Create Discord interactions endpoint for Vercel

cgen-86b60601b92648caaef781c7bc6ae941

api/discord/interactions.ts

@@ -0,0 +1,69 @@
+import { VercelRequest, VercelResponse } from "@vercel/node";
+import { createVerify } from "crypto";
+
+export default function handler(req: VercelRequest, res: VercelResponse) {
+  // Only accept POST requests
+  if (req.method !== "POST") {
+    res.setHeader("Allow", "POST");
+    return res.status(405).json({ error: "Method not allowed" });
+  }
+
+  try {
+    const signature = req.headers["x-signature-ed25519"] as string;
+    const timestamp = req.headers["x-signature-timestamp"] as string;
+    const publicKey = process.env.DISCORD_PUBLIC_KEY;
+
+    console.log("[Discord] Interaction received at", new Date().toISOString());
+
+    if (!publicKey) {
+      console.error("[Discord] DISCORD_PUBLIC_KEY not set");
+      return res.status(401).json({ error: "Server not configured" });
+    }
+
+    if (!signature || !timestamp) {
+      console.error(
+        "[Discord] Missing headers - signature:",
+        !!signature,
+        "timestamp:",
+        !!timestamp,
+      );
+      return res.status(401).json({ error: "Invalid request" });
+    }
+
+    // Get raw body
+    const rawBody =
+      typeof req.body === "string"
+        ? req.body
+        : JSON.stringify(req.body);
+
+    // Verify signature
+    const message = `${timestamp}${rawBody}`;
+    const signatureBuffer = Buffer.from(signature, "hex");
+    const verifier = createVerify("ed25519");
+    verifier.update(message);
+    const isValid = verifier.verify(publicKey, signatureBuffer);
+
+    if (!isValid) {
+      console.error("[Discord] Signature verification failed");
+      return res.status(401).json({ error: "Invalid signature" });
+    }
+
+    const interaction = typeof req.body === "string" ? JSON.parse(req.body) : req.body;
+    console.log("[Discord] Valid interaction type:", interaction.type);
+
+    // Discord sends a PING to verify the endpoint
+    if (interaction.type === 1) {
+      console.log("[Discord] ✓ PING verified");
+      return res.json({ type: 1 });
+    }
+
+    // For all other interactions, acknowledge them
+    return res.json({
+      type: 4,
+      data: { content: "Interaction received" },
+    });
+  } catch (err: any) {
+    console.error("[Discord] Error:", err?.message);
+    return res.status(500).json({ error: "Server error" });
+  }
+}