HTTPRequest with POST params on iOS

Question

I tried to follow the instructions from this post iOS: how to perform a HTTP POST request? but unfortunately the server answers but doesn't give me any data.

The connection didReceiveResponse is called as well as the connectionDidFinishLoading without an error.

Am I doing something wrong? I tested the service with Hurl.it and it worked just right.

requestUrlString = a normal url,

postString = something like "appId=1&last_update=0"

responseData = [[NSMutableData alloc] initWithLength:0];

NSURL *baseURL = [NSURL URLWithString:[requestUrlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:baseURL];
[request setHTTPMethod:@"POST"];
[request setValue:[NSString stringWithFormat:@"%d",[postString length]] forHTTPHeaderField:@"Content-Length"];
[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
[request setHTTPBody:[postString dataUsingEncoding:NSUTF8StringEncoding]];

NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];
[connection start];


- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    [responseData setLength:0];
    NSLog(@"Connection didReceiveResponse");
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    [responseData appendData:data];
    NSLog(@"Connection didReceiveData");
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    NSLog(@"Connection Error: %@", [error description]);

    [[[UIAlertView alloc] initWithTitle:@"Error"
                                 message:[error description]
                                delegate:nil
                       cancelButtonTitle:@"OK"
                       otherButtonTitles:nil] show];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    NSLog(@"Connection didFinishLoading");
    NSLog(@"data %@", [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding]);
}

Please don't refer to ASIHTTP I got the same here.

//edit: I fixxed it sorry for bothering you with my problems. The problem was the encoding type.

My NSMutableData responseData for example is empty because the didReceiveData function is not fired. So the request is successful but I don't get any data. — palme, Jul 17 '12 at 20:52
I don't have a complete solution for you, but I do have some ideas. Looking over the difference in your code and mine, the only major one I see is that I don't set Content-Length. I suppose if you're setting it incorrectly, that might cause this problem. It seems like a long shot, but I'd start by deleting that. Also, I suggest logging the `statusCode` in your `connectionDidFinishLoading`. It might be unexpected. — Steven Fisher, Jul 17 '12 at 20:59
Thanks Steven for your ideas. Unfortunately deleting the line with the content-length doesn't fix it and the status code in `didReceiveResponse` is 200, so everything should be fine. Is there a way to get the status in `connectionDidFinishLoading`? Because I only have a `NSURLConnection` there. — palme, Jul 17 '12 at 21:18
I should have asked about checking it in `didReceiveResponse` anyway. So you're getting code 200. :) — Steven Fisher, Jul 17 '12 at 21:21
Your code looks fine to me, except I use `addValue:forHTTPHeaderField`. Perhaps the URL is not the correct one, hence you are getting no response? Is this being done in the main thread? — ohr, Jul 17 '12 at 22:20
Tried to change `addValue:forHTTPHeaderField` but it didn't help. The URL because i already tried it on [link](http://hurl.it) and it gives me the right data. Alle this happens not in the Main-Thread because it is a asynchronous request. @Steven unfortunately I have never used curl before. Can you give me an example for that? — palme, Jul 18 '12 at 07:14
curl is a command line tool for making web queries. We use it all the time when developing our web services; if we can't recreate a problem in curl, we figure it doesn't actually exist. You use it like this: `curl -d "form=value&form2=value2" -D header_output.txt http://myurl/goes/here` — Steven Fisher, Jul 18 '12 at 16:51

score 0 · Answer 1 · answered Jul 17 '12 at 20:51

0

Does the web service generate a response body? OR does it just generate the response header? If there is no response body, there is no response to show on iOS.

Also, i believe you need an "Accept" header.

answered Jul 17 '12 at 20:51

Steven

974
6
18

The web service does generate a response body of the content type text/html. `[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Accept"];`and `[request setValue:@"application/json" forHTTPHeaderField:@"Accept"];`did not fix it. Sorry. – palme Jul 17 '12 at 21:00
With regard to the comment from @Steven above (I dont have enough reputation to comment there). If I am checking the response data on a Mac machine, I use a REST client [available here](http://code.google.com/p/rest-client/). Although i prefer to use [Fiddler 2](http://www.fiddler2.com/fiddler2/) which runs on a windows machine as it uses the .NET framework – Steven Jul 18 '12 at 13:19
1

Ah! Good news. You should write up the answer for posterity. :) – Steven Fisher Jul 18 '12 at 16:52

HTTPRequest with POST params on iOS

1 Answers1