lib/src/i18n/modules/InjectRequestLocale.ts

import {Request} from '../../http/lifecycle/Request'
import {Injectable} from '../../di'
import {Locale} from '../service/Locale'
import {HTTPKernelModule} from '../../http/kernel/HTTPKernelModule'
import {HTTPKernel} from '../../http/kernel/HTTPKernel'
import {InjectSessionHTTPModule} from '../../http/kernel/module/InjectSessionHTTPModule'
import {Session} from '../../http/session/Session'

/**
 * An HTTP kernel module that adds the Locale service to the request container.
 */
@Injectable()
export class InjectRequestLocale extends HTTPKernelModule {
    public executeWithBlockingWriteback = true

    /** Register this kernel module to the given kernel. */
    public static register(kernel: HTTPKernel): void {
        kernel.register(this).after(InjectSessionHTTPModule)
    }

    /**
     * Gets or sets the default locale in the session and instantiates a Locale
     * service into the Request container based on said locale.
     * @param request
     */
    public async apply(request: Request): Promise<Request> {
        const session = <Session> request.make(Session)
        const locale = <Locale> request.make(Locale)

        // Set the default locale in the session
        if ( !session.get('i18n.locale') ) {
            session.set('i18n.locale', locale.getDefaultLocale())
        }

        locale.setLocale(session.get('i18n.locale'))
        request.registerSingletonInstance(Locale, locale)

        return request
    }
}