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uniapp/Google Chrome/Resources/media_sniffer.js

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+// 资源嗅探脚本：在安装页面播放器脚本之前接管 fetch / XMLHttpRequest / createObjectURL，
+// 把真正被下载的媒体地址（mp4 / m3u8 等）回报给宿主程序，用于"下载视频"按钮。
+(function () {
+  if (window.__mediaSniffInstalled) return;
+  window.__mediaSniffInstalled = true;
+
+  window.__mediaUrls = [];
+  window.__m3u8Blobs = [];
+
+  var MEDIA_EXT =
+    /\.(mp4|flv|m3u8|mpd|mkv|mov|m4v|webm|f4v|3gp|mpg|mpeg|ts)(\?|#|$)/i;
+  var PLAIN_EXT =
+    /\.(jpg|jpeg|png|gif|webp|ico|svg|bmp|css|js|json|woff2?|ttf|map|txt)(\?|#|$)/i;
+
+  function isMediaUrl(u) {
+    if (!u) return false;
+    u = String(u);
+    if (u.indexOf("blob:") === 0 || u.indexOf("data:") === 0) return false;
+    if (PLAIN_EXT.test(u)) return false;
+    return MEDIA_EXT.test(u) || /\/(video|vod|playback|media)[\/-]/i.test(u);
+  }
+
+  function absUrl(u) {
+    try {
+      return new URL(String(u), location.href).href;
+    } catch (e) {
+      return String(u);
+    }
+  }
+
+  function post(msg) {
+    try {
+      if (
+        window.chrome &&
+        window.chrome.webview &&
+        window.chrome.webview.postMessage
+      ) {
+        window.chrome.webview.postMessage(JSON.stringify(msg));
+      }
+    } catch (e) {}
+  }
+
+  function remember(text) {
+    if (!text || typeof text !== "string") return;
+    if (text.indexOf("#EXTM3U") < 0) return;
+    if (window.__m3u8Blobs.indexOf(text) >= 0) return;
+    window.__m3u8Blobs.push(text);
+    post({ type: "hlsText", text: text });
+  }
+
+  function report(u) {
+    try {
+      var full = absUrl(u);
+      if (!isMediaUrl(full)) return;
+      if (window.__mediaUrls.indexOf(full) >= 0) return;
+      window.__mediaUrls.push(full);
+      // base 是发出这个请求的文档地址：播放器常在跨域 iframe 里，
+      // 宿主必须用它当 Referer，用顶层页面地址会被防盗链判为非法来源
+      post({ type: "media", url: full, base: location.href });
+    } catch (e) {}
+  }
+
+  window.__reportMedia = report;
+  window.__rememberHlsText = remember;
+
+  // 抖音等站点会用 atob(base64) 把播放地址还原出来，这里顺手抓一份解码结果
+  try {
+    var origAtob = window.atob;
+    if (origAtob) {
+      window.atob = function (s) {
+        var r = origAtob.apply(this, arguments);
+        try {
+          if (r && typeof r === "string") {
+            if (r.indexOf("#EXTM3U") >= 0) remember(r);
+            else if (isMediaUrl(r)) report(r);
+          }
+        } catch (e) {}
+        return r;
+      };
+    }
+  } catch (e) {}
+
+  try {
+    var origFetch = window.fetch;
+    if (origFetch) {
+      window.fetch = function (input, init) {
+        try {
+          var u =
+            typeof input === "string" || input instanceof URL
+              ? input
+              : input && input.url;
+          if (u) report(u);
+        } catch (e) {}
+        return origFetch.apply(this, arguments);
+      };
+    }
+  } catch (e) {}
+
+  try {
+    var xhrOpen = XMLHttpRequest.prototype.open;
+    var xhrSend = XMLHttpRequest.prototype.send;
+    XMLHttpRequest.prototype.open = function (method, u) {
+      try {
+        if (u) report(u);
+      } catch (e) {}
+      return xhrOpen.apply(this, arguments);
+    };
+    XMLHttpRequest.prototype.send = function () {
+      var xhr = this;
+      try {
+        xhr.addEventListener("load", function () {
+          try {
+            if (xhr.responseType === "" || xhr.responseType === "text") {
+              remember(xhr.responseText);
+            } else if (
+              xhr.responseType === "blob" &&
+              xhr.response &&
+              xhr.response.text
+            ) {
+              xhr.response.text().then(remember);
+            }
+          } catch (e) {}
+        });
+      } catch (e) {}
+      return xhrSend.apply(this, arguments);
+    };
+  } catch (e) {}
+
+  // MSE 播放时 video.src 只能是 blob:，抓不到 http 地址，所以靠上面的分片嗅探兜底；
+  // 这里额外记录 createObjectURL 的调用，方便识别"确实在用 MSE"。
+  try {
+    var ocu = window.URL && window.URL.createObjectURL;
+    if (ocu) {
+      window.URL.createObjectURL = function (obj) {
+        var u = ocu.apply(this, arguments);
+        try {
+          window.__usesMse = true;
+          if (obj && typeof obj.text === "function") obj.text().then(remember);
+        } catch (e) {}
+        return u;
+      };
+    }
+  } catch (e) {}
+})();