@2o3t/koa2-proxy-middleware/lib/createConfig.js

http proxy middleware for koa2

'use strict';

const utility = require('2o3t-utility');
const url = require('url');

const ERRORS = require('./errors');

function createConfig(context, opts) {
    // structure of config object to be returned
    const config = {
        context: undefined,
        options: {},
    };

    // app.use('/api', proxy({target:'http://localhost:9000'}));
    if (isContextless(context, opts)) {
        config.context = '/';
        config.options = Object.assign(config.options, context);

    // app.use('/api', proxy('http://localhost:9000'));
    // app.use(proxy('http://localhost:9000/api'));
    } else if (isStringShortHand(context)) {
        const oUrl = url.parse(context);
        const target = [ oUrl.protocol, '//', oUrl.host ].join('');

        config.context = oUrl.pathname || '/';
        config.options = Object.assign(config.options, { target }, opts);

        if (oUrl.protocol === 'ws:' || oUrl.protocol === 'wss:') {
            config.options.ws = true;
        }
    // app.use('/api', proxy({target:'http://localhost:9000'}));
    } else {
        config.context = context;
        config.options = Object.assign(config.options, opts);
    }

    if (!config.options.target) {
        throw new Error(ERRORS.ERR_CONFIG_FACTORY_TARGET_MISSING);
    }

    return config;
}

/**
   * Checks if a String only target/config is provided.
   * This can be just the host or with the optional path.
   *
   * @example
   *      app.use('/api', proxy('http://localhost:9000'));
          app.use(proxy('http://localhost:9000/api'));
   *
   * @param  {String}  context [description]
   * @return {Boolean}         [description]
   */
function isStringShortHand(context) {
    if (utility.isString(context)) {
        return !!(url.parse(context).host);
    }
}

/**
   * Checks if a Object only config is provided, without a context.
   * In this case the all paths will be proxied.
   *
   * @example
   *     app.use('/api', proxy({target:'http://localhost:9000'}));
   *
   * @param  {Object}  context [description]
   * @param  {*}       opts    [description]
   * @return {Boolean}         [description]
   */
function isContextless(context, opts) {
    return (utility.isPlainObject(context) && utility.isEmpty(opts));
}

module.exports = createConfig;