Merge pull request #141 from Snawoot/auto_user_agent

Discover fresh user-agent automatically

chromever.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net"
+	"net/http"
+	"time"
+)
+
+type chromeVerResponse struct {
+	Versions [1]struct {
+		Version string `json:"version"`
+	} `json:"versions"`
+}
+
+const chromeVerURL = "https://versionhistory.googleapis.com/v1/chrome/platforms/win/channels/stable/versions?alt=json&orderBy=version+desc&pageSize=1&prettyPrint=false"
+
+func GetChromeVer(ctx context.Context, dialer ContextDialer) (string, error) {
+	if dialer == nil {
+		dialer = &net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 30 * time.Second,
+		}
+	}
+
+	transport := &http.Transport{
+		DialContext:           dialer.DialContext,
+		ForceAttemptHTTP2:     true,
+		MaxIdleConns:          100,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+	}
+	defer transport.CloseIdleConnections()
+	httpClient := &http.Client{
+		Transport: transport,
+	}
+
+	req, err := http.NewRequestWithContext(ctx, "GET", chromeVerURL, nil)
+	if err != nil {
+		return "", fmt.Errorf("chrome browser version request construction failed: %w", err)
+	}
+
+	resp, err := httpClient.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("chrome browser version request failed: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		return "", fmt.Errorf("chrome browser version request failed: bad status code: %d", resp.StatusCode)
+	}
+
+	dec := json.NewDecoder(resp.Body)
+	var chromeVerResp chromeVerResponse
+	if err := dec.Decode(&chromeVerResp); err != nil {
+		return "", fmt.Errorf("unable to decode chrome browser version response: %w", err)
+	}
+
+	return chromeVerResp.Versions[0].Version, nil
+}

extver.go

@@ -86,7 +86,7 @@ func GetExtVer(ctx context.Context,
 	defer resp.Body.Close()
 
 	if resp.StatusCode != 200 {
-		return "", fmt.Errorf("bad status code: %d", resp.StatusCode)
+		return "", fmt.Errorf("chrome web store: bad status code: %d", resp.StatusCode)
 	}
 
 	reader := io.LimitReader(resp.Body, 64*1024)

go.mod

@@ -35,4 +35,5 @@ require (
 	golang.org/x/sys v0.32.0 // indirect
 	golang.org/x/text v0.24.0 // indirect
 	golang.org/x/tools v0.32.0 // indirect
+	google.golang.org/protobuf v1.36.6 // indirect
 )

go.sum

@@ -70,7 +70,7 @@ golang.org/x/time v0.11.0 h1:/bpjEDfN9tkoN/ryeYHnv5hcMlc8ncjMcM4XBk5NWV0=
 golang.org/x/time v0.11.0/go.mod h1:CDIdPxbZBQxdj6cxyCIdrNogrJKMJ7pr37NYpMcMDSg=
 golang.org/x/tools v0.32.0 h1:Q7N1vhpkQv7ybVzLFtTjvQya2ewbwNDZzUgfXGqtMWU=
 golang.org/x/tools v0.32.0/go.mod h1:ZxrU41P/wAbZD8EDa6dDCa6XfpkhJ7HFMjHJXfBDu8s=
-google.golang.org/protobuf v1.36.5 h1:tPhr+woSbjfYvY6/GPufUoYizxw1cF/yFoxJ2fmpwlM=
-google.golang.org/protobuf v1.36.5/go.mod h1:9fA7Ob0pmnwhb644+1+CVWFRbNajQ6iRojtC/QF5bRE=
+google.golang.org/protobuf v1.36.6 h1:z1NpPI8ku2WgiWnf+t9wTPsn6eP1L7ksHUlkfLvd9xY=
+google.golang.org/protobuf v1.36.6/go.mod h1:jduwjTPXsFjZGTmRluh+L6NjiWu7pchiJ2/5YcXBHnY=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

@@ -12,6 +12,7 @@ import (
 	"net/http"
 	"net/url"
 	"os"
+	"strings"
 	"time"
 
 	tls "github.com/refraction-networking/utls"
@@ -67,7 +68,7 @@ type CLIArgs struct {
 	initRetries                             int
 	initRetryInterval                       time.Duration
 	hideSNI                                 bool
-	userAgent                               string
+	userAgent                               *string
 }
 
 func parse_args() CLIArgs {
@@ -99,7 +100,12 @@ func parse_args() CLIArgs {
 		"Format: <http|https|socks5|socks5h>://[login:password@]host[:port] "+
 		"Examples: http://user:password@192.168.1.1:3128, socks5://10.0.0.1:1080")
 	flag.StringVar(&args.caFile, "cafile", "", "use custom CA certificate bundle file")
-	flag.StringVar(&args.userAgent, "user-agent", GetUserAgent(), "value of User-Agent header in requests")
+	flag.Func("user-agent",
+		"value of User-Agent header in requests. Default: User-Agent of latest stable Chrome for Windows",
+		func(s string) error {
+			args.userAgent = &s
+			return nil
+		})
 	flag.BoolVar(&args.hideSNI, "hide-SNI", true, "hide SNI in TLS sessions with proxy server")
 	flag.Parse()
 	if args.country == "" {
@@ -182,8 +188,6 @@ func run() int {
 		UpdateHolaDialer(dialer)
 	}
 
-	SetUserAgent(args.userAgent)
-
 	try := retryPolicy(args.initRetries, args.initRetryInterval, mainLogger)
 
 	if args.list_countries {
@@ -191,16 +195,48 @@ func run() int {
 	}
 
 	mainLogger.Info("hola-proxy client version %s is starting...", version)
+
+	var userAgent string
+	if args.userAgent == nil {
+		err := try("get latest version of Chrome browser", func() error {
+			ctx, cl := context.WithTimeout(context.Background(), args.timeout)
+			defer cl()
+			ver, err := GetChromeVer(ctx, dialer)
+			if err != nil {
+				return err
+			}
+			mainLogger.Info("latest Chrome version is %q", ver)
+			majorVer, _, _ := strings.Cut(ver, ".")
+			userAgent = fmt.Sprintf(
+				"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/%s.0.0.0 Safari/537.36",
+				majorVer)
+			mainLogger.Info("discovered latest Chrome User-Agent: %q", userAgent)
+			return err
+		})
+		if err != nil {
+			mainLogger.Critical("Can't detect latest Chrome version. "+
+				"Try to specify proper user agent with -user-agent parameter. Error: %v",
+				err)
+			return 8
+		}
+	} else {
+		userAgent = *args.userAgent
+	}
+	SetUserAgent(userAgent)
+
 	if args.extVer == "" {
 		err := try("get latest version of browser extension", func() error {
 			ctx, cl := context.WithTimeout(context.Background(), args.timeout)
 			defer cl()
 			extVer, err := GetExtVer(ctx, nil, HolaExtStoreID, dialer)
+			if err == nil {
+				mainLogger.Info("discovered latest browser extension version: %s", extVer)
 				args.extVer = extVer
+			}
 			return err
 		})
 		if err != nil {
-			mainLogger.Critical("Can't detect latest API version. Try to specify -ext-ver parameter. Error: %v", err)
+			mainLogger.Critical("Can't detect latest browser extension version. Try to specify -ext-ver parameter. Error: %v", err)
 			return 8
 		}
 		mainLogger.Warning("Detected latest extension version: %q. Pass -ext-ver parameter to skip resolve and speedup startup", args.extVer)