Objective-C POST request not sending data

Question

I have a method that should post some data to a PHP file:

-(void)submitForm { NSLog(@"name=%@", formName.text); // returns correct value NSString *post = [NSString stringWithFormat:@"name=%@&", formName.text]; NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES]; NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]]; NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init]; [request setURL:[NSURL URLWithString:@"http://path/to/file"]]; [request setHTTPMethod:@"POST"]; [request setValue:postLength forHTTPHeaderField:@"Content-Length"]; [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"]; [request setHTTPBody:postData]; NSURLResponse *response = NULL; NSError *requestError = NULL; NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&requestError]; NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding]; NSLog(@"%@",responseString); }

Note: I'm not actually using @"http://path/to/file". I've omitted the URL for privacy.

I believe it's connecting to the PHP script correctly, since I'm receiving the response I expect. The problem is that if I echo out $name, I get an empty string. Here's the script:

<?php include("config.php"); // Handles DB connection $name = mysql_escape_string($_POST["name"]); mysql_query("insert into objects(name) values('$name')") or die(mysql_error()); echo $name; // returns empty string

All I expect is some sort of syntax/logic error in the Obj-C code, but I can't spot it.

there is no problem in the php side. i can't help you in Obj-c anyway. — Alain
– Alain, Commented Sep 14, 2012 at 8:11
Does formName.text contain any strange characters? Technically this should be URL-encoded before putting into the POST data. — joerick
– joerick, Commented Sep 14, 2012 at 8:54
No, just a simple alphanumerical string; no punctuation or whitespace. — Jezen Thomas
– Jezen Thomas, Commented Sep 14, 2012 at 8:56
Can you try removing this line? [request setValue:postLength forHTTPHeaderField:@"Content-Length"]; Then tell me about the result. — yoninja
– yoninja, Commented Sep 14, 2012 at 11:27
Turns out, my path was incorrect. I had something like http://example/register, when it was expecting http://example/register/index.php. — Jezen Thomas
– Jezen Thomas, Commented Sep 14, 2012 at 12:23

jcrowson · Accepted Answer · 2012-09-14 09:50:49Z

I've got a feeling that your request is missing some mandatory data, a boundary and content-type, which might lead to your POST request being half complete.

I'll show you what I've done for uploading an HTML file to a webserver and then explain underneath.

Objective-C

NSString* str = formName.text; NSData* theData = [str dataUsingEncoding:NSUTF8StringEncoding]; NSString *urlString = @"http://whereyouarepostingto.com"; NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease]; [request setURL:[NSURL URLWithString:urlString]]; [request setHTTPMethod:@"POST"]; NSString *boundary = @"---------------------------14737809831466499882746641449"; NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary]; [request addValue:contentType forHTTPHeaderField: @"Content-Type"]; NSMutableData *body = [NSMutableData data]; [body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]]; [body appendData:[[NSString stringWithString:[NSString stringWithFormat: @"Content-Disposition: form-data; name=\"file\"; filename=\"%@.html\"\r\n", self.fileName]] dataUsingEncoding:NSUTF8StringEncoding]]; [body appendData:[@"Content-Type: application/octet-stream\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]]; [body appendData:[NSData dataWithData:theData]]; [body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]]; [request setHTTPBody:body]; NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil]; NSString *returnString = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding]; NSLog(@"%@", returnString);

PHP

 <?php echo "Connection made to server"; move_uploaded_file($_FILES["file"][tmp_name], "uploads/" . $_FILES["file"]["name"]); ?>

You'll need to change a few things around to fit your SQL insert and strip out my file stuff, but it's a start.

This is the part I think you're missing.

NSString *boundary = @"---------------------------14737809831466499882746641449"; NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary];

The boundary can be a series of random numbers, but it has to exist.

Also, watch out when constructing the body of the request, especially the slashes. Make sure you escape any " ".

Gloomcore · Accepted Answer · 2012-09-14 08:54:34Z

Man you are not encoding all your Variables. You should make URL-Encode for your variable. The sample of Encoding function you can find here:

+(NSString *)urlEncode:(NSString *)unencodedString{ return (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL, (CFStringRef)[NSHelper string:unencodedString], NULL, (CFStringRef)@"!*'();:@&=+$,/?%#[]", kCFStringEncodingUTF8 ); }

And by the way remove '&' character in the end of POST string.

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