AbstractURLConnection

//
//  AbstractNSUrlConnection.h
//
#import <Foundation/Foundation.h>

@interface AbstractNSUrlConnection : NSObject <NSURLConnectionDelegate>{

    // used to append the received data to
    NSMutableData *receivedData;
    // the connection that we are delegate of
    NSURLConnection *theConnection;
    // the object id of the caller
    id sender;
    // the callback method of the caller
    NSString *selector;
}

/*
 Properties for the local variables.
*/
@property (strong, retain) NSURLConnection * theConnection;
@property (strong, retain) NSString *selector;
@property (strong, retain) id sender;

// returns self and sets up the connection, caller and callback
- (AbstractNSUrlConnection *) initWithRequest:(NSURLRequest *) url sender:(id) sender withSelector: (NSString *)selector andRequestMethod:(NSString *) method;

/*
 Class methods to get different request types.
*/
+ (NSString *) MethodTypePOST;
+ (NSString *) MethodTypeGET;
+ (NSString *) MethodTypePUT;
+ (NSString *) MethodTypeREQUEST;

@end

#import "AbstractNSUrlConnection.h"

/*
    different request types
 */
#define METHOD_TYPE_POST @"POST"
#define METHOD_TYPE_PUT @"PUT"
#define METHOD_TYPE_GET @"GET"
#define METHOD_TYPE_REQUEST @"REQUEST"

@implementation AbstractNSUrlConnection

@synthesize theConnection, sender, selector;

/*
 This methods sets up the NSURLConneciton and tells it we're it's
 delegate. It also takes an url, a sender, a callback and initialises
 the received data array.
*/
- (AbstractNSUrlConnection *) initWithRequest:(NSURLRequest *)url
        sender:(id)theSender
        withSelector:(NSString *)theSelector
        andRequestMethod:(NSString *) method {

    // init ourself
    self = [super init];
    // allocate memory for the connection, give it an url and tell it we're delegate
    theConnection = [[NSURLConnection alloc] initWithRequest:url delegate:self];
    // hold the received data
    receivedData = [[NSMutableData alloc] init];
    // set the sender
    self.sender = theSender;
    // set the selector
    self.selector = theSelector;

    return self;
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    // This method is called when the server has determined that it
    // has enough information to create the NSURLResponse.

    // It can be called multiple times, for example in the case of a
    // redirect, so each time we reset the data.

    // receivedData is an instance variable declared elsewhere.
    [receivedData setLength:0];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    // Append the new data to receivedData.
    // receivedData is an instance variable declared elsewhere.
    [receivedData appendData:data];
}

- (void)connection:(NSURLConnection *)connection
  didFailWithError:(NSError *)error
{
    // inform the user
    NSLog(@"Connection failed! Error - %@ %@",
          [error localizedDescription],
          [[error userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]);
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    NSLog(@"Succeeded! Received %d bytes of data",[receivedData length]);

    // see if the sender responds to the selector befire we actually
    // call it.
    if([sender respondsToSelector:NSSelectorFromString(selector)] && self.sender) {
        // call the sender (callback)
        [self.sender performSelector: NSSelectorFromString(selector)];

        /*
         we don't need thease anymore...
        */
        receivedData = nil;
        theConnection = nil;
        sender = nil;
        selector = nil;
    }
}

/*
 Class methods to get different request types.
*/

+ (NSString *) MethodTypePOST{
    return METHOD_TYPE_POST;
}

+ (NSString *) MethodTypeGET{
    return METHOD_TYPE_GET;
}

+ (NSString *) MethodTypePUT{
    return METHOD_TYPE_POST;
}

+ (NSString *) MethodTypeREQUEST{
    return METHOD_TYPE_REQUEST;
}

@end