如何在iOS中调用URL以将传感器值发送到PHP脚本？

Question

I'm trying to write a simple iOS app which calls a URL once it receives a sensor value from a Bluetooth connected sensor (a Bean). I can connect to the sensor, but I cannot figure out how to append the sensor's value to the end of a URL and cause the phone to send that URL. Once I send the URL, a PHP script will pull off the sensor's value from the end of the URL.

Here is what I think it the relevant code. It compiles, but doesn't seem to call/send the URL. I'm guessing I am not handling variables correctly, but I don't know why.

// This reads the sensor value
-(void)readScratch
{
    int sNumber = 2;
    [_bean readScratchBank:sNumber];
    [NSTimer scheduledTimerWithTimeInterval:10.0 target:self selector:@selector(uploadData) userInfo:nil repeats:YES];
}

// This is supposed to be called when the sensor value has been read and forms the URL to upload the data.
-(void)uploadData
{
    NSString *sensedvalue = @"1";

    NSMutableString *webURL = [NSMutableString stringWithString:@""];
    [webURL appendString:@"value="];
    [webURL appendString:sensedvalue];

    NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration defaultSessionConfiguration];
    NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration: defaultConfigObject delegate: nil delegateQueue: [NSOperationQueue mainQueue]];

    NSURL * url = [NSURL URLWithString:@"http://www.example.com/folder/script.php?"];
    NSMutableURLRequest * urlRequest = [NSMutableURLRequest requestWithURL:url];
    [urlRequest setHTTPMethod:@"POST"];
    [urlRequest setHTTPBody:[webURL dataUsingEncoding:NSUTF8StringEncoding]];

    NSURLSessionDataTask * dataTask =[defaultSession dataTaskWithRequest:urlRequest completionHandler:^(NSData *dataRaw, NSURLResponse *header, NSError *error) {
        NSDictionary *json = [NSJSONSerialization
                              JSONObjectWithData:dataRaw
                              options:kNilOptions error:&error];
        NSString *status = json[@"status"];

        if([status isEqual:@"1"]){
            //Success

        } else {
            //Error

        }
    }];

    [dataTask resume];
}

Answer 1

Since you're using a GET request to push data to the server, you also need to add another parameter with a random value, for example: r=2341234. If you don't iOS will cache the response.

However, change this section of code:

NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"http://www.example.com/folder/script.php?value=%@&r=%d", sensedValue, arc4random()]];
NSMutableURLRequest * urlRequest = [NSMutableURLRequest requestWithURL:url];
[urlRequest setHTTPMethod:@"GET"];
// You can remove the following line 
//[urlRequest setHTTPBody:[webURL dataUsingEncoding:NSUTF8StringEncoding]];