WKWebView设置UserAgent踩坑

通过下面的方法给wkwebview设置自定义useragent，解决了常见的问题，如第一次设置不生效，第一次获取不到原来的useragent等问题

思路如下

单个webview设置：iOS9.0以后，可以设置customUserAgent来单个设置webview的自定义useragent

全局设置：先通过evaluateJavaScript("navigator.userAgent")获取原来的useragent，然后追加自定义useragent，通过UserDefaults.standard.register(defaults: ["UserAgent": newAgent])全局设置

代码如下

import UIKit
import WebKitclass WebViewManager: NSObject {static let shared = WebViewManager()var webView: WKWebView?private var isAddCustomUserAgent: Bool = falsefunc loadHtmlString(_ htmlString: String) {// 单个设置webview的userAgent
//        addCustomUserAgent()
//        webView?.loadHTMLString(htmlString)
//        webView?.evaluateJavaScript("navigator.userAgent") { (oldAgent, error) in
//            guard let oldAgent = oldAgent as? String else {//                print("没取到oldAgent")
//                return
//            }
//            print("设置后的新的user agent:\(oldAgent)")
//        }// 全局设置userAgentaddCustomUserAgent { [weak self] in// 一定要在useragent设置完成后在加载html页面self?.webView?.loadHTMLString(htmlString)self?.webView?.evaluateJavaScript("navigator.userAgent") { (oldAgent, error) inguard let oldAgent = oldAgent as? String else {print("没取到oldAgent")return}print("设置后的新的user agent:\(oldAgent)")}}}
}extension WebViewManager {// 单个webview设置useragentprivate func addCustomUserAgent() {let version = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String ?? ""let token = Authentication.shared.user?.accessToken ?? ""let refreshToken = Authentication.shared.user?.refreshToken ?? ""let customUserAgent = ";POSApp;platform=iOS;version=\(version);token=\(token);refreshToken=\(refreshToken)"webView?.customUserAgent = customUserAgent}// 全局设置useragentprivate func addCustomUserAgent(completed: @escaping ()->()) {guard !isAddCustomUserAgent else {print("不再重新设置agent")completed()return}// 这个地方使用evaluateJavaScript的webview一定要添加到界面的，不然取不到oldAgentwebView?.evaluateJavaScript("navigator.userAgent") { [weak self] (oldAgent, error) inlet version = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String ?? ""let token = Authentication.shared.user?.accessToken ?? ""let refreshToken = Authentication.shared.user?.refreshToken ?? ""let customUserAgent = ";POSApp;platform=iOS;version=\(version);token=\(token);refreshToken=\(refreshToken)"guard let oldAgent = oldAgent as? String else {print("evaluateJavaScript取不到旧的agent")let oldAgent = "Mozilla/5.0 (\(UIDevice.current.model); CPU iPhone OS \(UIDevice.current.systemVersion.replacingOccurrences(of: ".", with: "_")) like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148"let newAgent = "\(oldAgent)\(customUserAgent)"// 设置global User-AgentUserDefaults.standard.register(defaults: ["UserAgent": newAgent])// 一定要设置customUserAgent，因为全局useragent只会在设置后添加的webview生效self?.webView?.customUserAgent = newAgentself?.isAddCustomUserAgent = trueprint("evaluateJavaScript设置新的agent：\(newAgent)")completed()return}guard !oldAgent.hasSuffix(customUserAgent) else {print("evaluateJavaScript已经设置新的agent")completed()return}let newAgent = "\(oldAgent)\(customUserAgent)"UserDefaults.standard.register(defaults: ["UserAgent": newAgent])// 一定要设置customUserAgent，因为全局useragent只会在设置后添加的webview生效self?.webView?.customUserAgent = newAgentself?.isAddCustomUserAgent = trueprint("evaluateJavaScript设置新的agent：\(newAgent)")completed()}}
}

补充

真是too long too simple (^_)v

这样设置有两个个坑
1、切换useragent某些场景下也会失效。
2、第一次安装app，进入webview，设置useragent会失效；

没搞清楚具体原因是什么，但是找到了解决办法：
1、加载时强制不适用任何缓存

let request = URLRequest(url: url, cachePolicy: .reloadIgnoringLocalAndRemoteCacheData)
webView?.load(request)
webView?.reloadFromOrigin()

2、调用load后再设置一次customUserAgent

webView?.customUserAgent = customUserAgent
loadHTMLString(("\(self.webHostUrlString)\(self.htmlPath ?? "")"))
webView?.customUserAgent = customUserAgent

后来发现完全是多此一举了，其实是web端的bug

3、先获取原来的，再追加

private func addCustomUserAgent(completed: @escaping ()->()) {self.fakeWebView = WKWebView()self.fakeWebView?.evaluateJavaScript("navigator.userAgent") { [weak self] (oldAgent, error) inself?.fakeWebView = nilguard let oldAgent = oldAgent as? String else {let oldAgent = "Mozilla/5.0 (\(UIDevice.current.model); CPU iPhone OS \(UIDevice.current.systemVersion.replacingOccurrences(of: ".", with: "_")) like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148"let newAgent = "\(oldAgent)\(self?.customUserAgent ?? "")"self?.webView?.customUserAgent = newAgentcompleted()return}let newAgent = "\(oldAgent)\(self?.customUserAgent ?? "")"self?.webView?.customUserAgent = newAgentcompleted()}}

好了，问题总算比较完美的解决了^ - ^