How can I write a function which has lots of arguments better? - php

Question

I have a function like this:
public function myfunc ($arg1, $arg2, $arg3, $arg4, $arg5, $arg6, $arg7, $arg8) {
// do something
}
See? My function gets 8 arguments. Yes it works as well, but you know, it's ugly kinda ..! Isn't there any better idea? For example passing just one array contains all argument. Is it possible? or even something similar.

Answer 1

I do it this way..
$params = [];
put things in params..
$params[] = $a;
$params[] = $b;
pass the array to function
myFunction($params);
The function accept array as arg like, definition:
public function myFunction($params = []){}
Pass something in, and var_dump to check for yourself...

Answer 2

OK, now I know that it's an SQL operation you're doing then the best approach would be an associative array (assuming PDO and prepared statements).
public function myFunc (array $data)
{
// Using 3 values for example!
$stmt = $this -> pdo -> prepare ("INSERT INTO TABLE thisTable (
col1,
col2,
col3
) VALUES (
:val1,
:val2,
:val3
)");
if (false !== $stmt execute ($data))
{
return $stmt -> rowCount ();
} else {
return 0;
}
}
You'd call it with an array with the correct parameters in it:
$success = (bool) $obj -> myFunc (["val1" => "First value to insert",
"val2" => "Second value to insert",
"val3" => "Third value to insert"]);

Answer 3

It depends whether myfunc belongs to an exposed api or not (i.e.: public)
If it is public, the signature must break when you update the underlying model (your insert query), otherwise errors will be committed on the client-side.
With an array, you're losely mapping your Model to your Application, and you'd just expect programmers to send you the right values. With a tight/restricting mapping, this kind of error cannot happen.
I think that if you're saving an item in the database, you actually need all these fields. It is unelegant indeed, but it's not an anti-pattern as none of them are optional. And even if one or two were, it would not be a concern.
What you could do to improve your api is either:
If there are situation where you need to pass only a few of the parameters (i.e. most are optional or depend on a particular scenario) then you could specialize the method into separate functions. But PHP not accepting function polymorphism is quite a pain in the neck for this kind of things; you'd have to name the methods differently.
public function myfunctosavedatainaparticularcase ($arg1, $arg2, $arg3, $arg4)
// do something
}
public function myfunctosavedatainanotherparticularcase ($arg5, $arg6, $arg7, $arg8)
// do something
}
Use an object model mapper. For example, suppose you're saving a User data. You'd just pass a User object to the method:
public function myfunc (User $user)
// map fields to the User signature.
}
This would be acceptable if you're in control of the User class since you'd have to change it to reflect model changes.
Use an ORM to handle this for you. You'd only have to update the xml specifications of the schema after you decide to change the database model, all necessary changes would be propagated to the application automatically. Of course the objects definition would change but that is inevitable.