feat: add TypeORM support

CODEOWNERS

@@ -307,6 +307,14 @@
 # - Standby owner(s): @deepakrkris
 /extensions/apiconnect @raymondfeng @deepakrkris
 
+#
+# TypeORM
+#
+# - Issue label: TypeORM
+# - Primary owner(s): @hacksparrow
+# - Standby owner(s): n/a
+/extensions/typeorm @hacksparrow
+
 #
 # Build & internal tooling
 #

docs/site/MONOREPO.md

@@ -44,7 +44,8 @@ one in the monorepo: `npm run update-monorepo-file`
 | [extensions/health](https://github.com/strongloop/loopback-next/tree/master/extensions/health)                                       | @loopback/extension-health                 | An extension exposes health check related endpoints with LoopBack 4                                                                                                                                                                                                                             |
 | [extensions/logging](https://github.com/strongloop/loopback-next/tree/master/extensions/logging)                                     | @loopback/extension-logging                | An extension exposes logging for Winston and Fluentd with LoopBack 4                                                                                                                                                                                                                            |
 | [extensions/metrics](https://github.com/strongloop/loopback-next/tree/master/extensions/metrics)                                     | @loopback/extension-metrics                | An extension exposes metrics for Prometheus with LoopBack 4                                                                                                                                                                                                                                     |
-| [fixtures/mock-oauth2-provider](https://github.com/strongloop/loopback-next/tree/master/fixtures/mock-oauth2-provider)               | _(private)_                                | An internal application to mock the OAuth2 authorization flow login with a social app like facebook, google etc                                                                                                                                                                                 |
+| [extensions/typeorm](https://github.com/strongloop/loopback-next/tree/master/extensions/typeorm)                                     | @loopback/typeorm                          | Adds support for TypeORM in LoopBack                                                                                                                                                                                                                                                            |
+| [fixtures/mock-oauth2-provider](https://github.com/strongloop/loopback-next/tree/master/fixtures/mock-oauth2-provider)               | @loopback/mock-oauth2-provider             | An internal application to mock the OAuth2 authorization flow login with a social app like facebook, google etc                                                                                                                                                                                 |
 | [fixtures/tsdocs-monorepo](https://github.com/strongloop/loopback-next/tree/master/fixtures/tsdocs-monorepo)                         | _(private)_                                | A monorepo for tsdocs testing                                                                                                                                                                                                                                                                   |
 | [packages/authentication](https://github.com/strongloop/loopback-next/tree/master/packages/authentication)                           | @loopback/authentication                   | A LoopBack component for authentication support.                                                                                                                                                                                                                                                |
 | [packages/authorization](https://github.com/strongloop/loopback-next/tree/master/packages/authorization)                             | @loopback/authorization                    | A LoopBack component for authorization support.                                                                                                                                                                                                                                                 |

docs/site/Using-TypeORM-with-LoopBack.md

@@ -0,0 +1,10 @@
+---
+lang: en
+title: 'How to use TypeORM with LoopBack'
+keywords: LoopBack 4.0, LoopBack 4, TypeORM
+sidebar: lb4_sidebar
+layout: readme
+source: loopback-next
+file: extensions/typeorm/README.md
+permalink: /doc/en/lb4/Using-typeorm-with-loopback.html
+---

docs/site/sidebars/lb4_sidebar.yml

@@ -242,6 +242,13 @@ children:
       url: Database-migrations.html
       output: 'web, pdf'
 
+  - title: 'Using TypeORM'
+    output: 'web, pdf'
+    children:
+    - title: 'How to use TypeORM with LoopBack'
+      url: Using-typeorm-with-loopback.html
+      output: 'web, pdf'
+
   - title: 'Running and debugging apps'
     url: Running-and-debugging-apps.html
     output: 'web, pdf'

extensions/typeorm/CHANGELOG.md

@@ -0,0 +1,5 @@
+# Change Log
+
+All notable changes to this project will be documented in this file.
+See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
+

extensions/typeorm/LICENSE

@@ -0,0 +1,25 @@
+Copyright (c) IBM Corp. 2020.
+Node module: @loopback/typeorm
+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.

extensions/typeorm/README.md

@@ -0,0 +1,163 @@
+# @loopback/typeorm
+
+This module enables TypeORM support in LoopBack. For pending features, refer to
+the [Limitations](#limitations) section below.
+
+## Overview
+
+[TypeORM](https://typeorm.io/) is a TypeScript ORM for Node.js. It supports many
+databases and can be used an as alternative to LoopBack's Juggler ORM.
+
+## Stability: ⚠️Experimental⚠️
+
+> Experimental packages provide early access to advanced or experimental
+> functionality to get community feedback. Such modules are published to npm
+> using `0.x.y` versions. Their APIs and functionality may be subject to
+> breaking changes in future releases.
+
+## Installation
+
+```sh
+npm install --save @loopback/typeorm
+```
+
+## Basic Use
+
+### Enabling TypeORM support
+
+To enable TypeORM support, import `TypeOrmMixin` from `@loopback/typeorm` and
+apply it to your application class as shown below.
+
+```ts
+import {BootMixin} from '@loopback/boot';
+import {RestApplication} from '@loopback/rest';
+import {TypeOrmMixin} from '@loopback/typeorm';
+export class MyApplication extends BootMixin(TypeOrmMixin(RestApplication)) {
+  ...
+}
+```
+
+### Creating Connections
+
+[Connections](https://typeorm.io/#/connection) are equivalent to LoopBack's
+datasources. They contain the connectivity and other details about the
+databases. Define the connection in files with a `.connection.ts` extension and
+keep them in the `typeorm-connections` directory of your project.
+
+```ts
+// src/connections/sqlite.connection.ts
+import path from 'path';
+import {ConnectionOptions} from '@loopback/typeorm';
+import {Book} from '../entities/';
+
+export const SqliteConnection: ConnectionOptions = {
+  name: 'SQLite',
+  type: 'sqlite',
+  database: './mydb.sql',
+  entities: [Book],
+  synchronize: true,
+};
+```
+
+Make sure to install the underlying database driver. For example, if you are
+using SQlite, you'll need to install `sqlite3`.
+
+```sh
+npm install sqlite3
+```
+
+Refer to the
+[TypeORM documentation](https://github.com/typeorm/typeorm#installation) for the
+supported databases and the underlying drivers.
+
+### Creating Entities
+
+[Entities](https://typeorm.io/#/entities) are equivalent to LoopBack's Models.
+Define the entities as usual and keep them in a directory named
+`typeorm-entities`.
+
+```ts
+// src/typeorm-entities/book.entity.ts
+import {Entity, Column, PrimaryColumn} from 'typeorm';
+@Entity()
+export class Photo {
+  @PrimaryColumn()
+  id: number;
+
+  @Column()
+  title: string;
+
+  @Column()
+  isPublished: boolean;
+}
+```
+
+### Creating Controllers
+
+Controllers continue to work as usual. And you don't have to create repositories
+since TypeORM creates them for you; just inject them in the controllers. The
+repository API is 100% TypeORM
+[repository API](https://typeorm.io/#/repository-api).
+
+```ts
+// src/controllers/book.controller.ts
+import {get, post, Request, requestBody} from '@loopback/rest';
+import {getModelSchema, Repository, typeorm} from '@loopback/typeorm';
+import {Book} from '../typeorm-entities';
+
+export class BookController {
+  @typeorm.repository(Book) private bookRepo: Repository<Book>;
+
+  constructor() {}
+
+  // Create a new book
+  @post('/book')
+  async create(@requestBody() data: Book) {
+    const book = new Book();
+    book.title = data.title;
+    book.published = false;
+    return await this.bookRepo.save(book);
+  }
+
+  // Find book by title
+  @get('/note/{title}')
+  async findByTitle(@param.path.string('title') title: string) {
+    return await this.bookRepo.find({title});
+  }
+}
+```
+
+## Limitations
+
+Please note, the current implementation does not support the following:
+
+1. [Complete TypeORM to OpenAPI data type conversion](https://github.com/strongloop/loopback-next/issues/5893)
+   (currently only `number`, `string`, and `boolean` are supported)
+2. [Full JSON/OpenAPI schema for entities](https://github.com/strongloop/loopback-next/issues/5894),
+   including variants like with/without id, with/without relations, partial,
+   etc.
+3. [Support for LoopBack-style filters](https://github.com/strongloop/loopback-next/issues/5895)
+4. [JSON/OpenAPI schema to describe the supported filter format](https://github.com/strongloop/loopback-next/issues/5896)
+5. [Custom repository classes](https://github.com/strongloop/loopback-next/issues/5897)
+   (e.g. to implement bookRepo.findByTitle(title)).
+6. [Database migration](https://github.com/strongloop/loopback-next/issues/5898)
+
+Community contribution is welcome.
+
+## Contributions
+
+- [Guidelines](https://github.com/strongloop/loopback-next/blob/master/docs/CONTRIBUTING.md)
+- [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