agent-base 6.0.2

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:npm/agent-base@6.0.2
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/agent-base@6.0.2
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:b4dbc685ccfcab69af22e2e984049ada7c9bedbe5e277f46e370034d68ce13b9","constraints":{"executionContext":"node"},"contract":["createAgent wraps a synchronous or Promise-returning socket callback into an http.Agent compatible instance","Agent routes HTTP requests through custom sockets created by async callbacks","Agent supports 3-argument legacy style callback (req, opts, cb) with error and socket resolution","Agent delegates request handling when the callback returns another http.Agent instance","Agent emits ETIMEOUT on the request when the callback does not produce a socket within the specified timeout","Agent defaultPort and protocol getters dynamically reflect secureEndpoint state unless explicitly overridden"],"goal":"verify pkg:npm/agent-base@6.0.2","kind":"HOW","packages":["pkg:npm/agent-base@6.0.2"],"schemaVersion":1},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/agent-base@6.0.2"],"schemaVersion":1,"subject":"pkg:npm/agent-base@6.0.2","verifierAdapter":"node-typescript@1"}

{
  "name": "sample-agent-base",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-agent-base",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "agent-base": "6.0.2"
      }
    },
    "node_modules/agent-base": {
      "version": "6.0.2",
      "resolved": "https://registry.npmjs.org/agent-base/-/agent-base-6.0.2.tgz",
      "integrity": "sha512-RZNwNclF7+MS/8bDg70amg32dyeZGZxiDuQmZxKLAlQjr3jGyLx+4Kkk58UO7D2QdgFIQCovuSuZESne6RG6XQ==",
      "license": "MIT",
      "dependencies": {
        "debug": "4"
      },
      "engines": {
        "node": ">= 6.0.0"
      }
    },
    "node_modules/debug": {
      "version": "4.4.3",
      "resolved": "https://registry.npmjs.org/debug/-/debug-4.4.3.tgz",
      "integrity": "sha512-RGwwWnwQvkVfavKVt22FGLw+xYSdzARwm0ru6DhTVA3umU5hZc28V3kO4stgYryrTlLpuvgI9GiijltAjNbcqA==",
      "license": "MIT",
      "dependencies": {
        "ms": "^2.1.3"
      },
      "engines": {
        "node": ">=6.0"
      },
      "peerDependenciesMeta": {
        "supports-color": {
          "optional": true
        }
      }
    },
    "node_modules/ms": {
      "version": "2.1.3",
      "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.3.tgz",
      "integrity": "sha512-6FlzubTLZG3J2a/NVCAleEhjzq5oxgHyaCU9yYXvcLsvoVaHJq/s5xXI6/XXP6tz7R9xAOtHnSO/tXtF3WRTlA==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-agent-base",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification of agent-base",
  "main": "src/index.js",
  "license": "MIT-0",
  "dependencies": {
    "agent-base": "6.0.2"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/agent-base@6.0.2",
  "kind": "HOW",
  "packages": [
    "pkg:npm/agent-base@6.0.2"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

const createAgent = require('agent-base');
const { Agent } = createAgent;

/**
 * Creates a custom HTTP/HTTPS agent from a socket-producing callback.
 *
 * @param {Function} callback - Function(req, opts) returning a Duplex stream or Promise<Duplex>
 * @param {Object} [options] - Agent options such as timeout
 * @returns {Agent} Agent instance
 */
function createCustomAgent(callback, options) {
  return createAgent(callback, options);
}

/**
 * Custom agent class extending agent-base Agent with configurable default ports/protocols.
 */
class ConfigurableAgent extends Agent {
  constructor(callback, options = {}) {
    super(callback, options);
    if (options.defaultPort) {
      this.defaultPort = options.defaultPort;
    }
    if (options.protocol) {
      this.protocol = options.protocol;
    }
  }
}

module.exports = {
  createAgent,
  Agent,
  createCustomAgent,
  ConfigurableAgent
};

import assert from 'node:assert';
import http from 'node:http';
import net from 'node:net';
import { Duplex } from 'node:stream';
import { createRequire } from 'node:module';

const require = createRequire(import.meta.url);
const {
  createAgent,
  Agent,
  createCustomAgent,
  ConfigurableAgent
} = require('../src/index.js');

async function runContract() {
  const server = http.createServer((req, res) => {
    res.writeHead(200, { 'Content-Type': 'text/plain', 'X-Path': req.url });
    res.end(`echo:${req.url}`);
  });

  await new Promise((resolve) => server.listen(0, '127.0.0.1', resolve));
  const port = server.address().port;

  try {
    // 1. createAgent wraps a synchronous or Promise-returning socket callback into an http.Agent compatible instance
    const syncAgent = createAgent((req, opts) => {
      return net.connect(opts.port, opts.host);
    });
    assert.strictEqual(typeof syncAgent.addRequest, 'function', 'Agent must implement addRequest');
    assert(syncAgent instanceof Agent, 'Agent must be an instance of Agent');

    // 2. Agent routes HTTP requests through custom sockets created by async callbacks
    let asyncConnected = false;
    const asyncAgent = createCustomAgent(async (req, opts) => {
      await new Promise((r) => setTimeout(r, 10));
      asyncConnected = true;
      return net.connect(opts.port, opts.host);
    });

    const res1 = await new Promise((resolve, reject) => {
      const req = http.get(
        {
          host: '127.0.0.1',
          port: port,
          path: '/test-async',
          agent: asyncAgent
        },
        (res) => {
          let body = '';
          res.on('data', (chunk) => (body += chunk));
          res.on('end', () => resolve({ status: res.statusCode, body }));
        }
      );
      req.on('error', reject);
    });
    assert.strictEqual(asyncConnected, true, 'Async callback must be executed');
    assert.strictEqual(res1.status, 200, 'Response status must be 200');
    assert.strictEqual(res1.body, 'echo:/test-async', 'Response body must match');

    // 3. Agent supports 3-argument legacy style callback (req, opts, cb) with error and socket resolution
    let legacyCalled = false;
    const legacyAgent = createAgent((req, opts, cb) => {
      legacyCalled = true;
      const sock = net.connect(opts.port, opts.host, () => {
        cb(null, sock);
      });
      sock.on('error', cb);
    });

    const res2 = await new Promise((resolve, reject) => {
      const req = http.get(
        {
          host: '127.0.0.1',
          port: port,
          path: '/test-legacy',
          agent: legacyAgent
        },
        (res) => {
          let body = '';
          res.on('data', (chunk) => (body += chunk));
          res.on('end', () => resolve({ status: res.statusCode, body }));
        }
      );
      req.on('error', reject);
    });
    assert.strictEqual(legacyCalled, true, 'Legacy callback must be called');
    assert.strictEqual(res2.status, 200, 'Legacy response status must be 200');
    assert.strictEqual(res2.body, 'echo:/test-legacy', 'Legacy response body must match');

    // 4. Agent delegates request handling when the callback returns another http.Agent instance
    const standardAgent = new http.Agent();
    const delegatingAgent = createAgent((req, opts) => {
      return standardAgent;
    });

    const res3 = await new Promise((resolve, reject) => {
      const req = http.get(
        {
          host: '127.0.0.1',
          port: port,
          path: '/test-delegate',
          agent: delegatingAgent
        },
        (res) => {
          let body = '';
          res.on('data', (chunk) => (body += chunk));
          res.on('end', () => resolve({ status: res.statusCode, body }));
        }
      );
      req.on('error', reject);
    });
    assert.strictEqual(res3.status, 200, 'Delegated agent response status must be 200');
    assert.strictEqual(res3.body, 'echo:/test-delegate', 'Delegated agent response body must match');
    standardAgent.destroy();

    // 5. Agent emits ETIMEOUT on the request when the callback does not produce a socket within the specified timeout
    let timerId;
    const timeoutAgent = createAgent(
      () =>
        new Promise((resolve) => {
          timerId = setTimeout(() => {
            const dummy = new Duplex({
              read() {},
              write(chunk, enc, cb) {
                cb();
              }
            });
            resolve(dummy);
          }, 150);
        }),
      { timeout: 20 }
    );

    const timeoutError = await new Promise((resolve) => {
      const req = http.get(
        {
          host: '127.0.0.1',
          port: port,
          path: '/test-timeout',
          agent: timeoutAgent
        },
        () => {}
      );
      req.on('error', (err) => resolve(err));
    });
    clearTimeout(timerId);
    assert(timeoutError, 'Request must emit an error on timeout');
    assert.strictEqual(timeoutError.code, 'ETIMEOUT', 'Error code must be ETIMEOUT');

    // 6. Agent defaultPort and protocol getters dynamically reflect secureEndpoint state unless explicitly overridden
    const defaultAgent = new Agent();
    assert.strictEqual(defaultAgent.defaultPort, 80, 'Default port should be 80 for standard endpoint');
    assert.strictEqual(defaultAgent.protocol, 'http:', 'Default protocol should be http:');

    const customAgentInstance = new ConfigurableAgent(() => {}, {
      defaultPort: 8080,
      protocol: 'custom:'
    });
    assert.strictEqual(customAgentInstance.defaultPort, 8080, 'Configured defaultPort must match');
    assert.strictEqual(customAgentInstance.protocol, 'custom:', 'Configured protocol must match');

    console.log('Contract tests passed successfully.');
  } finally {
    server.close();
  }
}

runContract().catch((err) => {
  console.error('Contract test failed:', err);
  process.exit(1);
});