How to do offline playback with DRMToday on iOS

This how-to guide describes how to implement playback of downloadable content-protected HLS streams using the THEOplayer iOS SDK. Currently, FairPlay is supported together with the Irdeto and DRMToday integrations.

Prerequisites

In order to do offline DRM on iOS, your license key should be downloadable and cacheable. The SDK will not be able to decrypt your content if your key expired.

This feature only works on iOS 10.0 and above.

Known limitations

1. If your manifest gets redirected when you are caching and playing back a resource, you need to save your redirected manifest URL (what is being cached) and provide that (redirected) URL to the player when you would like to play back from the cache.
2. Only completely cached videos can be played offline. (When the CachingTask status is DONE, then the video is playable without any internet connection)
3. HLS manifests can have a tag #EXT-X-PLAYLIST-TYPE:VOD (https://developer.apple.com/documentation/http_live_streaming/example_playlists_for_http_live_streaming/video_on_demand_playlist_construction) If this tag is not present in the manifest of the cached quality, THEOplayer will make extra request for the manifest event if the video is completely cached. To avoid from these extra request, you need to provide EXT-X-PLAYLIST-TYPE:VOD in your manifests.

Code example

Download a FairPlay HLS asset.

//example source
public static var sourceToBeCached: SourceDescription {
    let src = "https://source.m3u8"
    let merchant = "merchant"
    let userId = "userId"
    let sessionId = "sessionId"
    let streamType = "application/x-mpegurl"
    let drmConfig = DRMTodayDRMConfiguration(
                        licenseAcquisitionURL: "https://lic.staging.drmtoday.com/license-server-fairplay/",
                        certificateURL: "https://lic.staging.drmtoday.com/license-server-fairplay/cert/",
                        userId: userId,
                        sessionId: sessionId,
                        merchant: merchant
                    )
    return SourceDescription(source: TypedSource(src: src, type: streamType, drm: drmConfig))
}

//example cache call
var cachingTask: CachingTask?

func cacheSource(SourceDescription source, Date expirationDate) {
            cachingTask = THEOplayer.cache.createTask(source: source, parameters: CachingParameters(expirationDate: expirationDate))
            if cachingTask != nil {
                _ = cachingTask!.addEventListener(type: CachingTaskEventTypes.STATE_CHANGE) { event in
                    print("Received state change on caching task \(self.cachingTask!.source.sources[0].src) Status: \(self.cachingTask!.status)")
                }
                _ = cachingTask!.addEventListener(type: CachingTaskEventTypes.PROGRESS) { event in
                    print("Received progress on caching task \(self.cachingTask!.source.sources[0].src) Cached: ")
                    for timeRange in self.cachingTask!.cached {
                        print(timeRange.start, timeRange.end)
                    }
                }
                cachingTask.start()
            }
}

func playSourceFromCache(SourceDescription source) {
    theoplayer.source = source
    theoplayer.play();
}

Delete all cached assets.

func cleanCache() {
    for cachingTask in THEOplayer.cache.tasks {
        print("Will remove caching task \(cachingTask.source.sources[0].src)")
        cachingTask.remove()
    }
}

Renew a DRM license with specific DRM configuration.

func renewLicense() {
    let newDrmConfig = DRMTodayDRMConfiguration(
                            licenseAcquisitionURL: "https://lic.staging.drmtoday.com/license-server-fairplay/",
                            certificateURL: "https://lic.staging.drmtoday.com/license-server-fairplay/cert/",
                            userId: userId,
                            sessionId: sessionId,
                            merchant: merchant
                        )

    cachingTask.license.renew(newDrmConfig) // or we can renew it with the old drmConfig too: cachingTask.license.renew()
}

Handle redirected manifest.

// cache source

let url = URL(string: "MASTER_MANIFEST_URL_THAT_GETS_REDIRECTED")

let task = URLSession.shared.dataTask(with: url!) { (data, response, error) in

    Streams.SAVED_REDIRECTED_URL = (response?.url)!
    cachingTaskSource.sources[0].src = Streams.SAVED_REDIRECTED_URL!
    self.cachingTask = THEOplayer.cache.createTask(source: cachingTaskSource, parameters: CachingParameters(expirationDate: Date.distantFuture, bandwidth: cachingTaskBandwidth))
    if self.cachingTask != nil {
        _ = self.cachingTask!.addEventListener(type: CachingTaskEventTypes.STATE_CHANGE) { event in
            if let cachingTask = self.cachingTask {
                print("Received state change on caching task \(cachingTask.source.sources[0].src) Status: \(cachingTask.status)")
            }
        }
        _ = self.cachingTask!.addEventListener(type: CachingTaskEventTypes.PROGRESS) { event in
            print("Received progress on caching task \(self.cachingTask!.source.sources[0].src) Cached: ")
            for timeRange in self.cachingTask!.cached {
                print(timeRange.start, timeRange.end)
            }
        }
        print("Did create caching task \(self.cachingTask!.source.sources[0].src)")
    }

}

task.resume()


// playback of cached source

var source = cachingTaskSource
source.sources[0].src = Streams.SAVED_REDIRECTED_URL!
theoplayer.source = source
theoplayer.play()