picture_upload.m

#define ENDPOINT_URL @"http://www.myawesomeserver.com/data/images"

// elsewhere: we will need this to send the request asynchronously
self.httpQueue = [[NSOperationQueue alloc] init];


/**
 *  upload method
 */
- (void)uploadImage:(UIImage*)image withImageName:(NSString*)imageName andParams:(NSDictionary*)paramsDict
{
    // creating a NSMutableURLRequest that we can manipulate before sending
    NSURL *theURL = [NSURL URLWithString:ENDPOINT_URL];
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:theURL];

    // setting the HTTP method
    [request setHTTPMethod:@"POST"];

    // we want a JSON response
    [request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
    
    // the boundary string. Can be whatever we want, as long as it doesn't appear as part of "proper" fields
    NSString *boundary = @"qqqq___winter_is_coming_!___qqqq";

    // setting the Content-type and the boundary
    NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundary];
    [request setValue:contentType forHTTPHeaderField: @"Content-Type"];

    // we need a buffer of mutable data where we will write the body of the request
    NSMutableData *body = [NSMutableData data];
    
    
    // writing the basic parameters
    for (NSString *key in paramsDict) {
        [body appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"\r\n\r\n", key] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[[NSString stringWithFormat:@"%@\r\n", [paramsDict objectForKey:key]] dataUsingEncoding:NSUTF8StringEncoding]];
    }
    
   
   
    
    // creating a NSData representation of the image
    NSData *imageData = UIImageJPEGRepresentation(image, 1.0);
    NSString *fileNameStr = [NSString stringWithFormat:@"%@.jpg", imageName];
    
    // if we have successfully obtained a NSData representation of the image
    if (imageData) {
        [body appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"photo\"; filename=\"%@\"\r\n", fileNameStr] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[@"Content-Type: image/jpeg\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:imageData];
        [body appendData:[[NSString stringWithFormat:@"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    }
    else
        NSLog(@"no image data!!!");
    
    
    // we close the body with one last boundary
    [body appendData:[[NSString stringWithFormat:@"--%@--\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    

    // assigning the completed NSMutableData buffer as the body of the HTTP POST request
    [request setHTTPBody:body];
    
    
      
    // send the request
    [NSURLConnection sendAsynchronousRequest:request
                                       queue:self.httpQueue
                           completionHandler:^(NSURLResponse *response, NSData *data, NSError *error){
                               NSLog(@"completion handler with response: %@", [NSHTTPURLResponse localizedStringForStatusCode:[(NSHTTPURLResponse*)response statusCode]]);
                               NSLog(@"response: %i",[(NSHTTPURLResponse*)response statusCode]);
                               
                               NSInteger status = [(NSHTTPURLResponse*)response statusCode];
                               
                               if(error){
                                   NSLog(@"http request error: %@", error.localizedDescription);
                                   // handle the error
                               }
                               else{
                                   if (status == 201)
                                       // handle the success
                                   else
                                       // handle the error
                               }
                           }];
    
}