golang.org/x/net v0.0.0-20220403103023-749bd193bc2b: proxy.Direct, proxy.FromEnvironment, proxy.SOCKS5

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:golang/golang.org/x/net@v0.0.0-20220403103023-749bd193bc2b
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.0.0-20220403103023-749bd193bc2b
Demonstrate these symbols/APIs:
  - golang.org/x/net/proxy.Direct
  - golang.org/x/net/proxy.FromEnvironment
  - golang.org/x/net/proxy.SOCKS5

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:sha256:4ee14d3310838579a6cbe39836d5ec2c82b60311d5bf995f9bc460b58f23ae32","contract":["proxy.Direct provides a direct network Dialer that dials network addresses without a proxy","proxy.SOCKS5 creates a SOCKS5 Dialer for a proxy address with optional authentication","proxy.FromEnvironment creates a Dialer configured from proxy environment variables"],"goal":"verify pkg:golang/golang.org/x/net@v0.0.0-20220403103023-749bd193bc2b","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.0.0-20220403103023-749bd193bc2b"],"schemaVersion":1,"symbols":["golang.org/x/net/proxy.Direct","golang.org/x/net/proxy.FromEnvironment","golang.org/x/net/proxy.SOCKS5"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/net@v0.0.0-20220403103023-749bd193bc2b"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.0.0-20220403103023-749bd193bc2b","symbols":["golang.org/x/net/proxy.Direct","golang.org/x/net/proxy.FromEnvironment","golang.org/x/net/proxy.SOCKS5"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.22

require golang.org/x/net v0.0.0-20220403103023-749bd193bc2b

golang.org/x/net v0.0.0-20220403103023-749bd193bc2b h1:vI32FkLJNAWtGD4BwkThwEy6XS7ZLLMHkSkYfF8M0W0=
golang.org/x/net v0.0.0-20220403103023-749bd193bc2b/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=

package main

import (
	"fmt"
	"log"
	"net"
	"os"

	"golang.org/x/net/proxy"
)

func main() {
	// 1. Direct dialer
	var directDialer proxy.Dialer = proxy.Direct
	fmt.Printf("Direct dialer initialized: %v\n", directDialer != nil)

	// 2. SOCKS5 dialer with authentication
	auth := &proxy.Auth{
		User:     "user",
		Password: "password",
	}
	socks5Dialer, err := proxy.SOCKS5("tcp", "127.0.0.1:1080", auth, proxy.Direct)
	if err != nil {
		log.Fatalf("failed to create SOCKS5 dialer: %v", err)
	}
	fmt.Printf("SOCKS5 dialer created: %v\n", socks5Dialer != nil)

	// 3. FromEnvironment dialer
	os.Setenv("ALL_PROXY", "socks5://127.0.0.1:1080")
	envDialer := proxy.FromEnvironment()
	fmt.Printf("Environment dialer created: %v\n", envDialer != nil)

	// 4. Dialing with Direct dialer to a local listener
	ln, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		log.Fatalf("failed to listen on local address: %v", err)
	}
	defer ln.Close()

	conn, err := proxy.Direct.Dial("tcp", ln.Addr().String())
	if err != nil {
		log.Fatalf("failed to dial local address: %v", err)
	}
	conn.Close()

	fmt.Println("golang.org/x/net/proxy sample completed successfully")
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/golang.org/x/net@v0.0.0-20220403103023-749bd193bc2b",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.0.0-20220403103023-749bd193bc2b"
  ],
  "symbols": [
    "golang.org/x/net/proxy.Direct",
    "golang.org/x/net/proxy.FromEnvironment",
    "golang.org/x/net/proxy.SOCKS5"
  ]
}

package main

import (
	"fmt"
	"net"
	"os"

	"golang.org/x/net/proxy"
)

func main() {
	// Assertion 1: proxy.Direct provides a direct network Dialer that dials network addresses without a proxy
	{
		var direct proxy.Dialer = proxy.Direct
		if direct == nil {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: proxy.Direct is nil\n")
			os.Exit(1)
		}

		ln, err := net.Listen("tcp", "127.0.0.1:0")
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: net.Listen error: %v\n", err)
			os.Exit(1)
		}
		defer ln.Close()

		conn, err := direct.Dial("tcp", ln.Addr().String())
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: direct.Dial error: %v\n", err)
			os.Exit(1)
		}
		conn.Close()
	}

	// Assertion 2: proxy.SOCKS5 creates a SOCKS5 Dialer for a proxy address with optional authentication
	{
		// SOCKS5 dialer without auth
		dNoAuth, err := proxy.SOCKS5("tcp", "127.0.0.1:1080", nil, proxy.Direct)
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: proxy.SOCKS5 without auth returned error: %v\n", err)
			os.Exit(1)
		}
		if dNoAuth == nil {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: proxy.SOCKS5 without auth returned nil dialer\n")
			os.Exit(1)
		}

		// SOCKS5 dialer with auth
		auth := &proxy.Auth{
			User:     "user",
			Password: "password",
		}
		dAuth, err := proxy.SOCKS5("tcp", "127.0.0.1:1080", auth, proxy.Direct)
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: proxy.SOCKS5 with auth returned error: %v\n", err)
			os.Exit(1)
		}
		if dAuth == nil {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: proxy.SOCKS5 with auth returned nil dialer\n")
			os.Exit(1)
		}
	}

	// Assertion 3: proxy.FromEnvironment creates a Dialer configured from proxy environment variables
	{
		os.Setenv("ALL_PROXY", "socks5://127.0.0.1:1080")
		defer os.Unsetenv("ALL_PROXY")

		envDialer := proxy.FromEnvironment()
		if envDialer == nil {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: proxy.FromEnvironment returned nil dialer\n")
			os.Exit(1)
		}
	}

	fmt.Println("All contract assertions passed.")
}