Http request properties

[shri-hari93]

Im working on a project to collect the metrics of the exoplayer. For my metrics, I'm looking forward to extract the http request properties(http list in dash.js) when the player request for fragments. Is there any possible way in the current api to get what I am looking for?

[FD-]

I believe one possibility would be to use the OkHttp extension. When creating the OkHttpClient to be passed to the OkHttpDataSourceFactory constructor, install an Interceptor. From within the Interceptor, you should be able to read the request header fields.

[AquilesCanta]

All media sources -I guess you are interested in DASH- allow you to inject a DataSourceFactory. You can provide your own DataSource implementation which intercepts all requests. Please let me know if this does not cover your needs. Have a look at the DefaultDashChunkSource.

[AquilesCanta]

Also, maybe @tonihei can provide better advise.

[tonihei]

You'll get some request details as a listener callback when you add an AnalyticsListener with SimpleExoPlayer.addAnalyticsListener and check for onLoadStarted, onLoadCompleted, onLoadCanceled and onLoadError. All these callback have a LoadEventInfo class containing the uri, byte range and post body of the request (in DataSpec).

However, I suppose you refer to the HTTP request headers and/or response headers? These are not currently part of the callback, but we can add them to LoadEventInfo as this information may be of general interest. Marking as an enhancement to track this.

[shri-hari93]

Thanks for your help. I will explore this and really looking forward for the enhancement. To clarify @tonihei doubt of what I'm looking for: http://cdn.dashjs.org/latest/jsdoc/streaming_vo_metrics_HTTPRequest.js.html
The metrics similar to the members of the class listed in above link

[tonihei]

Thanks. I think we already have all of the information in this class available and just need to add the response headers.

[shri-hari93]

@tonihei , as you said the members of the following class http://cdn.dashjs.org/latest/jsdoc/streaming_vo_metrics_HTTPRequest.js.html are already available in exoplayer library. Is it possible to extract these information in one of the event listener methods onLoadCompleted, onLoadStarted etc.

I checked the dataspec object returned from loadEventInfo, it doesn't really return the information tht I'm looking for.(trace, trequest, tresponse, tfinish). However I managed to find media duration, bytes loaded and source uri 👍

Could you suggest a way to get the following information:
Trace: Throughput traces, for successful requests
trequest: Time at which request is sent
tresponse: The real time at which the first byte of the response was received
tfinish: The real time at which the request finished

[tonihei]

"Time at which request is sent" - that corresponds to the elapsedRealtimeMs parameter in the LoadEventInfo of onLoadStarted.
"The real time at which the request finished" - same value in the onLoadCompleted callback.
"The real time at which the first byte of the response was received" - For more detailed information on that, you need to add a TransferListener to the DataSource which has a onBytesTransferred method which is called whenever new bytes are received.
"Throughput traces, for successful requests" - If you use a TransferListener as above, you'll get these traces as well (by listening to onBytesTransferred).

[shri-hari93]

Thanks @tonihei for your suggestion. Seems like I have my solution here.

However, I have small clarification on Transfer listener. I'm already using DefaultBandwidthMeter implemented with bandwidthMeter.EventListener in DataSource. Is it possible to implement Transfer listener along with it? I tried this but it didn't seem to work.

Moreover I could not override the DefaultBandwidthMeter since it is final class and it implements TransferListener.

[tonihei]

Good point. It's currently not possible to have multiple transfer listeners. However, we already changed the code to allow multiple transfer listeners per data source in the future. Will be in one of the next releases.

[shri-hari93]

@tonihei Thanks for the clarification. 👍

Regarding your suggested solution, I could able to get the information that I needed but the issue that I'm facing right now is that, I have to collect these metrics periodically when the load is completed and send it to metric server, since I'm listening to multiple event methods (onLoadingStarted, onLoadingCompleted and onBytestransferred) the veracity of the data is lost as these methods are called immediately which does seem like it doesn't happen in sequential manner.

My approach was, I created a class for HTTPList with the attributes as the details that I'm looking for and I write the data to object of this class during the execution of these event methods.

Is there a better way of implementation to overcome this issue. I'm sure having a class like this http://cdn.dashjs.org/latest/jsdoc/streaming_vo_metrics_HTTPRequest.js.html in library would be of great help in future. But for now, any suggestion from your perspective would be helpful.

Moreover, the media duration for the bytes that is transferred, is it possible to get it as well?

[tonihei]

I don't understand where the problem is with getting the callbacks immediately? Note that the TransferListener callbacks are called on the loading thread and AnalyticsListener callbacks on the main thread. Maybe that's the reason why you think there not called in sequential manner.

The media duration is often only known after the load finished. Please listen to updates in onTimelineChanged to check whether the duration is available.

[tonihei]

Closing the issue. The response headers are now part of the LoadEventInfo data.