Http Post Request With Parameters

Question

I have a simple asp.net web service which returns json format data. I want to send http post request with parameter for getting json data. How can I send request and get data ?

post request:

POST /JsonWS.asmx/FirmaGetir HTTP/1.1
Host: localhost
Content-Type: application/x-www-form-urlencoded
Content-Length: length

firID=string

answer:

HTTP/1.1 200 OK
Content-Type: text/xml; charset=utf-8
Content-Length: length    
<?xml version="1.0" encoding="utf-8"?>
<string xmlns="http://tempuri.org/">string</string>

I'm trying some codes but they didn't work.

NSString *firmadi =@"";
NSMutableData *response;


-(IBAction)buttonClick:(id)sender
{
    NSString *firid = [NSString stringWithFormat:@"800"];

    response = [[NSMutableData data] retain];

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://192.168.1.23/testService/JsonWS.asmx?op=FirmaGetir"]];

    NSString *params = [[NSString alloc] initWithFormat:@"firID=%@",firid];
    [request setHTTPMethod:@"POST"];
    [request setHTTPBody:[params dataUsingEncoding:NSUTF8StringEncoding]];
    [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
    [[NSURLConnection alloc] initWithRequest:request delegate:self];
NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

    if(theConnection)
    {
        response = [[NSMutableData data] retain];

    }
    else 
    {
        NSLog(@"theConnection is null");
    }

}

-(void)connection:(NSURLConnection*)connection didReceiveResponse:(NSURLResponse*)responsed
{
    [response setLength:0];
     NSURLResponse * httpResponse;

    httpResponse = (NSURLResponse *) responsed;

}

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData*)data
{
    [response appendData:data];
    //NSLog(@"webdata: %@", data);

}

-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError*)error
{
    NSLog(@"error with the connection");
    [connection release];
    [response release];
}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{

    response = [[NSMutableData data] retain];

 NSString *responseString = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding];
    NSLog(@"%@",responseString);

}

Answer 1

I suffered this problem this morning and I just figure it out now. I guess the key to your question is How to use POST method with parameter. Actually, it is quite simple.

(1) First, you should make sure your file is ready to send. Here we say it is an NSString called stringReady. We use it as a parameter in our method called postRequest (Here is not the HTTP POST parameter we want to talk about. Don't worry).

// Send JSON to server
- (void) postRequest:(NSString *)stringReady{
// Create a new NSMutableURLRequest
NSMutableURLRequest *req = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:@"http://www.xxxxxx.io/addcpd.php"]];
[req setHTTPMethod:@"POST"];

(2) Now, we say it the parameter that the server wants to get is called "data", this is the way how to insert your parameter to the HTTP body.

// Add the [data] parameter
NSString *bodyWithPara = [NSString stringWithFormat:@"data=%@",stringReady];

See, it's how you add a parameter when using POST method. You just simply put the parameter before the file that you want to send. If you aleary konw what your parameter then you may better to check this website:

https://www.hurl.it/

This will help you to test if you are sending files properly and it will show the response at the bottom of the website.

(3) Third, we pack our NSString to NSData and sent it to server.

// Convert the String to NSData
NSData *postData = [bodyWithPara dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
// Set the content length and http body
NSString *postLength = [NSString stringWithFormat:@"%lu",(unsigned long)[postData length]];
[req addValue:postLength forHTTPHeaderField:@"Content-Length"];
[req setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
[req setHTTPBody:postData];
// Create an NSURLSession
NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *task = [session dataTaskWithRequest:req
                                        completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                                            // Do something with response data here - convert to JSON, check if error exists, etc....
                                            if (!data) {
                                                NSLog(@"No data returned from the sever, error occured: %@", error);
                                                return;
                                            }

                                            NSLog(@"got the NSData fine. here it is...\n%@\n", data);
                                            NSLog(@"next step, deserialising");

                                            NSError *deserr;
                                            NSDictionary *responseDict = [NSJSONSerialization
                                                                          JSONObjectWithData:data
                                                                          options:kNilOptions
                                                                          error:&deserr];
                                            NSLog(@"so, here's the responseDict\n\n\n%@\n\n\n", responseDict);
                                        }];

[task resume];}

Hope this can help somebody who gets stuck at here.

Answer 2

What are you doing here:

[[NSURLConnection alloc] initWithRequest:request delegate:self];

This line returns a NSURLConnection but you are not storing it. This is doing nothing for you.

You are clearing your data before you read it:

-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    response = [[NSMutableData data] retain]; // This line is clearing your data get rid of it
    NSString *responseString = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding];
    NSLog(@"%@",responseString);

}

Edit

-(IBAction)buttonClick:(id)sender {

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://192.168.1.23/testService/JsonWS.asmx?op=FirmaGetir"]
                                                           cachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData
                                                       timeoutInterval:15];
    [request setHTTPMethod:@"POST"];
    [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
    [request setHTTPBody:[@"firID=800" dataUsingEncoding:NSUTF8StringEncoding]];
    self.connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
    [self.connection start];

}


#pragma NSURLConnection Delegates

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {

    if (!self.receivedData){
        self.receivedData = [NSMutableData data];
    }
    [self.receivedData appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {

     NSString *responseString = [[NSString alloc] initWithData:self.receivedData encoding:NSUTF8StringEncoding];
     NSLog(@"%@",responseString);
}