superstatic/lib/middleware/headers.js

A static file server for fancy apps

"use strict";
/**
 * Copyright (c) 2022 Google LLC
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
const _ = require("lodash");
const slasher = require("glob-slasher");
const urlParser = require("url");
const onHeaders = require("on-headers");
const patterns = require("../utils/patterns");
const normalizedConfigHeaders = function (spec, config) {
    const out = config || [];
    if (_.isArray(config)) {
        const _isAllowed = function (headerToSet) {
            return _.includes(spec.allowedHeaders, headerToSet.key.toLowerCase());
        };
        for (const c of config) {
            c.source = slasher(c.source);
            c.headers = c.headers || [];
            if (spec.allowedHeaders) {
                c.headers = c.headers.filter(_isAllowed);
            }
        }
    }
    return out;
};
const matcher = function (configHeaders) {
    return function (url) {
        return configHeaders
            .filter((configHeader) => {
            return patterns.configMatcher(url, configHeader);
        })
            .reduce((out, val) => {
            val.headers.forEach((headerToSet) => {
                out.push(headerToSet);
            });
            return out;
        }, []);
    };
};
module.exports = function (spec) {
    return function (req, res, next) {
        const config = _.get(req, "superstatic.headers");
        if (!config) {
            return next();
        }
        const headers = matcher(normalizedConfigHeaders(spec, config));
        const pathname = urlParser.parse(req.url).pathname;
        const matches = headers(slasher(pathname));
        onHeaders(res, () => {
            _.forEach(matches, (header) => {
                res.setHeader(header.key, header.value);
            });
        });
        return next();
    };
};