koa-http-proxy-middleware/build/index.js

koa-http-proxy-middleware

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
/**
 * Dependencies
 */
const url = require('url');
const HttpProxy = require('http-proxy');
const { mathPath } = require('match-path-plus');
/**
 * Constants
 */
const proxy = HttpProxy.createProxyServer();
let eventRegistered = false;
/**
 * Koa Http Proxy Middleware
 */
exports.httpProxy = (urlPattern, options) => (ctx, next) => {
    if (!mathPath(urlPattern, ctx.req.url))
        return next();
    let opts = Object.assign({}, options);
    if (typeof options === 'function') {
        const { params, path } = mathPath(urlPattern, ctx.req.url);
        opts = options.call(options, params);
    }
    // object-rest-spread is still in stage-3
    // https://github.com/tc39/proposal-object-rest-spread
    const { logs, rewrite, events } = opts;
    const httpProxyOpts = Object.keys(opts)
        .filter(n => ['logs', 'rewrite', 'events'].indexOf(n) < 0)
        .reduce((prev, cur) => {
        prev[cur] = opts[cur];
        return prev;
    }, {});
    return new Promise((resolve, reject) => {
        ctx.req.oldPath = ctx.req.url;
        if (typeof rewrite === 'function') {
            ctx.req.url = rewrite(ctx.req.url);
        }
        if (logs)
            logger(ctx, opts.target);
        if (events && typeof events === 'object' && !eventRegistered) {
            Object.entries(events).forEach(([event, handler]) => {
                proxy.on(event, handler);
            });
            eventRegistered = true;
        }
        proxy.web(ctx.req, ctx.res, httpProxyOpts, e => {
            const status = {
                ECONNREFUSED: 503,
                ETIMEOUT: 504
            }[e.code];
            if (status)
                ctx.status = status;
            resolve();
        });
    });
};
function logger(ctx, target) {
    console.log('%s - %s %s proxy to -> %s', new Date().toISOString(), ctx.req.method, ctx.req.oldPath, url.resolve(target, ctx.req.url));
}
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