How does this POST request works?

Question

"Send a message as a POST request to a web service. The address must start with “http://”, and may optionally include the port number (default is 80) and the path to a specific web service. The notification message fills the body of the content part of the POSTed message, with no key=value form-style formatting – you just read the input stream directly."

The above is extracted from the Alien UHF RFID F800 manual. The mentioned request is used to send the RFID tags that are scanned by the reader to a web service. The domain name is myrfidtest.com and the path is /insertdb.php. Now the insertdb.php is set up to accept two parameters, for example, id and RFID tag number. So the complete URL is http://myrfidtest.com/insertdb.php?id=21&rfid=2eda1. This data then gets successfully inserted into my database.

Hence I understand how to insert data into the cloud-hosted database using the above URL. However, I do not understand the extract, and what is meant by "you just read the input stream directly"?

In addition, how do I change the insert.php script to accept the tags from the reader?

My insert.php scritp:

<?php
 class data_new
 {
    public $conn='';

    function __construct($id,$rfid)
    {
       $this->storeInDB($id,$rfid);
    }

    function storeInDB($id,$rfid)
    {
       $conn = new mysqli('localhost','user','password','db');
    
       // Check connection
       if ($conn->connect_error) 
       {
          die("Connection failed: " . $conn->connect_error);
       }
    
       $sql = "insert into cloud set id='".$id."', rfid='".$rfid."'";
    
       if ($conn->query($sql) === TRUE) 
       {
           echo "New record created successfully";
       } 

       else 
       {
          echo "Error: " . $sql . "<br>" . $conn->error;
       }
   }
    
 }


 if($_GET['id'] != '' and $_GET['rfid'] != '')
 {
    $data_new = new data_new($_GET['id'],$_GET['rfid']);
 }

?>
    

Answer 1

Normally when you post form data in a HTTP request, you (or your browser) puts the posted data into the body of the HTTP request, and formats it rather like a querystring e.g. field1=value1&field2=value2, so that the server receiving the request can tell the fields apart and know which value belongs to which field. I think the article is saying that in this particular request, the entire body of the request is simply a single field containing the notification data, without any name=value style formatting - because there's only one parameter in the body.

In PHP, posted data normally appears in the $_POST array, with one entry in the array per parameter in the data (so you'd end up with $_POST["field1"], $_POST["field2"], etc. But you can also read the raw input data using:

$postdata = file_get_contents("php://input");

instead. This would be useful in the case mentioned above where the data is just one big stream of text inside the request body, rather than being formatted.

---

P.S. I can't answer the second part of your question " how do I change the insert.php" because I don't know what script you're referring to, what it does or looks like, or what tags you're talking about. I suggest asking a second, separate question about that as it sounds like a different issue, and giving a clear example of what you mean, within the question text.