PHP: How to dynamically add to http_build_query?

Question

I have a scraping object basically. I want to be able to add POST variables to it like

$obj->addvar('Name', 'Value');

What I have now is this:

  function addvar($var, $val) {
    $postvars[] = Array($var=>$val); 
  }
  function initiate() {
    $this->q = $postvars;
  }
  if(!empty($this->post)) {
    $this->params = http_build_query($q);
  }

I haven't tested because it's too incomplete, But would my addvar() function work? How on earth do I append a key+value to the array so http_build_query would accept it?

IE (this is what I want):

$obj->addvar('username', 'abc');
$obj->addvar('password', 'foobar');
$obj->send(); //..

Answer 1

You can do:

$postvars[$var] = $val;

Obviously you will need to make sure you call http_build_query() after all of values are in the array.

Also $postvars looks like a local variable, so it is only visible within that method (and will be reset on every call) . It would probably be better to make it a member of the class.

Answer 2

You have some problems with your addvars code here ($this->params seems outside the function initiate()), but otherwise it should work fine.

class test{
  var $postvars;
  function addvar($var, $val) {
    $this->postvars[] = Array($var=>$val); 
  }
  function initiate() {
    $this->q = $this->postvars;
    return http_build_query($this->q);
  }
}

    $obj = new test();
    $test->addvars('username', 'abc');

    $qry = $test->initiate();

This should work. Untested though.

Answer 3

You have serveral issues in your code:

• In your addvar method, you are not accessing any instance variables. You are assigning the alues to a local variable.
• Your initiate method cannot access the variable $postvar.
• In the if clause you are accessing a local variable $q instead of the instance variable $this->q.
• You want to pass an array of arrays to http_build_query but is has to be a "normal" array.

You are mixing up a lot!

A more complete example of your class would be helpful, but I think it should look more like this:

class QueryBuilder {
    private $params = array();

    public function addParameter($key, $value) {
        $this->params[$key] = $value;
    }

    public function send() {
        $query = http_build_query($this->params);
        // whatever else has to be done to send.
        // for the sake of this example, it just returns the query string:
        return $query;
    }
}

Example:

$obj = new QueryBuilder();
$obj->addParameter('username', 'abc');
$obj->addParameter('password', 'foobar');
echo $obj->send(); // echos 'username=abc&password=foobar'

---

In general, if you already have the query that was built by html_build_query you can just append to that string:

$query = http_build_query(array('foo' => 'bar', 'faa' => 'baz'));
$query .= '&key=value';
echo $query; // echos 'foo=bar&faa=baz&key=value'