124 lines
3.1 KiB
JavaScript
124 lines
3.1 KiB
JavaScript
"use strict";
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var etag = require("etag");
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var fresh = require("fresh");
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var fs = require("fs");
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var path = require("path");
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var zlib = require("zlib");
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var minifiedScript = path.join(__dirname, "dist", "index.min.js");
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var unminifiedScript = path.join(__dirname, "dist", "index.js");
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/**
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* Does the current request support compressed encoding?
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* @param {Object} req
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* @returns {boolean}
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*/
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function supportsGzip(req) {
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var accept = req.headers["accept-encoding"];
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return accept && accept.indexOf("gzip") > -1;
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}
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/**
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* Set headers on the response
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* @param {Object} res
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* @param {String} body
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*/
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function setHeaders(res, body) {
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res.setHeader("Cache-Control", "public, max-age=0");
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res.setHeader("Content-Type", "text/javascript");
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res.setHeader("ETag", etag(body));
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}
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/**
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* @param {Object} req
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* @returns {String}
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*/
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function isConditionalGet(req) {
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return req.headers["if-none-match"] || req.headers["if-modified-since"];
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}
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/**
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* Return a not-modified response
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* @param {Object} res
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*/
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function notModified(res) {
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res.removeHeader("Content-Type");
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res.statusCode = 304;
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res.end();
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}
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function processItems(items) {
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return [].concat(items)
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.filter(Boolean)
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.reduce((stringOutput, item) => {
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if (typeof item === 'string') {
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return stringOutput + item;
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}
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if (typeof item === 'function') {
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return stringOutput + item();
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}
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return stringOutput;
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}, "");
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}
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/**
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* Public method for returning either a middleware fn
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* or the content as a string
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* @param {Object} options
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* @param requestBody
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* @param {String} type - either `file` or `middleware`
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* @returns {*}
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*/
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function init(options, requestBody, type) {
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/**
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* If the user asked for a file, simply return the string.
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*/
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if (type && type === "file") {
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return processItems(requestBody);
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}
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/**
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* Otherwise return a function to be used a middleware
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*/
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return function(req, res) {
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/**
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* default to using the uncompressed string
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* @type {String}
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*/
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var output = processItems(requestBody);
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/**
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* Set the appropriate headers for caching
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*/
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setHeaders(res, output);
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var resHeaders = res.getHeaders ? res.getHeaders() : res._headers;
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if (isConditionalGet(req) && fresh(req.headers, resHeaders)) {
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return notModified(res);
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}
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/**
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* If gzip is supported, compress the string once
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* and save for future requests
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*/
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if (supportsGzip(req)) {
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res.setHeader("Content-Encoding", "gzip");
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var buf = Buffer.from(output, "utf-8");
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zlib.gzip(buf, function(_, result) {
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res.end(result);
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});
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} else {
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res.end(output);
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}
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};
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}
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module.exports.middleware = init;
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module.exports.plugin = init;
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module.exports.minified = function() {
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return fs.readFileSync(minifiedScript, "utf8");
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};
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module.exports.unminified = function() {
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return fs.readFileSync(unminifiedScript, "utf8");
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};
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