Core - Add IRequestContext.SetProxyAsync

Can be called on any Thread to change the proxy at runtime

Author: amaitland

CefSharp.Test/OffScreen/OffScreenBrowserBasicFacts.cs

@@ -432,5 +432,89 @@ public async Task CanLoadHttpWebsiteUsingProxy()
                 output.WriteLine("Url {0}", mainFrame.Url);
             }
         }
+
+        [SkipIfRunOnAppVeyorFact]
+        public async Task CanLoadHttpWebsiteUsingSetProxyAsync()
+        {
+            fixture.StartProxyServerIfRequired();
+
+            var tcs = new TaskCompletionSource<bool>();
+
+            var requestContext = RequestContext
+                .Configure()
+                .OnInitialize((ctx) =>
+                {
+                    tcs.SetResult(true);
+                })
+                .Create();
+
+            //Wait for our RequestContext to have initialized.
+            await tcs.Task;
+
+            var setProxyResponse = await requestContext.SetProxyAsync("127.0.0.1", 8080);
+
+            Assert.True(setProxyResponse.Success);
+
+            using (var browser = new ChromiumWebBrowser("http://cefsharp.github.io/", requestContext: requestContext))
+            {
+                await browser.LoadPageAsync();
+
+                var mainFrame = browser.GetMainFrame();
+                Assert.True(mainFrame.IsValid);
+                Assert.Contains("cefsharp.github.io", mainFrame.Url);
+
+                output.WriteLine("Url {0}", mainFrame.Url);
+            }
+        }
+
+        [SkipIfRunOnAppVeyorFact]
+        public async Task CanLoadHttpWebsiteUsingSetProxyOnUiThread()
+        {
+            fixture.StartProxyServerIfRequired();
+
+            var tcs = new TaskCompletionSource<bool>();
+
+            var requestContext = RequestContext
+                .Configure()
+                .OnInitialize((ctx) =>
+                {
+                    tcs.SetResult(true);
+                })
+                .Create();
+
+            //Wait for our RequestContext to have initialized.
+            await tcs.Task;
+
+            var success = false;
+
+            //To execute on the CEF UI Thread you can use 
+            await Cef.UIThreadTaskFactory.StartNew(delegate
+            {
+                string errorMessage;
+
+                if (!requestContext.CanSetPreference("proxy"))
+                {
+                    //Unable to set proxy, if you set proxy via command line args it cannot be modified.
+                    success = false;
+
+                    return;
+                }
+
+                success = requestContext.SetProxy("127.0.0.1", 8080, out errorMessage);
+            });
+
+            Assert.True(success);
+
+            using (var browser = new ChromiumWebBrowser("http://cefsharp.github.io/", requestContext: requestContext))
+            {
+                await browser.LoadPageAsync();
+
+                var mainFrame = browser.GetMainFrame();
+                Assert.True(mainFrame.IsValid);
+                Assert.Contains("cefsharp.github.io", mainFrame.Url);
+
+                output.WriteLine("Url {0}", mainFrame.Url);
+            }
+        }
     }
 }

CefSharp/CefSharp.csproj

@@ -130,6 +130,7 @@
     <Compile Include="JavascriptBinding\IJavascriptNameConverter.cs" />
     <Compile Include="JavascriptBinding\LegacyCamelCaseJavascriptNameConverter.cs" />
     <Compile Include="ModelBinding\IAsyncMethodInterceptor.cs" />
+    <Compile Include="Preferences\SetProxyResponse.cs" />
     <Compile Include="Preferences\SetPreferenceResponse.cs" />
     <Compile Include="ResourceRequestHandlerFactory.cs" />
     <Compile Include="ResourceRequestHandlerFactoryItem.cs" />

CefSharp/Preferences/SetProxyResponse.cs

@@ -0,0 +1,22 @@
+// Copyright © 2021 The CefSharp Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
+
+namespace CefSharp.Preferences
+{
+    /// <summary>
+    /// Response when <see cref="RequestContextExtensions.SetProxyAsync(IRequestContext, string, string, int?, out string)"/>
+    /// is called.
+    /// </summary>
+    public class SetProxyResponse : SetPreferenceResponse
+    {
+        /// <summary>
+        /// Default constructor
+        /// </summary>
+        /// <param name="success">success</param>
+        /// <param name="errorMessage">error message</param>
+        public SetProxyResponse(bool success, string errorMessage) : base(success, errorMessage)
+        {
+        }
+    }
+}

CefSharp/RequestContextExtensions.cs

@@ -66,10 +66,11 @@ public static void LoadExtensionsFromDirectory(this IRequestContext requestConte
         /// problem. This method must be called on the CEF UI thread.
         /// Preferences set via the command-line usually cannot be modified.
         /// </summary>
+        /// <param name="requestContext">request context</param>
         /// <param name="name">preference key</param>
         /// <param name="value">preference value</param>
         /// <param name="error">out error</param>
-        /// <returns>Returns true if the value is set successfully and false otherwise.</returns>
+        /// <returns>returns <see cref="SetPreferenceResponse.Success"/> true if successfull, false otherwise.</returns>
         /// <remarks>Use Cef.UIThreadTaskFactory to execute this method if required,
         /// <see cref="IBrowserProcessHandler.OnContextInitialized"/> and ChromiumWebBrowser.IsBrowserInitializedChanged are both
         /// executed on the CEF UI thread, so can be called directly.
@@ -98,6 +99,65 @@ public static Task<SetPreferenceResponse> SetPreferenceAsync(this IRequestContex
             return CefThread.ExecuteOnUiThread(func);
         }
 
+        /// <summary>
+        /// Sets the proxy server for the specified <see cref="IRequestContext"/>.
+        /// Protocol for the proxy server is http
+        /// </summary>
+        /// <param name="requestContext">request context</param>
+        /// <param name="host">proxy host</param>
+        /// <param name="port">proxy port</param>
+        /// <returns>returns <see cref="SetPreferenceResponse.Success"/> true if successfull, false otherwise.</returns>
+        /// <remarks>Internally calls <seealso cref="IRequestContext.SetPreference(string, object, out string)"/> with
+        /// preference 'proxy' and mode of 'fixed_servers'</remarks>
+        public static Task<SetProxyResponse> SetProxyAsync(this IRequestContext requestContext, string host, int? port)
+        {
+            return requestContext.SetProxyAsync(null, host, port);
+        }
+
+        /// <summary>
+        /// Sets the proxy server for the specified <see cref="IRequestContext"/>
+        /// </summary>
+        /// <param name="requestContext">request context</param>
+        /// <param name="scheme">is the protocol of the proxy server, and is one of: 'http', 'socks', 'socks4', 'socks5'. Also note that 'socks' is equivalent to 'socks5'.</param>
+        /// <param name="host">proxy host</param>
+        /// <param name="port">proxy port</param>
+        /// <returns>returns <see cref="SetPreferenceResponse.Success"/> true if successfull, false otherwise.</returns>
+        /// <remarks>Internally calls <seealso cref="IRequestContext.SetPreference(string, object, out string)"/> with
+        /// preference 'proxy' and mode of 'fixed_servers'</remarks>
+        public static Task<SetProxyResponse> SetProxyAsync(this IRequestContext requestContext, string scheme, string host, int? port)
+        {
+            if (CefThread.HasShutdown)
+            {
+                return Task.FromResult(new SetProxyResponse(false, "Cef.Shutdown has already been called, it is no longer possible to call SetProxyAsync."));
+            }
+
+            Func<SetProxyResponse> func = () =>
+            {
+                string error;
+                bool success = false;
+
+                if (requestContext.CanSetPreference("proxy"))
+                {
+                    var v = GetProxyDictionary(scheme, host, port);
+
+                    success = requestContext.SetPreference("proxy", v, out error);
+                }
+                else
+                {
+                    error = "Unable to set the proxy preference, it is read-only. If you specified the proxy settings with command line args it is not possible to change the proxy settings via this method.";
+                }
+
+                return new SetProxyResponse(success, error);
+            };
+
+            if (CefThread.CurrentlyOnUiThread)
+            {
+                return Task.FromResult(func());
+            }
+
+            return CefThread.ExecuteOnUiThread(func);
+        }
+
         /// <summary>
         /// Sets the proxy server for the specified <see cref="IRequestContext"/>
         /// MUST be called on the CEF UI Thread