lib/src/service/Middlewares.ts

import {CanonicalStatic} from './CanonicalStatic'
import {Singleton, Instantiable, StaticClass} from '../di'
import {CanonicalDefinition} from './Canonical'
import {Middleware} from '../http/routing/Middleware'

/**
 * A canonical unit that loads the middleware classes from `app/http/middlewares`.
 */
@Singleton()
export class Middlewares extends CanonicalStatic<Middleware, Instantiable<Middleware>> {
    protected appPath = ['http', 'middlewares']

    protected canonicalItem = 'middleware'

    protected suffix = '.middleware.js'

    public async initCanonicalItem(definition: CanonicalDefinition): Promise<StaticClass<Middleware, Instantiable<Middleware>>> {
        const item = await super.initCanonicalItem(definition)
        if ( !(item.prototype instanceof Middleware) ) {
            throw new TypeError(`Invalid middleware definition: ${definition.originalName}. Controllers must extend from @extollo/lib.http.routing.Middleware.`)
        }

        return item
    }
}