ios - UIWebView 用户代理未正确设置自定义值

Question

如果我们想改变用户代理的值

Mozilla/5.0 (iPhone; CPU iPhone OS 10_1 like Mac OS X) AppleWebKit/602.2.14 (KHTML, like Gecko) Mobile/14B72

到

Mozilla/5.0 (iPad; CPU OS 10_1 like Mac OS X) AppleWebKit/602.2.14 (KHTML, like Gecko) Mobile/14B72

即在iPhone应用上，我的应用需要设置iPad的User-Agent。

我的代码看起来像

class ViewController: UIViewController, UIWebViewDelegate {
    @IBOutlet weak var webView: UIWebView!
    var userAgent:String = ""
    override func viewDidLoad() {
        super.viewDidLoad()
        userAgent = self.webView.stringByEvaluatingJavaScript(from: "navigator.userAgent")!

        let range = userAgent.range(of: "iPhone")

        if range != nil {
            userAgent = userAgent.replacingCharacters(in: range!, with: "iPad")
            userAgent = userAgent.replacingOccurrences(of: "iPhone", with: "")
        }
        userAgent = userAgent.replacingOccurrences(of: "  ", with: " ")

        UserDefaults.standard.register(defaults: ["UserAgent": userAgent])

    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        self.webView.loadRequest(URLRequest(url: URL(string: "http://www.google.com")!))
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    func webView(_ webView: UIWebView, shouldStartLoadWith request: URLRequest, navigationType: UIWebViewNavigationType) -> Bool {
        let userAgent = request.allHTTPHeaderFields!["User-Agent"]
        print("\(userAgent)")
        return true
    }

}

在上述情况下，User-Agent 未设置并保持默认值

如果我更改并在 viewDidLoad 中设置硬编码值，而不是像 iPad 的用户代理那样操作字符串的逻辑

UserDefaults.standard.register(defaults: ["UserAgent": “Mozilla/5.0 (iPad; CPU OS 10_1 like Mac OS X) AppleWebKit/602.2.14 (KHTML, like Gecko) Mobile/14B72”])

那么它也不会更新。

但是如果我像这样硬编码

UserDefaults.standard.register(defaults: ["UserAgent": “MyValue”])

那么就设置好了

知道这里出了什么问题吗？

Answer 1

如果用js代码调用获取iOS浏览器用户代理值，此时iOS会创建并发送值。所以你不能在创建后更新用户代理。尝试手动编写所有用户代理，而不是像这样通过 javascript 调用:

    let manuelUserAgent = "Mozilla/5.0 (iPad; CPU OS 10_1 like Mac OS X) AppleWebKit/602.2.14 (KHTML, like Gecko) Mobile/14B72"

    let newUserAgent = "\(manuelUserAgent) YourOpt.Text"

    UserDefaults.standard.register(defaults: ["UserAgent": newUserAgent])