golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4: httpproxy.Config, httpproxy.FromEnvironment

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@v0.0.0-20210405180319-a5a99cb37ef4
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4

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:sha256:9c48957fb87105973936e5ec2b61331f5a5c2523068bded2ad60ab0fd3033eda","contract":["httpproxy.Config.ProxyFunc routes HTTP and HTTPS URLs to configured proxy endpoints while bypassing destinations matching NoProxy patterns","httpproxy.FromEnvironment initializes proxy configuration from HTTP_PROXY, HTTPS_PROXY, and NO_PROXY environment variables"],"goal":"verify pkg:golang/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4"],"schemaVersion":1,"symbols":["golang.org/x/net/http/httpproxy.Config","golang.org/x/net/http/httpproxy.FromEnvironment"]},"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@v0.0.0-20210405180319-a5a99cb37ef4"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4","symbols":["golang.org/x/net/http/httpproxy.Config","golang.org/x/net/http/httpproxy.FromEnvironment"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.25.0

require golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4

require golang.org/x/text v0.3.3 // indirect

golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4 h1:4nGaVu0QrbjT/AK2PRLuQfQuh6DJve+pELhqTdAj3x0=
golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
golang.org/x/text v0.3.3 h1:cokOdA+Jmi5PJGXLlLllQSgYigAEfHXJAERHVMaCc2k=
golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

package main

import (
	"fmt"
	"log"
	"net/url"

	"golang.org/x/net/http/httpproxy"
)

func main() {
	cfg := &httpproxy.Config{
		HTTPProxy:  "http://proxy.example.com:8080",
		HTTPSProxy: "https://secure-proxy.example.com:8443",
		NoProxy:    "localhost,127.0.0.1,.internal.example.com",
	}

	proxyFunc := cfg.ProxyFunc()

	targetURL, err := url.Parse("http://api.example.com/data")
	if err != nil {
		log.Fatalf("failed to parse url: %v", err)
	}

	proxyURL, err := proxyFunc(targetURL)
	if err != nil {
		log.Fatalf("failed to determine proxy: %v", err)
	}

	if proxyURL != nil {
		fmt.Printf("Routing %s via proxy: %s\n", targetURL, proxyURL)
	} else {
		fmt.Printf("Routing %s directly (no proxy)\n", targetURL)
	}

	envCfg := httpproxy.FromEnvironment()
	fmt.Printf("Environment proxy configured: HTTP=%q, HTTPS=%q, NO_PROXY=%q\n",
		envCfg.HTTPProxy, envCfg.HTTPSProxy, envCfg.NoProxy)

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

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4"
  ]
}

package main

import (
	"fmt"
	"net/url"
	"os"

	"golang.org/x/net/http/httpproxy"
)

func main() {
	// Assertion 1: httpproxy.Config.ProxyFunc routes HTTP and HTTPS URLs to configured proxy endpoints while bypassing destinations matching NoProxy patterns
	{
		cfg := &httpproxy.Config{
			HTTPProxy:  "http://proxy.example.com:8080",
			HTTPSProxy: "https://secure-proxy.example.com:8443",
			NoProxy:    "localhost,127.0.0.1,.internal.example.com,bypass.example.org",
		}

		proxyFunc := cfg.ProxyFunc()

		testCases := []struct {
			rawURL     string
			wantProxy  string
			shouldSkip bool
		}{
			{"http://api.example.com/items", "http://proxy.example.com:8080", false},
			{"https://secure.example.com/items", "https://secure-proxy.example.com:8443", false},
			{"http://service.internal.example.com/health", "", true},
			{"https://bypass.example.org/status", "", true},
			{"http://localhost:8080/test", "", true},
			{"http://127.0.0.1:9090/metrics", "", true},
		}

		for _, tc := range testCases {
			reqURL, err := url.Parse(tc.rawURL)
			if err != nil {
				fmt.Fprintf(os.Stderr, "assertion 1 failed: could not parse url %s: %v\n", tc.rawURL, err)
				os.Exit(1)
			}

			proxyURL, err := proxyFunc(reqURL)
			if err != nil {
				fmt.Fprintf(os.Stderr, "assertion 1 failed: proxyFunc error for %s: %v\n", tc.rawURL, err)
				os.Exit(1)
			}

			if tc.shouldSkip {
				if proxyURL != nil {
					fmt.Fprintf(os.Stderr, "assertion 1 failed: expected no proxy for %s, got %s\n", tc.rawURL, proxyURL.String())
					os.Exit(1)
				}
			} else {
				if proxyURL == nil {
					fmt.Fprintf(os.Stderr, "assertion 1 failed: expected proxy %s for %s, got nil\n", tc.wantProxy, tc.rawURL)
					os.Exit(1)
				}
				if proxyURL.String() != tc.wantProxy {
					fmt.Fprintf(os.Stderr, "assertion 1 failed: expected proxy %s for %s, got %s\n", tc.wantProxy, tc.rawURL, proxyURL.String())
					os.Exit(1)
				}
			}
		}
	}

	// Assertion 2: httpproxy.FromEnvironment initializes proxy configuration from HTTP_PROXY, HTTPS_PROXY, and NO_PROXY environment variables
	{
		os.Setenv("HTTP_PROXY", "http://env-proxy.example.com:3128")
		os.Setenv("HTTPS_PROXY", "https://env-secure.example.com:3129")
		os.Setenv("NO_PROXY", "local.example.com")
		defer func() {
			os.Unsetenv("HTTP_PROXY")
			os.Unsetenv("HTTPS_PROXY")
			os.Unsetenv("NO_PROXY")
		}()

		envCfg := httpproxy.FromEnvironment()
		if envCfg.HTTPProxy != "http://env-proxy.example.com:3128" {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: expected HTTPProxy %q, got %q\n", "http://env-proxy.example.com:3128", envCfg.HTTPProxy)
			os.Exit(1)
		}
		if envCfg.HTTPSProxy != "https://env-secure.example.com:3129" {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: expected HTTPSProxy %q, got %q\n", "https://env-secure.example.com:3129", envCfg.HTTPSProxy)
			os.Exit(1)
		}
		if envCfg.NoProxy != "local.example.com" {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: expected NoProxy %q, got %q\n", "local.example.com", envCfg.NoProxy)
			os.Exit(1)
		}

		proxyFunc := envCfg.ProxyFunc()
		uBypass, err := url.Parse("http://local.example.com/api")
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: url parse error: %v\n", err)
			os.Exit(1)
		}
		pBypass, err := proxyFunc(uBypass)
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: env proxyFunc error: %v\n", err)
			os.Exit(1)
		}
		if pBypass != nil {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: expected bypass for local.example.com, got %s\n", pBypass.String())
			os.Exit(1)
		}

		uProxy, err := url.Parse("http://external.example.com/api")
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: url parse error: %v\n", err)
			os.Exit(1)
		}
		pProxy, err := proxyFunc(uProxy)
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: env proxyFunc error: %v\n", err)
			os.Exit(1)
		}
		if pProxy == nil || pProxy.String() != "http://env-proxy.example.com:3128" {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: expected proxy %q, got %v\n", "http://env-proxy.example.com:3128", pProxy)
			os.Exit(1)
		}
	}

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