@ansvar/singapore-law-mcp/dist/api/mcp.js

Complete Singapore law database — 523 Acts, 28K+ provisions from Singapore Statutes Online (sso.agc.gov.sg) with full-text search, definitions, and citation support

import { Server } from '@modelcontextprotocol/sdk/server/index.js';
import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/streamableHttp.js';
import Database from '@ansvar/mcp-sqlite';
import { join } from 'path';
import { copyFileSync, existsSync, readFileSync, rmSync, statSync, writeFileSync } from 'fs';
import { createHash } from 'crypto';
import { registerTools } from '../src/tools/registry.js';
import { DB_ENV_VAR, SERVER_NAME, SERVER_VERSION, } from '../src/constants.js';
const SOURCE_DB = process.env[DB_ENV_VAR]
    || join(process.cwd(), 'data', 'database.db');
const TMP_DB = '/tmp/database.db';
const TMP_DB_LOCK = '/tmp/database.db.lock';
const TMP_DB_SHM = '/tmp/database.db-shm';
const TMP_DB_WAL = '/tmp/database.db-wal';
const TMP_DB_META = '/tmp/database.db.meta.json';
let db = null;
function computeSourceSignature() {
    const stats = statSync(SOURCE_DB);
    return `${stats.size}:${Math.trunc(stats.mtimeMs)}`;
}
function readTmpMeta() {
    if (!existsSync(TMP_DB_META))
        return null;
    try {
        const parsed = JSON.parse(readFileSync(TMP_DB_META, 'utf-8'));
        if (parsed.source_db && parsed.source_signature) {
            return { source_db: parsed.source_db, source_signature: parsed.source_signature };
        }
    }
    catch {
        // Ignore corrupted metadata
    }
    return null;
}
function clearTmpDbArtifacts() {
    rmSync(TMP_DB_LOCK, { recursive: true, force: true });
    rmSync(TMP_DB_SHM, { force: true });
    rmSync(TMP_DB_WAL, { force: true });
    rmSync(TMP_DB, { force: true });
    rmSync(TMP_DB_META, { force: true });
}
function ensureTempDbIsFresh() {
    const sourceSignature = computeSourceSignature();
    const meta = readTmpMeta();
    const shouldRefresh = !existsSync(TMP_DB) || !meta || meta.source_db !== SOURCE_DB || meta.source_signature !== sourceSignature;
    if (shouldRefresh) {
        clearTmpDbArtifacts();
        copyFileSync(SOURCE_DB, TMP_DB);
        writeFileSync(TMP_DB_META, JSON.stringify({ source_db: SOURCE_DB, source_signature: sourceSignature }), 'utf-8');
        return;
    }
    rmSync(TMP_DB_LOCK, { recursive: true, force: true });
}
function computeAboutContext() {
    let fingerprint = 'unknown';
    let dbBuilt = 'unknown';
    try {
        const buf = readFileSync(SOURCE_DB);
        fingerprint = createHash('sha256').update(buf).digest('hex').slice(0, 12);
    }
    catch { /* ignore */ }
    try {
        const database = getDatabase();
        const row = database.prepare("SELECT value FROM db_metadata WHERE key = 'built_at'").get();
        if (row?.value)
            dbBuilt = row.value;
    }
    catch { /* ignore */ }
    return { version: SERVER_VERSION, fingerprint, dbBuilt };
}
function getDatabase() {
    if (!db) {
        ensureTempDbIsFresh();
        db = new Database(TMP_DB, { readonly: true });
        db.pragma('foreign_keys = ON');
    }
    return db;
}
export default async function handler(req, res) {
    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, DELETE, OPTIONS');
    res.setHeader('Access-Control-Allow-Headers', 'Content-Type, mcp-session-id');
    res.setHeader('Access-Control-Expose-Headers', 'mcp-session-id');
    if (req.method === 'OPTIONS') {
        res.status(204).end();
        return;
    }
    if (req.method === 'GET') {
        res.status(200).json({
            name: SERVER_NAME,
            version: SERVER_VERSION,
            protocol: 'mcp-streamable-http',
        });
        return;
    }
    try {
        if (!existsSync(SOURCE_DB)) {
            res.status(500).json({ error: `Database not found at ${SOURCE_DB}` });
            return;
        }
        const database = getDatabase();
        const server = new Server({ name: SERVER_NAME, version: SERVER_VERSION }, { capabilities: { tools: {} } });
        registerTools(server, database, computeAboutContext());
        const transport = new StreamableHTTPServerTransport({
            sessionIdGenerator: undefined,
            enableJsonResponse: true,
        });
        await server.connect(transport);
        await transport.handleRequest(req, res, req.body);
    }
    catch (err) {
        const message = err instanceof Error ? err.message : String(err);
        console.error('MCP handler error:', message);
        if (!res.headersSent) {
            res.status(500).json({ error: message });
        }
    }
}
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