cohost/serverside/name-color.ts
2024-07-11 18:39:36 -04:00

127 lines
3.9 KiB
TypeScript

import {
DOMParser,
} from "https://deno.land/x/deno_dom@v0.1.46/deno-dom-wasm.ts";
import * as css from "https://deno.land/x/css@0.3.0/mod.ts";
// so, so brittle
function is_valid_color(color: string): boolean {
try {
const { stylesheet } = css.parse(`*{color:${color};}`);
return color.toLowerCase() != "example"
&& stylesheet.rules.length == 1
&& stylesheet.rules[0].declarations.length == 1;
} catch {
return false;
}
}
// maybe a bit high, maybe a bit low
const MAX_AGE_MS = 10 * 60 * 1000;
// > "light-dark(oklab(000, 000, 000), oklab(255, 255, 255))".length
// 54
const MAX_COLOR_LEN = 512;
const colors: Record<
string,
{ color: string | undefined; last_checked: Date }
> = {};
const dom_parser = new DOMParser();
function parse_color(str: string): string | undefined {
const text = str.replace(/^#/, "");
if (text.startsWith("name-color:")) {
const line = text.split("\n", 1)[0];
const color = line.split("name-color:")[1]
.trim()
.slice(0, MAX_COLOR_LEN)
.replaceAll(/[;{}"']|\/\*|\*\//g, "");
if (is_valid_color(color)) {
return color;
} else {
console.log(`invalid color!!!! ${color}`);
}
}
}
async function get_name_color(name: string): Promise<string | undefined> {
console.log(`fetching ${name}...`);
const resp = await fetch(`https://cohost.org/${name}`);
if (!resp.ok) {
console.log(`fetching https://cohost.org/${name} failed!`);
return;
}
const body = await resp.text();
const dom = dom_parser.parseFromString(body, "text/html");
if (!dom) {
console.log(`parsing https://cohost.org/${name} to the dom failed!`);
return;
}
const a = dom.querySelector("a[href*='name-color:']");
if (a) {
const href = a.getAttribute("href");
if (href) {
const color = parse_color(href);
if (color) return color;
}
}
for (const p of dom.querySelectorAll("p")) {
if (!p.textContent.includes("name-color:")) continue;
for (const node of p.childNodes) {
const color = parse_color(node.textContent);
if (color) return color;
}
}
}
async function update_name_color(name: string) {
const now = new Date();
if (
colors[name] &&
now.getTime() - colors[name].last_checked.getTime() <= MAX_AGE_MS
) {
return;
}
const color = await get_name_color(name);
colors[name] = { color, last_checked: now };
}
function cssify({ requester }: { requester?: string }): string {
const preamble = `/* customized: ${
Object.keys(colors)
.filter((name) => colors[name].color)
.sort()
.join(", ")
} */\n/* look, i don't like !important either, but i think it's a better choice than some lame .spec.ific.ity.hack.ing */\n\n`;
let vars = `:root {\n`;
if (requester && colors[requester]) {
vars += `--name-color: var(--name-color-${requester.toLowerCase()});\n`;
}
let classes = "";
for (const name of Object.keys(colors).sort()) {
const { color } = colors[name];
if (!color) continue;
vars += `--name-color-${name.toLowerCase()}: ${color};\n`;
classes +=
`a[href$='/${name}' i]{color: var(--name-color-${name.toLowerCase()}) !important;}\n`;
}
vars += "}\n\n";
return preamble + vars + classes;
}
Deno.serve({ port: 61266 }, async (req) => {
const url = new URL(req.url);
const names = url.searchParams.getAll("name").filter((name) =>
!name.match(/[\/\\?"';{}]/)
).map((name) => name.toLowerCase());
await Promise.all(names.map(update_name_color));
const css = cssify({
requester: url.searchParams.get("requester") ?? undefined,
});
return new Response(css, { headers: { "content-type": "text/css" } });
});