NSURLProtocol implementation to intercept HTTP networking and continue with original call.

gistfile1.txt

//
//  SLKURLProtocol.m
//  InterceptionHttp
//
//  Created by G.Tas on 1/14/14.
//  Copyright (c) 2014. All rights reserved.
//

#import "SLKURLProtocol.h"

#define kBgQueue dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)
#define WORKAROUND_MUTABLE_COPY_LEAK 1

#if WORKAROUND_MUTABLE_COPY_LEAK
// required to workaround http://openradar.appspot.com/11596316
@interface NSURLRequest(MutableCopyWorkaround)

- (id) mutableCopyWorkaround;

@end
#endif

@interface SLKURLProtocol ()

@property (nonatomic, readwrite, strong) NSURLConnection* connection;

@end

static NSString* SLKInterceptionURLHeader = @"X-SLKIntercepted";

@implementation SLKURLProtocol

+ (NSURLRequest*) canonicalRequestForRequest:(NSURLRequest *)request
    {
    return request;
    }

+ (BOOL) canInitWithRequest:(NSURLRequest *)request
    {
    // only handle http requests we haven't marked with our header.
    if ([[[request URL] scheme] isEqualToString:@"http"] &&
        ([request valueForHTTPHeaderField:SLKInterceptionURLHeader] == nil))
        {
        return YES;
        }
    return NO;
    }

- (void) startLoading
    {
//    dispatch_async(kBgQueue,
//        ^{
    NSString* dataString = [NSString stringWithUTF8String:[self.request.HTTPBody bytes]];
    NSUInteger length = [self.request.HTTPBody length];
    NSData* data = [NSData dataWithBytes:[self.request.HTTPBody bytes] length:length];
    
        NSLog(@"Intercept Request startLoading");
        NSURLRequest* request = self.request;
        NSLog(@"URL: %@", request.URL);
        NSLog(@"HTTP Method: %@", request.HTTPMethod);
        NSLog(@"Data: %@", dataString);
        
        NSMutableURLRequest *connectionRequest = 
#if WORKAROUND_MUTABLE_COPY_LEAK
      [[self request] mutableCopyWorkaround];
#else
      [[self request] mutableCopy];
#endif
    [connectionRequest setValue:@"" forHTTPHeaderField:SLKInterceptionURLHeader];
    NSURLConnection *connection = [NSURLConnection connectionWithRequest:connectionRequest
                                                                delegate:self];
    [self setConnection:connection];
    [[self client] URLProtocol:self didReceiveResponse:[[NSURLResponse alloc] init] cacheStoragePolicy:NSURLCacheStorageNotAllowed];
    [[self client] URLProtocol:self didLoadData:data];
    [[self client] URLProtocolDidFinishLoading:self];
//        });
    }

- (void) stopLoading
    {
//    dispatch_async(kBgQueue,
//        ^{
    [self.connection cancel];
        NSLog(@"Intercept Request stopLoading");
//        });
    }

@end

#if WORKAROUND_MUTABLE_COPY_LEAK
@implementation NSURLRequest(MutableCopyWorkaround)

- (id) mutableCopyWorkaround {
    NSMutableURLRequest *mutableURLRequest = [[NSMutableURLRequest alloc] initWithURL:[self URL]
                                                                          cachePolicy:[self cachePolicy]
                                                                      timeoutInterval:[self timeoutInterval]];
    [mutableURLRequest setAllHTTPHeaderFields:[self allHTTPHeaderFields]];
    return mutableURLRequest;
}

@end
#endif

In theory , you can just modify RNCachingURLProtocol for your purpose. You can just remove the logic for caching. I am working on a very similar project , but I am not allowed to open source it without permission. I can tell you that the modification of RNCachingURLProtocol works just fine for me in GET/PUT/POST and so on. It also works for AFNetworking and NSURLConnection