iPhone sending POST with NSURLConnection

Question

I'm having some problems with sending POST data to a PHP script with NSURLConnection. This is my code:

    const char *bytes = [[NSString stringWithFormat:@"<?xml version=\"1.0\"?>\n<mydata>%@</mydata>", data] UTF8String];

    NSURL *url = [NSURL URLWithString:@"http://myurl.com/script.php"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];

    [request setHTTPMethod:@"POST"];
    [request setHTTPBody:[NSData dataWithBytes:bytes length:strlen(bytes)]];

    NSURLResponse *response;
    NSError *err;
    NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&err];
    NSLog(@"responseData: %@", responseData);

And my script.php is as simple as this:

<?php
    echo $_POST['mydata'];
?>

This have worked for me in the past, but for some reason the output I get from NSLog(@"responseData: %@", responseData); now is just "<>" instead of "theData".

Probably some lame mistake somewhere but I can't seem to find it? Any ideas?

Answer 1

Your data is wrong. If you expect the data to be found in the $_POST array of PHP, it should look like this:

const char *bytes = "mydata=Hello%20World";

If you want to send XML Data, you need to set a different HTTP Content Type. E.g. you might set

application/xml; charset=utf-8

If you set no HTTP Content Type, the default type

application/x-www-form-urlencoded

will be used. And this type expects the POST data to have the same format as it would have in a GET request.

However, if you set a different HTTP Content Type, like application/xml, then this data is not added to the $_POST array in PHP. You will have to read the raw from the input stream.

Try this:

NSString * str = [[NSString stringWithFormat:@"<?xml version=\"1.0\"?>\n<mydata>%@</mydata>", data];
[request setHTTPMethod:@"POST"];
[request setValue:@"application/xml; charset=utf-8" forHTTPHeaderField:@"Content-Type"];
[request setHTTPBody:[str dataUsingEncoding:NSUTF8StringEncoding]];

and on the server try the following PHP:

$handle = fopen("php://input", "rb");
$http_raw_post_data = '';
while (!feof($handle)) {
    $http_raw_post_data .= fread($handle, 8192);
}
fclose($handle);

Please note that this only works if the HTTP header of your POST is not application/x-www-form-urlencoded. If it is application/x-www-form-urlencoded then PHP itself reads all the post data, decodes it (splitting it into key/value pairs), and finally adds it to the $_POST array.

Answer 2

POST data and XML data are not the same. You can send XML data just as you did, but the PHP code must parse the XML from the request body. PHP's xml_parse (http://php.net/manual/en/function.xml-parse.php) can help you do this.

Alternatively, if you would prefer sending POST data, set the request body like this:

const char *bytes = [[NSString stringWithFormat:@"mydata=%@", data] UTF8String];