feat: add integration for service-oriented backends

packages/service/.npmrc

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+package-lock=false

packages/service/LICENSE

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+Copyright (c) IBM Corp. 2018. All Rights Reserved.
+Node module: @loopback/service
+This project is licensed under the MIT License, full text below.
+
+--------
+
+MIT license
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

packages/service/README.md

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+# @loopback/service
+
+This module provides a common set of interfaces for interacting with service
+oriented backends such as REST APIs, SOAP Web Services, and gRPC microservices.
+
+## Overview
+
+## Installation
+
+```
+$ npm install --save @loopback/service
+```
+
+## Basic use
+
+## Concepts
+
+### Service
+
+## Use Service
+
+### Define legacy data sources
+
+## Contributions
+
+- [Guidelines](https://github.com/strongloop/loopback-next/wiki/Contributing##guidelines)
+- [Join the team](https://github.com/strongloop/loopback-next/issues/110)
+
+## Tests
+
+run 'npm test' from the root folder.
+
+## Contributors
+
+See [all contributors](https://github.com/strongloop/loopback-next/graphs/contributors).
+
+## License
+
+MIT

packages/service/docs.json

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+{
+  "content": [
+    "./index.ts",
+    "./src/index.ts",
+    "./src/service-proxy.ts"
+  ],
+  "codeSectionDepth": 4
+}

packages/service/index.d.ts

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+// Copyright IBM Corp. 2017. All Rights Reserved.
+// Node module: @loopback/service
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+export * from './dist';

packages/service/index.js

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+// Copyright IBM Corp. 2017. All Rights Reserved.
+// Node module: @loopback/service
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+module.exports = require('./dist');

packages/service/index.ts

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+// Copyright IBM Corp. 2017,2018. All Rights Reserved.
+// Node module: @loopback/service
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+// DO NOT EDIT THIS FILE
+// Add any additional (re)exports to src/index.ts instead.
+export * from './src';

packages/service/package.json

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+{
+  "name": "@loopback/service",
+  "version": "0.2.0",
+  "description": "Service integration for LoopBack 4",
+  "engines": {
+    "node": ">=8"
+  },
+  "main": "index",
+  "scripts": {
+    "acceptance": "lb-mocha \"DIST/test/acceptance/**/*.js\"",
+    "build": "lb-tsc es2017",
+    "build:apidocs": "lb-apidocs",
+    "clean": "lb-clean loopback-service*.tgz dist package api-docs",
+    "pretest": "npm run build",
+    "test": "lb-mocha \"DIST/test/unit/**/*.js\" \"DIST/test/acceptance/**/*.js\"",
+    "unit": "lb-mocha \"DIST/test/unit/**/*.js\"",
+    "verify": "npm pack && tar xf loopback-service*.tgz && tree package && npm run clean"
+  },
+  "author": "IBM",
+  "copyright.owner": "IBM Corp.",
+  "license": "MIT",
+  "devDependencies": {
+    "@loopback/build": "^0.2.0",
+    "@loopback/testlab": "^0.2.0",
+    "loopback-connector-rest": "^3.1.0"
+  },
+  "dependencies": {
+    "@loopback/context": "^0.8.0",
+    "@loopback/core": "^0.6.0",
+    "loopback-datasource-juggler": "^3.15.2"
+  },
+  "files": [
+    "README.md",
+    "index.js",
+    "index.d.ts",
+    "dist/src",
+    "api-docs",
+    "src"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/strongloop/loopback-next.git"
+  }
+}

packages/service/src/decorators/service.decorator.ts

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+// Copyright IBM Corp. 2018. All Rights Reserved.
+// Node module: @loopback/service
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+import {
+  MetadataAccessor,
+  inject,
+  Context,
+  Injection,
+  InjectionMetadata,
+} from '@loopback/context';
+import {getService, juggler} from '..';
+
+/**
+ * Type definition for decorators returned by `@serviceProxy` decorator factory
+ */
+export type ServiceProxyDecorator = PropertyDecorator | ParameterDecorator;
+
+export const SERVICE_PROXY_KEY = MetadataAccessor.create<
+  string,
+  ServiceProxyDecorator
+>('service.proxy');
+
+/**
+ * Metadata for a service proxy
+ */
+export class ServiceProxyMetadata implements InjectionMetadata {
+  decorator = '@serviceProxy';
+  dataSourceName?: string;
+  dataSource?: juggler.DataSource;
+
+  constructor(dataSource: string | juggler.DataSource) {
+    if (typeof dataSource === 'string') {
+      this.dataSourceName = dataSource;
+    } else {
+      this.dataSource = dataSource;
+    }
+  }
+}
+
+export function serviceProxy(dataSource: string | juggler.DataSource) {
+  return function(
+    target: Object,
+    key: symbol | string,
+    parameterIndex?: number,
+  ) {
+    if (key || typeof parameterIndex === 'number') {
+      const meta = new ServiceProxyMetadata(dataSource);
+      inject('', meta, resolve)(target, key, parameterIndex);
+    } else {
+      throw new Error(
+        '@serviceProxy can only be applied to properties or method parameters',
+      );
+    }
+  };
+}
+
+/**
+ * Resolve the @repository injection
+ * @param ctx Context
+ * @param injection Injection metadata
+ */
+async function resolve(ctx: Context, injection: Injection) {
+  const meta = injection.metadata as ServiceProxyMetadata;
+  if (meta.dataSource) return getService(meta.dataSource);
+  if (meta.dataSourceName) {
+    const ds = await ctx.get<juggler.DataSource>(
+      'datasources.' + meta.dataSourceName,
+    );
+    return getService(ds);
+  }
+}

packages/service/src/index.ts

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+// Copyright IBM Corp. 2017,2018. All Rights Reserved.
+// Node module: @loopback/service
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+export * from './legacy-juggler-bridge';
+export * from './loopback-datasource-juggler';
+export * from './service-proxy';
+export * from './decorators/service.decorator';

packages/service/src/legacy-juggler-bridge.ts

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+// Copyright IBM Corp. 2017,2018. All Rights Reserved.
+// Node module: @loopback/service
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+const jugglerModule = require('loopback-datasource-juggler');
+
+import {juggler} from './loopback-datasource-juggler';
+
+export const DataSourceConstructor = jugglerModule.DataSource as typeof juggler.DataSource;
+
+export function getService<T>(ds: juggler.DataSource): T {
+  return ds.DataAccessObject as T;
+}

packages/service/src/loopback-datasource-juggler.ts

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+// Copyright IBM Corp. 2018. All Rights Reserved.
+// Node module: @loopback/service
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+// tslint:disable:no-any
+
+export declare namespace juggler {
+  /**
+   * DataSource instance properties/operations
+   */
+  export class DataSource {
+    name: string;
+    settings: {[name: string]: any};
+    DataAccessObject: {[name: string]: any};
+
+    constructor(name?: string, settings?: {[name: string]: any});
+    constructor(settings?: {[name: string]: any});
+  }
+}

packages/service/src/service-proxy.ts

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+// Copyright IBM Corp. 2018. All Rights Reserved.
+// Node module: @loopback/service
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+// tslint:disable:no-any
+
+/**
+ * Invocable represents a weakly-typed object that has a generic `invoke` method
+ * to handle method invocations
+ */
+export interface Invocable {
+  /**
+   * Properties or methods
+   */
+  [property: string]: any;
+  /**
+   * Invoke an operation with an array of arguments
+   * @param operationName Name of the operation
+   * @param args An array of arguments
+   */
+  invoke(operationName: string, ...args: any[]): any;
+}
+
+/**
+ * An invoker is responsible for implementing method invocations on the given
+ * target
+ */
+export interface Invoker {
+  invoke(target: any, operationName: string, ...args: any[]): any;
+}
+
+function isInvocable(obj: any): obj is Invocable {
+  return obj != null && typeof obj.invoke === 'function';
+}
+
+class InvocableProxyHandler<T extends {[property: string]: any}>
+  implements ProxyHandler<T> {
+  get(target: T, propKey: PropertyKey, receiver: any) {
+    if (propKey in target) {
+      return target[propKey];
+    }
+    if (isInvocable(target)) {
+      return function(...args: any[]) {
+        return target.invoke(propKey.toString(), ...args);
+      };
+    } else {
+      return undefined;
+    }
+  }
+}
+
+class InvokerProxyHandler<T extends object> implements ProxyHandler<T> {
+  constructor(private invoker: Invoker) {}
+  get(target: T, propKey: PropertyKey, receiver: any) {
+    return (...args: any[]) =>
+      this.invoker.invoke(target, propKey.toString(), ...args);
+  }
+}
+
+const DEFAULT_HANDLER = new InvocableProxyHandler<any>();
+
+/**
+ * Create a proxy for the given object
+ * @param obj The source object
+ * @param invoker The optional invoker that handles invocation of methods that
+ * do not exist on the source object. If not provided, the proxy will try to
+ * use the `invoke` method if it is implemented by the source object. If
+ * neither an invoker nor the invoke method is present, the proxy only allows
+ * existing properties and methods on the source object.
+ */
+export function proxify<T extends object>(obj: T, invoker?: Invoker): T {
+  if (invoker) {
+    return new Proxy<T>(obj, new InvokerProxyHandler(invoker));
+  }
+  return new Proxy<T>(obj, DEFAULT_HANDLER);
+}