WKWebView+Additions.swift

extension WKWebView {
    /// sync version
    ///
    /// - Parameters:
    ///   - js: 要执行的javascript代码
    ///   - timeout: 限时返回（单位秒），0表示不限时
    /// - Returns: 执行结果
    func evaluatingJavaScript(_ js: String, timeout: TimeInterval = 0) -> Any? {
        var res: Any? = nil
        var finish = false
        var count = 0, maxCount = Int(timeout * 10) // 0.1秒为间隔
        evaluateJavaScript(js) { (result, error) in
            res = result
            finish = true
        }
        while !finish {
            RunLoop.current.run(until: Date(timeIntervalSinceNow: 0.1))
            if maxCount > 0 && count >= maxCount {
                finish = true
            }
            count += 1
        }
        return res
    }
}


enum URLType {
    case about
    case http       // 普通的 http(s)
    case appStore
    case map
    case custom     // 例如 weiyun://, txent:    
}


extension URLComponents {
    var type: URLType {
        let s = scheme?.lowercased()
        if s == "http" || s == "https"  {
            let h = host?.lowercased()
            if h == "itunes.apple.com" { // 居然不是 Universal Link，亮瞎
                return .appStore
            }
            if h == "maps.apple.com" && query != nil {
                return .map
            }
            return .http
        }
        if s == "about" {
            return .about
        }
        return .custom
    }
}


// MARK: - WKNavigationDelegate

    func webView(_ wv: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
        guard let url = navigationAction.request.url, let uc = URLComponents(url: url, resolvingAgainstBaseURL: true), let _ = uc.scheme else {
            print("这个request不正常\(navigationAction.request)")
            decisionHandler(.cancel)
            return
        }
        handleURL(url, decisionHandler: decisionHandler)
    }

    func handleURL(_ url: URL, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
        // url 可能是 about:blank，即 navigationAction.targetFrame == nil，亦即 target="_blank"
        // 典型例子：“软件许可及服务协议”跳转到“微信公众平台服务协议”后再跳转时
        guard let uc = URLComponents.init(url: url, resolvingAgainstBaseURL: true) else {
            decisionHandler(.cancel)
            return
        }
        let t = uc.type
        switch t {
        case .http:
            handleHttpURL(url, decisionHandler: decisionHandler)

        case .about:
            decisionHandler(.allow)

        case .appStore, .map:
            decisionHandler(.cancel)

            // 保持跟微信的体验一致
            let appName = t == .appStore ? "App Store" : "地图"
            let ac = UIAlertController(title: nil, message: "将会离开\"\(Global.displayName)\"\n并跳转到\(appName)", preferredStyle: .alert)
            ac.addAction(UIAlertAction(title: "取消", style: .cancel))
            ac.addAction(UIAlertAction(title: "确定", style: .default, handler: { (aa) in
                UIApplication.shared.openURL(url)
                log.i("open application with url: \(url)")
            }))
            present(ac, animated: true, completion: nil)

        case .custom:
            decisionHandler(.cancel)
            handleCustomURL(url)
        }
    }

    /// Can be override
    /// 需识别 universal link
    func handleHttpURL(_ url: URL, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
        decisionHandler(.allow)
    }

    /// Can be override
    func handleCustomURL(_ url: URL) {
        if #available(iOS 10, *) {
            UIApplication.shared.open(url, options: [:], completionHandler: nil)
        } else {
            UIApplication.shared.openURL(url)
        }
    }