handlers.js/src/router.ts

import handler from './handler';
import {
    path,
    response,
    request,
    AllMismatchInterrupted,
    responder,
    method,
} from './interface/index';
import { defaultHeaders } from './interface/response';
import route from './route';
import { methodENUM } from './interface/method';
import {
    createPlatformAdapater,
    platformAdapaterConstructor,
    platformAdapater,
} from './platform/index';
import { platformAdapaterMapping } from './platform/export';
import { platform } from './lib';

export class router<K = any, V = any> {
    public routes: route[];

    public errorResponder: (
        errorCode: number,
        errorMessage?: string,
    ) => responder<K, V>;

    constructor(routes: route[] = []) {
        this.routes = routes;
    }

    add(route: route) {
        this.routes.push(route);
        return this;
    }

    binding(path: path, handler: handler<K, V>) {
        this.add(new route([path], [handler]));
        return this;
    }

    create(
        method: method,
        responder: (
            request: request<K>,
        ) =>
            | Promise<response<V>>
            | Promise<string>
            | Promise<object>
            | Promise<number>
            | Promise<void>,
    ) {
        return new handler<K, V>(method, [
            async (request: request<K>) => {
                const answer = await responder(request);
                if (answer instanceof response) {
                    return answer;
                } else if (typeof answer == 'string') {
                    return new response(answer);
                } else if (typeof answer == 'number') {
                    return new response(answer.toString());
                } else if (typeof answer == 'object') {
                    return new response(
                        JSON.stringify(answer),
                        200,
                        new defaultHeaders({
                            'Content-Type': 'application/json; charset=utf-8',
                        }),
                    );
                } else {
                    return new response('', 204);
                }
            },
        ]);
    }

    use(routers: router[], path: path): void {
        routers.forEach((router) => {
            this.binding(path, router.toHandler());
        });
    }

    route(path: path): router {
        const Router = new router([]);
        this.use([Router], path);
        return Router;
    }

    async _respond(
        request: request<K>,
        responseMessage: response<V> = new response<V>(''),
    ): Promise<response<V>> {
        request.originURL = request.url;
        request.url.pathname = request.params['0']
            ? '/' + request.params['0']
            : request.originURL.pathname;

        let mismatchCount = 0;

        for (const route of this.routes) {
            const isMatched = await route.exec(request.url.pathname);

            if (!isMatched.matched) {
                mismatchCount++;
                continue;
            }

            isMatched.attributes.forEach((e) => {
                request.params[e.name] = e.value;
            });

            try {
                let thisResponse: response<V> | void = responseMessage;
                for (const handler of route.handlers) {
                    if (
                        handler.method != request.method &&
                        handler.method != methodENUM.ANY
                    ) {
                        continue;
                    }
                    thisResponse = await handler.respond(
                        request,
                        thisResponse ?? responseMessage,
                    );
                }
                if (thisResponse instanceof response) {
                    responseMessage = thisResponse;
                } else {
                    // means that the handler is a middleware that doesn't change the response
                    throw AllMismatchInterrupted;
                }
            } catch (e) {
                if (e instanceof response) {
                    throw e;
                }
                if (e === AllMismatchInterrupted) mismatchCount++;
                else {
                    if (typeof this.errorResponder == 'function') {
                        responseMessage =
                            (await this.errorResponder(
                                500,
                                e.toString() + '\n',
                            )(request)) ?? new response(e.toString(), 500);
                        console.log(e);
                    } else {
                        throw e;
                    }
                }
            }
        }

        if (mismatchCount == this.routes.length) {
            throw AllMismatchInterrupted;
        }

        return responseMessage;
    }

    public respond = this._respond;

    toHandler(): handler<K, V> {
        return new handler(methodENUM.ANY, [
            (request: request<K>, responseMessage?: response<V>) => {
                return this.respond(
                    request,
                    responseMessage ?? new response(''),
                );
            },
        ]);
    }

    useErrorResponder(
        errorResponder: (
            errorCode: number,
            errorMessage?: string,
        ) => responder<K, V>,
    ): this {
        this.errorResponder = errorResponder;
        return this;
    }
}

export default router;

export class rootRouter<K = any, V = any> extends router<K, V> {
    public adapater: platformAdapater<K, V>;
    errorResponder =
        (errorCode: number, errorMessage?: string) =>
        async (_request: request<K>): Promise<response<V>> =>
            new response(errorMessage ?? '', errorCode);

    respond = async (request: request<K>): Promise<response<V>> => {
        let responseMessage: response<V> = new response('');
        try {
            responseMessage = await this._respond(request, responseMessage);
        } catch (e) {
            if (e instanceof response) {
                return e;
            } else if (e === AllMismatchInterrupted) {
                responseMessage =
                    (await this.errorResponder(
                        404,
                        '404 Not Found\n',
                    )(request)) ?? new response('404 Not Found\n', 404);
            } else {
                responseMessage =
                    (await this.errorResponder(
                        500,
                        e.toString() + '\n',
                    )(request)) ?? new response(e.toString(), 500);
                console.log(e);
            }
        }

        return responseMessage;
    };

    useAdapater(adapater: platformAdapaterConstructor): this {
        this.adapater = createPlatformAdapater(adapater, this);
        return this;
    }

    useMappingAdapter(
        mapping: {
            [platform: string]: platformAdapaterConstructor;
        } = platformAdapaterMapping,
    ): this {
        if (typeof platform == 'undefined')
            throw new Error('Cannot detect platform');
        if (mapping[platform] == undefined)
            throw new Error('Platform not found in mapping');
        else this.useAdapater(mapping[platform]);
        return this;
    }

    listen(port: number): void {
        if (this.adapater == null) throw new Error('No platform adapter set');
        this.adapater.listen(port);
    }

    close(): void {
        if (this.adapater == null) throw new Error('No platform adapter set');
        this.adapater.close();
    }
}