[php] Manipulate a url string by adding GET parameters

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?

This question is related to php url string

The answer is


$parameters = array();

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

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

This function overwrites an existing argument

function addToURL( $key, $value, $url) {
    $info = parse_url( $url );
    parse_str( $info['query'], $query );
    return $info['scheme'] . '://' . $info['host'] . $info['path'] . '?' . http_build_query( $query ? array_merge( $query, array($key => $value ) ) : array( $key => $value ) );
}

Example with updating existent parameters.

Also url_encode used, and possibility to don't specify parameter value

    <?
    /**
     * Add parameter to URL
     * @param string $url
     * @param string $key
     * @param string $value
     * @return string result URL
     */
    function addToUrl($url, $key, $value = null) {
        $query = parse_url($url, PHP_URL_QUERY);
        if ($query) {
            parse_str($query, $queryParams);
            $queryParams[$key] = $value;
            $url = str_replace("?$query", '?' . http_build_query($queryParams), $url);
        } else {
            $url .= '?' . urlencode($key) . '=' . urlencode($value);
        }
        return $url;
    }

$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

 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;
}

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;

After searching for many resources/answers on this topic, I decided to code my own. Based on @TaylorOtwell's answer here, this is how I process incoming $_GET request and modify/manipulate each element.

Assuming the url is: http://domain.com/category/page.php?a=b&x=y And I want only one parameter for sorting: either ?desc=column_name or ?asc=column_name. This way, single url parameter is enough to sort and order simultaneously. So the URL will be http://domain.com/category/page.php?a=b&x=y&desc=column_name on first click of the associated table header row.

Then I have table row headings that I want to sort DESC on my first click, and ASC on the second click of the same heading. (Each first click should "ORDER BY column DESC" first) And if there is no sorting, it will sort by "date then id" by default.

You may improve it further, like you may add cleaning/filtering functions to each $_GET component but the below structure lays the foundation.

foreach ($_GET AS $KEY => $VALUE){
    if ($KEY == 'desc'){
        $SORT = $VALUE;
        $ORDER = "ORDER BY $VALUE DESC";
        $URL_ORDER = $URL_ORDER . "&asc=$VALUE";
    } elseif ($KEY == 'asc'){
        $SORT = $VALUE;
        $ORDER = "ORDER BY $VALUE ASC";
        $URL_ORDER = $URL_ORDER . "&desc=$VALUE";
    } else {
        $URL_ORDER .= "&$KEY=$VALUE";
        $URL .= "&$KEY=$VALUE";
    }
}
if (!$ORDER){$ORDER = 'ORDER BY date DESC, id DESC';}
if ($URL_ORDER){$URL_ORDER = $_SERVER[SCRIPT_URL] . '?' . trim($URL_ORDER, '&');}
if ($URL){$URL = $_SERVER[SCRIPT_URL] . '?' . trim($URL, '&');}

(You may use $_SERVER[SCRIPT_URI] for full URL beginning with http://domain.com)

Then I use resulting $ORDER I get above, in the MySQL query:

"SELECT * FROM table WHERE limiter = 'any' $ORDER";

Now the function to look at the URL if there is a previous sorting and add sorting (and ordering) parameter to URL with "?" or "&" according to the sequence:

        function sort_order ($_SORT){
            global $SORT, $URL_ORDER, $URL;
            if ($SORT == $_SORT){
                return $URL_ORDER;
            } else {
                if (strpos($URL, '?') !== false){
                    return "$URL&desc=$_SORT";
                } else {                        
                    return "$URL?desc=$_SORT";
                }
            }
        }

Finally, the table row header to use the function:

        echo "<th><a href='".sort_order('id')."'>ID</a></th>";

Summary: this will read the URL, modify each of the $_GET components and make the final URL with parameters of your choice with the correct form of usage of "?" and "&"


another improved function version. Mix of existing answers with small improvements (port support) and bugfixes (checking keys properly).

/**
 * @param string $url original url to modify - can be relative, partial etc
 * @param array $paramsOverride associative array, can be empty
 * @return string modified url
 */
protected function overrideUrlQueryParams($url, $paramsOverride){
    if (!is_array($paramsOverride)){
        return $url;
    }

    $url_parts = parse_url($url);

    if (isset($url_parts['query'])) {
        parse_str($url_parts['query'], $params);
    } else {
        $params = [];
    }

    $params = array_merge($params, $paramsOverride);

    $res = '';

    if(isset($url_parts['scheme'])) {
        $res .= $url_parts['scheme'] . ':';
    }

    if(isset($url_parts['host'])) {
        $res .= '//' . $url_parts['host'];
    }

    if(isset($url_parts['port'])) {
        $res .= ':' . $url_parts['port'];
    }

    if (isset($url_parts['path'])) {
        $res .= $url_parts['path'];
    }

    if (count($params) > 0) {
        $res .= '?' . http_build_query($params);
    }

    return $res;
}

Use strpos to detect a ?. Since ? can only appear in the URL at the beginning of a query string, you know if its there get params already exist and you need to add params using &

function addGetParamToUrl(&$url, $varName, $value)
{
    // is there already an ?
    if (strpos($url, "?"))
    {
        $url .= "&" . $varName . "=" . $value; 
    }
    else
    {
        $url .= "?" . $varName . "=" . $value;
    }
}

<?php
$url1 = '/test?a=4&b=3';
$url2 = 'www.baidu.com/test?a=4&b=3&try_count=1';
$url3 = 'http://www.baidu.com/test?a=4&b=3&try_count=2';
$url4 = '/test';
function add_or_update_params($url,$key,$value){
    $a = parse_url($url);
    $query = $a['query'] ? $a['query'] : '';
    parse_str($query,$params);
    $params[$key] = $value;
    $query = http_build_query($params);
    $result = '';
    if($a['scheme']){
        $result .= $a['scheme'] . ':';
    }
    if($a['host']){
        $result .= '//' . $a['host'];
    }
    if($a['path']){
        $result .=  $a['path'];
    }
    if($query){
        $result .=  '?' . $query;
    }
    return $result;
}
echo add_or_update_params($url1,'try_count',1);
echo "\n";
echo add_or_update_params($url2,'try_count',2);
echo "\n";
echo add_or_update_params($url3,'try_count',3);
echo "\n";
echo add_or_update_params($url4,'try_count',4);
echo "\n";

 /**
 * @example addParamToUrl('/path/to/?find=1', array('find' => array('search', 2), 'FILTER' => 'STATUS'))
 * @example addParamToUrl('//example.com/path/to/?find=1', array('find' => array('search', 2), 'FILTER' => 'STATUS'))
 * @example addParamToUrl('https://example.com/path/to/?find=1&FILTER=Y', array('find' => array('search', 2), 'FILTER' => 'STATUS'))
 *
 * @param       $url string url
 * @param array $addParams
 *
 * @return string
 */
function addParamToUrl($url, array $addParams) {
  if (!is_array($addParams)) {
    return $url;
  }

  $info = parse_url($url);

  $query = array();

  if ($info['query']) {
    parse_str($info['query'], $query);
  }

  if (!is_array($query)) {
    $query = array();
  }

  $params = array_merge($query, $addParams);

  $result = '';

  if ($info['scheme']) {
    $result .= $info['scheme'] . ':';
  }

  if ($info['host']) {
    $result .= '//' . $info['host'];
  }

  if ($info['path']) {
    $result .= $info['path'];
  }

  if ($params) {
    $result .= '?' . http_build_query($params);
  }

  return $result;
}

In case you are using WordPress you can simply use

    add_query_args(['sort' => 'asc'], 'http:/example.com/?search=news')

Docs https://developer.wordpress.org/reference/functions/add_query_arg/


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().


Try this function to add URL parameters.

Then you can disable the link when parameter is set so there is no url parameter duplicate.

<?php
  function addQueryString($a)
                {
             if (empty($_SERVER['QUERY_STRING']))
               return '?' . $a;
             else if (!empty($_SERVER['QUERY_STRING']))
              return '?' . $_SERVER['QUERY_STRING'] . '&' . $a;
                }
?>

 <a href="<?php echo addQueryString('lang=en'); ?>">test</a>
 <a href="<?php echo addQueryString('category=5'); ?>">sat</a>

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