run lint:fix",
+          "name": "format",
+          "hide": false
+        },
+        "packageManager": {
+          "type": "String",
+          "description": "Change the default package manager",
+          "alias": "pm",
+          "name": "packageManager",
+          "hide": false
+        }
+      },
+      "arguments": [],
+      "name": "cache"
     }
   }
 }

packages/cli/generators/cache/cache-component.js

@@ -0,0 +1,78 @@
+'use strict';
+const ast = require('ts-morph');
+const path = require('path');
+
+/**
+ * Update `src/application.ts`
+ * @param projectRoot - Project root directory
+ */
+async function updateApplicationTs(projectRoot) {
+  const CACHE_COMPONENT = 'CacheComponent';
+  const CACHE_BINDINGS = 'CacheBindings';
+  const PROVIDER = 'CacheStrategyProvider';
+  const applicationTsFile = path.join(projectRoot, 'src/application.ts');
+
+  // Create an AST project
+  const project = new ast.Project({
+    manipulationSettings: {
+      indentationText: ast.IndentationText.TwoSpaces,
+      insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces: false,
+      newLineKind: ast.NewLineKind.LineFeed,
+      quoteKind: ast.QuoteKind.Single,
+    },
+  });
+
+  // import {CacheBindings, CacheComponent} from 'loopback-api-cache';
+  const cacheImportDeclaration = {
+    kind: ast.StructureKind.ImportDeclaration,
+    moduleSpecifier: 'loopback-api-cache',
+    namedImports: [CACHE_BINDINGS, CACHE_COMPONENT],
+  };
+
+  const pFile = project.addSourceFileAtPath(applicationTsFile);
+
+  // Check if `import {CacheBindings, CacheComponent} from 'loopback-api-cache'` exists
+  const cacheImport = pFile.getImportDeclaration('loopback-api-cache');
+
+  if (cacheImport == null) {
+    // Not found
+    pFile.addImportDeclaration(cacheImportDeclaration);
+  } else {
+    // Further check named import for CacheComponent
+    const names = cacheImport.getNamedImports().map(i => i.getName());
+    if (!names.includes(CACHE_COMPONENT)) {
+      cacheImport.addNamedImport(CACHE_COMPONENT);
+    }
+    if (!names.includes(CACHE_BINDINGS)) {
+      cacheImport.addNamedImport(CACHE_BINDINGS);
+    }
+  }
+
+  // import {CacheStrategyProvider} from './providers';
+  const providerImportDeclaration = {
+    kind: ast.StructureKind.ImportDeclaration,
+    moduleSpecifier: './providers',
+    namedImports: [PROVIDER],
+  };
+  const providerImport = pFile.getImportDeclaration('./providers');
+  if (providerImport == null) {
+    // Not found
+    pFile.addImportDeclaration(providerImportDeclaration);
+  }
+
+  // Find the constructor
+  const ctor = pFile.getClasses()[0].getConstructors()[0];
+  const body = ctor.getBodyText();
+
+  // Check if `this.component(CacheComponent)` exists
+  if (!body.includes(`this.component(${CACHE_COMPONENT}`)) {
+    ctor.addStatements(`this.component(${CACHE_COMPONENT});`);
+    ctor.addStatements(
+      `this.bind(${CACHE_BINDINGS}.CACHE_STRATEGY).toProvider(${PROVIDER});`,
+    );
+  }
+
+  await pFile.save();
+}
+
+exports.updateApplicationTs = updateApplicationTs;