前言: 之前有项目要实现m3u8本地播放，后面自己写了一个多线程下载的demo，里面坑很多。因为时间问题，也没时间去填坑，后面还是采用单线程下载。但想了下m3u8本地缓存播放这个需求，每个公司的需求可能有所差异。但m3u8是协议好的东西，解析跟组装的部分应该都差不多。所以下面就记录下这部分的内容。
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定义模型存储信息
@class ZBLM3u8TsInfo;@interface ZBLM3u8Info : NSObject@property (nonatomic, copy) NSString *targetduration;@property (nonatomic, copy) NSString *version;@property (nonatomic, copy) NSString *mediaSequence;///key信息@property (nonatomic, copy) NSString *keyMethod;@property (nonatomic, copy) NSString *keyUri;@property (nonatomic, copy) NSString *keyLocalUri;@property (nonatomic, copy) NSString *keyIv;@property (nonatomic, strong) NSMutableArray
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定义处理类，根据m3u8文本信息把信息保存到模型中并做相关的容错处理
.h定义
@class ZBLM3u8Info;typedef void (^ZBLM3u8AnalysiseCompletaionHandler)(ZBLM3u8Info *m3u8Info,NSError *error);@interface ZBLM3u8Analysiser : NSObject/** m3u8解析 @param urlStr m3u8网络url @param completaionHandler 回调 */+ (void)analysisWithUrlString:(NSString*)urlStr completaionHandler:(ZBLM3u8AnalysiseCompletaionHandler)completaionHandler;/** m3u8文本组装 @param m3u8Info m3u8信息模型 @return m3u8文本 */+ (NSString*)synthesisLocalM3u8Withm3u8Info:(ZBLM3u8Info *)m3u8Info;FOUNDATION_EXPORT NSString * const ZBLM3u8AnalysiserResponeErrorDomain;FOUNDATION_EXPORT NSString * const ZBLM3u8AnalysiserAnalysisErrorDomain;@end复制代码
.m实现
/*解析m3u8 和组装m3u8*/NSString * const ZBLM3u8AnalysiserResponeErrorDomain = @"error.m3u8.analysiser.respone";NSString * const ZBLM3u8AnalysiserAnalysisErrorDomain = @"error.m3u8.analysiser.analysis";@implementation ZBLM3u8Analysiser+ (void)analysisWithUrlString:(NSString*)urlStr completaionHandler:(ZBLM3u8AnalysiseCompletaionHandler)completaionHandler{ NSLog(@"analysis start"); //判断m3u8文本是否已经保存到本地，因为下载m3u8文本是耗时操作 NSString *oriM3u8String = [NSString stringWithContentsOfFile:[[ZBLM3u8Setting fullCommonDirPrefixWithUrl:urlStr] stringByAppendingPathComponent:[ZBLM3u8Setting oriM3u8InfoFileName]] encoding:0 error:nil]; __block BOOL happenException = NO; if (oriM3u8String.length) { NSLog(@"use local oriM3u8Info"); //处理有可能失败，所有需要加try-catch-finally，保护程序 @try { [self analysisWithM3u8String:oriM3u8String completaionHandler:completaionHandler]; } @catch (NSException *exception) { happenException = YES; [[ZBLM3u8FileManager shareInstance]removeFileWithPath:[[ZBLM3u8Setting fullCommonDirPrefixWithUrl:urlStr] stringByAppendingPathComponent:[ZBLM3u8Setting oriM3u8InfoFileName]]]; completaionHandler(nil,[[NSError alloc]initWithDomain:ZBLM3u8AnalysiserAnalysisErrorDomain code:NSURLErrorUnknown userInfo:@{@"info":exception.reason}]); } @finally { } if (!happenException) { return; } } happenException = NO; //异步获取 dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ NSString *m3u8Str = nil; //处理有可能失败，所有需要加try-catch-finally，保护程序 @try { NSError *error = nil; //根据url请求获取m3u8文本，耗时操作 m3u8Str = [[NSString alloc] initWithContentsOfURL:[NSURL URLWithString:urlStr] usedEncoding:0 error:&error]; if (error) { completaionHandler(nil,error); return ; } if (m3u8Str.length == 0) { completaionHandler(nil,[[NSError alloc]initWithDomain:ZBLM3u8AnalysiserResponeErrorDomain code:NSURLErrorBadServerResponse userInfo:nil]); return; } //解析 [self analysisWithM3u8String:m3u8Str completaionHandler:completaionHandler]; } @catch (NSException *exception) { happenException = YES; completaionHandler(nil,[[NSError alloc]initWithDomain:ZBLM3u8AnalysiserAnalysisErrorDomain code:NSURLErrorUnknown userInfo:@{@"info":exception.reason}]); } @finally { } if (!happenException) { //保存原m3u8文本，方便二次利用 [[ZBLM3u8FileManager shareInstance]saveDate:[m3u8Str dataUsingEncoding:NSUTF8StringEncoding] ToFile:[[ZBLM3u8Setting fullCommonDirPrefixWithUrl:urlStr] stringByAppendingPathComponent:[ZBLM3u8Setting oriM3u8InfoFileName]] completaionHandler:nil]; } });}/** private method m3u8文本解析 @param m3u8String m3u8文本 @param completaionHandler 回调 */+ (void)analysisWithM3u8String:(NSString*)m3u8String completaionHandler:(ZBLM3u8AnalysiseCompletaionHandler)completaionHandler{ ZBLM3u8Info *info = [ZBLM3u8Info new]; info.version = [[m3u8String subStringFrom:@"#EXT-X-VERSION:" to:@"#"] removeSpaceAndNewline]; info.targetduration = [[m3u8String subStringFrom:@"#EXT-X-TARGETDURATION:" to:@"#"] removeSpaceAndNewline]; info.mediaSequence = [[m3u8String subStringFrom:@"#EXT-X-MEDIA-SEQUENCE:" to:@"#"] removeSpaceAndNewline]; info.keyMethod = [m3u8String subStringFrom:@"#EXT-X-KEY:METHOD=" to:@","]; info.keyUri = [m3u8String subStringFrom:@"URI=\"" to:@"\""]; info.keyIv = [[m3u8String subStringFrom:@"IV=" to:@"#"] removeSpaceAndNewline]; NSRange tsRange = [m3u8String rangeOfString:@"#EXTINF:"]; if (tsRange.location == NSNotFound) { completaionHandler(nil,[[NSError alloc]initWithDomain:ZBLM3u8AnalysiserAnalysisErrorDomain code:NSURLErrorUnknown userInfo:@{@"info":@"none downloadUrl for .ts file"}]); return; } NSInteger index = 0; NSMutableArray *tsInfos = @[].mutableCopy; m3u8String = [m3u8String substringFromIndex:tsRange.location]; while (tsRange.location != NSNotFound) { ZBLM3u8TsInfo *tsInfo = [ZBLM3u8TsInfo new]; tsInfo.duration = [m3u8String subStringFrom:@"#EXTINF:" to:@","]; m3u8String = [m3u8String subStringForm:@"," offset:1]; tsInfo.oriUrlString = [[m3u8String subStringTo:@"#"] removeSpaceAndNewline]; NSRange exRange = [m3u8String rangeOfString:@"#EX"]; NSRange discontinuityRange = [m3u8String rangeOfString:@"#EXT-X-DISCONTINUITY"]; if (exRange.location == discontinuityRange.location) { tsInfo.hasDiscontiunity = YES; } tsInfo.index = index ++; [tsInfos addObject:tsInfo]; tsRange = [m3u8String rangeOfString:@"#EXTINF:"]; if (tsRange.location != NSNotFound) { m3u8String = [m3u8String subStringForm:@"#EXTINF:" offset:0]; } } NSLog(@"analysis compelte"); info.tsInfos = tsInfos; NSParameterAssert(completaionHandler); completaionHandler(info,nil);}复制代码 -
根据本地保存的ts信息更新模型，并重新组装m3u8文本信息
+ (NSString*)synthesisLocalM3u8Withm3u8Info:(ZBLM3u8Info *)m3u8Info{ NSString *newM3u8String = @""; NSString *header = @"#EXTM3U\n"; if (m3u8Info.version.length) { header = [header stringByAppendingString:[NSString stringWithFormat:@"#EXT-X-VERSION:%ld\n",(long)m3u8Info.version.integerValue]]; } if (m3u8Info.targetduration.length) { header = [header stringByAppendingString:[NSString stringWithFormat:@"#EXT-X-TARGETDURATION:%ld\n",(long)m3u8Info.targetduration.integerValue]]; } if (m3u8Info.mediaSequence.length) { header = [header stringByAppendingString:[NSString stringWithFormat:@"#EXT-X-MEDIA-SEQUENCE:%ld\n",(long)m3u8Info.mediaSequence.integerValue]]; } NSString *keyStr = @""; if(m3u8Info.keyUri.length) { keyStr = [NSString stringWithFormat:@"#EXT-X-KEY:METHOD=%@,URI=\"%@\",IV=%@\n",m3u8Info.keyMethod,m3u8Info.keyLocalUri,m3u8Info.keyIv]; } __block NSString *body = @""; [m3u8Info.tsInfos enumerateObjectsUsingBlock:^(ZBLM3u8TsInfo * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) { NSString *tsInfo = [NSString stringWithFormat:@"#EXTINF:%.6lf,\n%@\n",obj.duration.floatValue,obj.localUrlString]; body = [body stringByAppendingString:tsInfo]; if (obj.isHasDiscontiunity) body = [body stringByAppendingString:@"#EXT-X-DISCONTINUITY\n"]; }]; newM3u8String = [[[[newM3u8String stringByAppendingString:header] stringByAppendingString:keyStr] stringByAppendingString:body] stringByAppendingString:@"#EXT-X-ENDLIST"]; return newM3u8String; }复制代码
demo: