How do I repeat an ASIHTTPRequest?

问题

Given the example code below:

// ExampleModel.h

@interface ExampleModel : NSObject <ASIHTTPRequestDelegate> {

}

@property (nonatomic, retain) ASIFormDataRequest *request;
@property (nonatomic, copy) NSString *iVar;

- (void)sendRequest;


// ExampleModel.m

@implementation ExampleModel

@synthesize request;
@synthesize iVar;

# pragma mark NSObject

- (void)dealloc {
    [request clearDelegatesAndCancel];
    [request release];
    [iVar release];
    [super dealloc];
}

- (id)init {
    if ((self = [super init])) {
        // These parts of the request are always the same.
        NSURL *url = [[NSURL alloc] initWithString:@"https://example.com/"];
        request = [[ASIFormDataRequest alloc] initWithURL:url];
        [url release];
        request.delegate = self;
        [request setPostValue:@"value1" forKey:@"key1"];
        [request setPostValue:@"value2" forKey:@"key2"];
    }
    return self;
}

# pragma mark ExampleModel

- (void)sendRequest {
    // Reset iVar for each repeat request because it might've changed.
    [request setPostValue:iVar forKey:@"iVarKey"];
    [request startAsynchronous];
}

@end

# pragma mark ASIHTTPRequestDelegate

- (void)requestFinished:(ASIHTTPRequest *)request {
    // Handle response.
}

- (void)requestFailed:(ASIHTTPRequest *)request {
    // Handle error.
}

When I do something like [exampleModel sendRequest] from a UIViewController, it works! But, then I do [exampleModel sendRequest] again from another UIViewController and get:

Terminating app due to uncaught exception 'NSInvalidArgumentException',
reason: '*** -[NSOperationQueue addOperation:]:
operation is finished and cannot be enqueued`

How can I fix this?

回答1:

You shouldn't attempt to reuse the request object. It maintains state. Really designed to be disposed off after the request is over.

The design isn't as clean as the NSURLConnection, NSURLRequest, NSURLResponse classes (basically mashing all three into one and wrapping the low level core foundation classes underneath). It's still far better than using NSURLConnection in a vanilla fashion if you need to deal with low level HTTP stuff. If you don't, the high level classes have some advantages (like access to the same cache the UIWebView uses).

回答2:

I think I found the answer: https://groups.google.com/d/msg/asihttprequest/E-QrhJApsrk/Yc4aYCM3tssJ

回答3:

ASIHTTPRequest and its subclasses conform to the NSCopying protocol. Just do this:

 ASIFormDataRequest *newRequest = [[request copy] autorelease];
 [newRequest startAsynchronous];

来源：https://stackoverflow.com/questions/6222009/how-do-i-repeat-an-asihttprequest

标签

iphone

objective-c

asihttprequest

nsoperationqueue