SJMediaCacheServer

SJMediaCacheServer is an efficient HTTP media caching framework designed to proxy media data requests and prioritize serving cached data, thereby reducing network traffic and enhancing playback smoothness. The framework supports two types of remote resources: file-based media, such as common formats like MP3, AAC, WAV, FLAC, OGG, MP4, and MOV, as well as HLS (HTTP Live Streaming) streams. It automatically parses HLS playlists and proxies individual media segments.

The design of SJMediaCacheServer effectively reduces the number of network requests by serving cached content, thereby improving the playback experience for remote media resources whenever possible.

Installation

pod 'SJUIKit/SQLite3', :podspec => 'https://gitee.com/changsanjiang/SJUIKit/raw/master/SJUIKit-YYModel.podspec'
pod 'SJMediaCacheServer'

Features

• Proxy Playback Requests: Efficiently proxy playback requests by converting original URLs into local proxy URLs. The media player retrieves the data from the local server, which serves cached data if available, or fetches it from the remote server if necessary. This mechanism reduces network usage and enhances playback speed and reliability.

• Format Support: Supports two types of remote resources:

  • file-based media (e.g., MP3, AAC, WAV, FLAC, OGG, MP4, MOV)
  • HLS (HTTP Live Streaming) streams.

• Cache Management Options:

  • Cache Count Limits: Control the number of items stored in the cache to avoid overuse of local storage.
  • Maximum Disk Storage Time: Configure how long items are retained in the cache before being purged, managing long-term storage effectively.
  • Available Disk Space Limits: Ensure the cache stays within a specified disk usage limit, preventing cache overflow from occupying too much local storage.

• Advanced Prefetching Capabilities:

  • Concurrent Prefetching: Use the maxConcurrentPrefetchCount property to control the maximum number of concurrent prefetch tasks, optimizing the prefetching process without overwhelming system resources.
  • Flexible Prefetching Methods:
    • Full Data Prefetching: Use prefetchWithURL: to download all data related to a specific media asset, ensuring that the entire resource is available for playback without additional network requests.
    • Size-Specific Prefetching: With prefetchWithURL:prefetchSize:, request a predefined amount of data for partial prefetching. This is particularly useful for optimizing both bandwidth and storage while ensuring smooth playback.
    • File Count Prefetching for HLS: Leverage the prefetchWithURL:prefetchFileCount: method to prefetch a certain number of segment files for HLS assets. This ensures uninterrupted playback by caching multiple segments in advance, which is especially useful in low-bandwidth environments.

• Custom Request Configuration:

  • Request Modification: Modify outgoing requests by adding custom headers. Example:

    self.requestHandler = ^(NSMutableURLRequest *request) {
        [request addValue:@"YourHeaderValue" forHTTPHeaderField:@"YourHeaderField"];
    };

  • Custom HTTP Headers: Configure HTTP headers for specific asset URLs, such as HLS keys or segments. Example:

    [self setHTTPHeaderField:@"YourHeaderField" withValue:@"YourHeaderValue" forAssetURL:assetURL ofType:MCSDataTypeHLS];

  • Data Encryption & Decryption: Encrypt data before writing to the cache and decrypt after reading. Example:

    self.writeDataEncryptor = ^NSData *(NSURLRequest *request, NSUInteger offset, NSData *data) {
        return encryptedData; // Apply encryption
    };
    
    self.readDataDecryptor = ^NSData *(NSURLRequest *request, NSUInteger offset, NSData *data) {
        return decryptedData; // Apply decryption
    };

  • Asset Type & Identifier Resolution: Use custom logic to determine the asset type and identifier. Example:

    self.resolveAssetType = ^MCSAssetType(NSURL *URL) {
        return [URL.pathExtension isEqualToString:@"m3u8"] ? MCSAssetTypeHLS : MCSAssetTypeFILE;
    };
    
    self.resolveAssetIdentifier = ^NSString *(NSURL *URL) {
        return [NSURLComponents componentsWithURL:URL resolvingAgainstBaseURL:NO].URL.absoluteString;
    };

Example Use Case

@implementation YourPlayerController {
    AVPlayer *_player;
}

- (instancetype)initWithURL:(NSURL *)URL {
    self = [super init];
    if ( self ) {
        // Convert the original URL to a proxy URL
        NSURL *playbackURL = [SJMediaCacheServer.shared proxyURLFromURL:URL];
        _player = [AVPlayer playerWithURL:playbackURL];
    }
    return self;
}

- (void)play {
    [SJMediaCacheServer.shared setActive:YES];
    [_player play];
}

- (void)seekToTime:(NSTimeInterval)time {
    [SJMediaCacheServer.shared setActive:YES];
    [_player seekToTime:time];
}
@end

License

SJMediaCacheServer is released under the MIT license.

Feedback

• GitHub : changsanjiang
• Email : changsanjiang@gmail.com
• QQGroup: 930508201

Reference

• KTVHTTPCache - KTVHTTPCache is a powerful media cache framework. It can cache HTTP request, and very suitable for media resources.

• https://tools.ietf.org/html/rfc7233#section-2.1