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Middlewares

Creating Middlewares

To create a middleware class, must extends ProtonMiddleware. A middleware may have one Middleware Function.

Example:

import { Middleware, MiddlewareFunctionParams, ProtonMiddleware } from 'protontype';
export class ExampleMiddleware extends ProtonMiddleware {

    @Middleware()
    exampleMiddlewareFunc(params: MiddlewareFunctionParams) {
        cosole.log(params.req);
        console.log(params.res);
        params.next();
    }
}

Middleware Function

A Middleware Function is a function into ProtonMiddleware class, with @Middleware decorator and has as parameter a object of type MiddlewareFunctionParams. This function defines the middleware behavior.

@Middleware()
exampleMiddlewareFunc(params: MiddlewareFunctionParams) {
    cosole.log(params.req);
    console.log(params.res);
    params.next();
}

The @Middleware decorator has the autoNext: boolean optional parameter. If is true, the next() function will be called implicitly as last instruction of function. Not is necessary call params.next().

Example:

@Middleware(true)
exampleMiddlewareFunc(params: MiddlewareFunctionParams) {
    cosole.log(params.req);
    console.log(params.res);
}

@Middleware

The @Middleware() decorator indicates what function contains the middleware behavior.

Properties

• autoNext: boolean. Enables the implicit call of the next() function on middleware finsh execution.

MiddlewareFunctionParams

Middleware Function parameter

Properties

• req: The object that contains the HTTP request. Matches with Express request object.
• res: Object used to send the HTTP response. Matches with Express response object.
• next: Function used to call the next middlewere of the chain.
• app: Protontype application instance. Through it you can access the application properties.

Middlewares's Scopes

The middlewares can act in diferents scopes

Application's Scope

This middleware will act in global scope, that is, before any configured route. To make a global midlleware, must to add it in application's bootstrap methods: addMiddleware ou addMiddlewareAs:

new ProtonApplication()
    .addMiddleware(new ExampleMiddleware())
    .addMiddlewareAs(ExampleMiddleware2)
    .start();

• addMiddleware: Allows to pass a created instance of the middleware
• addMiddlewareAs: Allows to pass the middleware type, and the application will instantiate it.

Router's Scope

This middleware will act to all Router Functions into ExpressRouter class. To add router's scope middlewares, you must use @RouterClass() decorator.

@RouterClass({
    baseUrl: "/tasks",
    middlewares: [ new ExampleMiddleware(), new ExampleMiddleware2() ]
})
export class TaskRouter extends ExpressRouter {
 ...
}

Route's Scope (Router Function)

This middleware will act only to specific route. To add route's spcope middleware, you must use the @Route() decorator Este middleware atuará somente para aquela rota específica. Para adicionar middlewares ao escopo da rota, este deve ser configurado no decorator @Route().

@RouterClass({baseUrl: "/tasks"})
export class TaskRouter extends ExpressRouter {
    @Route({
        endpoint: '/',
        method: Method.GET,
        middlewares: [ new ExampleMiddleware(), new ExampleMiddleware2() ]
    })
    listTask(params: RouterFunctionParams) {
        ...
    }
}

Hook Methods

The configMiddlewares() can to be overwritten. In him we can access the ExpressJs instance and to make anything.

Example:

export class DefaultMiddleware extends Middleware {
    private port: number = 5555;
    private jsonSpaces: number = 2;

public configMiddlewares(): void {
    this.express.set("port", this.port);
    this.express.set("json spaces", this.jsonSpaces);
    this.express.use(bodyParser.json());
    this.express.use((req, res, next) => {
        delete req.body.id;
        next();
    })
}