How to insert header info into MPMoviePlayerContro

问题:

I need to implement video streaming service with http protocol. I know how to set url into MPMoviePlayerController, and how to set headerField into NSMutableURLRequest, but I have no idea how to combine them. I implement like below code, but not working, and I assume because there is no file info in the binary data.

- (void) openUrl
{
    NSMutableURLRequest *reqURL = [NSMutableURLRequest requestWithURL:
                               [NSURL URLWithString:@"http://111.222.33.44/MOV/2013/4/123123123"] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:30.0];

    [reqURL setHTTPMethod:@"GET"];
    [reqURL setValue:@"Mozilla/4.0 (compatible;)" forHTTPHeaderField:@"User-Agent"];
    [reqURL setValue:@"AAA-bb" forHTTPHeaderField:@"Auth-Token"];
    [reqURL setValue:@"bytes=0-1024" forHTTPHeaderField:@"Range"];
    [reqURL setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];

    [NSURLConnection connectionWithRequest:reqURL delegate:self];

}


- (void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{    
    NSLog(@"Received");
    NSError * jsonERR = nil;

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *path = [documentsDirectory stringByAppendingPathComponent:@"myMove.ts"];

    [data writeToFile:path atomically:YES];
    NSLog(@"copied");
    NSURL *moveUrl = [NSURL fileURLWithPath:path];

    MPMoviePlayerController *player = [[MPMoviePlayerController alloc]init];
    [player setContentURL:moveUrl];
    player.view.frame = self.view.bounds;
    player.controlStyle = MPMovieControlStyleEmbedded;
    [self.view addSubview:player.view];
    [player play];
}

I confirmed there is data in the delegate method, but I don't know how to play it. Please somebody let me know how to play it. Auth-Token and Range are necessary parameters.

Thanks.

回答1:

It's true that Apple doesn't expose an easy way to inject headers into a MPMoviePlayerController's request. With a bit of effort, you can get this done using a custom NSURLProtocol. So, let's do it!

MyCustomURLProtocol.h:

@interface MyCustomURLProtocol : NSURLProtocol <NSURLConnectionDelegate, NSURLConnectionDataDelegate>

@property (nonatomic, strong) NSURLConnection* connection;

@end

MyCustomURLProtocol.m:

@implementation  MyCustomURLProtocol

// Define which protocols you want to handle
// In this case, I'm only handling "customProtocol" manually
// Everything else, (http, https, ftp, etc) is handled by the system
+ (BOOL) canInitWithRequest:(NSURLRequest *)request {
    NSURL* theURL = request.URL;
    NSString* scheme = theURL.scheme;
    if([scheme isEqualToString:@"customProtocol"]) {
        return YES;
    }
    return NO;
}

// You could modify the request here, but I'm doing my legwork in startLoading
+ (NSURLRequest *)canonicalRequestForRequest:(NSURLRequest *)request {
    return request;
}

// I'm not doing any custom cache work
+ (BOOL) requestIsCacheEquivalent:(NSURLRequest *)a toRequest:(NSURLRequest *)b {
    return [super requestIsCacheEquivalent:a toRequest:b];
}

// This is where I inject my header
// I take the handled request, add a header, and turn it back into http
// Then I fire it off
- (void) startLoading {
    NSMutableURLRequest* mutableRequest = [self.request mutableCopy];
    [mutableRequest setValue:@"customHeaderValue" forHTTPHeaderField:@"customHeaderField"];

    NSURL* newUrl = [[NSURL alloc] initWithScheme:@"http" host:[mutableRequest.URL host] path:[mutableRequest.URL path]];
    [mutableRequest setURL:newUrl];

    self.connection = [NSURLConnection connectionWithRequest:mutableRequest delegate:self];
}

- (void) stopLoading {
    [self.connection cancel];
}

// Below are boilerplate delegate implementations
// They are responsible for letting our client (the MPMovePlayerController) what happened

- (void) connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    [self.client URLProtocol:self didFailWithError:error];
    self.connection = nil;
}

- (void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [self.client URLProtocol:self didLoadData:data];
}

- (void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    [self.client URLProtocol:self didReceiveResponse:response cacheStoragePolicy:NSURLCacheStorageAllowed];
}

- (void) connectionDidFinishLoading:(NSURLConnection *)connection {
    [self.client URLProtocolDidFinishLoading:self];
    self.connection = nil;
}

@end

Before you can use your custom URL Protocol, you must register it. In your AppDelegate.m:

#import "MyCustomURLProtocol.h"

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    // ... Your normal setup ...

    [NSURLProtocol registerClass:[MyCustomURLProtocol class]];

    return YES;
}

Finally, you need to user your custom URL Protocol with the MPMediaPlayerController.

NSString* theURLString = [NSString stringWithFormat:@"customProtocol://%@%@", [_url host],[_url path]];
_player = [[MPMoviePlayerController alloc] initWithContentURL:[NSURL URLWithString:theURLString]];

The MPMoviePlayerController will now attempt to make the request with customProtocol:// instead of normal http://. Using this setup, we then intercept that request, add our headers, turn it into http, and then fire everything off.

回答2:

Go back and read the documentation for NSURLConnection, and the URL-loading system in general. -connection:didReceiveData: is likely called more than once, as each chunk of the file arrives. You need to handle that, rather than assuming only the complete data arrives all at once.