How can I pass a function as an optional variable to call_user_func in PHP

Question

So I'd like to use the call_user_func to pass data to an optional parameter of a function.

Here's the example of a code, the optional parameter $data represents a functional called data that was declared in another file. I just want it to be called by using call_user_func that will set the parameter with the function's name and call it within the createtable function, but doesn't seem to work.

I got the example from the PHP Manual, but createTable contains many parameters. How can I make call_user_func only assign the string data to the optional parameter $data set to NULL as default?

function createTable($database, $table, $patch,$data = NULL)
{

    echo "INFO: Adding '$table'in database '$database'.\n";
    $sql = "SHOW TABLES FROM $database WHERE Tables_in_$database='$table';";
    $result = mysql_query($sql);
    $result_count = mysql_num_rows($result);

    if ( $result_count != 1 ) {
          echo "ERROR: Can not find table '$table' in database '$database'.\n";
          $result = mysql_query($patch);
          if ( false === $result ) {
                echo "ERROR: Adding Table '$table' in database '$database' ... Failed\n";
                return false;
            }
          else {
          echo "INFO: Adding Table '$table'in database '$database' ... Success\n";
             // using the optional parameter here 
              $data();
          return true;
               }

    } else {

        if ( $result_count == 1 ) {
            echo "ERROR: Table '$table'already in database '$database'.\n";
            return false;
        }

    }
}

// Now I'm passing value to the optional parameter $ data that is NULL as default.

call_user_func('createTable', "data");

Answer 1

you must pass value like this

call_user_func('createTable', $database, $table, $patch,$data);

or this for call from class

call_user_func(array(&$objectName->{$anotherObject},$functionName), $arg1, $arg2, $arg2);

or you can use this can get arg as array

call_user_func_array("createTable", array("one", "two"));

or this for call from class can get arg as array

call_user_func_array(array($foo, "bar"), array("three", "four"));

or This can help you too it not need to pass all args

 function __named($method, array $args = array()) 
{ 

$reflection = new ReflectionFunction( $method); 

$pass = array(); 
foreach($reflection->getParameters() as $param) 
{ 
  /* @var $param ReflectionParameter */ 
  if(isset($args[$param->getName()])) 
  { 
    $pass[] = $args[$param->getName()]; 
  } 
  else 
  { 
    try{
       $pass[] = $param->getDefaultValue();
    }catch(Exception $e){
       $pass[] = NULL; 
    }
  } 
} 

  return $reflection->invokeArgs( $pass); 
 } 

I hope It Work

sample:

__named('createTable', array('data' => 'value')); 

and it is for use in class

public function __named($method, array $args = array()) 
{ 

   $reflection = new ReflectionMethod($this, $method); 

   $pass = array(); 
   foreach($reflection->getParameters() as $param) 
   { 
      /* @var $param ReflectionParameter */ 
      if(isset($args[$param->getName()])) 
      { 
         $pass[] = $args[$param->getName()]; 
      } 
      else 
      { 
     try{
           $pass[] = $param->getDefaultValue();
         }catch(Exception $e){
            $pass[] = NULL; 
         }
      } 
   } 

   return $reflection->invokeArgs($this,$pass); 
} 

if you Don't set any value __named Put Null instead of Unset Value

Answer 2

Even with call_user_func you have to pass all the parameters.

Anyway, call_user_func is intended for use when the name of the function isn't necessarily known up front. For instance, you might have several functions and a variable, and the variable contains the name of the function to call.

Personally I think it's on par with eval and variable variables: A horrible idea. After all, if you have $foo = "function_name"; then you can call $foo() and it will call function_name.

Anyway, back to the point, just call it as a normal function and give it the parameters it needs. Pass null if you have to.

Answer 3

It seems you just want to pass the last param, and not worry about the 1st three. I don't think call_user_func is the right tool here at all.

Why not just make a function that calls your function?

function call_createTable($data){
    $database = '...';
    $table = '...';
    $patch = '...';

    return createTable($database, $table, $patch, $data);
}

Then just simply call it like this: call_createTable("data");.