First commit

README.md

@@ -0,0 +1,11 @@
+# GoLangProxy
+- simple application written in go lang for proxing http and https with built in self signed certificate function.
+
+### setup project
+go mod init proxy
+
+### Running Proxy app without compiling.
+go run main.go config.go certificate.go proxy.go utils.go
+
+### Building app:
+go build -o proxy

certificate.go

@@ -0,0 +1,125 @@
+package main
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/tls"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+	"fmt"
+	"log"
+	"math/big"
+	"os"
+	"time"
+)
+
+func generateSelfSignedCert() error {
+	if err := os.MkdirAll(certDir, 0755); err != nil {
+		return fmt.Errorf("failed to create certificate directory %s: %v", certDir, err)
+	}
+
+	priv, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		return fmt.Errorf("failed to generate private key: %v", err)
+	}
+
+	notBefore := time.Now()
+	notAfter := notBefore.Add(365 * 24 * time.Hour)
+	serialNumber, err := rand.Int(rand.Reader, new(big.Int).Lsh(big.NewInt(1), 128))
+	if err != nil {
+		return fmt.Errorf("failed to generate serial number: %v", err)
+	}
+
+	template := x509.Certificate{
+		SerialNumber: serialNumber,
+		Subject: pkix.Name{
+			Organization: []string{"Proxy Self-Signed"},
+			CommonName:   "localhost",
+		},
+		NotBefore:             notBefore,
+		NotAfter:              notAfter,
+		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
+		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
+		BasicConstraintsValid: true,
+		DNSNames:              []string{"localhost", "*.example.com"},
+	}
+
+	certDER, err := x509.CreateCertificate(rand.Reader, &template, &template, &priv.PublicKey, priv)
+	if err != nil {
+		return fmt.Errorf("failed to create certificate: %v", err)
+	}
+
+	certOut, err := os.Create(certPath)
+	if err != nil {
+		return fmt.Errorf("failed to open %s for writing: %v", certPath, err)
+	}
+	if err := pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: certDER}); err != nil {
+		certOut.Close()
+		return fmt.Errorf("failed to encode certificate: %v", err)
+	}
+	certOut.Close()
+
+	keyOut, err := os.OpenFile(keyPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		return fmt.Errorf("failed to open %s for writing: %v", keyPath, err)
+	}
+	if err := pem.Encode(keyOut, &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(priv)}); err != nil {
+		keyOut.Close()
+		return fmt.Errorf("failed to encode private key: %v", err)
+	}
+	keyOut.Close()
+
+	log.Printf("Generated self-signed certificate in %s", certDir)
+	return nil
+}
+
+func loadCertificate() error {
+	certFile, err := os.ReadFile(certPath)
+	if err != nil {
+		return fmt.Errorf("failed to read certificate %s: %v", certPath, err)
+	}
+	keyFile, err := os.ReadFile(keyPath)
+	if err != nil {
+		return fmt.Errorf("failed to read key %s: %v", keyPath, err)
+	}
+
+	newCert, err := tls.X509KeyPair(certFile, keyFile)
+	if err != nil {
+		return fmt.Errorf("failed to parse certificate: %v", err)
+	}
+
+	configMux.Lock()
+	cert = &newCert
+	configMux.Unlock()
+	return nil
+}
+
+func monitorCertificates() {
+	var lastModTime time.Time
+	for {
+		certInfo, err := os.Stat(certPath)
+		if err != nil {
+			log.Printf("Error checking certificate: %v", err)
+			time.Sleep(5 * time.Second)
+			continue
+		}
+
+		keyInfo, err := os.Stat(keyPath)
+		if err != nil {
+			log.Printf("Error checking key: %v", err)
+			time.Sleep(5 * time.Second)
+			continue
+		}
+
+		if certInfo.ModTime() != lastModTime || keyInfo.ModTime() != lastModTime {
+			if err := loadCertificate(); err != nil {
+				log.Printf("Error reloading certificate: %v", err)
+			} else {
+				log.Println("Certificate reloaded successfully")
+				lastModTime = certInfo.ModTime()
+			}
+		}
+		time.Sleep(5 * time.Second)
+	}
+}

config.go

@@ -0,0 +1,154 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"time"
+
+	"gopkg.in/yaml.v2"
+)
+
+type Config struct {
+	ListenHTTP      string            `yaml:"listen_http"`
+	ListenHTTPS     string            `yaml:"listen_https"`
+	CertDir         string            `yaml:"cert_dir"`
+	CertFile        string            `yaml:"cert_file"`
+	KeyFile         string            `yaml:"key_file"`
+	Routes          map[string]string `yaml:"routes"`
+	TrustTarget     map[string]bool   `yaml:"trust_target"`
+	NoHTTPSRedirect map[string]bool   `yaml:"no_https_redirect"` // New field
+}
+
+func loadConfig() (Config, error) {
+	data, err := os.ReadFile(configPath)
+	if err != nil {
+		return Config{}, fmt.Errorf("failed to read config %s: %v", configPath, err)
+	}
+
+	var cfg Config
+	err = yaml.Unmarshal(data, &cfg)
+	if err != nil {
+		return Config{}, fmt.Errorf("failed to unmarshal config: %v", err)
+	}
+	return cfg, nil
+}
+
+func generateDefaultConfig() Config {
+	return Config{
+		ListenHTTP:  ":80",
+		ListenHTTPS: ":443",
+		CertDir:     "./certificates", // default current directory creates certificates folder
+		CertFile:    "certificate.pem",
+		KeyFile:     "key.pem",
+		Routes: map[string]string{
+			"*":                "http://127.0.0.1:80",
+			"main.example.com": "http://127.0.0.1:80",
+		},
+		TrustTarget: map[string]bool{
+			"*":                true,  // default trust all certificates
+			"main.example.com": false, // use only trusted certificate
+		},
+		NoHTTPSRedirect: map[string]bool{
+			"*":                false, // Default: redirect to HTTPS
+			"main.example.com": true,  // set to not redirect HTTP to HTTPS
+		},
+	}
+}
+
+func saveConfig(cfg Config) error {
+	if err := os.MkdirAll(baseDir, 0755); err != nil {
+		return fmt.Errorf("failed to create base directory %s: %v", baseDir, err)
+	}
+
+	data, err := yaml.Marshal(cfg)
+	if err != nil {
+		return fmt.Errorf("failed to marshal config: %v", err)
+	}
+
+	err = os.WriteFile(configPath, data, 0644)
+	if err != nil {
+		return fmt.Errorf("failed to write config to %s: %v", configPath, err)
+	}
+	return nil
+}
+
+func monitorConfig() {
+	var lastModTime time.Time
+	for {
+		configInfo, err := os.Stat(configPath)
+		if err != nil {
+			log.Printf("Error checking config file: %v", err)
+			time.Sleep(5 * time.Second)
+			continue
+		}
+
+		if configInfo.ModTime() != lastModTime {
+			newConfig, err := loadConfig()
+			if err != nil {
+				log.Printf("Error reloading config: %v", err)
+			} else {
+				configMux.Lock()
+				if newConfig.ListenHTTP != config.ListenHTTP {
+					config.ListenHTTP = newConfig.ListenHTTP
+					log.Printf("Updated listen_http to %s", config.ListenHTTP)
+				}
+				if newConfig.ListenHTTPS != config.ListenHTTPS {
+					config.ListenHTTPS = newConfig.ListenHTTPS
+					log.Printf("Updated listen_https to %s", config.ListenHTTPS)
+				}
+				if newConfig.CertDir != config.CertDir || newConfig.CertFile != config.CertFile || newConfig.KeyFile != config.KeyFile {
+					config.CertDir = newConfig.CertDir
+					config.CertFile = newConfig.CertFile
+					config.KeyFile = newConfig.KeyFile
+					updatePaths()
+					if err := loadCertificate(); err != nil {
+						log.Printf("Error reloading certificate after path change: %v", err)
+					} else {
+						log.Println("Updated certificate paths and reloaded certificate")
+					}
+				}
+				for k, v := range newConfig.Routes {
+					if oldV, exists := config.Routes[k]; !exists || oldV != v {
+						config.Routes[k] = v
+						log.Printf("Updated route %s to %s", k, v)
+					}
+				}
+				for k := range config.Routes {
+					if _, exists := newConfig.Routes[k]; !exists {
+						delete(config.Routes, k)
+						log.Printf("Removed route %s", k)
+					}
+				}
+				for k, v := range newConfig.TrustTarget {
+					if oldV, exists := config.TrustTarget[k]; !exists || oldV != v {
+						config.TrustTarget[k] = v
+						log.Printf("Updated trust_target %s to %v", k, v)
+					}
+				}
+				for k := range config.TrustTarget {
+					if _, exists := newConfig.TrustTarget[k]; !exists {
+						delete(config.TrustTarget, k)
+						log.Printf("Removed trust_target %s", k)
+					}
+				}
+				for k, v := range newConfig.NoHTTPSRedirect {
+					if oldV, exists := config.NoHTTPSRedirect[k]; !exists || oldV != v {
+						config.NoHTTPSRedirect[k] = v
+						log.Printf("Updated no_https_redirect %s to %v", k, v)
+					}
+				}
+				for k := range config.NoHTTPSRedirect {
+					if _, exists := newConfig.NoHTTPSRedirect[k]; !exists {
+						delete(config.NoHTTPSRedirect, k)
+						log.Printf("Removed no_https_redirect %s", k)
+					}
+				}
+				configMux.Unlock()
+				log.Println("Config reloaded successfully")
+				lastModTime = configInfo.ModTime()
+			}
+		}
+		time.Sleep(5 * time.Second)
+	}
+}

go.mod

@@ -0,0 +1,5 @@
+module main
+
+go 1.24.0
+
+require gopkg.in/yaml.v2 v2.4.0

go.sum

@@ -0,0 +1,4 @@
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
+gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=

main.go

@@ -0,0 +1,105 @@
+package main
+
+// go run main.go config.go certificate.go proxy.go utils.go
+// go build -o proxy
+import (
+	"crypto/tls"
+	"log"
+	"net/http"
+	"os"
+	"path/filepath"
+	"runtime"
+	"sync"
+)
+
+// Shared global variables (declared only here)
+var (
+	config     Config
+	configMux  sync.RWMutex
+	cert       *tls.Certificate
+	baseDir    string
+	certDir    string
+	certPath   string
+	keyPath    string
+	configPath string
+)
+
+func init() {
+	if runtime.GOOS == "windows" && len(os.Args) > 0 && filepath.Ext(os.Args[0]) == ".go" {
+		var err error
+		baseDir, err = os.Getwd()
+		if err != nil {
+			log.Fatalf("Failed to get working directory: %v", err)
+		}
+	} else {
+		exePath, err := os.Executable()
+		if err != nil {
+			log.Fatalf("Failed to get executable path: %v", err)
+		}
+		baseDir = filepath.Dir(exePath)
+	}
+}
+
+func main() {
+	configPath = filepath.Join(baseDir, "config.yaml")
+	if _, err := os.Stat(configPath); os.IsNotExist(err) {
+		config = generateDefaultConfig()
+		if err := saveConfig(config); err != nil {
+			log.Fatalf("Failed to save default config: %v", err)
+		}
+		log.Println("Generated default config file")
+	} else {
+		cfg, err := loadConfig()
+		if err != nil {
+			log.Fatalf("Failed to load config: %v", err)
+		}
+		config = cfg
+	}
+
+	updatePaths()
+
+	_, certErr := os.Stat(certPath)
+	_, keyErr := os.Stat(keyPath)
+	if os.IsNotExist(certErr) || os.IsNotExist(keyErr) {
+		if err := generateSelfSignedCert(); err != nil {
+			log.Fatalf("Failed to generate self-signed certificate: %v", err)
+		}
+	}
+
+	if err := loadCertificate(); err != nil {
+		log.Fatalf("Failed to load certificate: %v", err)
+	}
+
+	go monitorCertificates()
+	go monitorConfig()
+
+	httpServer := &http.Server{
+		Addr:    config.ListenHTTP,
+		Handler: http.HandlerFunc(handler),
+	}
+
+	tlsConfig := &tls.Config{
+		GetCertificate: func(*tls.ClientHelloInfo) (*tls.Certificate, error) {
+			configMux.RLock()
+			defer configMux.RUnlock()
+			return cert, nil
+		},
+	}
+	httpsServer := &http.Server{
+		Addr:      config.ListenHTTPS,
+		Handler:   http.HandlerFunc(handler),
+		TLSConfig: tlsConfig,
+	}
+
+	go func() {
+		log.Printf("Starting HTTP server on %s", config.ListenHTTP)
+		if err := httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			log.Fatalf("HTTP server error: %v", err)
+		}
+	}()
+
+	log.Printf("Starting HTTPS server on %s", config.ListenHTTPS)
+	if err := httpsServer.ListenAndServeTLS("", ""); err != nil && err != http.ErrServerClosed {
+		log.Fatalf("HTTPS server error: %v", err)
+	}
+}

proxy.go

@@ -0,0 +1,93 @@
+package main
+
+import (
+	"crypto/tls"
+	"log"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"strings"
+)
+
+func getReverseProxy(target string, skipVerify bool) *httputil.ReverseProxy {
+	targetURL, err := url.Parse(target)
+	if err != nil {
+		log.Printf("Error parsing target URL %s: %v", target, err)
+		return nil
+	}
+
+	director := func(req *http.Request) {
+		req.URL.Scheme = targetURL.Scheme
+		req.URL.Host = targetURL.Host
+		req.Host = targetURL.Host // Set Host header to match target
+
+		// Preserve original headers
+		for k, v := range req.Header {
+			if k != "Host" { // Host is set above
+				req.Header[k] = v
+			}
+		}
+
+		// Ensure the full path is preserved
+		if targetURL.Path != "" {
+			req.URL.Path = strings.TrimPrefix(req.URL.Path, "/") // Avoid double slashes
+			req.URL.Path = singleJoin(targetURL.Path, req.URL.Path)
+		}
+	}
+
+	transport := &http.Transport{
+		TLSClientConfig: &tls.Config{InsecureSkipVerify: skipVerify},
+	}
+
+	return &httputil.ReverseProxy{
+		Director:  director,
+		Transport: transport,
+		ErrorHandler: func(w http.ResponseWriter, r *http.Request, err error) {
+			log.Printf("Proxy error for %s: %v", r.Host, err)
+			http.Error(w, "Proxy error", http.StatusBadGateway)
+		},
+	}
+}
+
+// singleJoin ensures a single slash between path segments
+func singleJoin(prefix, suffix string) string {
+	prefix = strings.TrimSuffix(prefix, "/")
+	suffix = strings.TrimPrefix(suffix, "/")
+	return prefix + "/" + suffix
+}
+
+func handler(w http.ResponseWriter, r *http.Request) {
+	configMux.RLock()
+	defer configMux.RUnlock()
+
+	target, exists := config.Routes[r.Host]
+	skipVerify := config.TrustTarget[r.Host]
+	noHTTPSRedirect := config.NoHTTPSRedirect[r.Host]
+
+	if !exists {
+		if target, exists = config.Routes["*"]; !exists {
+			http.Error(w, "Host not configured", http.StatusNotFound)
+			return
+		}
+		skipVerify = config.TrustTarget["*"]
+		noHTTPSRedirect = config.NoHTTPSRedirect["*"]
+	}
+
+	// Check if request is HTTP and target is HTTPS
+	isHTTPS := target[:5] == "https"
+	isHTTPReq := r.TLS == nil // r.TLS is nil for HTTP, non-nil for HTTPS
+
+	if isHTTPReq && isHTTPS && !noHTTPSRedirect {
+		// Redirect to HTTPS version of the host
+		redirectURL := "https://" + r.Host + r.RequestURI
+		http.Redirect(w, r, redirectURL, http.StatusMovedPermanently)
+		return
+	}
+
+	proxy := getReverseProxy(target, skipVerify)
+	if proxy == nil {
+		http.Error(w, "Invalid target configuration", http.StatusInternalServerError)
+		return
+	}
+	proxy.ServeHTTP(w, r)
+}

utils.go

@@ -0,0 +1,10 @@
+package main
+
+import "path/filepath"
+
+func updatePaths() {
+	certDir = filepath.Join(baseDir, config.CertDir)
+	certPath = filepath.Join(certDir, config.CertFile)
+	keyPath = filepath.Join(certDir, config.KeyFile)
+	configPath = filepath.Join(baseDir, "config.yaml")
+}