AFNetworking post request not getting through to Sinatra app - objective-c

Question

I'm trying to post a request from my iPhone with a Sinatra API I made. Currently all my Sinatra app is doing is printing out the request that has been sent to it. This is the code for that:
post '/profile' do
puts "#{params}"
end
My objective-c is pretty simple as well. All it does is send a post request to my API:
NSURL *url = [NSURL URLWithString:kBaseURLString];
AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:url];
NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:JSON, #"json", nil];
NSMutableURLRequest *request = [httpClient requestWithMethod:#"POST" path:#"/profile" parameters:dictionary];
AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
NSLog(#"SUCCESS");
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"%#", error);
}];
[operation start];
When JSON (in line 3 of the obj-c) is a very short string, such as #"test", Sinatra prints it out correctly like this:
{"json"=>"test"}
When I use the actual JSON profile data, which is a very long JSON blob, Sinatra prints it out as this:
{"json"=>"(null)"}
I can't figure out why the long blob is getting through. I am 100% sure that i'm passing the correct string, but Sinatra is not receiving it. My current theory is that Sinatra has a max character limit on requests, but I am new to Sinatra and Ruby, and I have no idea how I'd test that. What is going wrong?
UPDATE:
First off, thanks Kjuly for your suggestions. I figured out that I was wrong on the character limit on Sinatra thing. In obj-c I'm doing a log of the dictionary that has the JSON blob on line 3, and it has the json blob. However, when I log the body of the NSMutableURLRequest on line 4, the body is empty. When I use my tiny JSON blob, the body is filled.
Does NSMutableURLRequest have a character limit? Can anyone think of a reason why it would not accept my very large dictionary with the large JSON blob, but not with the small one.
Thanks!
UPDATE AGAIN:
The request body now fills correctly. I had to add this line into line 3:
[httpClient setParameterEncoding:AFJSONParameterEncoding];
Now I am getting this response back in the HTTPResponse from Sinatra:
Error Domain=com.alamofire.networking.error Code=-1016 "Expected content type {(
"text/json",
"application/json",
"text/javascript"
)}, got text/html"
Sinatra is now just printing
{}
Instead of {"json"=>"(null)"}
Still not sure what's going on.
Update 3
Okay, what I thought was the HTTPResponse from Sinatra - the text/json stuff - was because I was returning a text/html from Sinatra back in AFNetworking. I have now checked the body that Sinatra is receiving, and my giant JSON blob is in there. However, "params" is still empty.
Anyone have any idea why?
FIXED IT
Looks like when you post JSON to sinatra you have to read the body of the request directly. In Sinatra, you do this like so:
profile = JSON.parse(request.body.read.to_s)
Then profile is your parsed object.

Answer 1

I think you need to use AFJSONRequestOperation instead, here's a sample code:
// Fetch Data from server
NSURL *url = [NSURL URLWithString:#"https://gowalla.com/users/mattt.json"];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
AFJSONRequestOperation * operation =
[AFJSONRequestOperation JSONRequestOperationWithRequest:request
success:^(NSURLRequest * request, NSHTTPURLResponse * response, id JSON) {
NSLog(#"Name: %# %#", [JSON valueForKeyPath:#"first_name"], [JSON valueForKeyPath:#"last_name"]);
}
failure:nil];
[operation start];
Or you can visit the WIKI PAGE, see Step 4: Download and Parse JSON.