@betit/orion/lib/client/index.js

Pluggable microservice framework

"use strict";
const codec_1 = require('../codec');
const transport_1 = require('../transport');
const utils_1 = require('../utils');
const debug = utils_1.debugLog('orion:client');
/**
 * Provides an interface to make requests to services.
 */
class Client {
    /**
     * Create new client.
     */
    constructor(options) {
        this.options = options;
        this.options = Object.assign({
            timeout: 3000
        }, options);
        this.codec = this.options.codec || new codec_1.DefaultBinaryCodec();
        this.transport = this.options.transport || new transport_1.DefaultTransport();
    }
    /**
     * Publish to a topic.
     * @param {any} topic
     * @param {Object} message
     */
    emit(topic, message) {
        debug('emit:', topic);
        this.transport.publish(topic, this.codec.encode(message));
    }
    /**
     * Call service method.
     * @param {Object} request
     * @param {Object} [params]
     * @param {Function} callback
     */
    call(request, callback) {
        // supports method call without params
        if (arguments.length === 3) {
            request = {
                path: request,
                params: callback
            };
            callback = arguments[2];
        }
        else if (typeof request === 'string') {
            request = {
                path: request
            };
        }
        let route = request.path;
        // services registered with names like `service.method`
        // but we support `/service/method` style calls as well
        // hence we need to "normalize" the route here. 
        route = route.replace(/\//gi, '.');
        if (route.startsWith('.')) {
            route = route.substring(1);
        }
        if (!route) {
            return callback(new Error('Invalid request path'));
        }
        if (this.options.service) {
            route = `${this.options.service}.${route}`;
        }
        debug('calling:', route);
        const req = this.codec.encode(request);
        debug('sending request:', request);
        this.transport.request(route, req, res => {
            if (res instanceof Error) {
                callback(res);
            }
            else {
                const response = this.codec.decode(res);
                debug('got response:', response);
                callback(response.err, response.res);
            }
        }, this.options.timeout);
    }
    /**
     * Close underlying transport connection.
     */
    close() {
        debug('close');
        this.transport.close();
    }
}
Object.defineProperty(exports, "__esModule", { value: true });
exports.default = Client;