zhengwu119 · June 27, 2016 04:45 · May 20, 2014
diff --git a/AVPlayerCaching.m b/AVPlayerCaching.m
@@ -0,0 +1,192 @@
+//
+//  ViewController.m
+//  AVPlayerCaching
+//
+//  Created by Anurag Mishra on 5/19/14.
+//  Sample code to demonstrate how to cache a remote audio file while streaming it with AVPlayer
+//
+
+#import "ViewController.h"
+#import <AVFoundation/AVFoundation.h>
+#import <MobileCoreServices/MobileCoreServices.h>
+
+@interface ViewController () <NSURLConnectionDataDelegate, AVAssetResourceLoaderDelegate>
+
+@property (nonatomic, strong) NSMutableData *songData;
+@property (nonatomic, strong) AVPlayer *player;
+@property (nonatomic, strong) NSURLConnection *connection;
+
+@property (nonatomic, strong) NSHTTPURLResponse *response;
+@property (nonatomic, strong) NSMutableArray *pendingRequests;
+
+
+@end
+
+@implementation ViewController
+
+- (void)viewDidLoad
+{
+    [super viewDidLoad];
+	// Do any additional setup after loading the view, typically from a nib.
+}
+
+- (void)didReceiveMemoryWarning
+{
+    [super didReceiveMemoryWarning];
+    // Dispose of any resources that can be recreated.
+}
+
+- (NSURL *)songURL
+{
+    return [NSURL URLWithString:@"http://sampleswap.org/mp3/artist/earthling/Chuck-Silva_Ninety-Nine-Percent-320.mp3"];
+}
+
+- (NSURL *)songURLWithCustomScheme:(NSString *)scheme
+{
+    NSURLComponents *components = [[NSURLComponents alloc] initWithURL:[self songURL] resolvingAgainstBaseURL:NO];
+    components.scheme = scheme;
+
+    return [components URL];
+}
+
+- (IBAction)playSong:(id)sender
+{
+    AVURLAsset *asset = [AVURLAsset URLAssetWithURL:[self songURLWithCustomScheme:@"streaming"] options:nil];
+    [asset.resourceLoader setDelegate:self queue:dispatch_get_main_queue()];
+
+    self.pendingRequests = [NSMutableArray array];
+
+    AVPlayerItem *playerItem = [AVPlayerItem playerItemWithAsset:asset];
+    self.player = [[AVPlayer alloc] initWithPlayerItem:playerItem];
+    [playerItem addObserver:self forKeyPath:@"status" options:NSKeyValueObservingOptionNew context:NULL];
+}
+
+#pragma mark - NSURLConnection delegate
+
+- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
+{
+    self.songData = [NSMutableData data];
+    self.response = (NSHTTPURLResponse *)response;
+
+    [self processPendingRequests];
+}
+
+- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
+{
+    [self.songData appendData:data];
+
+    [self processPendingRequests];
+}
+
+- (void)connectionDidFinishLoading:(NSURLConnection *)connection
+{
+    [self processPendingRequests];
+
+    NSString *cachedFilePath = [NSTemporaryDirectory() stringByAppendingPathComponent:@"cached.mp3"];
+
+    [self.songData writeToFile:cachedFilePath atomically:YES];
+}
+
+#pragma mark - AVURLAsset resource loading
+
+- (void)processPendingRequests
+{
+    NSMutableArray *requestsCompleted = [NSMutableArray array];
+
+    for (AVAssetResourceLoadingRequest *loadingRequest in self.pendingRequests)
+    {
+        [self fillInContentInformation:loadingRequest.contentInformationRequest];
+
+        BOOL didRespondCompletely = [self respondWithDataForRequest:loadingRequest.dataRequest];
+
+        if (didRespondCompletely)
+        {
+            [requestsCompleted addObject:loadingRequest];
+
+            [loadingRequest finishLoading];
+        }
+    }
+
+    [self.pendingRequests removeObjectsInArray:requestsCompleted];
+}
+
+- (void)fillInContentInformation:(AVAssetResourceLoadingContentInformationRequest *)contentInformationRequest
+{
+    if (contentInformationRequest == nil || self.response == nil)
+    {
+        return;
+    }
+
+    NSString *mimeType = [self.response MIMEType];
+    CFStringRef contentType = UTTypeCreatePreferredIdentifierForTag(kUTTagClassMIMEType, (__bridge CFStringRef)(mimeType), NULL);
+
+    contentInformationRequest.byteRangeAccessSupported = YES;
+    contentInformationRequest.contentType = CFBridgingRelease(contentType);
+    contentInformationRequest.contentLength = [self.response expectedContentLength];
+}
+
+- (BOOL)respondWithDataForRequest:(AVAssetResourceLoadingDataRequest *)dataRequest
+{
+    long long startOffset = dataRequest.requestedOffset;
+    if (dataRequest.currentOffset != 0)
+    {
+        startOffset = dataRequest.currentOffset;
+    }
+
+    // Don't have any data at all for this request
+    if (self.songData.length < startOffset)
+    {
+        return NO;
+    }
+
+    // This is the total data we have from startOffset to whatever has been downloaded so far
+    NSUInteger unreadBytes = self.songData.length - (NSUInteger)startOffset;
+
+    // Respond with whatever is available if we can't satisfy the request fully yet
+    NSUInteger numberOfBytesToRespondWith = MIN((NSUInteger)dataRequest.requestedLength, unreadBytes);
+
+    [dataRequest respondWithData:[self.songData subdataWithRange:NSMakeRange((NSUInteger)startOffset, numberOfBytesToRespondWith)]];
+
+    long long endOffset = startOffset + dataRequest.requestedLength;
+    BOOL didRespondFully = self.songData.length >= endOffset;
+
+    return didRespondFully;
+}
+
+
+- (BOOL)resourceLoader:(AVAssetResourceLoader *)resourceLoader shouldWaitForLoadingOfRequestedResource:(AVAssetResourceLoadingRequest *)loadingRequest
+{
+    if (self.connection == nil)
+    {
+        NSURL *interceptedURL = [loadingRequest.request URL];
+        NSURLComponents *actualURLComponents = [[NSURLComponents alloc] initWithURL:interceptedURL resolvingAgainstBaseURL:NO];
+        actualURLComponents.scheme = @"http";
+
+        NSURLRequest *request = [NSURLRequest requestWithURL:[actualURLComponents URL]];
+        self.connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];
+        [self.connection setDelegateQueue:[NSOperationQueue mainQueue]];
+
+        [self.connection start];
+    }
+
+    [self.pendingRequests addObject:loadingRequest];
+
+    return YES;
+}
+
+- (void)resourceLoader:(AVAssetResourceLoader *)resourceLoader didCancelLoadingRequest:(AVAssetResourceLoadingRequest *)loadingRequest
+{
+    [self.pendingRequests removeObject:loadingRequest];
+}
+
+#pragma KVO
+
+- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
+{
+    if (self.player.currentItem.status == AVPlayerItemStatusReadyToPlay)
+    {
+        [self.player play];
+    }
+}
+
+@end
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