我正在将 NSOperation 子类化为后台线程中的 http 帖子。
那些特定的 http 帖子不需要返回任何值。

我想要做的是当我遇到错误或超时时，我希望它在增加延迟(斐波那契)后发送。

到目前为止，我已经这样做了:

NSInternetOperation.h:

#import <Foundation/Foundation.h>

@interface NSInternetOperation : NSOperation
@property (nonatomic) BOOL executing;
@property (nonatomic) BOOL finished;
@property (nonatomic) BOOL completed;
@property (nonatomic) BOOL cancelled;
- (id)initWebServiceName:(NSString*)webServiceName andPerameters:(NSString*)parameters;
- (void)start;
@end

#import "NSInternetOperation.h"

static NSString * const kFinishedKey = @"isFinished";
static NSString * const kExecutingKey = @"isExecuting";

@interface NSInternetOperation ()
@property (strong, nonatomic) NSString *serviceName;
@property (strong, nonatomic) NSString *params;
- (void)completeOperation;
@end

@implementation NSInternetOperation

- (id)initWebServiceName:(NSString*)webServiceName andPerameters:(NSString*)parameters
{
    self = [super init];
    if (self) {
        _serviceName = webServiceName;
        _params = parameters;
        _executing = NO;
        _finished = NO;
        _completed = NO;
    }
    return self;
}

- (BOOL)isExecuting { return self.executing; }
- (BOOL)isFinished { return self.finished; }
- (BOOL)isCompleted { return self.completed; }
- (BOOL)isCancelled { return self.cancelled; }
- (BOOL)isConcurrent { return YES; }

- (void)start
{
    if ([self isCancelled]) {
        [self willChangeValueForKey:kFinishedKey];
        self.finished = YES;
        [self didChangeValueForKey:kFinishedKey];
        return;
    }

    // If the operation is not cancelled, begin executing the task
    [self willChangeValueForKey:kExecutingKey];
    self.executing = YES;
    [self didChangeValueForKey:kExecutingKey];

    [self main];
}

- (void)main
{
    @try {
        //
        // Here we add our asynchronized code
        //
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
            NSURL *completeURL = [NSURL URLWithString:[NSString stringWithFormat:@"%@/%@", kWEB_SERVICE_URL, self.serviceName]];
            NSData *body = [self.params dataUsingEncoding:NSUTF8StringEncoding];
            NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:completeURL];
            [request setHTTPMethod:@"POST"];
            [request setValue:kAPP_PASSWORD_VALUE forHTTPHeaderField:kAPP_PASSWORD_HEADER];
            [request setHTTPBody:body];
            [request setValue:[NSString stringWithFormat:@"%lu", (unsigned long)body.length] forHTTPHeaderField:@"Content-Length"];
            [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];


            if (__iOS_7_AND_HIGHER)
            {
                NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
                NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration delegate:[Netroads sharedInstance] delegateQueue:[NSOperationQueue new]];
                NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                    if (error)
                    {
                        NSLog(@"%@ Error: %@", self.serviceName, error.localizedDescription);
                    }
                    else
                    {
                        //NSString *responseXML = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
                        //NSLog(@"\n\nResponseXML(%@):\n%@", webServiceName, responseXML);
                    }
                }];
                [dataTask resume];
            }
            else
            {
                [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue new] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
                    if (connectionError)
                    {
                        NSLog(@"%@ Error: %@", self.serviceName, connectionError.localizedDescription);
                    }
                    else
                    {
                        //NSString *responseXML = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
                        //NSLog(@"\n\nResponseXML(%@):\n%@", webServiceName, responseXML);
                    }
                }];
            }
        });

        [self completeOperation];
    }
    @catch (NSException *exception) {
        NSLog(@"%s exception.reason: %@", __PRETTY_FUNCTION__, exception.reason);
        [self completeOperation];
    }
}

- (void)completeOperation
{
    [self willChangeValueForKey:kFinishedKey];
    [self willChangeValueForKey:kExecutingKey];

    self.executing = NO;
    self.finished = YES;

    [self didChangeValueForKey:kExecutingKey];
    [self didChangeValueForKey:kFinishedKey];
}

@end

最佳答案

几个 react :

- (void)main
{
    NSURLRequest *request = [self createRequest]; // maybe move the request creation stuff into its own method

    [self tryRequest:request currentDelay:1.0];
}

- (void)tryRequest:(NSURLRequest *)request currentDelay:(NSTimeInterval)delay
{
    [NSURLConnection sendAsynchronousRequest:request queue:[self networkOperationCompletionQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {

        BOOL success = NO;

        if (connectionError) {
            NSLog(@"%@ Error: %@", self.serviceName, connectionError.localizedDescription);
        } else {
            if ([response isKindOfClass:[NSHTTPURLResponse class]]) {
                NSInteger statusCode = [(NSHTTPURLResponse *)response statusCode];
                if (statusCode == 200) {
                    // parse XML response here; if successful, set `success` to `YES`
                }
            }
        }

        if (success) {
            [self completeOperation];
        } else {
            dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delay * NSEC_PER_SEC));
            dispatch_after(popTime, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void){
                NSTimeInterval nextDelay = [self nextDelayFromCurrentDelay:delay];
                [self tryRequest:request currentDelay:nextDelay];
            });
        }
    }];
}

@property (nonatomic, readwrite, getter=isExecuting) BOOL executing;
@property (nonatomic, readwrite, getter=isFinished)  BOOL finished;

@synthesize finished  = _finished;
@synthesize executing = _executing;

- (void)setExecuting:(BOOL)executing
{
    [self willChangeValueForKey:kExecutingKey];
    _executing = executing;
    [self didChangeValueForKey:kExecutingKey];
}

- (void)setFinished:(BOOL)finished
{
    [self willChangeValueForKey:kFinishedKey];
    _finished = finished;
    [self didChangeValueForKey:kFinishedKey];
}

关于ios - 通过重试将 NSOperation 子类化为 Internet 操作，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/22127427/