How can I send post data through nsurlrequest?

Question

Hi.
I'm working on an application which needs to make requests to a php gateway. I tried many examples I found on google, but none of them worked for me.
First I was working with GET, and it worked just fine, but now, as I need to send more complex data, GET isn't a solution anymore. I have three params to send: module which is a string containing a php class name, method: the function in the class, and params for the function which is usually an indexed array.
The following method makes the request to the server, but for some reason, doesn't send the POST data. If I var_dump($_REQUEST) or var_dump($_POST), it turns out, the array is empty. Can somebody tell me, what am I doing wrong? Is there some kind of a sandbox, which prevents data from being sent to the? I also tried to send some random strings, which aren't json encoded, no luck. The sdk version is 5.1, and I'm using the iPhone simulator from xcode.
If it is possible I would like to solve this problem without any additional libraries (like asihttp).
And here is the code:
+(NSObject *)createRequest:(NSString *)module: (NSString *)method: (NSArray *)params
    NSString *url       = @"http://url/gateway.php";
    NSData *requestData = nil;
    NSDictionary *data  = [NSDictionary dictionaryWithObjectsAndKeys:
            module, @"module",
            method, @"method",
            params, @"params",
            nil];
    NSString *jsonMessage = [data JSONRepresentation];
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:url]];
    NSString *msgLength = [NSString stringWithFormat:@"%d", [jsonMessage length]];
    [request addValue: @"text/xml; charset=utf-8" forHTTPHeaderField:@"Content-Type"];
    [request addValue: msgLength forHTTPHeaderField:@"Content-Length"];
    [request setHTTPMethod:@"POST"];
    [request setHTTPBody: [jsonMessage dataUsingEncoding:NSUTF8StringEncoding]];
    requestData     = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
    NSString *get   = [[NSString alloc] initWithData:requestData encoding:NSUTF8StringEncoding];
    NSLog(@">>>>>>%@<<<<<<",get);
Thank you.

Answer 1

raczzoli wrote:
I'm working on an application which needs to make requests to a php gateway. I tried many examples I found on google, but none of them worked for me.
Why not?
Unfortunately, you are dealing with a number of different technologies that have been cobbled together over the years. You could write a PHP server that would respond correctly to this request, but not using basic methods like the $_POST variable. PHP was designed for HTML and true forms. What you are trying to do is make it work as a general purpose web service over the HTTP protocol. You can do that, but not with the form-centric convenience variables.
The following is a basic program that will populate the $_POST variable.
#import <Foundation/Foundation.h>
int main(int argc, const char * argv[])
  @autoreleasepool
    // insert code here...
    NSLog(@"Hello, World!");
    NSString  * module = @"coolmodule";
    NSString * method = @"slickmethod";
    //NSArray * params = @[@"The", @"Quick", @"Brown", @"Fox"];
    NSString * params = @"TheQuickBrownFox";
    NSString * url = @"http://localhost/~jdaniel/test.php";
    NSDictionary * data  =
      [NSDictionary
        dictionaryWithObjectsAndKeys:
          module, @"module",
          method, @"method",
          params, @"params",
          nil];
    //NSString *jsonMessage = [data JSONRepresentation];
    //NSData * jsonMessage =
    //  [NSJSONSerialization
    //    dataWithJSONObject: data options: 0 error: nil];
    NSMutableArray * content = [NSMutableArray array];
    for(NSString * key in data)
      [content
        addObject: [NSString stringWithFormat: @"%@=%@", key, data[key]]];
    NSString * body = [content componentsJoinedByString: @"&"];
    NSData * bodyData = [body dataUsingEncoding: NSUTF8StringEncoding];
    NSMutableURLRequest * request =
      [[NSMutableURLRequest alloc] initWithURL: [NSURL URLWithString:url]];
    //NSString * msgLength =
    //  [NSString stringWithFormat: @"%ld", [jsonMessage length]];
    NSString * msgLength =
      [NSString stringWithFormat: @"%ld", [bodyData length]];
    [request
      addValue: @"application/x-www-form-urlencoded; charset=utf-8"
      forHTTPHeaderField: @"Content-Type"];
    [request addValue: msgLength forHTTPHeaderField: @"Content-Length"];
    [request setHTTPMethod: @"POST"];
    //[request setHTTPBody: jsonMessage];
    [request setHTTPBody: bodyData];
    NSData * requestData =
      [NSURLConnection
        sendSynchronousRequest: request returningResponse: nil error: nil];
    NSString * get =
      [[NSString alloc]
        initWithData: requestData encoding: NSUTF8StringEncoding];
    NSLog(@">%@<",get);
  return 0;
I have written this type of low-level server in PHP using the Zend framework. I don't know how to do it in basic PHP and wouldn't bother to learn.
Also, you should review how you are sending data. I changed your example to send the appropriate data and content-type for the $_POST variable. If you had a server that could support something else, you could use either JSON or XML, but your data and content-type would have to match.