Manipulate a url string by adding GET parameters

Question

I want to add GET parameters to URLs that may and may not contain GET parameters without repeating ? or &.

Example:

If I want to add category=action

$url="http://www.acme.com";
 // will add ?category=action at the end

$url="http://www.acme.com/movies?sort=popular";
 // will add &category=action at the end

If you notice I'm trying to not repeat the question mark if it's found.

The URL is just a string.

What is a reliable way to append a specific GET parameter?

Answer 1

Basic method

$query = parse_url($url, PHP_URL_QUERY);

// Returns a string if the URL has parameters or NULL if not
if ($query) {
    $url .= '&category=1';
} else {
    $url .= '?category=1';
}

More advanced

$url = 'http://example.com/search?keyword=test&category=1&tags[]=fun&tags[]=great';

$url_parts = parse_url($url);
parse_str($url_parts['query'], $params);

$params['category'] = 2;     // Overwrite if exists
$params['tags'][] = 'cool';  // Allows multiple values

// Note that this will url_encode all values
$url_parts['query'] = http_build_query($params);

// If you have pecl_http
echo http_build_url($url_parts);

// If not
echo $url_parts['scheme'] . '://' . $url_parts['host'] . $url_parts['path'] . '?' . $url_parts['query'];

You should put this in a function at least, if not a class.

Answer 2

$parameters = array();

foreach ($get as $key => $value)
{
     $parameters[] = $key.'='.$value;
}

$url = 'http://example.com/movies?'.implode('&', $parameters);

Answer 3

$data = array('foo'=>'bar',
              'baz'=>'boom',
              'cow'=>'milk',
              'php'=>'hypertext processor');

$queryString =  http_build_query($data);
//$queryString = foo=bar&baz=boom&cow=milk&php=hypertext+processor

echo 'http://domain.com?'.$queryString;
//output: http://domain.com?foo=bar&baz=boom&cow=milk&php=hypertext+processor

Answer 4

 public function addGetParamToUrl($url, $params)
{
    foreach ($params as $param) {
         if (strpos($url, "?"))
        {
            $url .= "&" .http_build_query($param); 
        }
        else
        {
            $url .= "?" .http_build_query($param); 
        }
    }
    return $url;
}

Answer 5

I think you should do it something like this.

class myURL {
    protected $baseURL, $requestParameters;

    public function __construct ($newURL) {
        $this->baseurl = $newURL;
        $this->requestParameters = array();
    }

    public function addParameter ($parameter) {
        $this->requestParameters[] = $parameter;
    }

    public function __toString () {
        return $this->baseurl.
               ( count($this->requestParameters) ?
                 '?'.implode('&', $this->requestParameters) :
                 ''
                 );
    }
}

$url1 = new myURL ('http://www.acme.com');
$url2 = new myURL ('http://www.acme.com');
$url2->addParameter('sort=popular');
$url2->addParameter('category=action');
$url1->addParameter('category=action');

echo $url1."\n".$url2;

Answer 6

Here's a shorter version of the accepted answer:

$url .= (parse_url($url, PHP_URL_QUERY) ? '&' : '?') . 'category=action';

Edit: as discussed in the accepted answer, this is flawed in that it doesn't check to see if category already exists. A better solution would be to treat the $_GET for what it is - an array - and use functions like in_array().