Induct
Induct provides abstractions over ExpressJS in order to quickly create REST APIs from an SQL Database for prototyping purposes. Usage with Typescript is fully supported and strongly encouraged!
Induct uses Knex to query databases, and therefore only supports databases supported by Knex.
Getting Started
Install Induct Core as a dependency of your project:
npm install @yeseh/induct-core --save
Define a schema
Define a class to provide Induct with type information. Class-validator decorators are supported for incoming schema validation.
// schema.ts
export class UserSchema {
@IsUUID()
uuid: string;
@IsString()
name: string;
@IsInt()
age: number;
constructor(val: UserSchema) {
this.uuid = val.uuid;
this.name = val.name;
this.age = val.age;
}
}Create a router
Initialize Induct and provide a database object, an object schema, the table to query, and the field to use as ID parameter.
// router.ts
const induct = new Induct({
connection: knex, // Knex connection object to your database
schema: UserSchema,
tableName: "dbo.users",
idField: "uuid",
idParam: "user_uuid", // OPTIONAL: custom param name for the id field
fieldsList: ["uuid", "name"], // OPTIONAL: limit fields retrieved
});
export const inductRouter = induct.router();This method will create an express router with the following routes:
- GET / retrieve all records in the table
- GET /:idParam retrieve one record
- POST / create one record
- PATCH /:idParam update one record
- DELETE /:idParam delete one record
Setup a server
Finally, create an express entry point as usual, and bring in the created router:
// index.ts
import {createServer} from "http";
import express from "express";
import {inductRouter} from "./router";
import bodyParser from "body-parser";
const app = express();
app.use(bodyParser.json({limit: "50mb"})); // Make sure you are using body parser!
app.use("/users", inductRouter);
const server = createServer(app);
server.listen(4000, () => console.log(`Server is listening on port 4000`));Other usage options
Induct exposes several levels of abstraction. The getting started example highlights the quickest way to expose a full table as a REST API, but the individual building blocks can be used separately too.
Generic route handlers
You can create generic express route handlers for InductModel methods using the induct.handler() method:
const router = express.Router();
router.get("/", induct.handler("findAll", {all: true}));
router.post(`/`, induct.handler("create", {validate: true}));
router.get(`/:${induct.idParam}`, induct.handler("findOneById"));
router.patch(`/:${induct.idParam}`,induct.handler("update", {validate: true}));
router.delete(`/:${induct.idParam}`, induct.handler("update"));These handlers use the generic InductModel methods to query your database.
Use InductModel in custom route handler
You can use Inducts generic model class in your own route handlers as follows:
// Create an Induct instance
const induct = new Induct({
connection: knex, // Knex connection object to your database
schema: UserSchema,
tableName: "dbo.users",
idField: "uuid",
});
// Create your custom route handler
export const routeHandler = async (
req: Request,
res: Response
): Promise<Response> => {
// Get a model instance and lookup using the id parameter
const model = await induct.model({uuid: req.params.id});
const result = await model.findOneById();
// Return a response based on the results of the query
if (result && result[0]) return res.status(200).json(result);
else return res.status(404).json({message: "Resource not found"});
};Using custom models
Not supported yet, hopefully in a future version.
Example Application
An full example application can be found here.
License
MIT
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