Arcrun/.component-builds/kbdb_get/src/index.ts

/**
 * arcrun WASM 零件 Worker (kbdb_get)
 *
 * POST / → JSON input → WASM (WASI preview1 stdin/stdout) → JSON output
 *
 * host function: http_request（用於呼叫 KBDB API）
 * SDD: polaris/mira/.agents/specs/mira-app/design.md §6 / tasks.md §5.3
 */

import componentWasm from '../component.wasm' assert { type: 'webassembly' };
import { Hono } from 'hono';
import { cors } from 'hono/cors';
import { createWasiShim, type WasiHostFunctions } from '../../../cypher-executor/src/lib/wasi-shim';

const app = new Hono();
app.use('*', cors());

app.get('/', (c) => c.json({ ok: true, component: 'kbdb_get' }));

app.post('/', async (c) => {
  let input: unknown;
  try {
    input = await c.req.json();
  } catch {
    return c.json({ success: false, error: 'request body must be JSON' }, 400);
  }

  try {
    const result = await runWasm(input);
    return c.json(result);
  } catch (e) {
    return c.json(
      { success: false, error: e instanceof Error ? e.message : String(e) },
      500,
    );
  }
});

export default app;

// ── WASM runner ──────────────────────────────────────────────────────────────

async function runWasm(input: unknown): Promise<unknown> {
  const hostFunctions: WasiHostFunctions = {
    http_request: async (url, method, headersJson, body) => {
      const headers: Record<string, string> = {};
      if (headersJson) {
        try {
          const parsed = JSON.parse(headersJson);
          if (parsed && typeof parsed === 'object') {
            for (const [k, v] of Object.entries(parsed as Record<string, unknown>)) {
              if (typeof v === 'string') headers[k] = v;
            }
          }
        } catch {
          // ignore header parse errors
        }
      }
      const init: RequestInit = { method, headers };
      if (body && method.toUpperCase() !== 'GET' && method.toUpperCase() !== 'HEAD') {
        init.body = body;
      }
      const res = await fetch(url, init);
      return await res.text();
    },
  };

  const shim = createWasiShim(JSON.stringify(input), hostFunctions);

  const instance = await WebAssembly.instantiate(
    componentWasm as WebAssembly.Module,
    shim.imports,
  );
  shim.setMemory(instance.exports.memory as WebAssembly.Memory);
  await shim.run(instance);

  const stdout = shim.getStdout().trim();
  const stderr = shim.getStderr().trim();
  if (stderr) console.error('[kbdb_get wasm stderr]', stderr);
  if (!stdout) throw new Error('WASM component produced no output');
  return JSON.parse(stdout);
}