"use strict";
const express = require("express");
const fetch = require("node-fetch");
const { encode } = require("html-entities");
const cleanBaseURL = require("clean-base-url");
const path = require("path");
const { promises: fs } = require("fs");
const { JSDOM } = require("jsdom");
// via https://stackoverflow.com/a/6248722/165668
function generateUID() {
let firstPart = (Math.random() * 46656) | 0; // eslint-disable-line no-bitwise
let secondPart = (Math.random() * 46656) | 0; // eslint-disable-line no-bitwise
firstPart = ("000" + firstPart.toString(36)).slice(-3);
secondPart = ("000" + secondPart.toString(36)).slice(-3);
return firstPart + secondPart;
}
function htmlTag(buffer, bootstrap) {
let classList = "";
if (bootstrap.html_classes) {
classList = ` class="${bootstrap.html_classes}"`;
}
buffer.push(``);
}
function head(buffer, bootstrap, headers, baseURL) {
if (bootstrap.csrf_token) {
buffer.push(``);
buffer.push(``);
}
if (bootstrap.theme_id) {
buffer.push(
``
);
}
if (bootstrap.theme_color) {
buffer.push(``);
}
if (bootstrap.authentication_data) {
buffer.push(
``
);
}
let setupData = "";
Object.keys(bootstrap.setup_data).forEach((sd) => {
let val = bootstrap.setup_data[sd];
if (val) {
if (Array.isArray(val)) {
val = JSON.stringify(val);
} else {
val = val.toString();
}
setupData += ` data-${sd.replace(/\_/g, "-")}="${encode(val)}"`;
}
});
buffer.push(``);
(bootstrap.stylesheets || []).forEach((s) => {
let attrs = [];
if (s.media) {
attrs.push(`media="${s.media}"`);
}
if (s.target) {
attrs.push(`data-target="${s.target}"`);
}
if (s.theme_id) {
attrs.push(`data-theme-id="${s.theme_id}"`);
}
if (s.class) {
attrs.push(`class="${s.class}"`);
}
let link = ``;
buffer.push(link);
});
if (bootstrap.preloaded.currentUser) {
let staff = JSON.parse(bootstrap.preloaded.currentUser).staff;
if (staff) {
buffer.push(``);
}
}
bootstrap.plugin_js.forEach((src) =>
buffer.push(``)
);
buffer.push(bootstrap.theme_html.translations);
buffer.push(bootstrap.theme_html.js);
buffer.push(bootstrap.theme_html.head_tag);
buffer.push(bootstrap.html.before_head_close);
}
function localeScript(buffer, bootstrap) {
buffer.push(``);
}
function beforeScriptLoad(buffer, bootstrap) {
buffer.push(bootstrap.html.before_script_load);
localeScript(buffer, bootstrap);
(bootstrap.extra_locales || []).forEach((l) =>
buffer.push(``)
);
}
function body(buffer, bootstrap) {
buffer.push(bootstrap.theme_html.header);
buffer.push(bootstrap.html.header);
}
function bodyFooter(buffer, bootstrap, headers) {
buffer.push(bootstrap.theme_html.body_tag);
buffer.push(bootstrap.html.before_body_close);
let v = generateUID();
buffer.push(`
`);
}
function hiddenLoginForm(buffer, bootstrap) {
if (!bootstrap.preloaded.currentUser) {
buffer.push(`
`);
}
}
function preloaded(buffer, bootstrap) {
buffer.push(
``
);
}
const BUILDERS = {
"html-tag": htmlTag,
"before-script-load": beforeScriptLoad,
head,
body,
"hidden-login-form": hiddenLoginForm,
preloaded,
"body-footer": bodyFooter,
"locale-script": localeScript,
};
function replaceIn(bootstrap, template, id, headers, baseURL) {
let buffer = [];
BUILDERS[id](buffer, bootstrap, headers, baseURL);
let contents = buffer.filter((b) => b && b.length > 0).join("\n");
return template.replace(``, contents);
}
function extractPreloadJson(html) {
const dom = new JSDOM(html);
const dataElement = dom.window.document.querySelector("#data-preloaded");
if (!dataElement || !dataElement.dataset) {
return;
}
return dataElement.dataset.preloaded;
}
async function applyBootstrap(bootstrap, template, response, baseURL, preload) {
bootstrap.preloaded = Object.assign(JSON.parse(preload), bootstrap.preloaded);
Object.keys(BUILDERS).forEach((id) => {
template = replaceIn(bootstrap, template, id, response.headers, baseURL);
});
return template;
}
async function buildFromBootstrap(proxy, baseURL, req, response, preload) {
try {
const template = await fs.readFile(
path.join(process.cwd(), "dist", "index.html"),
"utf8"
);
let url = new URL(`${proxy}${baseURL}bootstrap.json`);
url.searchParams.append("for_url", req.url);
const res = await fetch(url, { headers: req.headers });
const json = await res.json();
return applyBootstrap(json.bootstrap, template, response, baseURL, preload);
} catch (error) {
throw new Error(
`Could not get ${proxy}${baseURL}bootstrap.json\n\n${error}`
);
}
}
async function handleRequest(proxy, baseURL, req, res) {
const originalHost = req.headers.host;
req.headers.host = new URL(proxy).host;
if (req.headers["Origin"]) {
req.headers["Origin"] = req.headers["Origin"]
.replace(req.headers.host, originalHost)
.replace(/^https/, "http");
}
if (req.headers["Referer"]) {
req.headers["Referer"] = req.headers["Referer"]
.replace(req.headers.host, originalHost)
.replace(/^https/, "http");
}
let url = `${proxy}${req.path}`;
const queryLoc = req.url.indexOf("?");
if (queryLoc !== -1) {
url += req.url.substr(queryLoc);
}
if (req.method === "GET") {
req.headers["X-Discourse-Ember-CLI"] = "true";
}
const response = await fetch(url, {
method: req.method,
body: /GET|HEAD/.test(req.method) ? null : req.body,
headers: req.headers,
redirect: "manual",
});
response.headers.forEach((value, header) => {
res.set(header, value);
});
res.set("content-encoding", null);
const location = response.headers.get("location");
if (location) {
const newLocation = location.replace(proxy, `http://${originalHost}`);
res.set("location", newLocation);
}
const csp = response.headers.get("content-security-policy");
if (csp) {
const emberCliAdditions = [
`http://${originalHost}/assets/`,
`http://${originalHost}/ember-cli-live-reload.js`,
`http://${originalHost}/_lr/`,
];
const newCSP = csp
.replace(new RegExp(proxy, "g"), `http://${originalHost}`)
.replace(
new RegExp("script-src ", "g"),
`script-src ${emberCliAdditions.join(" ")} `
);
res.set("content-security-policy", newCSP);
}
const contentType = response.headers.get("content-type");
const isHTML = contentType && contentType.startsWith("text/html");
const responseText = await response.text();
const preloadJson = isHTML ? extractPreloadJson(responseText) : null;
if (preloadJson) {
const html = await buildFromBootstrap(
proxy,
baseURL,
req,
response,
extractPreloadJson(responseText)
);
res.set("content-type", "text/html");
res.send(html);
} else {
res.status(response.status);
res.send(responseText);
}
}
module.exports = {
name: require("./package").name,
isDevelopingAddon() {
return true;
},
serverMiddleware(config) {
const app = config.app;
let { proxy, rootURL, baseURL } = config.options;
if (!proxy) {
// eslint-disable-next-line no-console
console.error(`
Discourse can't be run without a \`--proxy\` setting, because it needs a Rails application
to serve API requests. For example:
yarn run ember serve --proxy "http://localhost:3000"\n`);
throw "--proxy argument is required";
}
baseURL = rootURL === "" ? "/" : cleanBaseURL(rootURL || baseURL);
const rawMiddleware = express.raw({ type: () => true, limit: "100mb" });
app.use(rawMiddleware, async (req, res, next) => {
try {
if (this.shouldHandleRequest(req)) {
await handleRequest(proxy, baseURL, req, res);
}
} catch (error) {
res.send(`
Discourse Ember CLI Proxy Error
${error.stack}
`);
} finally {
if (!res.headersSent) {
return next();
}
}
});
},
shouldHandleRequest(request) {
if (request.path === "/tests/index.html") {
return false;
}
if (request.get("Accept") && request.get("Accept").includes("text/html")) {
return true;
}
const contentType = request.get("Content-Type");
if (!contentType) {
return false;
}
if (
contentType.includes("application/x-www-form-urlencoded") ||
contentType.includes("multipart/form-data") ||
contentType.includes("application/json")
) {
return true;
}
return false;
},
};