fixup! Fixed external links in the viewer iframe

Before this fix clicking an external link in the viewer iframe had no
effect (other than an error being reported in the browser dev tools
console) because the attempt to navigate the top browser context was
suppressed due to sandboxing.

src/server/internalServer.cpp

@@ -1088,6 +1088,7 @@ const std::string CONTENT_CSP_HEADER =
 
     "sandbox allow-scripts "
             "allow-same-origin "
+            "allow-top-navigation-by-user-activation "
             "allow-modals "
             "allow-popups "
             "allow-forms "

static/skin/viewer.js

@@ -257,7 +257,7 @@ function isExternalUrl(url) {
       || url.startsWith("https:");
 }
 
-function onClickEvent(e) {
+function handleLinkClick(e) {
   const iframeDocument = contentIframe.contentDocument;
   const target = matchingAncestorElement(e.target, iframeDocument, "a");
   if (target !== null && "href" in target) {
@@ -266,6 +266,8 @@ function onClickEvent(e) {
       if ( viewerSettings.linkBlockingEnabled ) {
         return blockLink(target);
       }
+    } else {
+      target.setAttribute("target", "content_iframe");
     }
   }
 }
@@ -301,7 +303,7 @@ this.Element && function(ElementPrototype) {
 }(Element.prototype);
 
 function setup_external_link_blocker() {
-  setupEventHandler(contentIframe.contentDocument, 'a', 'click', onClickEvent);
+  setupEventHandler(contentIframe.contentDocument, 'a', 'click', handleLinkClick);
 }
 
 ////////////////////////////////////////////////////////////////////////////////

static/viewer.html

@@ -69,6 +69,7 @@
     </div>
 
     <iframe id="content_iframe"
+            name="content_iframe"
             referrerpolicy="no-referrer"
             onload="on_content_load()"
             src="./skin/blank.html?KIWIXCACHEID" title="ZIM content" width="100%"

test/server.cpp

@@ -73,7 +73,7 @@ const ResourceCollection resources200Compressible{
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/taskbar.css" },
   { STATIC_CONTENT,  "/ROOT%23%3F/skin/taskbar.css?cacheid=bbdaf425" },
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/viewer.js" },
-  { STATIC_CONTENT,  "/ROOT%23%3F/skin/viewer.js?cacheid=b9a574d4" },
+  { STATIC_CONTENT,  "/ROOT%23%3F/skin/viewer.js?cacheid=b548ad94" },
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/fonts/Poppins.ttf" },
   { STATIC_CONTENT,  "/ROOT%23%3F/skin/fonts/Poppins.ttf?cacheid=af705837" },
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/fonts/Roboto.ttf" },
@@ -312,7 +312,7 @@ R"EXPECTEDRESULT(    <link type="text/css" href="./skin/taskbar.css?cacheid=bbda
     <link type="text/css" href="./skin/css/autoComplete.css?cacheid=08951e06" rel="Stylesheet" />
     <script type="module" src="./skin/i18n.js?cacheid=2cf0f8c5" defer></script>
     <script type="text/javascript" src="./skin/languages.js?cacheid=b00b12db" defer></script>
-    <script type="text/javascript" src="./skin/viewer.js?cacheid=b9a574d4" defer></script>
+    <script type="text/javascript" src="./skin/viewer.js?cacheid=b548ad94" defer></script>
     <script type="text/javascript" src="./skin/autoComplete.min.js?cacheid=1191aaaf"></script>
       const blankPageUrl = root + "/skin/blank.html?cacheid=6b1fa032";
             <img src="./skin/langSelector.svg?cacheid=00b59961">