我正在尝试使用随机数据实现上传并测量速度。现在，我正在生成这样的随机NSData：
void * bytes = malloc("");
NSData * myData = [NSData dataWithBytes:bytes length:"bytes"];
free("bytes");
但是，如果我要上传一个大文件，将会出现内存问题。
我的上传过程是这样的：
NSURLSessionConfiguration *sessionConfig =
[NSURLSessionConfiguration defaultSessionConfiguration];
NSURLSession *session =
[NSURLSession sessionWithConfiguration:sessionConfig
delegate:self
delegateQueue:nil];
NSURL * urll = [NSURL URLWithString:UPLOAD_SERVER];
NSMutableURLRequest * urlRequest = [NSMutableURLRequest requestWithURL:urll];
[urlRequest setHTTPMethod:@"POST"];
[urlRequest addValue:@"Keep-Alive" forHTTPHeaderField:@"Connection"];
NSString *boundary = @"*****";
NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary];
[urlRequest addValue:contentType forHTTPHeaderField: @"Content-Type"];
NSMutableData *body = [NSMutableData data];
[body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[@"Content-Type: application/octet-stream\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
// setting the body of the post to the reqeust
[urlRequest setHTTPBody:body];
void * bytes = malloc(250000000);
NSData * uploadData = [NSData dataWithBytes:bytes length:250000000];
free(bytes);
ulTask = [session uploadTaskWithRequest:urlRequest fromData:uploadData];
[ulTask resume];
有没有办法用缓冲区或其他东西上传？例如生成小数据，将其上传并生成一个新数据，然后再次上传？
我建议只是开始上传并继续发送数据。您还可以通过使用uploadTaskWithStreamedRequest然后创建一个NSInputStream子类来避免创建250mb缓冲区，而该子类将一直提供更多数据，直到您停止它为止。您可以实施URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:监视上传进度（因此可以监视发送数据的速度）。
无论如何，要创建上传请求：
@interface ViewController () <NSURLSessionDelegate, NSURLSessionTaskDelegate>
@property (nonatomic, strong) CustomStream *inputStream;
@end
@implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
self.inputStream = [[CustomStream alloc] init];
NSURL *url = [NSURL URLWithString:kURLString];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:@"POST"];
NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration delegate:self delegateQueue:nil];
NSURLSessionUploadTask *task = [session uploadTaskWithStreamedRequest:request];
[task resume];
// I don't know how you want to finish the upload, but I'm just going
// to stop it after 10 seconds
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(10.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
self.inputStream.finished = YES;
});
}
您显然必须实现适当的委托方法：
#pragma mark - NSURLSessionTaskDelegate
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didSendBodyData:(int64_t)bytesSent totalBytesSent:(int64_t)totalBytesSent totalBytesExpectedToSend:(int64_t)totalBytesExpectedToSend
{
NSLog(@"%lld %lld %lld", bytesSent, totalBytesSent, totalBytesExpectedToSend);
}
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task needNewBodyStream:(void (^)(NSInputStream *bodyStream))completionHandler
{
completionHandler(self.inputStream);
}
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{
NSLog(@"%s: error = %@; data = %@", __PRETTY_FUNCTION__, error, [[NSString alloc] initWithData:self.responseData encoding:NSUTF8StringEncoding]);
}
#pragma mark - NSURLSessionDataDelegate
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition disposition))completionHandler
{
self.responseData = [NSMutableData data];
completionHandler(NSURLSessionResponseAllow);
}
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data
{
[self.responseData appendData:data];
}
和CustomStream：
static NSInteger const kBufferSize = 32768;
@interface CustomStream : NSInputStream
@property (nonatomic, readonly) NSStreamStatus streamStatus;
@property (nonatomic, getter = isFinished) BOOL finished;
@end
@interface CustomStream ()
@property (nonatomic) NSStreamStatus streamStatus;
@property (nonatomic) void *buffer;
@end
@implementation CustomStream
- (instancetype)init
{
self = [super init];
if (self) {
_buffer = malloc(kBufferSize);
NSAssert(_buffer, @"Unable to create buffer");
memset(_buffer, 0, kBufferSize);
}
return self;
}
- (void)dealloc
{
if (_buffer) {
free(_buffer);
self.buffer = NULL;
}
}
- (void)open
{
self.streamStatus = NSStreamStatusOpen;
}
- (void)close
{
self.streamStatus = NSStreamStatusClosed;
}
- (NSInteger)read:(uint8_t *)buffer maxLength:(NSUInteger)len
{
if ([self isFinished]) {
if (self.streamStatus == NSStreamStatusOpen) {
self.streamStatus = NSStreamStatusAtEnd;
}
return 0;
}
NSUInteger bytesToCopy = MIN(len, kBufferSize);
memcpy(buffer, _buffer, bytesToCopy);
return bytesToCopy;
}
- (BOOL)getBuffer:(uint8_t **)buffer length:(NSUInteger *)len
{
return NO;
}
- (BOOL)hasBytesAvailable
{
return self.streamStatus == NSStreamStatusOpen;
}
- (void)scheduleInRunLoop:(__unused NSRunLoop *)aRunLoop
forMode:(__unused NSString *)mode
{}
- (void)removeFromRunLoop:(__unused NSRunLoop *)aRunLoop
forMode:(__unused NSString *)mode
{}
#pragma mark Undocumented CFReadStream Bridged Methods
- (void)_scheduleInCFRunLoop:(__unused CFRunLoopRef)aRunLoop
forMode:(__unused CFStringRef)aMode
{}
- (void)_unscheduleFromCFRunLoop:(__unused CFRunLoopRef)aRunLoop
forMode:(__unused CFStringRef)aMode
{}
- (BOOL)_setCFClientFlags:(__unused CFOptionFlags)inFlags
callback:(__unused CFReadStreamClientCallBack)inCallback
context:(__unused CFStreamClientContext *)inContext {
return NO;
}
@end
我建议您参考BJ Homer的文章Subclassing NSInputStream来获得该子类中一些隐秘方法的一些背景知识NSInputStream。
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