feat(browser): restore custom request interceptor

This enables blocking of external resources in docsets.

The original implementation of the request interceptor was
temporary removed in 373606a1ed.

src/libs/browser/CMakeLists.txt

@@ -1,6 +1,7 @@
 add_library(Browser STATIC
     searchtoolbar.cpp
     settings.cpp
+    urlrequestinterceptor.cpp
     webbridge.cpp
     webcontrol.cpp
     webpage.cpp

src/libs/browser/settings.cpp

@@ -22,6 +22,8 @@
 
 #include "settings.h"
 
+#include "urlrequestinterceptor.h"
+
 #include <core/settings.h>
 
 #include <QFileInfo>
@@ -49,6 +51,13 @@ Settings::Settings(Core::Settings *appSettings, QObject *parent)
     // Create a new off-the-record profile.
     m_webProfile = new QWebEngineProfile(this);
 
+    // Setup URL interceptor.
+#if QT_VERSION >= QT_VERSION_CHECK(5, 13, 0)
+    m_webProfile->setUrlRequestInterceptor(new UrlRequestInterceptor(this));
+#else
+    m_webProfile->setRequestInterceptor(new UrlRequestInterceptor(this));
+#endif
+
     // Listen to settings changes.
     connect(m_appSettings, &Core::Settings::updated, this, &Settings::applySettings);
     applySettings();

src/libs/browser/urlrequestinterceptor.cpp

@@ -0,0 +1,74 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 Oleg Shparber
+** Copyright (C) 2019 Kay Gawlik
+** Contact: https://go.zealdocs.org/l/contact
+**
+** This file is part of Zeal.
+**
+** Zeal is free software: you can redistribute it and/or modify
+** it under the terms of the GNU General Public License as published by
+** the Free Software Foundation, either version 3 of the License, or
+** (at your option) any later version.
+**
+** Zeal is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+** GNU General Public License for more details.
+**
+** You should have received a copy of the GNU General Public License
+** along with Zeal. If not, see <http://www.gnu.org/licenses/>.
+**
+****************************************************************************/
+
+#include "urlrequestinterceptor.h"
+
+#include <core/networkaccessmanager.h>
+
+#include <QLoggingCategory>
+
+using namespace Zeal::Browser;
+
+static Q_LOGGING_CATEGORY(log, "zeal.browser.urlrequestinterceptor")
+
+UrlRequestInterceptor::UrlRequestInterceptor(QObject *parent)
+    : QWebEngineUrlRequestInterceptor(parent)
+{
+}
+
+void UrlRequestInterceptor::interceptRequest(QWebEngineUrlRequestInfo &info)
+{
+    const QUrl requestUrl = info.requestUrl();
+    const QUrl firstPartyUrl = info.firstPartyUrl();
+
+    // Block invalid requests.
+    if (!requestUrl.isValid() || !firstPartyUrl.isValid()) {
+        blockRequest(info);
+        return;
+    }
+
+    bool isFirstPartyUrlLocal = Core::NetworkAccessManager::isLocalUrl(firstPartyUrl);
+    bool isRequestUrlLocal = Core::NetworkAccessManager::isLocalUrl(requestUrl);
+
+    // Direct links are controlled in the WebPage
+    if (info.resourceType() == QWebEngineUrlRequestInfo::ResourceTypeMainFrame) {
+        return;
+    }
+
+    // Allow local resources on local pages and external resources on external pages.
+    if (isFirstPartyUrlLocal == isRequestUrlLocal) {
+        return;
+    }
+
+    blockRequest(info);
+}
+
+void UrlRequestInterceptor::blockRequest(QWebEngineUrlRequestInfo &info)
+{
+    qCDebug(log, "Blocked request: %s '%s' (resource_type=%d, navigation_type=%d).",
+            info.requestMethod().data(),
+            qPrintable(info.requestUrl().toString()),
+            info.resourceType(), info.navigationType());
+
+    info.block(true);
+}

src/libs/browser/urlrequestinterceptor.h

@@ -0,0 +1,47 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 Oleg Shparber
+** Copyright (C) 2019 Kay Gawlik
+** Contact: https://go.zealdocs.org/l/contact
+**
+** This file is part of Zeal.
+**
+** Zeal is free software: you can redistribute it and/or modify
+** it under the terms of the GNU General Public License as published by
+** the Free Software Foundation, either version 3 of the License, or
+** (at your option) any later version.
+**
+** Zeal is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+** GNU General Public License for more details.
+**
+** You should have received a copy of the GNU General Public License
+** along with Zeal. If not, see <http://www.gnu.org/licenses/>.
+**
+****************************************************************************/
+
+#ifndef ZEAL_BROWSER_URLREQUESTINTERCEPTOR_H
+#define ZEAL_BROWSER_URLREQUESTINTERCEPTOR_H
+
+#include <QWebEngineUrlRequestInterceptor>
+
+namespace Zeal {
+namespace Browser {
+
+class UrlRequestInterceptor final : public QWebEngineUrlRequestInterceptor
+{
+    Q_OBJECT
+    Q_DISABLE_COPY(UrlRequestInterceptor)
+public:
+    UrlRequestInterceptor(QObject *parent = nullptr);
+    void interceptRequest(QWebEngineUrlRequestInfo &info) override;
+
+private:
+    void blockRequest(QWebEngineUrlRequestInfo &info);
+};
+
+} // namespace Browser
+} // namespace Zeal
+
+#endif // ZEAL_BROWSER_URLREQUESTINTERCEPTOR_H