notes/IOS/WKWebView_logging.md

import SwiftUI
import WebKit
import JavaScriptCore

struct ContentView: View {
    var body: some View {
        WebView()
    }
}

#Preview {
    ContentView()
}

struct WebView: UIViewRepresentable {
 
    let webView: WKWebView
    
    init() {
        webView = WKWebView(frame: .zero)
      
    }
    
    func makeUIView(context: Context) -> WKWebView {
        let source = "function captureLog(msg) { window.webkit.messageHandlers.logHandler.postMessage(msg); } window.console.log = captureLog;"
        let script = WKUserScript(source: source, injectionTime: .atDocumentEnd, forMainFrameOnly: false)
        webView.configuration.userContentController.addUserScript(script)
        
        webView.configuration.userContentController.add(Controller(), name: "logHandler")
        
        return webView
    }
    func updateUIView(_ uiView: WKWebView, context: Context) {
        webView.load(URLRequest(url: URL(string: "http://localhost:8000/demo")!))
    }
}


class Controller: NSObject, WKScriptMessageHandler{
    func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
        if message.name == "logHandler" {
            print("LOG: \(message.body)")
        }
    }
}