Socket Broker

Java Socket library supporting SOCKS and HTTP proxy servers with authentication

Build Requirements

• Java 21
• Maven 3.9

Runtime Requirements

• Java 8

Versioning

Socket Broker follows the Semantic Versioning Specification 2.0.0.

The public API consists of interfaces and classes in the following Java packages:

• com.exceptionfactory.socketbroker
• com.exceptionfactory.socketbroker.configuration

Standards

Socket Broker supports client capabilities for several protocols defined in referenced standards.

SOCKS

• RFC 1928: SOCKS Protocol Version 5
• RFC 1929: Username/Password Authentication for SOCKS V5

HTTP

• RFC 7231: Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content
• RFC 7235: Hypertext Transfer Protocol (HTTP/1.1): Authentication
• RFC 7617: The 'Basic' HTTP Authentication Scheme

Building

Run the following Maven command to build the library:

./mvnw clean install

Integrating

The BrokeredSocketFactory class provides the primary point of integration for external applications.

Configuration

The BrokerConfiguration interface and StandardBrokerConfiguration class provide the proxy protocol, proxy server address, and optional authentication credentials necessary for creating a connection through a proxy server.

Proxy Type

The ProxyType enumeration defines supported protocols including SOCKS5 and HTTP_CONNECT.

Proxy Socket Address

The proxy server address must be defined using an instance of java.net.InetSocketAddress that includes the server address and port number.

Authentication Credentials

Access to proxy servers that require authentication involves configuring an instance of AuthenticationCredentials. The StandardUsernamePasswordAuthenticationCredentials class supports defining a username string and a password character array.

Socket Factory

The BrokeredSocketFactory class requires an instance of BrokerConfiguration as well as a javax.net.SocketFactory. The SocketFactory provides the opportunity to supply standard settings for the connection to the configured proxy server. The SocketFactory.getDefault() method is sufficient for standard integrations.

Alternatives

Several alternative implementations are available depending on usage requirements.

Java Socket Proxy

The java.net.Socket class can be configured using an instance of java.net.Proxy for connections to SOCKS or HTTP proxies that do not require authentication.

The standard java.net.Authenticator class supports configurable proxy authentication through the static setDefault() method. Standard Socket implementations invoke password request methods on a configured Authenticator to return instances of java.net.PasswordAuthentication. This integration approach is sufficient for applications that allow defining an instance of the Authenticator class for the Java Virtual Machine.

Netty

The Netty project provides component modules that support both SOCKS 4 and SOCKS 5 as well as HTTP. Netty does not provide a direct implementation of java.net.Socket supporting proxy connections, but applications using Netty can integrate support for proxy access using available components.

SocksLib

The SocksLib library provides client and server socket implementations for the SOCKS 5 protocol. SocksLib supports both TCP and UDP client connections.

Licensing

Socket Broker is released under the Apache License, Version 2.0.