spoof USO referrer for their style search API

fixes #413

content/install-hook-userstyles.js

@@ -330,12 +330,13 @@
   }
 })();
 
-document.documentElement.appendChild(document.createElement('script')).text = '(' +
-  function () {
+// run in page context
+document.documentElement.appendChild(document.createElement('script')).text = `(${
+  EXTENSION_ORIGIN => {
     document.currentScript.remove();
 
     // spoof Stylish extension presence in Chrome
-    if (chrome.app) {
+    if (window.chrome && chrome.app) {
       const realImage = window.Image;
       window.Image = function Image(...args) {
         return new Proxy(new realImage(...args), {
@@ -354,6 +355,29 @@ document.documentElement.appendChild(document.createElement('script')).text = '(
       };
     }
 
+    // spoof USO referrer for style search in the popup
+    if (window !== top && location.pathname === '/') {
+      window.addEventListener('message', ({data, origin}) => {
+        if (!data ||
+            !data.xhr ||
+            origin !== EXTENSION_ORIGIN) {
+          return;
+        }
+        const xhr = new XMLHttpRequest();
+        xhr.responseType = 'json';
+        xhr.onloadend = xhr.onerror = () => {
+          window.stop();
+          top.postMessage({
+            id: data.xhr.id,
+            status: xhr.status,
+            response: xhr.response,
+          }, EXTENSION_ORIGIN);
+        };
+        xhr.open('GET', data.xhr.url);
+        xhr.send();
+      });
+    }
+
     // USO bug workaround: use the actual style settings in API response
     let settings;
     const originalResponseJson = Response.prototype.json;
@@ -426,7 +450,8 @@ document.documentElement.appendChild(document.createElement('script')).text = '(
         return json;
       });
     };
-  } + ')()';
+  }
+})('${chrome.runtime.getURL('').slice(0, -1)}')`;
 
 // TODO: remove the following statement when USO pagination is fixed
 if (location.search.includes('category=')) {

manifest.json

@@ -14,6 +14,8 @@
   "permissions": [
     "tabs",
     "webNavigation",
+    "webRequest",
+    "webRequestBlocking",
     "contextMenus",
     "storage",
     "alarms",
@@ -60,7 +62,7 @@
     {
       "matches": ["http://userstyles.org/*", "https://userstyles.org/*"],
       "run_at": "document_start",
-      "all_frames": false,
+      "all_frames": true,
       "js": ["content/install-hook-userstyles.js"]
     },
     {

popup/search-results.js

@@ -51,6 +51,9 @@ window.addEventListener('showStyles:done', function _() {
   let searchCurrentPage = 1;
   let searchExhausted = false;
 
+  let searchFrame;
+  let searchFrameQueue;
+
   const processedResults = [];
   const unprocessedResults = [];
 
@@ -697,15 +700,7 @@ window.addEventListener('showStyles:done', function _() {
     return readCache(cacheKey)
       .then(json =>
         json ||
-        download(searchURL, {
-          method: 'GET',
-          headers: {
-            'Content-type': 'application/json',
-            'Accept': '*/*'
-          },
-          responseType: 'json',
-          body: null
-        }).then(writeCache))
+        searchInFrame(searchURL).then(writeCache))
       .then(json => {
         searchCurrentPage = json.current_page + 1;
         searchTotalPages = json.total_pages;
@@ -783,5 +778,78 @@ window.addEventListener('showStyles:done', function _() {
     ignoreChromeError();
   }
 
+  //endregion
+  //region USO referrer spoofing via iframe
+
+  function searchInFrame(url) {
+    return searchFrame ? new Promise((resolve, reject) => {
+      const id = performance.now();
+      const timeout = setTimeout(() => {
+        searchFrameQueue.get(id).reject();
+        searchFrameQueue.delete(id);
+      }, 10e3);
+      searchFrameQueue.set(id, {resolve, reject, timeout});
+      searchFrame.contentWindow.postMessage({xhr: {id, url}}, '*');
+    }) : setupFrame().then(() => searchInFrame(url));
+  }
+
+  function setupFrame() {
+    searchFrame = $create('iframe', {src: BASE_URL});
+    searchFrameQueue = new Map();
+
+    const stripHeaders = info => ({
+      responseHeaders: info.responseHeaders.filter(({name}) => !/^X-Frame-Options$/i.test(name)),
+    });
+    chrome.webRequest.onHeadersReceived.addListener(stripHeaders, {
+      urls: [BASE_URL + '/'],
+      types: ['sub_frame'],
+    }, [
+      'blocking',
+      'responseHeaders',
+    ]);
+
+    let frameId;
+    const stripResources = info => {
+      if (!frameId && info.url === BASE_URL + '/') {
+        frameId = info.frameId;
+      } else if (frameId === info.frameId && info.type !== 'xmlhttprequest') {
+        return {redirectUrl: 'data:,'};
+      }
+    };
+    chrome.webRequest.onBeforeRequest.addListener(stripResources, {
+      urls: ['<all_urls>'],
+    }, [
+      'blocking',
+    ]);
+    setTimeout(() => {
+      chrome.webRequest.onBeforeRequest.removeListener(stripResources);
+    }, 10e3);
+
+    window.addEventListener('message', ({data, origin}) => {
+      if (!data || origin !== BASE_URL) return;
+      const {resolve, reject, timeout} = searchFrameQueue.get(data.id) || {};
+      if (!resolve) return;
+      chrome.webRequest.onBeforeRequest.removeListener(stripResources);
+      searchFrameQueue.delete(data.id);
+      clearTimeout(timeout);
+      if (data.response && data.status < 400) {
+        resolve(data.response);
+      } else {
+        reject(data.status);
+      }
+    });
+
+    return new Promise((resolve, reject) => {
+      const done = event => {
+        chrome.webRequest.onHeadersReceived.removeListener(stripHeaders);
+        (event.type === 'load' ? resolve : reject)();
+      };
+      searchFrame.addEventListener('load', done, {once: true});
+      searchFrame.addEventListener('error', done, {once: true});
+      searchFrame.style.setProperty('display', 'none', 'important');
+      document.body.appendChild(searchFrame);
+    });
+  }
+
   //endregion
 });