IOS4 execution - [NSURLConnection sendAsynchronousRequest: queue: completHandler:]?
How can I implement -[NSURLConnection sendAsynchronousRequest:queue:completionHandler:]
for iOS <5?
#if __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_5_0
#import <objc/runtime.h>
#import "NSURLConnection+iOS4.h"
// Dynamically add -[NSURLConnection sendAsynchronousRequest:queue:completionHandler:].
void *sendAsynchronousRequest4(id self, SEL _cmd, NSURLRequest *request, NSOperationQueue *queue, void (^handler)(NSURLResponse*, NSData*, NSError*));
void *sendAsynchronousRequest4(id self, SEL _cmd, NSURLRequest *request, NSOperationQueue *queue, void (^handler)(NSURLResponse*, NSData*, NSError*)) {
// How should we implement this?
}
@implementation NSURLConnection (SendAsync)
+ (void)load {
SEL sendAsyncSelector = @selector(sendAsynchronousRequest:queue:completionHandler:);
if (![NSURLConnection instancesRespondToSelector:]) {
class_addMethod([self class], sendAsyncSelector, (IMP)sendAsynchronousRequest4, "v@:@@@");
}
}
@end
#endif
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// NSURLConnection+SendAsync.h
#if __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_5_0
#import <Foundation/Foundation.h>
@interface NSURLConnection (SendAsync)
@end
#endif
// NSURLConnection+SendAsync.m
#if __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_5_0
typedef void (^URLConnectionCompletionHandler)(NSURLResponse *response, NSData *data, NSError *error);
@interface URLConnectionDelegate : NSObject <NSURLConnectionDataDelegate>
@property (nonatomic, strong) NSURLResponse *response;
@property (nonatomic, strong) NSMutableData *data;
@property (nonatomic, strong) NSOperationQueue *queue;
@property (nonatomic, copy) URLConnectionCompletionHandler handler;
@end
@implementation URLConnectionDelegate
@synthesize response;
@synthesize data;
@synthesize queue;
@synthesize handler;
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)theResponse {
self.response = theResponse;
[data setLength:0]; // reset data
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)theData {
[data appendData:theData]; // append incoming data
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
self.data = nil;
if (handler) { [queue addOperationWithBlock:^{ handler(response, nil, error); }]; }
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
// TODO: Are we passing the arguments to the block correctly? Should we copy them?
if (handler) { [queue addOperationWithBlock:^{ handler(response, data, nil); }]; }
}
@end
#import <objc/runtime.h>
#import "NSURLConnection+SendAsync.h"
// Dynamically add @property (nonatomic,readonly) UIViewController *presentingViewController.
void sendAsynchronousRequest4(id self, SEL _cmd, NSURLRequest *request, NSOperationQueue *queue,
URLConnectionCompletionHandler handler);
void sendAsynchronousRequest4(id self, SEL _cmd, NSURLRequest *request, NSOperationQueue *queue,
URLConnectionCompletionHandler handler) {
URLConnectionDelegate *connectionDelegate = [[URLConnectionDelegate alloc] init];
connectionDelegate.data = [NSMutableData data];
connectionDelegate.queue = queue;
connectionDelegate.handler = handler;
NSURLConnection *connection = [NSURLConnection connectionWithRequest:request
delegate:connectionDelegate];
NSAssert(connection, nil);
}
@implementation NSURLConnection (SendAsync)
+ (void)load {
SEL sendAsyncSelector = @selector(sendAsynchronousRequest:queue:completionHandler:);
if (![NSURLConnection instancesRespondToSelector:sendAsyncSelector]) {
class_addMethod(object_getClass([self class]),
sendAsyncSelector, (IMP)sendAsynchronousRequest4, "v@:@@@");
}
}
@end
#endif
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I usually subclass NSOperation and execute the sync request inside the main operation method. To invoke the operation, I create an instance of the subclass and throw it onto the queue (not the main thread). Then, when the operation completes, it either calls the delegate with the received data, or sends a notification through the NSNotificationCenter.
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I would go with an already built framework like ASIHTTPRequest (not developed anymore, but still very good) or RestKit (I've never used it before, but heard it's decent). They will provide you with the same functionality (asynchronous HTTP requests) on different OS versions.
ifdefs are not suitable because they are executed at compile time and you will not compile separate versions of your application for each platform.
Maybe you can do some runtime tweaks to get it working, but that seems like more trouble than it's worth.
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