CefSharpでリダイレクトURLを取得する方法

Ⅰ. はじめに

タイトルの通り「CefSharpでリダイレクトURLを取得する方法」です。

CefSharpに関する基本的な情報はこちら
http://kagasu.hatenablog.com/entry/2017/12/16/154109

Platform	動作確認
WPF	OK
WinForms	NG

2018/02/11時点でWinForms版CefSharpはCefSharp.IRequestHandlerに対応していないので動作しません。

Ⅱ. サンプルプログラム

MainWindow.xaml

public MainWindow()
{
  InitializeComponent();

  var browser = new ChromiumWebBrowser();
  browser.RequestHandler = new MyRequestHandler();
  browser.Load("http://127.0.0.1/test.php");
  Content = browser;
}

test.php

<?php
header("HTTP/1.1 302");
header("Location: http://example.com");

MyRequestHandler.cs

using CefSharp;
using System;
using System.Security.Cryptography.X509Certificates;

class MyRequestHandler : IRequestHandler
{
  bool IRequestHandler.OnBeforeBrowse(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, bool isRedirect)
  {
    if (isRedirect)
    {
      Console.WriteLine($"リダイレクトURL: {request.Url}");
    }
    return false;
  }

  bool IRequestHandler.OnOpenUrlFromTab(IWebBrowser browserControl, IBrowser browser, IFrame frame, string targetUrl, WindowOpenDisposition targetDisposition, bool userGesture)
  {
    return false;
  }

  bool IRequestHandler.OnCertificateError(IWebBrowser browserControl, IBrowser browser, CefErrorCode errorCode, string requestUrl, ISslInfo sslInfo, IRequestCallback callback)
  {
    return false;
  }

  void IRequestHandler.OnPluginCrashed(IWebBrowser browserControl, IBrowser browser, string pluginPath)
  {
  }

  CefReturnValue IRequestHandler.OnBeforeResourceLoad(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IRequestCallback callback)
  {
    return CefReturnValue.Continue;
  }

  bool IRequestHandler.GetAuthCredentials(IWebBrowser browserControl, IBrowser browser, IFrame frame, bool isProxy, string host, int port, string realm, string scheme, IAuthCallback callback)
  {
    callback.Dispose();
    return false;
  }
  void IRequestHandler.OnRenderProcessTerminated(IWebBrowser browserControl, IBrowser browser, CefTerminationStatus status)
  {
  }

  bool IRequestHandler.OnQuotaRequest(IWebBrowser browserControl, IBrowser browser, string originUrl, long newSize, IRequestCallback callback)
  {
    return false;
  }
  
  bool IRequestHandler.OnProtocolExecution(IWebBrowser browserControl, IBrowser browser, string url)
  {
    return false;
  }

  void IRequestHandler.OnRenderViewReady(IWebBrowser browserControl, IBrowser browser)
  {
  }

  bool IRequestHandler.OnResourceResponse(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IResponse response)
  {
    return false;
  }

  void IRequestHandler.OnResourceLoadComplete(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IResponse response, UrlRequestStatus status, long receivedContentLength)
  {
  }

  public bool OnSelectClientCertificate(IWebBrowser browserControl, IBrowser browser, bool isProxy, string host, int port, X509Certificate2Collection certificates, ISelectClientCertificateCallback callback)
  {
    return false;
  }

  public void OnResourceRedirect(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IResponse response, ref string newUrl)
  {
  }

  public IResponseFilter GetResourceResponseFilter(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IResponse response)
  {
    return null;
  }
}

実行結果

参考

• WPFでCefSharp（Chromiumの.NET向け実装）を使う - 3
  https://qiita.com/GHKEN/items/1de12740c13350efec67
• CefSharp の IRequestHandler は最低限どう実装すればよいか
  https://peta.okechan.net/blog/archives/4672
• ChromiumWebBrowser URL changed event
  https://github.com/cefsharp/CefSharp/issues/1437