scramjet/src/shared/rewriters/html.ts
2024-12-05 06:44:15 +00:00

420 lines
9.3 KiB
TypeScript

import { ElementType, Parser } from "htmlparser2";
import { ChildNode, DomHandler, Element } from "domhandler";
import render from "dom-serializer";
import { URLMeta, rewriteUrl } from "./url";
import { rewriteCss } from "./css";
import { rewriteJs } from "./js";
import { CookieStore } from "../cookie";
import { unrewriteBlob } from "../../shared/rewriters/url";
import { $scramjet } from "../../scramjet";
export function rewriteHtml(
html: string,
cookieStore: CookieStore,
meta: URLMeta,
fromTop: boolean = false
) {
const handler = new DomHandler((err, dom) => dom);
const parser = new Parser(handler);
parser.write(html);
parser.end();
traverseParsedHtml(handler.root, cookieStore, meta);
function findhead(node) {
if (node.type === ElementType.Tag && node.name === "head") {
return node as Element;
} else if (node.childNodes) {
for (const child of node.childNodes) {
const head = findhead(child);
if (head) return head;
}
}
return null;
}
if (fromTop) {
let head = findhead(handler.root);
if (!head) {
head = new Element("head", {}, []);
handler.root.children.unshift(head);
}
const dump = JSON.stringify(cookieStore.dump());
const injected = `
self.COOKIE = ${dump};
self.$scramjet.config = ${JSON.stringify($scramjet.config)};
if ("document" in self && document?.currentScript) {
document.currentScript.remove();
}
`;
const script = (src) => new Element("script", { src });
// for compatibility purpose
const base64Injected = bytesToBase64(new TextEncoder().encode(injected));
head.children.unshift(
script($scramjet.config.files.wasm),
script($scramjet.config.files.shared),
script("data:application/javascript;base64," + base64Injected),
script($scramjet.config.files.client)
);
}
return render(handler.root);
}
// type ParseState = {
// base: string;
// origin?: URL;
// };
export function unrewriteHtml(html: string) {
const handler = new DomHandler((err, dom) => dom);
const parser = new Parser(handler);
parser.write(html);
parser.end();
function traverse(node: ChildNode) {
if ("attribs" in node) {
for (const key in node.attribs) {
if (key == "scramjet-data-script-source-src") {
if (node.children[0] && "data" in node.children[0])
node.children[0].data = atob(node.attribs[key]);
continue;
}
if (key.startsWith("scramjet-data-")) {
node.attribs[key.slice("scramjet-data-".length)] = node.attribs[key];
delete node.attribs[key];
}
}
}
if ("childNodes" in node) {
for (const child of node.childNodes) {
traverse(child);
}
}
}
traverse(handler.root);
return render(handler.root);
}
export const htmlRules: {
[key: string]: "*" | string[] | ((...any: any[]) => string | null);
fn: (value: string, meta: URLMeta, cookieStore: CookieStore) => string | null;
}[] = [
{
fn: (value: string, meta: URLMeta) => {
return rewriteUrl(value, meta);
},
// url rewrites
src: [
"embed",
"script",
"img",
"iframe",
"frame",
"source",
"input",
"track",
],
href: ["a", "link", "area", "use", "image"],
data: ["object"],
action: ["form"],
formaction: ["button", "input", "textarea", "submit"],
poster: ["video"],
"xlink:href": ["image"],
},
{
fn: (value: string, meta: URLMeta) => {
if (value.startsWith("blob:")) {
// for media elements specifically they must take the original blob
// because they can't be fetch'd
return unrewriteBlob(value);
}
return rewriteUrl(value, meta);
},
src: ["video", "audio"],
},
{
fn: () => "",
integrity: ["script", "link"],
},
{
fn: () => null,
// csp stuff that must be deleted
nonce: "*",
csp: ["iframe"],
credentialless: ["iframe"],
},
{
fn: (value: string, meta: URLMeta) => rewriteSrcset(value, meta),
// srcset
srcset: ["img", "source"],
imagesrcset: ["link"],
},
{
fn: (value: string, meta: URLMeta, cookieStore: CookieStore) =>
rewriteHtml(
value,
cookieStore,
{
// for srcdoc origin is the origin of the page that the iframe is on. base and path get dropped
origin: new URL(meta.origin.origin),
base: new URL(meta.origin.origin),
},
true
),
// srcdoc
srcdoc: ["iframe"],
},
{
fn: (value: string, meta: URLMeta) => rewriteCss(value, meta),
style: "*",
},
{
fn: (value: string) => {
if (["_parent", "_top", "_unfencedTop"].includes(value)) return "_self";
},
target: ["a", "base"],
},
];
// i need to add the attributes in during rewriting
function traverseParsedHtml(
node: any,
cookieStore: CookieStore,
meta: URLMeta
) {
if (node.name === "base" && node.attribs.href !== undefined) {
meta.base = new URL(node.attribs.href, meta.origin);
}
if (node.attribs) {
for (const rule of htmlRules) {
for (const attr in rule) {
const sel = rule[attr.toLowerCase()];
if (typeof sel === "function") continue;
if (sel === "*" || sel.includes(node.name)) {
if (node.attribs[attr] !== undefined) {
const value = node.attribs[attr];
const v = rule.fn(value, meta, cookieStore);
if (v === null) delete node.attribs[attr];
else {
node.attribs[attr] = v;
}
node.attribs[`scramjet-data-${attr}`] = value;
}
}
}
}
for (const [attr, value] of Object.entries(node.attribs)) {
if (eventAttributes.includes(attr)) {
node.attribs[`scramjet-data-${attr}`] = value;
node.attribs[attr] = rewriteJs(
value as string,
`(inline ${attr} on element)`,
meta
);
}
}
}
if (node.name === "style" && node.children[0] !== undefined)
node.children[0].data = rewriteCss(node.children[0].data, meta);
if (
node.name === "script" &&
/(application|text)\/javascript|module|importmap|undefined/.test(
node.attribs.type
) &&
node.children[0] !== undefined
) {
let js = node.children[0].data;
// node.attribs[`scramjet-data-script-source-src`] = btoa(js);
node.attribs["scramjet-data-script-source-src"] = bytesToBase64(
new TextEncoder().encode(js)
);
const htmlcomment = /<!--[\s\S]*?-->/g;
js = js.replace(htmlcomment, "");
node.children[0].data = rewriteJs(js, "(inline script element)", meta);
}
if (node.name === "meta" && node.attribs["http-equiv"] !== undefined) {
if (
node.attribs["http-equiv"].toLowerCase() === "content-security-policy"
) {
node = {};
} else if (
node.attribs["http-equiv"] === "refresh" &&
node.attribs.content.includes("url")
) {
const contentArray = node.attribs.content.split("url=");
if (contentArray[1])
contentArray[1] = rewriteUrl(contentArray[1].trim(), meta);
node.attribs.content = contentArray.join("url=");
}
}
if (node.childNodes) {
for (const childNode in node.childNodes) {
node.childNodes[childNode] = traverseParsedHtml(
node.childNodes[childNode],
cookieStore,
meta
);
}
}
return node;
}
export function rewriteSrcset(srcset: string, meta: URLMeta) {
const sources = srcset.split(",").map((src) => src.trim());
const rewrittenSources = sources.map((source) => {
// Split into URLs and descriptors (if any)
// e.g. url0, url1 1.5x, url2 2x
const [url, ...descriptors] = source.split(/\s+/);
// Rewrite the URLs and keep the descriptors (if any)
const rewrittenUrl = rewriteUrl(url.trim(), meta);
return descriptors.length > 0
? `${rewrittenUrl} ${descriptors.join(" ")}`
: rewrittenUrl;
});
return rewrittenSources.join(", ");
}
// function base64ToBytes(base64) {
// const binString = atob(base64);
// return Uint8Array.from(binString, (m) => m.codePointAt(0));
// }
function bytesToBase64(bytes: Uint8Array) {
const binString = Array.from(bytes, (byte) =>
String.fromCodePoint(byte)
).join("");
return btoa(binString);
}
const eventAttributes = [
"onbeforexrselect",
"onabort",
"onbeforeinput",
"onbeforematch",
"onbeforetoggle",
"onblur",
"oncancel",
"oncanplay",
"oncanplaythrough",
"onchange",
"onclick",
"onclose",
"oncontentvisibilityautostatechange",
"oncontextlost",
"oncontextmenu",
"oncontextrestored",
"oncuechange",
"ondblclick",
"ondrag",
"ondragend",
"ondragenter",
"ondragleave",
"ondragover",
"ondragstart",
"ondrop",
"ondurationchange",
"onemptied",
"onended",
"onerror",
"onfocus",
"onformdata",
"oninput",
"oninvalid",
"onkeydown",
"onkeypress",
"onkeyup",
"onload",
"onloadeddata",
"onloadedmetadata",
"onloadstart",
"onmousedown",
"onmouseenter",
"onmouseleave",
"onmousemove",
"onmouseout",
"onmouseover",
"onmouseup",
"onmousewheel",
"onpause",
"onplay",
"onplaying",
"onprogress",
"onratechange",
"onreset",
"onresize",
"onscroll",
"onsecuritypolicyviolation",
"onseeked",
"onseeking",
"onselect",
"onslotchange",
"onstalled",
"onsubmit",
"onsuspend",
"ontimeupdate",
"ontoggle",
"onvolumechange",
"onwaiting",
"onwebkitanimationend",
"onwebkitanimationiteration",
"onwebkitanimationstart",
"onwebkittransitionend",
"onwheel",
"onauxclick",
"ongotpointercapture",
"onlostpointercapture",
"onpointerdown",
"onpointermove",
"onpointerrawupdate",
"onpointerup",
"onpointercancel",
"onpointerover",
"onpointerout",
"onpointerenter",
"onpointerleave",
"onselectstart",
"onselectionchange",
"onanimationend",
"onanimationiteration",
"onanimationstart",
"ontransitionrun",
"ontransitionstart",
"ontransitionend",
"ontransitioncancel",
"oncopy",
"oncut",
"onpaste",
"onscrollend",
"onscrollsnapchange",
"onscrollsnapchanging",
];