File size: 1,626 Bytes
6bc074c | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | package util
import (
"fmt"
"math/rand"
"strings"
"sync"
"time"
)
const FixedUserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/148.0.0.0 Safari/537.36"
// userAgentSpec 描述一个主流桌面浏览器的 User-Agent 模板
// 模板中可使用 %d 作为版本占位符
type userAgentSpec struct {
Template string
MinVersion int
MaxVersion int // 闭区间上界
Family string
}
// 保留 RandomUserAgent 用于其它场景(测试、临时抓包等)。生产路径走 FixedUserAgent。
var userAgentSpecs = []userAgentSpec{
{
Template: "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/%d.0.0.0 Safari/537.36",
MinVersion: 148,
MaxVersion: 148,
Family: "Chrome-Win",
},
}
var (
uaRand *rand.Rand
uaRandOnce sync.Once
)
func initUARand() {
uaRandOnce.Do(func() {
uaRand = rand.New(rand.NewSource(time.Now().UnixNano()))
})
}
// RandomUserAgent 返回一个随机的主流桌面浏览器 User-Agent
func RandomUserAgent() string {
initUARand()
spec := userAgentSpecs[uaRand.Intn(len(userAgentSpecs))]
version := spec.MinVersion
if spec.MaxVersion > spec.MinVersion {
version += uaRand.Intn(spec.MaxVersion - spec.MinVersion + 1)
}
// 数一下模板里 %d 的个数,按个数填充 version
placeholders := strings.Count(spec.Template, "%d")
switch placeholders {
case 1:
return fmt.Sprintf(spec.Template, version)
default:
// 0 个或 2+ 个(兼容老 Edge 模板): 都用 version 填充
return fmt.Sprintf(strings.Replace(spec.Template, "%d", "%v", -1), version)
}
}
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