(iOS) Parsing JSON - iOS 5+

1.getJSON.mm

-(void)parseJSONFromURL:(NSString *)jsonURL {

//Prepare URL request to get the user timeline
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:jsonURL]];

/*******************Sychronous Call Request**************/
//Perform request
NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
/********************************************************/



/*******************Asychronous Call Request*************/
NSURL *URL = [NSURL URLWithString:jsonURL];
NSURLRequest *Request = [NSURLRequest requestWithURL:URL];

//Using Grand Central Dispatch
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0ul);

    dispatch_async(queue, ^{
        NSURLResponse *response = nil;
        NSError *error = nil;
 
        NSData *receivedData = [NSURLConnection sendSynchronousRequest:Request
                                                     returningResponse:&response
                                                                 error:&error];
                          });

    /*******************************
    USE THIS IF YOU WANT TO BE RUN ON MAIN THREAD

    You're not allowed to perform user interface updates in the background queue,
    so use the dispatch_get_main_queue to let that background queue dispatch the user interface updates back
    to the main queue, once the main queue is available

    dispatch_async(dispatch_get_main_queue(), ^{
                
    });

    *******************************/


//OR

//Without Grand Central Dispatch
responseData = [[NSMutableData data] retain];
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://localhost/json"]];//asynchronous call

//If you plan to check for cookies
NSHTTPCookieStorage *cookieStorage = [NSHTTPCookieStorage sharedHttpCookieStorage];
[cookieStorage setCookieAcceptPolicy:NSHTTPCookieAcceptPolicyAlways];

[request setHTTPShouldHandleCookies:YES];


NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

//It might need this if it doesn't work
[connection scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];

[connection start];
 
 
#pragma mark - Delegate methods

//MUST COMFORM THE NSURLConnectionDelegate protocol
 
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {

    // cast the response to NSHTTPURLResponse (if needed) so we can look for 404 etc
    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;

    /*******************/
    //If you want to check for the cookie
    //Ex. to see if he is logged in or something

    if (httpResponse != nil) { 
        NSArray* cookies = [NSHTTPCookie 
                              cookiesWithResponseHeaderFields:[response allHeaderFields] 
                              forURL:[NSURL URLWithString:@""]];
        
        if ([cookies count] > 0) {
            NSLog(@"cookies from the http POST %@", authToken);
        }
    }

    //Store the cookie
    [[NSHTTPCookieStorage sharedHTTPCookieStorage] setCookies:cookies forURL:[NSURL URLWithString:@""] mainDocumentURL:nil];

    // Now we can print all of the cookies we have:
    for (NSHTTPCookie *cookie in cookies)
    NSLog(@"Name: %@ : Value: %@, Expires: %@", cookie.name, cookie.value, cookie.expiresDate); 


    /*****/
    You can store only 1 cookie if you want to store one
    [[NSHTTPCookieStorage sharedHTTPCookieStorage] setCookie:thecookie];
    /*****/

    /*******************/

    //Check http://www.w3.org/Protocols/HTTP/HTRESP.html for status codes
    if ([httpResponse statusCode] >= 400) {
        // do error handling here
    }
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [responseData appendData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    NSLog(@"%@", error);
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
    [responseData release];
    NSDictionary *jsonObject = [responseString JSONValue];
    NSLog(@"type :  %@", [jsonObject objectForKey:@"Type"] );

    //OR

    //A model class containing properties with the same name as the keys in the json object
    Record *record = [[Record alloc] init];

    //jsonObject is a NSDictionary. Set the corresponding values to our model class
    [record setValuesForKeysWithDictionary:jsonObject];

    //Which means
    //record.keyValue = [jsonObject objectForkey: @"keyValue"];
    //keyValue is a @property of Record class

    [connection release];
}
/********************************************************/

//Parse the retrieved json
NSError *jsonParsingError = nil;
id *json_object = [NSJSONSerialization JSONObjectWithData:response options:NSJSONReadingAllowFragments error:&jsonParsingError];

//The json_object is either a NSArray or a NSDictionary depending on the structure of the original JSON document
  if ( [jsonObject isKindOfClass:[NSArray class]] )
  {
    //json_object is a NSArray object
  }
  else
  {
    //json_object is a NSDictionary object
    for(NSDictionary *jsonObject in json_object) 
    {
      NSLog(@"Item: %@", item);
    }
  }
}

2.createJSON.mm

/*********************************************************/
//Here are some POST method examples
//PHP will hndle them with $_POST[''];

//1. Send an image
NSData *imageData = UIImagePNGRepresentation([UIImage imageNamed@"localimage.png"]);
 
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] 
        initWithURL:[NSURL URLWithString:@"http://www.cimgf.com/testpostimage.php"]]; // Not a real URL. 
 
[request setHTTPMethod:@"POST"];

//Sets the specified HTTP header field.
[request setValue:@"image/png" forHTTPHeaderField:@"Content-type"];

[request setValue:[NSString stringWithFormat:@"%d", [imageData length]] forHTTPHeaderField:@"Content-length"];

[request setHTTPBody:imageData];
 
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

//It might need this if it doesn't work
[connection scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];

[connection start];


//2. Some values
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:
            [NSURL URLWithString:@"http://www.cimgf.com/test/testform.php"]];
 
[request setHTTPMethod:@"POST"];
 
NSString *postString = @"go=1&name=Bad%20Bad%20Bug&description=This%20bug%20is%20really%20really%20super%20bad.";

//Sets the specified HTTP header field.
[request setValue:[NSString stringWithFormat:@"%d", [postString length]] forHTTPHeaderField:@"Content-length"];
 
[request setHTTPBody:[postString dataUsingEncoding:NSUTF8StringEncoding]];
 
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

//It might need this if it doesn't work
[connection scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];

[connection start];


//3. Send an XML string
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] 
        initWithURL:[NSURL 
        URLWithString:@"http://www.cimgf.com/testpost.php"]];
 
[request setHTTPMethod:@"POST"];

[request setValue:@"text/xml" forHTTPHeaderField:@"Content-type"];
 
NSString *xmlString = @"<data><item>Item 1</item><item>Item 2</item></data>";
 
[request setValue:[NSString stringWithFormat:@"%d", [xmlString length]] forHTTPHeaderField:@"Content-length"];
 
[request setHTTPBody:[xmlString dataUsingEncoding:NSUTF8StringEncoding]];
 
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

//It might need this if it doesn't work
[connection scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];

[connection start];


#pragma mark - NSURLConnection delegate methods

//MUST COMFORM THE NSURLConnectionDelegate protocol

-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{

    // cast the response to NSHTTPURLResponse so we can look for 404 etc
    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;

    //Check http://www.w3.org/Protocols/HTTP/HTRESP.html
    if ([httpResponse statusCode] >= 400) {
        // do error handling here
    }
}

-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{

}

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{

}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection{

}

/*************************************************************************/

//NOW TO JSON

-(NSString*)serializeJSON {

    //First json object
    //{ "username" : "obj1" , "surname" : "obj2" , "name" : "obj3" }
    NSMutableDictionary* mineDictionary = [[NSMutableDictionary alloc] init];

    [mineDictionary setObject:@"obj1" forKey:@"username"];
    [mineDictionary setObject:@"obj2" forKey:@"surname"];
    [mineDictionary setObject:@"obj3" forKey:@"name"];

    //Second json object
    //{ "username" : "obj3" , "surname" : "obj4" , "name" : "obj5" }
    NSMutableDictionary* yourDictionary = [[NSMutableDictionary alloc] init];

    [yourDictionary setObject:@"obj3" forKey:@"username"];
    [yourDictionary setObject:@"obj4" forKey:@"surname"];
    [yourDictionary setObject:@"obj5" forKey:@"name"];

    //Our json array containing both objects
    NSMutableArray* jsonArray = [[NSMutableArray alloc] init];

    [jsonArray addObject:mineDictionary];
    [jsonArray addObject:yourDictionary];

    
    NSData* nsdata = [NSJSONSerialization dataWithJSONObject:jsonArray options:NSJSONReadingMutableContainers error:nil];

    NSString* jsonString =[[NSString alloc] initWithData:nsdata encoding:NSUTF8StringEncoding];

    return jsonString;
}


//SEND THE JSON
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:
            [NSURL URLWithString:@"something.php"]];
 
[request setHTTPMethod:@"POST"];
 
NSString *json = [self serializeJSON];
 
//Sets the specified HTTP header field.
[request setValue:[NSString stringWithFormat:@"%d", [json length]] forHTTPHeaderField:@"Content-length"];

[request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];

[request setHTTPBody:json];
 
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
 
//It might need this if it doesn't work
[connection scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
 
[connection start];

3.-InputStream_JSON.mm

//Get JSON object from an input stream

NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://url_that_returns_json_stream"]];

NSInputStream *stream = [[NSInputStream alloc] initWithData:data];

[stream open];

if (stream)
{
  NSError *parseError = nil;
  id jsonObject = [NSJSONSerialization JSONObjectWithStream:stream options:NSJSONReadingAllowFragments error:&parseError];

  if ([jsonObject respondsToSelector:@selector(objectForKey:)]) 
  {
    for (NSDictionary *dict in [jsonObject objectForKey:@"results"]) 
    {
      NSLog(@"Tweet: %@", [tweet objectForKey:@"text"]);
    }
  }
}
else 
{
  NSLog(@"Failed to open stream.");
  }
}

4.usingAFNetworking.mm

//http://www.raywenderlich.com/30445/afnetworking-crash-course
//https://github.com/AFNetworking/AFNetworking/wiki/Getting-Started-with-AFNetworking

#import "AFHTTPClient.h"
#import "AFHTTPRequestOperation.h"

AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:[NSURL URLWithString:@"http://yourServerAddress.com/"]];

//Accept headers (for cookies)
[httpClient setDefaultHeader:@"Accept" value:@"application/json"];

[httpClient setParameterEncoding:AFFormURLParameterEncoding];



//GET REQUEST

NSMutableURLRequest *request = [httpClient requestWithMethod:@"GET"
                                                        path:@"http://yourServerAddress.com/example?name=foo"
                                                        parameters:nil];

[httpClient registerHTTPOperationClass:[AFHTTPRequestOperation class]];
AFHTTPRequestOperation *operation = [httpClient HTTPRequestOperationWithRequest:request
           success:^(AFHTTPRequestOperation *operation, id responseObject)
           {
              //-- This block gets invoked when the operation is successful
           } 
           failure:^(AFHTTPRequestOperation *operation, NSError *error)
           {
              //-- This block gets invoked when the operation fails
           }];

//OR

NSString *pathStr = @"/example?name=foo";

[httpClient getPath:pathStr parameters:paramaters 
    success:^(AFHTTPRequestOperation *operation, id responseObject) 
    {
        //Get the cookie if you need to validate the user
        NSString *cookie = [[((NSHTTPURLResponse *)[operation response]) allHeaderFields] objectForKey:@"Set-Cookie"];

        //If  you first login, save the cookie for future requests.
        [httpClient setDefaultHeader:@"cookie" value:cookie];
        //To remove it just put @"" to the value


        //OR


        /***************************************/
        //VALIDATE USER WITH COOKIE

        if (cookie != nil) 
        {
          //Get the cookie you have saved prevously and check if they are the same
          NSString *savedCookie = [httpClient defaultValueForHeader:@"cookie"];
        
          if (savedCookie != nil && ![savedCookie isEqualToString:cookie]) 
          {
             //they are the same, user is authenticated
          }
        }
        /***************************************/


        //Get the response
        NSString *responseStr = [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding];
    } 
    failure:^(AFHTTPRequestOperation *operation, NSError *error) 
    {
        NSLog(@"Error: %@", error.localizedDescription);
    }];

//-- The following codes allow you to track the download progress (if required)
[operation setDownloadProgressBlock:^(NSUInteger bytesRead, long long totalBytesRead, long long totalBytesExpectedToRead) 
{
        //-- This block gets invoked periodically as the download progress
        NSLog(@"bytesRead: %i; totalBytesRead: %lld; totalexpected: %lld", bytesRead, totalBytesRead, totalBytesExpectedToRead);
}];

//-- end of the download progress tracking code

[httpClient enqueueHTTPRequestOperation:operation];


/****************************/

//POST REQUEST

AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:[NSURL URLWithString:@"http://yourServerAddress.com/"]];

//-- the content of the POST request is passed in as an NSDictionary
//-- in this example, there are two keys with an object each
NSDictionary *parameters = [NSDictionary dictionaryWithObjectsAndKeys:
                                   object1, @"KEY_NAME_1",
                                   object2, @"KEY_NAME_2",
                                   nil];

[httpClient postPath:@"/postExample/" parameters:parameters 
   success:^(AFHTTPRequestOperation *operation, id responseObject) 
   {
      NSString *responseStr = [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding];
      NSLog(@"Request Successful, response '%@'", responseStr);
   }
   failure:^(AFHTTPRequestOperation *operation, NSError *error) 
   {
      NSLog(@"Error: %@", error.localizedDescription);
   }];