agent-base HTTP Agent

Create custom `http.Agent` instances by implementing a `connect()` function. This skill helps you build specialized HTTP/HTTPS agents for proxies, custom protocols, or advanced networking scenarios.

What This Skill Does

The `agent-base` module (v7.1.4) provides an abstract base class for creating custom `http.Agent` implementations. Instead of manually managing socket connections, you define a `connect()` function that creates the underlying socket. The agent handles the rest.

Key Capabilities

When to Use This

Installation

```bash

npm install agent-base

```

Instructions for AI Agent

When a user asks to create a custom HTTP agent using `agent-base`, follow these steps:

1. **Understand the Use Case**

- Ask what type of connections they need (HTTP, HTTPS, or both)

- Determine if they need proxy support, custom protocols, or special socket handling

- Check if async operations are required

2. **Create the Agent Class**

- Import `Agent` from `agent-base`

- Import necessary Node.js modules (`net`, `tls`, `http`, `https`)

- Create a class that extends `Agent`

3. **Implement the `connect()` Method**

- Accept `req` (request) and `opts` (options) parameters

- Check `opts.secureEndpoint` to determine if HTTPS is being used

- Return appropriate socket type:

- `net.Socket` for HTTP

- `tls.Socket` for HTTPS

- Another `http.Agent` instance to delegate

- Any `Duplex` stream

- Use `async` if asynchronous operations are needed

4. **Configure Agent Options**

- Set `keepAlive: true` to reuse connections

- Configure timeout, maxSockets, and other `http.Agent` options as needed

5. **Usage Pattern**

- Instantiate the agent

- Pass it as the `agent` option to `http.get()`, `http.request()`, or `https.request()`

Example: Basic HTTP/HTTPS Agent

```typescript

import * as net from 'net';

import * as tls from 'tls';

import * as http from 'http';

import { Agent } from 'agent-base';

class MyAgent extends Agent {

connect(req, opts) {

// Use TLS for HTTPS, plain TCP for HTTP

if (opts.secureEndpoint) {

return tls.connect(opts);

} else {

return net.connect(opts);

}

}

}

// Create agent with keep-alive

const agent = new MyAgent({ keepAlive: true });

// Use with HTTP request

http.get('http://nodejs.org/api/', { agent }, (res) => {

console.log('Status:', res.statusCode);

res.pipe(process.stdout);

});

```

Example: Async Agent with Custom Logic

```typescript

import { Agent } from 'agent-base';

import * as net from 'net';

class AsyncAgent extends Agent {

async connect(req, opts) {

// Perform async operations (e.g., lookup, authentication)

await someAsyncOperation();

// Return socket after async work completes

return net.connect(opts);

}

}

```

Example: Delegating Agent

```typescript

import { Agent } from 'agent-base';

import { HttpProxyAgent } from 'http-proxy-agent';

class ConditionalProxyAgent extends Agent {

connect(req, opts) {

// Use proxy for specific domains

if (opts.host.includes('example.com')) {

const proxy = new HttpProxyAgent('http://proxy.corp.com:8080');

return proxy;

}

// Direct connection otherwise

return net.connect(opts);

}

}

```

Common Subclasses

Users may want to know about existing implementations:

Important Notes

Constraints