server.js

"use strict";

const express = require("express");
const { resolveNamespace } = require("./fabricConnect");
const { getCached, setCached, cacheStats } = require("./cache");

const PORT = process.env.PORT || 3000;
const DID_PREFIX = "did:rwp:";

// UUIDv4 per RWP-23 (canonical Global Namespace Identifier).
const NAMESPACE_RE =
  /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;

const app = express();
app.disable("x-powered-by");

/**
 * Extracts a namespace from either a raw namespace or a full did:rwp DID.
 * Returns null if the input is neither.
 */
function extractNamespace(id) {
  if (typeof id !== "string" || id.length === 0) return null;
  if (id.startsWith(DID_PREFIX)) {
    const namespace = id.slice(DID_PREFIX.length).split(":")[0];
    return NAMESPACE_RE.test(namespace) ? namespace : null;
  }
  return NAMESPACE_RE.test(id) ? id : null;
}

// No Fabric round-trip: cheap liveness probe for container/orchestrator health checks.
app.get("/health", (_req, res) => {
  res.json({ status: "ok", cache: cacheStats() });
});

app.get("/resolve", async (req, res) => {
  const rawId = req.query.id;
  const namespace = extractNamespace(rawId);

  if (!namespace) {
    return res.status(400).json({
      error: "Invalid id. Provide a namespace (UUIDv4) or a did:rwp:<namespace>:... identifier.",
    });
  }

  const cached = getCached(namespace);
  if (cached) {
    return res.json({
      namespace,
      resolverEndpoint: cached.resolverEndpoint,
      cacheAge: cached.ageSeconds,
    });
  }

  try {
    const result = await resolveNamespace(namespace);

    if (!result || !result.resolverEndpoint) {
      return res.status(404).json({ error: `Namespace not registered: ${namespace}` });
    }

    setCached(namespace, result.resolverEndpoint);
    return res.json({
      namespace,
      resolverEndpoint: result.resolverEndpoint,
      cacheAge: 0,
    });
  } catch (err) {
    console.error("Resolution failed:", err.message);
    return res.status(502).json({ error: "Root-resolver network unreachable or chaincode error." });
  }
});

app.use((_req, res) => res.status(404).json({ error: "Not found." }));

app.listen(PORT, () => {
  console.log(`rootresolver listening on http://localhost:${PORT}`);
});