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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210// email worker for comments. cloudflare email routing hands it everything// sent to reply@replies.danieldaum.net. each message goes through the checks// below in order; a good one is saved (live, or held if it has a link) and// daniel gets an email with a link to approve or delete it.//// a fixable mistake (bad subject, empty body) bounces so the sender knows.// anything that looks like abuse is dropped silently, since a bounce would// go to whoever's address was forged.//// the sender's address is used for the author check and then forgotten:// it is never stored, hashed or logged.
import PostalMime from "postal-mime";import { EmailMessage } from "cloudflare:email";import { hmacHex } from "../../../functions/_lib/hmac.js";import { isLikeable } from "../../../functions/_lib/likes.js";
const SITE_URL = "https://danieldaum.net";const AUTHOR = "daniel@danieldaum.net";const NOTIFY_FROM = "notify@replies.danieldaum.net";
// "re: https://danieldaum.net/now/sep-2026/" with an optional// "#comment-<id>" when replying to a comment. mail apps may add more "re:"sconst SUBJECT_RE = /^\s*(?:re:\s*)*https:\/\/danieldaum\.net(\/[a-z0-9\/-]*)(?:#comment-([0-9a-f-]{36}))?\s*$/i;
const MAX_PER_HOUR = 20;const MAX_BODY = 2000;const MAX_LINKS = 2;const MAX_NAME = 40;
export default { async email(message, env) { // 1. the mail really comes from the domain it claims const auth = (message.headers.get("Authentication-Results") || "").toLowerCase(); if (!auth.includes("dkim=pass") || !(auth.includes("spf=pass") || auth.includes("dmarc=pass"))) { console.log("drop: failed authentication"); return; }
// 2. site-wide cap, counted from rows only, nothing per sender const since = new Date(Date.now() - 60 * 60 * 1000).toISOString(); const recent = await env.DB.prepare("SELECT COUNT(*) AS n FROM Comments WHERE created_at > ?").bind(since).first(); if (recent.n >= MAX_PER_HOUR) { console.log("drop: hourly cap reached"); return; }
const email = await PostalMime.parse(message.raw);
// 3. subject names a real post. /now/ itself is excluded because it // moves to a new edition; comments belong to the edition const match = (email.subject || "").match(SUBJECT_RE); const page = match ? match[1].toLowerCase() : ""; if (!isLikeable(page) || page === "/now/" || !(await pageExists(env, page))) { message.setReject("Please use the reply link on the post, so the subject is the post's address"); return; }
// 4. a reply to a comment hangs under that comment's top-level // comment (one level of nesting). unknown ids become top-level const parent = match[2] ? await topLevelParent(env, match[2].toLowerCase(), page) : null;
// 5. the text itself, without quoted mail or signatures. everyone // but daniel (proven by dmarc) picks their own name const { name, body } = cleanBody(email); const from = (email.from?.address || "").trim().toLowerCase(); const isAuthor = from === AUTHOR && auth.includes("dmarc=pass"); if (!name && !isAuthor) { message.setReject(`Please start your comment with a line like "name: sam". That name is shown with your comment`); return; } if (body.length < 2 || body.length > MAX_BODY) { message.setReject(`Comments must be between 2 and ${MAX_BODY} characters`); return; } const links = (body.match(/https?:\/\//g) || []).length; if (links > MAX_LINKS) { message.setReject(`Comments can have at most ${MAX_LINKS} links`); return; }
// 6. plain comments go live at once. links are what spam is for, so // a comment with one waits for approval. daniel's are always live const approved = isAuthor || links === 0;
const id = crypto.randomUUID(); const shownName = isAuthor ? "daniel" : name; await env.DB .prepare( "INSERT INTO Comments (id, page, parent, name, body, is_author, approved, created_at) VALUES (?, ?, ?, ?, ?, ?, ?, ?)" ) .bind(id, page, parent, shownName, body, isAuthor ? 1 : 0, approved ? 1 : 0, new Date().toISOString()) .run();
// 7. tell daniel about every comment, his own included, so each one // has a delete link. the comment is already saved, so a failure // here only logs try { const sig = await hmacHex(env.SOCIAL_SECRET, "moderate:" + id); const raw = notification({ page, id, name: shownName, body, approved, link: `${env.SITE_ORIGIN || SITE_URL}/api/moderate?id=${id}&sig=${sig}` }); await env.NOTIFY.send(new EmailMessage(NOTIFY_FROM, AUTHOR, raw)); } catch (err) { console.log("notify failed: " + (err?.message || err)); } },};
// ===== checks =====
// SITE_ORIGIN is for local testing only (.dev.vars): it points the page// check and the moderation link at wrangler pages dev instead of the live siteasync function pageExists(env, page) { try { const res = await fetch((env.SITE_ORIGIN || SITE_URL) + page, { method: "HEAD" }); return res.status === 200; } catch { return false; }}
async function topLevelParent(env, id, page) { const row = await env.DB.prepare("SELECT page, parent FROM Comments WHERE id = ? AND approved = 1").bind(id).first(); if (!row || row.page !== page) { return null; } return row.parent || id;}
// ===== text =====
// plain text with quoted history and signatures cut off. a "name: ..."// first line sets the display name (empty if missing).// stored as plain text, escaped when the page is renderedfunction cleanBody(email) { const text = (email.text?.trim() ? email.text : htmlToText(email.html || "")).replace(/\r\n?/g, "\n"); const lines = text.split("\n");
let name = ""; const kept = []; for (let i = 0; i < lines.length; i++) { const line = lines[i].trimEnd(); const t = line.trim();
// where the previous message or a signature starts. gmail can wrap // "On <date> <name> wrote:" over two lines if ( /^On\s.*wrote:$/.test(t) || (/^On\s/.test(t) && /wrote:$/.test((lines[i + 1] || "").trim())) || /^-{2,}\s*(original|forwarded) message/i.test(t) || /^From:\s/.test(t) || /^_{5,}$/.test(t) || t === "--" || /reply above this line/i.test(t) || /^sent from my /i.test(t) ) { break; } if (t.startsWith(">")) { continue; } const nameLine = t.match(/^name:\s*(.*)$/i); if (nameLine && !name && !kept.some((k) => k.trim())) { name = nameLine[1]; continue; } kept.push(line); }
name = name.replace(/[\x00-\x1f\x7f]/g, "").replace(/\s+/g, " ").trim().slice(0, MAX_NAME); const body = kept.join("\n").replace(/\n{3,}/g, "\n\n").trim(); return { name, body };}
function htmlToText(html) { return html .replace(/<(script|style)[\s\S]*?<\/\1>/gi, "") .replace(/<br\s*\/?>/gi, "\n") .replace(/<\/(p|div|li|blockquote|h[1-6]|tr)>/gi, "\n") .replace(/<[^>]+>/g, "") .replace(/ /g, " ") .replace(/</g, "<") .replace(/>/g, ">") .replace(/"/g, "\"") .replace(/'/g, "'") .replace(/&/g, "&");}
// ===== notification =====
// a minimal plain-text email, built by hand. its reply-to and subject make// hitting reply post an answer under the comment. the marker line keeps the// quoted notification (and its moderation link) out of that answerfunction notification({ page, id, name, body, approved, link }) { const headers = [ `From: ${NOTIFY_FROM}`, `To: ${AUTHOR}`, `Reply-To: reply@replies.danieldaum.net`, `Subject: re: ${SITE_URL}${page}#comment-${id}`, `Date: ${new Date().toUTCString().replace(/GMT$/, "+0000")}`, `Message-ID: <${crypto.randomUUID()}@replies.danieldaum.net>`, `MIME-Version: 1.0`, `Content-Type: text/plain; charset=utf-8`, `Content-Transfer-Encoding: 8bit`, ]; const status = approved ? "It is live." : "It has a link, so it is waiting for approval."; const action = approved ? "Delete" : "Approve or delete"; const text = [`## reply above this line to answer on the site ##`, ``, `${name} commented on ${page}:`, ``, body, ``, status, `${action}: ${link}`, ``].join("\n"); return headers.join("\r\n") + "\r\n\r\n" + text.replace(/\n/g, "\r\n");}