parse json data

Question

I need to pass json to POST parameters. Input params look like this:

{ "type":"facebook",
  "friends":[{ "id": "facebook id", "avatar": "url to avatar image", "first_name" : "first_name", "last_name" :"last_name"}] }

The server response error states it's a bad request parameter

Error - code: 400, message: {"status":"bad request","message":"undefined method `each' for #<String:0x00000005473e48>"}

It could be erroneous when I prepare the JSON data in "friends" part. Can you help me review?

Here's my code-

{
NSMutableArray *aFriends = [[NSMutableArray alloc] init];
int nCount = [[self savedSelIndexPath] count];

    for (int i = 0; i < nCount && nCount > 0; i++) 
    {
        NSIndexPath *path = [[self savedSelIndexPath] objectAtIndex:i];
        NSDictionary *data = nil;

            NSString *key = [[self keysArray] objectAtIndex:path.section]; 
            NSArray *nameSection = [[self listContentDict] objectForKey:key];
            data = [nameSection objectAtIndex:[path row]];

        NSDictionary *dictFriends = [NSDictionary dictionaryWithObjectsAndKeys:
                                     [data objectForKey:@"id"], @"id",
                                     [data objectForKey:@"picture"], @"avatar",
                                     [data objectForKey:@"first_name"], @"first_name",
                                     [data objectForKey:@"last_name"], @"last_name",
                                     nil];

        [aFriends addObject:dictFriends];
        dictFriends = nil;
    }

DLog(@"aFriends: %@", aFriends);

NSDictionary *teamProfile = [[Global sharedGlobal] getPlistFile];
NSDictionary *params = [NSDictionary dictionaryWithObjectsAndKeys:
                                @"facebook", @"type",
                                aFriends, @"friends", nil];
DLog(@"params: %@", params);

NSString *sPath = [NSString stringWithFormat:@"/users/%@/friends", [teamProfile valueForKey:@"userId"]];

NSMutableURLRequest *request = [[[Global sharedGlobal] httpClient] requestWithMethod:@"POST" path:sPath parameters:params]; 
DLog(@"request: %@", request);  
….
[aFriends release]; 
    }

Answer 1

If you want to pass JSON to the server you have to set it up like this:

    NSMutableURLRequest *networkRequest;
    networkRequest = [[NSMutableURLRequest alloc] initWithURL:
                          [NSURL URLWithString:[networkServerAddress stringByAppendingString:@""]]];
    send = [[json objectAtIndex:i] dataUsingEncoding:NSUTF8StringEncoding];
    //Set the headers appropriately
    [networkRequest setHTTPMethod:@"POST"];  
    [networkRequest setValue:@"application/json"    
          forHTTPHeaderField: @"Content-type"];
    [networkRequest setValue:[NSString stringWithFormat:@"%d", [send length]]  
          forHTTPHeaderField:@"Content-length"]; 
    [networkRequest setValue:@"application/json"    
          forHTTPHeaderField:@"Accept"];
    //Set the body to the json encoded string
    [networkRequest setHTTPBody:send]; 

Send has to be a NSData, not a dictionary. You must first parse the dictionary if you want to do it like that. There are many good parsers/writers for JSON out there, I personally like and use SBJson. With SBJson you can do something like this:

SBJsonWriter *writer = [[SBJsonWriter alloc] init];
NSData *dataToSend = [writer dataWithObject:data];

Answer 2

I'm not sure if I understood what you ask, but you said you need to encode data to JSON and I can't see any JSON encode instruction for your parameters. You are simply passing a NSDictionary *dictFriends... Is it correct?

See you!