99 lines
3.2 KiB
C#
99 lines
3.2 KiB
C#
/*
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* Copyright (c) 2019 ETH Zürich, Educational Development and Technology (LET)
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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using System;
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using System.Collections.Specialized;
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using CefSharp;
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using SafeExamBrowser.Configuration.Contracts;
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using SafeExamBrowser.Logging.Contracts;
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using BrowserSettings = SafeExamBrowser.Settings.Browser.BrowserSettings;
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namespace SafeExamBrowser.Browser.Handlers
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{
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internal class ResourceRequestHandler : CefSharp.Handler.ResourceRequestHandler
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{
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private AppConfig appConfig;
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private BrowserSettings settings;
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private ILogger logger;
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internal ResourceRequestHandler(AppConfig appConfig, BrowserSettings settings, ILogger logger)
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{
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this.appConfig = appConfig;
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this.settings = settings;
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this.logger = logger;
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}
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protected override IResourceHandler GetResourceHandler(IWebBrowser webBrowser, IBrowser browser, IFrame frame, IRequest request)
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{
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if (FilterMainRequest(request) || FilterContentRequest(request))
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{
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return ResourceHandler.FromString("<html><body>Blocked!</body></html>");
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}
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return base.GetResourceHandler(webBrowser, browser, frame, request);
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}
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protected override CefReturnValue OnBeforeResourceLoad(IWebBrowser webBrowser, IBrowser browser, IFrame frame, IRequest request, IRequestCallback callback)
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{
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// TODO: CEF does not yet support intercepting requests from service workers, thus the user agent must be statically set at browser
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// startup for now. Once CEF has full support of service workers, the static user agent should be removed and the method below
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// reactivated. See https://bitbucket.org/chromiumembedded/cef/issues/2622 for the current status of development.
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// AppendCustomUserAgent(request);
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if (IsMailtoUrl(request.Url))
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{
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return CefReturnValue.Cancel;
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}
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ReplaceCustomScheme(request);
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return base.OnBeforeResourceLoad(webBrowser, browser, frame, request, callback);
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}
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private void AppendCustomUserAgent(IRequest request)
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{
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var headers = new NameValueCollection(request.Headers);
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var userAgent = request.Headers["User-Agent"];
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headers["User-Agent"] = $"{userAgent} SEB/{appConfig.ProgramInformationalVersion}";
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request.Headers = headers;
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}
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private bool FilterContentRequest(IRequest request)
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{
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return settings.FilterContentRequests && request.ResourceType != ResourceType.MainFrame;
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}
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private bool FilterMainRequest(IRequest request)
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{
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return settings.FilterMainRequests && request.ResourceType == ResourceType.MainFrame;
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}
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private bool IsMailtoUrl(string url)
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{
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return url.StartsWith(Uri.UriSchemeMailto);
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}
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private void ReplaceCustomScheme(IRequest request)
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{
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if (Uri.IsWellFormedUriString(request.Url, UriKind.RelativeOrAbsolute))
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{
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var uri = new Uri(request.Url);
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if (uri.Scheme == appConfig.SebUriScheme)
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{
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request.Url = new UriBuilder(uri) { Scheme = Uri.UriSchemeHttp }.Uri.AbsoluteUri;
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}
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else if (uri.Scheme == appConfig.SebUriSchemeSecure)
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{
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request.Url = new UriBuilder(uri) { Scheme = Uri.UriSchemeHttps }.Uri.AbsoluteUri;
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}
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}
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}
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}
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}
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