iOS NSURLConnection (sendAsynchronousRequest:)缓存太多

Question

我有几个内存泄漏(不！)参见我的应用程序中的更新1)，它们都归结为异步URLRequest。下面的代码给了我一个内存泄漏，似乎‘数据’从来没有释放(下面的代码在我的应用程序中逻辑上没有使用，因为它是一个完全无用的无限循环，我写它只是为了显示内存泄漏。这使得使用的RAM在不到1秒的时间内从5 MB变为20 MB。我的互联网速度与此相匹配，只是为了记录一下)：

- (void)start{
    NSOperationQueue *oQC = [[NSOperationQueue alloc] init];
    NSLog(@"a");
    [NSURLConnection sendAsynchronousRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.online-image-editor.com//styles/2014/images/example_image.png"]] queue:oQC completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
        NSLog(@"b");
        [self start];
    }];
}

我也尝试过设置数据=零，但就像假设的那样，这是行不通的。有没有人知道如何避免内存泄漏，以及这是否是NSURLConnection的正常行为？

更新1:

这似乎与内存泄漏无关，而是与缓存问题有关。(感谢@rdelmar，他发现了这个问题，但他的解决方案不太奏效)

基于this post，我尝试在它的.h文件中创建一个新的“Loader”类：

#import <Foundation/Foundation.h>

@interface Loader : NSObject <NSURLConnectionDelegate, NSURLConnectionDataDelegate>

@property NSMutableData *mData;
@property (nonatomic, copy) void (^returnBlock)(NSData *data, NSError *error);

- (id)initForWhateverWithURLString:(NSString*)urlString andHandler:(void (^)(NSData *data, NSError *error))handler;

@end

在它的.m文件中：

#import "Loader.h"

@implementation Loader

@synthesize mData;

- (id)initForWhateverWithURLString:(NSString*)urlString andHandler:(void (^)(NSData *data, NSError *error))handler{
    self = [super init];
    if (self) {
        /*NSOperationQueue *oQC = [NSOperationQueue mainQueue];
        [NSURLConnection sendAsynchronousRequest:mUR queue:oQC completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
            [[NSURLCache sharedURLCache] removeCachedResponseForRequest:mUR];
            handler(nil, nil);
         }];*/
        mData = [NSMutableData new];
        self.returnBlock = handler;
        NSMutableURLRequest *mUR = [[NSURLRequest requestWithURL:[NSURL URLWithString:urlString] cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:60] mutableCopy];
        NSURLConnection *URLCon = [[NSURLConnection alloc] initWithRequest:mUR delegate:self];
        [URLCon start];
    }
    return self;
}

- (NSCachedURLResponse *)connection:(NSURLConnection *)connection willCacheResponse:(NSCachedURLResponse *)cachedResponse{
    return nil;
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
    [mData appendData:data];
    data = nil;
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection{
    self.returnBlock(mData, nil);
    mData = nil;
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{
    self.returnBlock(nil, error);
}

@end

我还实施了：

NSURLCache *sharedCache = [[NSURLCache alloc] initWithMemoryCapacity:0 diskCapacity:0 diskPath:@"nsurlcache"];
[NSURLCache setSharedURLCache:sharedCache];

尽管如此，这两种方法都没有帮助减少剧烈的RAM使用！

Answer 1

我觉得你看到的不是泄密。我认为内存不断增加，因为数据正在被缓存。如果更改请求的缓存协议，问题就解决了(通过使用requestWithURL:)获得默认行为requestWithURL：)

- (void)viewDidLoad {
    [super viewDidLoad];
    self.req = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.online-image-editor.com//styles/2014/images/example_image.png"] cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:10];
    [self start];
}

- (void)start{
    NSOperationQueue *oQC = [NSOperationQueue mainQueue]; // this queue is where the completion block runs, so you should use mainQueue if you want to do any UI updating
    NSLog(@"a");
    [NSURLConnection sendAsynchronousRequest:self.req queue:oQC completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
        NSLog(@"b");
        [self start];
    }];
}

编辑后的：

再看一看，我不知道为什么sendAsynchronousRequest:会导致内存使用量随着时间的增加而增加。我使用NSURLSession进行了测试(这也是我们现在应该使用的)，而且这似乎没有增加内存。

- (void)viewDidLoad {
    [super viewDidLoad];
    NSString *urlString = @"http://www.online-image-editor.com//styles/2014/images/example_image.png";
    self.req = [NSURLRequest requestWithURL:[NSURL URLWithString:urlString] cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:10];
    [self start];
}

- (void)start{
    NSLog(@"a");
    NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[NSOperationQueue mainQueue]];
    NSURLSessionDataTask *task = [session dataTaskWithRequest:self.req completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
        self.counter ++;
        NSLog(@"counter is: %ld", self.counter);
        [self start];
    }];
    [task resume];
}

Answer 2

如果不使用ARC，则更改

[[NSOperationQueue alloc] init];

至

[[[NSOperationQueue alloc] init] autorelease];

和

[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.online-image-editor.com//styles/2014/images/example_image.png"]]

至

[[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.online-image-editor.com//styles/2014/images/example_image.png"]] autorelease]