Added custom file-not-found page

When we try to open or navigate a zim that no longer exists, this page is displayed. Contains the url of the requested zim article

resources/i18n/en.json

@@ -167,5 +167,8 @@
     "no-pictures": "No Pictures",
     "no-videos": "No Videos",
     "open-previous-tabs-at-startup": "Open previous tabs at startup",
-    "preview-book-in-web-browser": "Preview book in web browser"
+    "preview-book-in-web-browser": "Preview book in web browser",
+    "file-not-found-title": "Zim File Not Found",
+    "file-not-found-text": "We can't find the Zim file corresponding to this page. Please check that your file exists.",
+    "zim-url": "Zim Url"
 }

resources/i18n/qqq.json

@@ -174,5 +174,8 @@
 	"clear-filter": "Represents the action of clearing the filters selected for a filter type.",
 	"no-details": "A content type for Zim files representing it only has an introduction.",
 	"no-pictures": "A content type for Zim files that does not contain pictures.",
-	"no-videos": "A content type for Zim files that does not contain videos."
+	"no-videos": "A content type for Zim files that does not contain videos.",
+	"file-not-found-title": "Error title text displayed when the desktop application cannot find the Zim file needed to display the web page.",
+	"file-not-found-text": "Error description text for when the desktop application cannot find the Zim file needed to display the web page.",
+	"zim-url": "The Zim Url path for the currently displayed tab"
 }

src/urlschemehandler.cpp

@@ -44,7 +44,7 @@ UrlSchemeHandler::handleContentRequest(QWebEngineUrlRequestJob *request)
     try {
       archive = library->getArchive(zim_id);
     } catch (std::out_of_range& e) {
-      request->fail(QWebEngineUrlRequestJob::UrlNotFound);
+      replyZimNotFoundPage(request, qurl);
       return;
     }
     try {
@@ -176,6 +176,30 @@ UrlSchemeHandler::handleSearchRequest(QWebEngineUrlRequestJob* request)
     request->reply("text/html", buffer);
 }
 
+void UrlSchemeHandler::replyZimNotFoundPage(QWebEngineUrlRequestJob *request,
+                                            const QUrl &url)
+{
+    QBuffer *buffer = new QBuffer;
+    QString contentHtml = "<section><div><div>"
+                          "<h1>" +
+                          gt("file-not-found-title") +
+                          "</h1>"
+                          "<p>" +
+                          gt("file-not-found-text") +
+                          "</p>"
+                          "<p>" +
+                          gt("zim-url") + ": <b>" + url.url() +
+                          "</b></p>"
+                          "</div></div></section>";
+
+    buffer->open(QIODevice::WriteOnly);
+    buffer->write(contentHtml.toStdString().c_str());
+    buffer->close();
+
+    connect(request, SIGNAL(destroyed()), buffer, SLOT(deleteLater()));
+    request->reply("text/html", buffer);
+}
+
 void
 UrlSchemeHandler::requestStarted(QWebEngineUrlRequestJob *request)
 {

src/urlschemehandler.h

@@ -13,6 +13,8 @@ class UrlSchemeHandler : public QWebEngineUrlSchemeHandler
     void handleMetaRequest(QWebEngineUrlRequestJob *request);
     void handleContentRequest(QWebEngineUrlRequestJob *request);
     void handleSearchRequest(QWebEngineUrlRequestJob *request);
+
+    void replyZimNotFoundPage(QWebEngineUrlRequestJob *request, const QUrl& url);
 };
 
 #endif // URLSCHEMEHANDLER_H