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Posted by Jochem Maas on 10/20/74 11:19
olivier wrote:
> Sorry for typo error, just need my cup of cofee...
:-) no probs ... I think we gave the OP plenty to think about!
liked you 'Register' idea - seems like it could work well.
also nice one for pointing out my php5isms - I forget that alot
of stuff I use is php5 only (e.g. second the arg. to class_exists())!
>
> Here is a good post for:
> http://fr.php.net/manual/fr/function.call-user-func-array.php
>
> ################################################################
> from taylor
> 08-May-2005 12:04
> <?php
> /**
> * Create an object of a specified type using an array as the parameters
> * to the constructor. NOTE: does not maintain proper
> * types for the arguments. They are all converted to strings.
> * @param $type Type type of object to create (class name)
> * @param $args The arguments to pass to the constructor
> */
> function createObjArray($type, $args=array()) {
> if ( !class_exists($type) ) {
> return NULL;
> }
>
> // build argument list; be sure to escape string delimeters
> $func = create_function('$str', 'return str_replace("\'","\\\'",
> $str);');
> $sargs = "'" . join( "','", array_map($func,$args) ). "'";
>
> // build & eval code; return result
> $seval = "return new $type($sargs);";
> return eval($seval);
> }
> ?>
> #################################################################
>
> I dont like eval too but i think that is depending on the pb we want to
> solve... if you can change contrutor from each object may be better to use
> jockem solution that is more secure (added some change for php4).
>
> #################################################################
> class Test
> {
> var $v;
> // constructor for php4
> function Test($args){
> $this->__construct($args);
> }
> // constructor for php5
> function __construct($args = array())
> {
> extract((array) $args);
> $this->v=$v;
> }
> }
>
> $className = "Test";
> $construct_params = array("v"=>"param1","param2","param3");
>
> //if (class_exists($className, false)) { ---> for php5
> if (class_exists($className)) { // for php4
> $obj = new $className($construct_params);
> } else {
> die("Hack off mate.");
> }
>
> var_dump($obj);
> ##################################################################
>
>
>> // I had to test this to see if it works! the first 2 attempts are
>>bogus // but you can run them to see what happens -- also the 3 attempt is
>>a pretty // weird construction and I would be interested to know if anybody
>>has thoughts // on calling the ctor in this way (essentially calling it
>>twice) //
>
>
> Never see a such solution, but may use a register funct instead...
>
> ##################################################################
> class Test
> {
> var $v;
>
> function Register($objName, $v=1){
> # auto register object if needed
> if(!isset($GLOBALS[$objName])){
> $GLOBALS[$objName]=true;
> $GLOBALS[$objName]=new Test($v);
> }else{
> return $GLOBALS[$objName];
> }
> }
>
> function Test($v){
> $this->__construct($v);
> }
>
> function __construct($v)
> {
> $this->v=$v;
> }
> }
>
> $className = "Test";
> $construct_params = array("obj", "param1","param2","param3");
> //if (class_exists($className, false)) { ---> for php5
> if (class_exists($className)) { // for php4
> call_user_func_array(array(($className), "Register"), $construct_params);
> } else {
> die("Hack off mate.");
> }
>
> var_dump($obj);
> ##################################################################
>
> Love phpsec too ;-)
> Hope this finaly help!
> Olivier
>
> Le Mercredi 22 Juin 2005 11:38, Jochem Maas a écrit :
>
>>olivier wrote:
>>
>>>Hi,
>>
>>I answered this also, but apparently I only replied to the OP...
>>(reproduced here - minus the typos in my first post on this topic :-/)
>>
>>if (class_exists($className, false)) {
>> $obj = new $className($construct_params);
>>} else {
>> die("Hack off mate.");
>>}
>>
>>
>>>Try something like:
>>>
>>>$classname = "MyClass";
>>>$construct_params = array("param1","param2","param3");
>>>
>>>$return =null;
>>>if(class_exists($classname)){
>>> $param=explode(" ',' ", $construct_param);
>>
>>this should be join() not explode(), but even then it won't work,
>>and even if it did you would only be able to pass strings (i.e. no objects,
>>arrays, resources, etc)
>>
>>for this you should probably be looking at call_user_func_array() e.g:
>>
>>class Test
>>{
>> public $v;
>> function __construct($v = 1) { $this->v = $v; }
>>}
>>
>>$className = "Test";
>>
>>if (class_exists($className, false)) {
>> // I had to test this to see if it works! the first 2 attempts are
>>bogus // but you can run them to see what happens -- also the 3 attempt is
>>a pretty // weird construction and I would be interested to know if anybody
>>has thoughts // on calling the ctor in this way (essentially calling it
>>twice) //
>> // ATTEMPT 1
>> //$obj = call_user_func_array(array($className,"__construct"),
>>array(3)); // ATTEMPT 2
>> //$obj = call_user_func_array(array(new $className,"__construct"),
>>array(3)); // ATTEMPT 3
>> call_user_func_array(array(($obj = new $className),"__construct"),
>>array(3));
>>
>>} else {
>> die("Hack off mate.");
>>}
>>
>>var_dump($obj);
>>
>>
>>># You must add here some security checks....
>>> eval("$retrun = new $className($param)");
>>
>>typo! 'retrun' (I spell 'return' like that alot too :-)
>>
>>btw eval() sucks and is not really needed, although granted it's an
>>easy/flexible solution in terms on being able to pass args to the ctor
>>(constructor), my thought would be that the classes you wish to init this
>>way should have a specific interface/design with regard to accepting ctor
>>args. A very simple example:
>>
>>class Test
>>{
>> function __construct($args = array())
>> {
>> extract((array) $args);
>> }
>>}
>>
>>
>>> var_dump($return);
>>>}
>>>
>>>Hope this help!
>>>Olivier
>>>
>>>Le Mercredi 22 Juin 2005 05:33, Eli a écrit :
>>>
>>>>Hi,
>>>>
>>>>I want to create an object in a form that I get the class name and its
>>>>parameters, and I need to create that object...
>>
>>oh and don't blindly accept whatever is sent by the form - sanitize the
>>class name and args before you use them! best general resource for this
>>kind [php-]thing is (IMHO) http://phpsec.org/ [ "Shifting Expectations" ;-)
>>]
>>
>>
>>>>How can this been done?
>>>>
>>>>i.e:
>>>>$classname = "MyClass";
>>>>$construct_params = array("param1","param2","param3");
>>>>/* Now create the object with the given classname and params... how? */
>>>>
>>>>-thanks, Eli
>
>
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