[v5] Fix CommonMediaResponse.resourceTiming info (#4367)

* Fix CommonMediaResponse.resourceTiming info in case PerformanceResourceTiming is not usable (due to cross-origin restrictions)
Dash-Industry-Forum · Jan 24, 2024 · 894d80a · 894d80a
1 parent 14a0d33
commit 894d80a
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Showing 2 changed files with 31 additions and 49 deletions.
diff --git a/src/streaming/models/ThroughputModel.js b/src/streaming/models/ThroughputModel.js
@@ -185,20 +185,14 @@ function ThroughputModel(config) {
      * @private
      */
     function _calculateThroughputValuesForXhr(httpRequest, latencyInMs) {
-        let resourceTimingValues = null;
         let downloadedBytes = NaN;
         let downloadTimeInMs = NaN;
         let deriveThroughputViaResourceTimingApi = false;
 
-
-        if (settings.get().streaming.abr.throughput.useResourceTimingApi) {
-            resourceTimingValues = _deriveDownloadValuesFromResourceTimingApi(httpRequest)
-        }
-
-        // Calculate the throughput using the ResourceTimingAPI if we got useful values
-        if (resourceTimingValues && !isNaN(resourceTimingValues.downloadedBytes) && !isNaN(resourceTimingValues.downloadTimeInMs)) {
-            downloadTimeInMs = resourceTimingValues.downloadTimeInMs;
-            downloadedBytes = resourceTimingValues.downloadedBytes;
+        // Calculate the throughput using the ResourceTimingAPI if available
+        if (settings.get().streaming.abr.throughput.useResourceTimingApi && httpRequest._resourceTimingValues) {
+            downloadedBytes = httpRequest._resourceTimingValues.transferSize;
+            downloadTimeInMs = httpRequest._resourceTimingValues.responseEnd - httpRequest._resourceTimingValues.responseStart;
             deriveThroughputViaResourceTimingApi = true;
         }
 
@@ -231,36 +225,6 @@ function ThroughputModel(config) {
         };
     }
 
-    /**
-     * Calculate the downloaded bytes and the download times using the resource timing API
-     * @param httpRequest
-     * @returns {{downloadTimeInMs: (*|number|NaN), downloadedBytes: (*|number|NaN)}}
-     * @private
-     */
-    function _deriveDownloadValuesFromResourceTimingApi(httpRequest) {
-        let downloadedBytes = NaN;
-        let downloadTimeInMs = NaN;
-
-        if (_areResourceTimingValuesUsable(httpRequest)) {
-            downloadedBytes = httpRequest._resourceTimingValues.transferSize;
-            downloadTimeInMs = httpRequest._resourceTimingValues.responseEnd - httpRequest._resourceTimingValues.responseStart;
-        }
-
-        return { downloadedBytes, downloadTimeInMs }
-    }
-
-    /**
-     * Checks if we got useful ResourceTimingAPI values
-     * @param httpRequest
-     * @param {boolean} ignoreTransferSize
-     * @returns {null|*|boolean}
-     * @private
-     */
-    function _areResourceTimingValuesUsable(httpRequest, ignoreTransferSize = false) {
-        return settings.get().streaming.abr.throughput.useResourceTimingApi && httpRequest._resourceTimingValues && !isNaN(httpRequest._resourceTimingValues.responseStart) && httpRequest._resourceTimingValues.responseStart > 0
-            && !isNaN(httpRequest._resourceTimingValues.responseEnd) && httpRequest._resourceTimingValues.responseEnd > 0 && ((!isNaN(httpRequest._resourceTimingValues.transferSize) && httpRequest._resourceTimingValues.transferSize > 0) || ignoreTransferSize)
-    }
-
     /**
      * Return the current estimated bandwidth based on NetworkInformation.downlink if the API is available
      * @returns {*|number}
@@ -285,7 +249,7 @@ function ThroughputModel(config) {
      */
     function _isCachedResponse(mediaType, cacheReferenceTime, httpRequest) {
 
-        if (_areResourceTimingValuesUsable(httpRequest, true)) {
+        if (settings.get().streaming.abr.throughput.useResourceTimingApi && httpRequest._resourceTimingValues) {
             return httpRequest._resourceTimingValues.transferSize === 0 && httpRequest._resourceTimingValues.decodedBodySize > 0
         }
 

diff --git a/src/streaming/net/HTTPLoader.js b/src/streaming/net/HTTPLoader.js
@@ -490,16 +490,34 @@ function HTTPLoader(cfg) {
             i += 1;
         }
 
+        // Check if PerformanceResourceTiming values are usable
+        // Note: to allow seeing cross-origin timing information, the Timing-Allow-Origin HTTP response header needs to be set
+        // See https://developer.mozilla.org/en-US/docs/Web/API/PerformanceResourceTiming#cross-origin_timing_information
+        if (!_areResourceTimingValuesUsable(resource)) {
+            return;
+        }
+
         httpRequest.customData.request.resourceTimingValues = resource;
 
-        // Use Resource Timing info when available for CommonMediaResponse
-        if (resource) {
-            httpResponse.resourceTiming.startTime = resource.startTime;
-            httpResponse.resourceTiming.encodedBodySize = resource.encodedBodySize;
-            httpResponse.resourceTiming.responseStart = resource.startTime;
-            httpResponse.resourceTiming.responseEnd = resource.responseEnd;
-            httpResponse.resourceTiming.duration = resource.duration;
-        }
+        // Update CommonMediaResponse Resource Timing info
+        httpResponse.resourceTiming.startTime = resource.startTime;
+        httpResponse.resourceTiming.encodedBodySize = resource.encodedBodySize;
+        httpResponse.resourceTiming.responseStart = resource.startTime;
+        httpResponse.resourceTiming.responseEnd = resource.responseEnd;
+        httpResponse.resourceTiming.duration = resource.duration;
+    }
+
+    /**
+     * Checks if we got usable ResourceTimingAPI values
+     * @param httpRequest
+     * @returns {boolean}
+     * @private
+     */
+    function _areResourceTimingValuesUsable(resource) {
+        return resource &&
+            !isNaN(resource.responseStart) && resource.responseStart > 0 &&
+            !isNaN(resource.responseEnd) && resource.responseEnd > 0 &&
+            !isNaN(resource.transferSize) && resource.transferSize > 0
     }
 
     /**