Objective-C Programming: The Big Nerd Ranch Guide

Writing an NSData object to a file

An NSData object represents a buffer of bytes. For example, if you fetch some data from a URL, you get an instance of NSData. And you can ask an NSData to write itself to a file. Create a new Foundation Command Line Tool named ImageFetch that fetches an image from the Google website into an instance of NSData. Then ask the NSData to write its buffer of bytes to a file:

#import <Foundation/Foundation.h>

int main (int argc, const char * argv[])
{
    @autoreleasepool {

        NSURL *url = [NSURL URLWithString: @"http://www.google.com/images/logos/ps_logo2.png"]; NSURLRequest *request = [NSURLRequest requestWithURL:url]; NSError *error = nil; NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:NULL ...