fix(contact): send the contact form through the mail service's /v1/send/message

POST /api/contact posted { to, subject, body, replyTo } to ${mailApiUrl}/send,
which the mail service (libreshop/mail src/app.py) does not have, so every
message failed with a 500. It now posts { to_email, subject, message } to
POST /v1/send/message, still to paperwork@muellerprints.de, with the same
subject and text as before. The service sets no Reply-To; the sender's
address stays in the text. A line break in the subject is replaced by a
space, so it cannot start another mail header.

mailApiUrl was read from runtimeConfig without being declared there, so
NUXT_MAIL_API_URL could not set it and the fallback http://mail:2222 was
always used. It is declared now, with that default; mp's compose.yml sets
no NUXT_MAIL_API_URL.

contactMail and mailSendUrl (server/utils/contactMail.ts) are pure and tested.

Refs libretech/mp#71

nuxt.config.ts

@@ -29,6 +29,7 @@ export default defineNuxtConfig({
 		// Server-only (private) - never exposed to client
 		shopApiToken: "", // NUXT_SHOP_API_TOKEN
 		cmsInternalUrl: "http://cms:5555", // NUXT_CMS_INTERNAL_URL - internal docker network URL
+		mailApiUrl: "http://mail:2222", // NUXT_MAIL_API_URL - mail service (libreshop/mail) on the internal docker network
 		siteUrl: "https://muellerprints-paperwork.com", // NUXT_SITE_URL - for sitemap
 
 		// Public (client + server)

server/api/contact.post.ts

@@ -1,55 +1,18 @@
+import { contactMail, mailSendUrl } from "~/server/utils/contactMail";
+
 export default defineEventHandler(async (event) => {
-	const body = await readBody(event);
+	const result = contactMail(await readBody(event));
-
+	if (result.ok === false) {
-	const { name, email, subject, message } = body;
+		throw createError({ statusCode: 400, message: result.message });
-
-	if (!name || !email || !message) {
-		throw createError({
-			statusCode: 400,
-			message: "Name, E-Mail und Nachricht sind erforderlich",
-		});
-	}
-
-	// Validate email format
-	const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
-	if (!emailRegex.test(email)) {
-		throw createError({
-			statusCode: 400,
-			message: "Ungültige E-Mail-Adresse",
-		});
 	}
 
 	try {
-		// Send email via Mail service
 		const config = useRuntimeConfig();
-		const mailApiUrl = config.mailApiUrl || "http://mail:2222";
+		await $fetch(mailSendUrl(config.mailApiUrl || "http://mail:2222"), { method: "POST", body: result.mail });
-
-		await $fetch(`${mailApiUrl}/send`, {
-			method: "POST",
-			body: {
-				to: "paperwork@muellerprints.de",
-				subject: `Kontaktanfrage: ${subject || "Anfrage über Website"}`,
-				body: `
-Name: ${name}
-E-Mail: ${email}
-Betreff: ${subject || "Kontaktanfrage über Website"}
-
-Nachricht:
-${message}
-
----
-Diese Nachricht wurde über das Kontaktformular auf muellerprints.de gesendet.
-				`.trim(),
-				replyTo: email,
-			},
-		});
 
 		return { success: true };
 	} catch (error) {
 		console.error("Failed to send contact email:", error);
-		throw createError({
+		throw createError({ statusCode: 500, message: "E-Mail konnte nicht gesendet werden" });
-			statusCode: 500,
-			message: "E-Mail konnte nicht gesendet werden",
-		});
 	}
 });

server/utils/contactMail.ts

@@ -0,0 +1,56 @@
+// The mail of the contact form (components/ContactForm.vue → POST /api/contact). The mail service (libreshop/mail src/app.py)
+// sends it from POST /v1/send/message, whose JSON body is { to_email, subject, message, html? }. It sets no Reply-To, so the
+// sender's address is in the text. Pure: no Nuxt, Nitro or h3 imports, tested in tests/unit/contactMail.test.ts.
+
+export const CONTACT_RECIPIENT = "paperwork@muellerprints.de";
+export const MAIL_SEND_PATH = "/v1/send/message";
+
+/** The body of POST /v1/send/message. */
+export type ContactMail = { to_email: string; subject: string; message: string };
+
+/** The mail to send, or the German message of the 400 for the form. */
+export type ContactMailResult = { ok: true; mail: ContactMail } | { ok: false; message: string };
+
+const EMAIL = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
+
+const isObject = (value: unknown): value is Record<string, unknown> => typeof value === "object" && value !== null && !Array.isArray(value);
+
+const isFilled = (value: unknown): value is string => typeof value === "string" && value.trim() !== "";
+
+// A line break in the subject would end its header and start another one.
+const oneLine = (text: string): string => text.replace(/[\r\n]+/g, " ").trim();
+
+/** The URL of the mail service's send endpoint, from its base URL (runtimeConfig.mailApiUrl). */
+export const mailSendUrl = (mailApiUrl: string): string => `${mailApiUrl.replace(/\/+$/, "")}${MAIL_SEND_PATH}`;
+
+/** Checks the form's body { name, email, subject?, message } and builds the mail to the shop. */
+export const contactMail = (body: unknown): ContactMailResult => {
+	const fields: Record<string, unknown> = isObject(body) ? body : {};
+	const { name, email, subject, message } = fields;
+	if (!isFilled(name) || !isFilled(email) || !isFilled(message)) {
+		return { ok: false, message: "Name, E-Mail und Nachricht sind erforderlich" };
+	}
+	if (!EMAIL.test(email)) {
+		return { ok: false, message: "Ungültige E-Mail-Adresse" };
+	}
+
+	const topic = typeof subject === "string" ? oneLine(subject) : "";
+	return {
+		ok: true,
+		mail: {
+			to_email: CONTACT_RECIPIENT,
+			subject: `Kontaktanfrage: ${topic || "Anfrage über Website"}`,
+			message: [
+				`Name: ${name}`,
+				`E-Mail: ${email}`,
+				`Betreff: ${topic || "Kontaktanfrage über Website"}`,
+				"",
+				"Nachricht:",
+				message,
+				"",
+				"---",
+				"Diese Nachricht wurde über das Kontaktformular auf muellerprints.de gesendet."
+			].join("\n")
+		}
+	};
+};

tests/unit/contactMail.test.ts

@@ -0,0 +1,70 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { CONTACT_RECIPIENT, contactMail, mailSendUrl } from "../../server/utils/contactMail.ts";
+
+// components/ContactForm.vue posts these fields; it sends "Kontaktanfrage über Website" when the subject is left empty.
+const form = {
+	name: "Erika Mustermann",
+	email: "erika@example.org",
+	subject: "Notizbuch mit Firmenlogo",
+	message: "Hallo,\nkönnt ihr 50 Stück liefern?"
+};
+
+const required = { ok: false, message: "Name, E-Mail und Nachricht sind erforderlich" };
+
+test("sends to the mail service's /v1/send/message", () => {
+	assert.equal(mailSendUrl("http://mail:2222"), "http://mail:2222/v1/send/message");
+	assert.equal(mailSendUrl("http://mail:2222/"), "http://mail:2222/v1/send/message");
+});
+
+test("builds the body the mail service reads: to_email, subject and message", () => {
+	assert.deepEqual(contactMail(form), {
+		ok: true,
+		mail: {
+			to_email: "paperwork@muellerprints.de",
+			subject: "Kontaktanfrage: Notizbuch mit Firmenlogo",
+			message: [
+				"Name: Erika Mustermann",
+				"E-Mail: erika@example.org",
+				"Betreff: Notizbuch mit Firmenlogo",
+				"",
+				"Nachricht:",
+				"Hallo,\nkönnt ihr 50 Stück liefern?",
+				"",
+				"---",
+				"Diese Nachricht wurde über das Kontaktformular auf muellerprints.de gesendet."
+			].join("\n")
+		}
+	});
+	assert.equal(CONTACT_RECIPIENT, "paperwork@muellerprints.de");
+});
+
+test("fills in the subject when the form sends none", () => {
+	for (const subject of [undefined, "", "  "]) {
+		const result = contactMail({ ...form, subject });
+
+		assert.equal(result.ok && result.mail.subject, "Kontaktanfrage: Anfrage über Website");
+		assert.equal(result.ok && result.mail.message.split("\n")[2], "Betreff: Kontaktanfrage über Website");
+	}
+});
+
+test("keeps a line break in the subject from starting another mail header", () => {
+	const result = contactMail({ ...form, subject: "Frage\r\nBcc: someone@example.org\nX-Spam: yes" });
+
+	assert.equal(result.ok && result.mail.subject, "Kontaktanfrage: Frage Bcc: someone@example.org X-Spam: yes");
+});
+
+test("requires a name, an e-mail address and a message", () => {
+	for (const field of ["name", "email", "message"]) {
+		assert.deepEqual(contactMail({ ...form, [field]: undefined }), required, field);
+		assert.deepEqual(contactMail({ ...form, [field]: " " }), required, field);
+		assert.deepEqual(contactMail({ ...form, [field]: ["a"] }), required, field);
+	}
+	for (const body of [undefined, null, "name=Erika", [form]]) assert.deepEqual(contactMail(body), required);
+});
+
+test("rejects an invalid e-mail address", () => {
+	for (const email of ["erika", "erika@example", "erika @example.org", "@example.org"]) {
+		assert.deepEqual(contactMail({ ...form, email }), { ok: false, message: "Ungültige E-Mail-Adresse" }, email);
+	}
+});