polyserve/lib/make_app.js

A simple dev server for bower components

"use strict";
/**
 * @license
 * Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at
 * http://polymer.github.io/LICENSE.txt
 * The complete set of authors may be found at
 * http://polymer.github.io/AUTHORS.txt
 * The complete set of contributors may be found at
 * http://polymer.github.io/CONTRIBUTORS.txt
 * Code distributed by Google as part of the polymer project is also
 * subject to an additional IP rights grant found at
 * http://polymer.github.io/PATENTS.txt
 */
Object.defineProperty(exports, "__esModule", { value: true });
const escapeHtml = require("escape-html");
const express = require("express");
const path = require("path");
const url_1 = require("url");
const send = require("send");
/**
 * Make a polyserve express app.
 * @param  {Object} options
 * @param  {string} options.componentDir The directory to serve components from.
 * @param  {string} options.packageName A name for this polyserve package.
 * @param  {Object} options.headers An object keyed by header name containing
 *         header values.
 * @param  {string} options.root The root directory to serve a package from
 * @return {Object} An express app which can be served with `app.get`
 */
function makeApp(options) {
    const root = path.resolve(options.root);
    const baseComponentDir = options.componentDir;
    const componentDir = path.resolve(root, baseComponentDir);
    const packageName = options.packageName;
    const headers = options.headers || {};
    if (packageName == null) {
        throw new Error('packageName not provided');
    }
    const app = express();
    app.get('*', (req, res) => {
        // Serve local files from . and other components from bower_components
        const url = url_1.parse(req.url, true);
        let splitPath = url.pathname.split('/').slice(1);
        const splitPackagePath = packageName.split('/');
        if (arrayStartsWith(splitPath, splitPackagePath)) {
            if (root) {
                splitPath = [root].concat(splitPath.slice(splitPackagePath.length));
            }
            else {
                splitPath = splitPath.slice(splitPackagePath.length);
            }
        }
        else {
            splitPath = [componentDir].concat(splitPath);
        }
        const filePath = splitPath.join('/');
        if (headers) {
            for (const header in headers) {
                res.setHeader(header, headers[header]);
            }
        }
        const _send = send(req, filePath, { etag: false, lastModified: false });
        // Uncomment this to disable 304s from send(). This will make the
        // compileMiddleware used in startServer always compile. Useful for testing
        // and working on the compilation middleware.
        // _send.isFresh = () => false;
        // The custom redirect is needed becuase send() redirects to the
        // _file_ path plus a leading slash, not the URL. :(
        // https://github.com/pillarjs/send/issues/132
        _send
            .on('directory', () => {
            res.statusCode = 301;
            res.setHeader('Location', req.originalUrl + '/');
            res.end('Redirecting to ' + req.originalUrl + '/');
        })
            .on('error', (err) => {
            res.status(err.statusCode);
            res.type('html');
            res.end(escapeHtml(err.Error));
        })
            .pipe(res);
    });
    app.packageName = packageName;
    return app;
}
exports.makeApp = makeApp;
function arrayStartsWith(array, prefix) {
    for (let i = 0; i < prefix.length; i++) {
        if (i >= array.length || array[i] !== prefix[i]) {
            return false;
        }
    }
    return true;
}
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