NSURLRequest : Post data and read the posted page

A few things first

• Decide how you want to encode your data - JSON or url-encoding are a good start.
• Decide upon a return value - will it be 1, TRUE or 0, FALSE, or even YES/non-nil nothing/nil.
• Read up on the URL Loading System, it's your friend.

Aim to make all your url connections asynchronous so your UI remains responsive. You can do this with NSURLConnectionDelegate callbacks. NSURLConnection has a small drawback: your code must be decoupled. Any variables you want available in the delegate functions will need to be saved to ivars or in your request's userInfo dict.

Alternatively you can use GCD, which, when coupled with the __block qualifiers, allows you to specify error/return code at the point you declare it - useful for one off fetches.

Without further ado, here's a quick and dirty url-encoder:

- (NSData*)encodeDictionary:(NSDictionary*)dictionary {      NSMutableArray *parts = [[NSMutableArray alloc] init];      for (NSString *key in dictionary) {        NSString *encodedValue = [[dictionary objectForKey:key] stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];        NSString *encodedKey = [key stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];         NSString *part = [NSString stringWithFormat: @"%@=%@", encodedKey, encodedValue];        [parts addObject:part];      }      NSString *encodedDictionary = [parts componentsJoinedByString:@"&"];      return [encodedDictionary dataUsingEncoding:NSUTF8StringEncoding];    }

Using a JSON library like JSONKit makes encoding things easier, consider it!

Method 1 - NSURLConnectionDelegate async callbacks:

// .h@interface ViewController : UIViewController<NSURLConnectionDelegate>@end// .m@interface ViewController () {  NSMutableData *receivedData_;}@end...- (IBAction)asyncButtonPushed:(id)sender {  NSURL *url = [NSURL URLWithString:@"http://localhost/"];  NSDictionary *postDict = [NSDictionary dictionaryWithObjectsAndKeys:@"user", @"username",                             @"password", @"password", nil];  NSData *postData = [self encodeDictionary:postDict];  // Create the request  NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];  [request setHTTPMethod:@"POST"];  [request setValue:[NSString stringWithFormat:@"%d", postData.length] forHTTPHeaderField:@"Content-Length"];  [request setValue:@"application/x-www-form-urlencoded charset=utf-8" forHTTPHeaderField:@"Content-Type"];  [request setHTTPBody:postData];  NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request                                                                 delegate:self];  [connection start];  }- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {  [receivedData_ setLength:0];}- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {   [receivedData_ appendData:data];}- (void)connectionDidFinishLoading:(NSURLConnection *)connection {  NSLog(@"Succeeded! Received %d bytes of data", [receivedData_ length]);  NSString *responeString = [[NSString alloc] initWithData:receivedData_                                                  encoding:NSUTF8StringEncoding];  // Assume lowercase   if ([responeString isEqualToString:@"true"]) {    // Deal with true    return;  }      // Deal with an error}

Method 2 - Grand Central Dispatch async function:

// .m- (IBAction)dispatchButtonPushed:(id)sender {  NSURL *url = [NSURL URLWithString:@"http://www.apple.com/"];  NSDictionary *postDict = [NSDictionary dictionaryWithObjectsAndKeys:@"user", @"username",                             @"password", @"password", nil];  NSData *postData = [self encodeDictionary:postDict];  // Create the request  NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];  [request setHTTPMethod:@"POST"];  [request setValue:[NSString stringWithFormat:@"%d", postData.length] forHTTPHeaderField:@"Content-Length"];  [request setValue:@"application/x-www-form-urlencoded charset=utf-8" forHTTPHeaderField:@"Content-Type"];  [request setHTTPBody:postData];  dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{    // Peform the request    NSURLResponse *response;    NSError *error = nil;    NSData *receivedData = [NSURLConnection sendSynchronousRequest:request                                             returningResponse:&response                                                       error:&error];        if (error) {      // Deal with your error      if ([response isKindOfClass:[NSHTTPURLResponse class]]) {        NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse*)response;        NSLog(@"HTTP Error: %d %@", httpResponse.statusCode, error);        return;      }      NSLog(@"Error %@", error);      return;    }    NSString *responeString = [[NSString alloc] initWithData:receivedData                                                    encoding:NSUTF8StringEncoding];    // Assume lowercase     if ([responeString isEqualToString:@"true"]) {      // Deal with true      return;    }        // Deal with an error    // When dealing with UI updates, they must be run on the main queue, ie:    //      dispatch_async(dispatch_get_main_queue(), ^(void){    //          //      });  }); }

Method 3 - Use an NSURLConnection convenience function

+ (void)sendAsynchronousRequest:(NSURLRequest *)request queue:(NSOperationQueue *)queue completionHandler:(void (^)(NSURLResponse*, NSData*, NSError*))handler

Hope this helps.

  NSData *postData = [someStringToPost dataUsingEncoding:NSUTF8StringEncoding];  NSURL *url = [NSURL URLWithString:someURLString];  NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:url];  [req setHTTPMethod:@"POST"];  [req setValue:[NSString stringWithFormat:@"%d", postData.length] forHTTPHeaderField:@"Content-Length"];  [req setValue:@"application/x-www-form-urlencoded charset=utf-8" forHTTPHeaderField:@"Content-Type"];  [req setHTTPBody:postData];  NSError *err = nil;  NSHTTPURLResponse *res = nil;  NSData *retData = [NSURLConnection sendSynchronousRequest:req returningResponse:&res error:&err];  if (err)  {    //handle error  }  else  {    //handle response and returning data  }

This project might be quite handy for your purpose. It will take care of your downloads and store it locally. Check out the link https://github.com/amitgowda/AGInternetHandler