Intercept Request with Wkwebview

Intercept request with WKWebView

I see that after 5 years this question still generates curiosity, so I describe how I solved it and about some main problems I faced up.
As many who answered here, I have implemented WKURLSchemeHandler and used new schemes.

First of all the URL that wkwebview launches must not be HTTP (or HTTPS) but one of yours new schemes.

Example

mynewscheme://your-server-application.com

In you WKWebViewConfiguration conf, I set the handler:

[conf setURLSchemeHandler:[CustomSchemeHandler new] forURLScheme:@"mynewscheme"];
[conf setURLSchemeHandler:[CustomSchemeHandler new] forURLScheme:@"mynewschemesecure"];

In CustomSchemeHandler I have implemented webView:startURLSchemeTask: and webView:stopURLSchemeTask:.

In my case I check if the request is for a file that I just saved locally, otherwise I change actual protocol ("mynewscheme or "mynewschemesecure") with http (or https) and I make request by myself.

At this point I solved the "interception problem".

In this new way we have the webview "location" (location.href via javascript) with my new scheme and with it new problems started.

• First problem is that my applications work mainly with javascript,
  and document.cookie has stopped working. I'm using Cordova
  framework, so I've develeped a plugin to set and get cookie to
  replace document.cookie (I had to do this, because, obviously, I
  have also http header set-cookie).

• Second problem is that I've got a lot of "cross-origin" problems, then
  I changed all my urls in relative url (or with new schemes)

• Third problem is that browser automatically handle server port 80
  and 443, omitting them, but has now stopped (maybe because of "not
  http location"). In my server code I had to handle this.

Writing down these few rows I admit that it seems to was an easy problem to solve, but I ensure that find out a workaround, how to solve it and integrate with the infinite amount of code has been hard. Every step towards the solution corresponded to a new problem.

How to intercept all http(s) requests on ios WKWebView?

Take a look at this github repository called as WKWebViewWithURLProtocol Casolorz. This library enables you to use NSURLProtocol to intercept your network requests using method swizzling.

Ios WKWebView intercepting http/https requests

Eventually I've ended up using. GCDWebServer

I've setup local webserver like so:

let webServer: GCDWebServer = GCDWebServer()

webServer.addGETHandler(forBasePath: "/", directoryPath: baseResourcePath, indexFilename: "index.html", cacheAge: 0, allowRangeRequests: true)

Then to provide files that are located outside of index.html contained directory
one has to attach custom get handler:

webServer.addHandler(forMethod: "GET", pathRegex: "images", request: GCDWebServerRequest.self) { request in
        let fileName = request.path.components(separatedBy: "/images/")[1]
        var documentsURL = FileManager.default.urls(for: .docmentDirectory, in: .userDomainMask)[0]
        documentsURL.appendPathComponent("images/\(fileName)")
        let response = GCDWebServerFileResponse(file: documentsURL.path)
        return response
    }

Intercept links in wkwebview

You can implement a Coordinator object and set it as your WKNavigationDelegate. Then you can implement decidePolicyFor navigationAction method and decide what to do on each request:

---

import SwiftUI
import WebKit

struct ContentView: View {
    var body: some View {
        WebView(request: .init(url: URL(string: "https://google.com")!))
    }
}

---

struct WebView: UIViewRepresentable {
    let request: URLRequest
    func makeCoordinator() -> Coordinator { .init(self) }
    func makeUIView(context: Context) -> WKWebView  {
        let webView = WKWebView()
        webView.navigationDelegate = context.coordinator
        return webView
    }
    func updateUIView(_ webView: WKWebView, context: Context) {
        webView.load(request)
    }
    class Coordinator: NSObject, WKNavigationDelegate {
        var webView: WebView
        init(_ webView: WebView) { self.webView = webView }
        func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
            if navigationAction.navigationType == .linkActivated  {
                if let url = navigationAction.request.url,
                    let host = url.host, !host.hasPrefix("www.google.com"),
                    UIApplication.shared.canOpenURL(url) {
                    UIApplication.shared.open(url)
                    print(url)
                    print("Redirected to browser. No need to open it locally")
                    decisionHandler(.cancel)
                } else {
                    print("Open it locally")
                    decisionHandler(.allow)
                }
            } else {
                print("not a user click")
                decisionHandler(.allow)
            }
        }
    }
}

---

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}
 

---

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