直接下载文件时NSURLConnection的NSData不匹配

Question

我正在尝试在NSData对象中找到FFF9十六进制表示，当我在我的网络浏览器中输入网址并将文件下载到我的mac然后打开它时，我会使用NSURLConnection文本编辑器我得到以下看似真实的值

从开始几行：

4944 3304 0000 0000 025f 5449 5432 0000
0006 0000 0353 7479 6c65 5450 4531 0000
000e 0000 0354 6179 6c6f 7220 5377 6966
7400 5758 5858 0000 016e 0000 0055 524c
0073 6f6e 675f 7370 6f74 3d22 4d22 204d
6564 6961 4261 7365 4964 3d22 3230 3632
3435 3622 2069 7475 6e65 7354 7261 636b
4964 3d22 3022 2061 6d67 5472 6163 6b49
643d 222d 3122 2061 6d67 4172 7469 7374
4964 3d22 3022 2054 4149 443d 2233 3332
3231 2220 5450 4944 3d22 3239 3139 3533
3234 2220 6361 7274 6375 7449 643d 2230
3838 3030 3832 3030 3122 2061 6d67 4172
7477 6f72 6b55 524c 3d22 6874 7470 3a2f
2f61 7373 6574 732e 6968 6561 7274 2e63
6f6d 2f69 6d61 6765 732f 3130 3830 2f4d
4930 3030 3337 3936 3333 3622 206c 656e
6774 683d 2230 303a 3033 3a34 3722 2075
6e73 4944 3d22 2d31 2200 5052 4956 0000
0035 0000 636f 6d2e 6170 706c 652e 7374
7265 616d 696e 672e 7472 616e 7370 6f72
7453 7472 6561 6d54 696d 6573 7461 6d70
0000 0000 0084 e5fb 8eff f95c 4022 a000
0148 3614 56a8 4506 0b42 7230 602c 1419
9813 6c2d 7863 46ef 3805 6845 ded6 0387
9d24 4253 30ed 0210 5d45 1dd6 a660 8aa0
0063 5e6a 83a6 44ba 7136 154c 321e af45
a499 eb24 e389 a7ab 7184 79cc 3b10 61ff
d83c 95ff 22a2 1738 7236 1a30 0ccb 3996
772d b001 930f 5023 1e57 2bfb a9dd b80b
6f34 0441 3b06 ad59 0cf7 07a1 b151 710b

然后当我使用nsurl获取Objective-c中的数据时，我得到以下数据

来自nsdata

的几行

3c21444f 43545950 45206874 6d6c2050 55424c49 4320222d 2f2f5733 432f2f44 54442058 48544d4c 20312e31 2f2f454e 22202268 7474703a 2f2f7777 772e7733 2e6f7267 2f54522f 7868746d 6c31312f 4454442f 7868746d 6c31312e 64746422 3e0a0a3c 68746d6c 20786d6c 6e733d22 68747470 3a2f2f77 77772e77 332e6f72 672f3139 39392f78 68746d6c 2220786d 6c3a6c61 6e673d22 656e223e 0a202020 203c6865 61643e0a 20202020 20202020 3c746974 6c653e54 68652070 61676520 6973206e 6f742066 6f756e64 3c2f7469 746c653e 0a202020 20202020 203c6d65 74612068 7474702d 65717569 763d2243 6f6e7465 6e742d54 79706522 20636f6e 74656e74 3d227465 78742f68 746d6c3b 20636861 72736574 3d555446 2d382220 2f3e0a20 20202020 2020203c 7374796c 65207479 70653d22 74657874 2f637373 223e0a20 20202020 20202020 2020202f 2a3c215b 43444154 415b2a2f 0a202020 20202020 20202020 20626f64 79207b0a 20202020 20202020 20202020 20202020 6261636b 67726f75 6e642d63 6f6c6f72 3a202366 66663b0a 20202020 20202020 20202020 20202020 636f6c6f 723a2023 3030303b 0a202020 20202020 20202020 20202020 20666f6e 742d7369 7a653a20 302e3965 6d3b0a20 20202020 20202020 20202020 20202066 6f6e742d 66616d69 6c793a20 73616e73 2d736572 69662c68 656c7665 74696361 3b0a2020 20202020 20202020 20202020 20206d61 7267696e 3a20303b 0a202020 20202020 20202020 20202020 20706164 64696e67 3a20303b 0a202020 20202020 20202020 207d0a20 20202020 20202020 2020203a 6c696e6b 207b0a20 20202020 20202020 20202020 20202063 6f6c6f72 3a202363 30303b0a 20202020 20202020 20202020 7d0a2020 20202020 20202020 20203a76 69736974 6564207b 0a202020 20202020 20202020 20202020 20636f6c 6f723a20 23633030 3b0a2020 20202020 20202020 20207d0a 20202020 20202020 20202020 613a686f 76657220 7b0a2020 20202020 20202020 20202020 2020636f 6c6f723a 20236635 303b0a20 20202020 20202020 2020207d 0a202020 20202020 20202020 20683120 7b0a2020 20202020 20202020 20202020 20207465 78742d61 6c69676e 3a206365 6e746572 3b0a2020 20202020 20202020 20202020 20206d61 7267696e 3a20303b 0a202020 20202020 20202020 20202020 20706164 64696e67 3a20302e 36656d20 32656d20 302e3465 6d3b0a20 20202020 20202020 20202020 20202062 61636b67 726f756e 642d636f 6c6f723a 20233239 34313732 3b0a2020 

这显然不一样。

当我在通过webbrowser下载的文件上运行以下代码时，它可以正常工作

NSDate *start = [NSDate date];
// The magic start data object is only created once safely and
// then reused each time
static NSData* magicStartData = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
    static const uint8_t magic[] = { 0xff, 0xf9 };
    magicStartData = [NSData dataWithBytesNoCopy:(void*)magic length:2 freeWhenDone:NO];
});

// assume data is the NSData with embedded data
NSLog(@"data %@",audioData);
NSData* subdata;
NSRange rangeCost = [audioData rangeOfData:magicStartData options:0 range:NSMakeRange(0, [audioData length])];
if (rangeCost.location != NSNotFound) {
    // This assumes the subdata doesn't have a specific range and is just everything
    // after the magic, otherwise adjust
    subdata = [audioData subdataWithRange:NSMakeRange(rangeCost.location, [audioData length] - rangeCost.location)];
    NSLog(@"Sub data %@",subdata);

    NSDate *methodFinish = [NSDate date];
    NSTimeInterval executionTime = [methodFinish timeIntervalSinceDate:start];
    NSLog(@"Execution Time: %f", executionTime);


}

显然，相同的代码在我通过FFF9获取的NSData中找不到NSURLConnection

我的连接代码;

 (void)downloadDataWithUrl:(NSURL *)url andFileName:(NSString *)fileName
{
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    [NSURLConnection sendAsynchronousRequest:request
                                       queue:[NSOperationQueue mainQueue]
                           completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
                               if ( !error )
                               {
                                      //NSLog(@"data %@",data);
                                   [self audioFileReaderWithData:data andFileName:fileName];

                               } else{
                                    NSLog(@"downloadDataWithUrl failed");
                               }
                           }];
}

有什么想法，我该如何解决这个问题？

EDIT :::::::::
我觉得我需要在这里解释确切的故事 我先下载以下网址  http://playlists.ihrhls.com/c5/1469/playlist.m3u8 解析该链接会提供.m3u文件链接，类似于此

#EXTM3U
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=49000,CODECS="mp4a.40.5"
http://playlists.ihrhls.com/c5/1469/playlist.m3u8?listeningSessionID=54868da4e3b93b4a_5943659_OcMl11nw_0000006Uz93&downloadSessionID=0

下载此内容  http://playlists.ihrhls.com/c5/1469/playlist.m3u8?listeningSessionID=54868da4e3b93b4a_5943659_OcMl11nw_0000006Uz93&downloadSessionID=0

这里它提供了3个.aac文件块。

#EXTM3U
#EXT-X-ALLOW-CACHE:NO

#EXT-X-TARGETDURATION:11
#EXT-X-MEDIA-SEQUENCE:0
#EXTINF:10,title="Spotblockend",artist="Spotblockend",url="song_spot=\"O\" MediaBaseId=\"0\" itunesTrackId=\"0\" amgTrackId=\"-1\" amgArtistId=\"0\" TAID=\"0\" TPID=\"0\" cartcutId=\"1\" amgArtworkURL=\"\" length=\"00:00:00\" unsID=\"-1\""
http://chunks.ihrhls.com/1469/khHfMfxGiN5-241374-9984.aac
#EXTINF:10,title="Spotblockend",artist="Spotblockend",url="song_spot=\"O\" MediaBaseId=\"0\" itunesTrackId=\"0\" amgTrackId=\"-1\" amgArtistId=\"0\" TAID=\"0\" TPID=\"0\" cartcutId=\"1\" amgArtworkURL=\"\" length=\"00:00:00\" unsID=\"-1\""
http://chunks.ihrhls.com/1469/lvwjN9sH8Ke-241375-9984.aac
#EXTINF:10,title="Spotblockend",artist="Spotblockend",url="song_spot=\"O\" MediaBaseId=\"0\" itunesTrackId=\"0\" amgTrackId=\"-1\" amgArtistId=\"0\" TAID=\"0\" TPID=\"0\" cartcutId=\"1\" amgArtworkURL=\"\" length=\"00:00:00\" unsID=\"-1\""
http://chunks.ihrhls.com/1469/iE906eJEm2i-241376-10031.aac

我需要那些NSData格式的.aac文件。

正如我在我的问题中解释的那样，当我在网络浏览器中输入http://chunks.ihrhls.com/1469/iE906eJEm2i-241376-10031.aac链接时，它会向我发送实际的.aac文件，但当我使用与NSURL connection NSDATA response相同的链接时带有The page is not found响应的html页面。

为什么会这样？！

注意：m3u文件和.aac文件每隔两小时就会过期，因此当您阅读此链接时，这些链接将无法使用，因此您需要再次查看此链接http://playlists.ihrhls.com/c5/1469/playlist.m3u8

Answer 1

更新问题附加信息（再次）：

测试代码：

NSURL *url;
NSMutableURLRequest *request;
NSURLResponse *response;
NSError *error;
NSData *data;
NSString *string;
NSRange range;

// First get the current URL
url = [NSURL URLWithString:@"http://playlists.ihrhls.com/c5/1469/playlist.m3u8"];
request = [NSMutableURLRequest requestWithURL:url];
data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

// Get the audio URL
range = [string rangeOfString:@"http"];
string = [string substringFromIndex:range.location];
string = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
url = [NSURL URLWithString:string];
NSLog(@"url:\n%@", url);

// Get the Audio info
request = [NSMutableURLRequest requestWithURL:url];
data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(@"string:\n%@", string);

// Get the first chunk URL
range = [string rangeOfString:@"http"];
string = [string substringFromIndex:range.location];
range = [string rangeOfString:@"#"];
string = [string substringToIndex:range.location];

string = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
url = [NSURL URLWithString:string];
NSLog(@"url: %@", url);

// Get the first audio chunk
request = [NSMutableURLRequest requestWithURL:url];
[NSURLConnection sendAsynchronousRequest:request
                                   queue:[NSOperationQueue mainQueue]
                       completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
                           if ( !error ) {
                               NSLog(@"data: %@", [data subdataWithRange:NSMakeRange(0, 20)]);
                               NSLog(@"data+296: %@", [data subdataWithRange:NSMakeRange(296, 20)]);
                               //                                       [self audioFileReaderWithData:data andFileName:fileName];

                           }
                           else {
                               NSLog(@"downloadDataWithUrl failed");
                           }
                       }];

输出：

SingleView[19993:1612455] url:
http://playlists.ihrhls.com/c5/1469/playlist.m3u8?listeningSessionID=54868d904e0d78ec_5989234_FIJrewys_000000NAxC3&downloadSessionID=0

string:
#EXTM3U
#EXT-X-ALLOW-CACHE:NO
#EXT-X-TARGETDURATION:11
#EXT-X-MEDIA-SEQUENCE:0
#EXTINF:10,title="Z100",artist="NY's #1 Hit Music Station",url="song_spot=\"T\" MediaBaseId=\"0\" itunesTrackId=\"0\" amgTrackId=\"0\" amgArtistId=\"0\" TAID=\"0\" TPID=\"0\" cartcutId=\"0\" amgArtworkURL=\"\" length=\"00:00:00\" unsID=\"0\""
http://chunks.ihrhls.com/1469/0GmnHSSGis2-245920-10031.aac
#EXTINF:10,title="Z100",artist="NY's #1 Hit Music Station",url="song_spot=\"T\" MediaBaseId=\"0\" itunesTrackId=\"0\" amgTrackId=\"0\" amgArtistId=\"0\" TAID=\"0\" TPID=\"0\" cartcutId=\"0\" amgArtworkURL=\"\" length=\"00:00:00\" unsID=\"0\""
http://chunks.ihrhls.com/1469/AA2skPqDDCc-245921-9984.aac
#EXTINF:10,title="Z100",artist="NY's #1 Hit Music Station",url="song_spot=\"T\" MediaBaseId=\"0\" itunesTrackId=\"0\" amgTrackId=\"0\" amgArtistId=\"0\" TAID=\"0\" TPID=\"0\" cartcutId=\"0\" amgArtworkURL=\"\" length=\"00:00:00\" unsID=\"0\""
http://chunks.ihrhls.com/1469/Dzt4rpXJBlg-245922-9984.aac

url: http://chunks.ihrhls.com/1469/0GmnHSSGis2-245920-10031.aac

data: 49443304 00000000 021e5449 54320000 00050000

data+296: fff95c40 21c00001 4a36298c c4489589 0150b166

这是所需aac数据的前20个字节，296个字节是您要查找的值“FFF9”。

回答最初的问题： 转换问题中的十六进制后你有什么：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
    <head>
        <title>The page is not found</title>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
        <style type="text/css">
            /*<![CDATA[*/
            body {
                background-color: #fff;
                color: #000;
                font-size: 0.9em;
                font-family: sans-serif,helvetica;
                margin: 0;
                padding: 0;
            }
            :link {
                color: #c00;
            }
            :visited {
                color: #c00;
            }
            a:hover {
                color: #f50;
            }
            h1 {
                text-align: center;
                margin: 0;
                padding: 0.6em 2em 0.4em;
                background-color: #294172;

特别注意标题：“找不到页面”。

网址可能不正确。