I'm trying to make a very basic routing class and learn PHP closures by example. Basically, I want to make a routing feature like in Laravel but only with using closures.
function get($uri)
{
if($uri == '/account')
{
return true;
}
else
{
return false;
}
}
function Boo()
{
echo "Boo";
}
$route = new Route();
$route->get('/account', function() {
return $route->Boo();
});
I can do this without closures and see "Boo" as output.
How can I do this with closures? I currently see a blank output.
Ps. Functions are in correct class.
You need to actually accept the closure as a parameter of your get method, and call it, here's an example
class Route
{
function get($uri, Closure $closure=null)
{
if($uri == '/account')
{
// if the closure exists, call it, passing it this instance as its parameter
if (null !== $closure) {
$closure($this);
}
return true;
}
else
{
return false;
}
}
function Boo()
{
echo "Boo";
}
}
$route = new Route();
// have the closure accept a route as it's parameter
$route->get('/account', function($route) {
return $route->Boo();
});
Related
Say I have to similar function :
public function auth(){
return $someResponse;
}
public function collect(){
return $someOtherResponse
}
Question : When one of the response get passed to another class, is there any way to check which function returned the response ?
In a purely object-oriented way, wanting to attach information to a value is akin to wrapping it into a container possessing context information, such as:
class ValueWithContext {
private $value;
private $context;
public function __construct($value, $context) {
$this->value = $value;
$this->context = $context;
}
public value() {
return $this->value;
}
public context() {
return $this->context;
}
}
You can use it like this:
function auth()
{
return new ValueWithContext($someresponse, "auth");
}
function collect()
{
return new ValueWithContext($someotherrpesonse, "collect");
}
This forces you to be explicit about the context attached to the value, which has the benefit of protecting you from accidental renamings of the functions themselves.
As per my comment, using arrays in the return will give you a viable solution to this.
It will allow a way to see what has been done;
function auth()
{
return (array("auth" => $someresponse));
}
function collect()
{
return (array("collect" => $someotherrpesonse));
}
class myClass
{
function doSomething($type)
{
if (function_exists($type))
{
$result = $type();
if (isset($result['auth']))
{
// Auth Used
$auth_result = $result['auth'];
}
else if (isset($result['collect']))
{
// Collect used
$collect_result = $result['collect'];
}
}
}
}
It can also give you a way to fail by having a return array("fail" => "fail reason")
As comments say also, you can just check based on function name;
class myClass
{
function doSomething($type)
{
switch ($type)
{
case "auth" :
{
$result = auth();
break;
}
case "collect" :
{
$result = collect();
break;
}
default :
{
// Some error occurred?
}
}
}
}
Either way works and is perfectly valid!
Letting the two user defined functions auth() & collect() call a common function which makes a call to debug_backtrace() function should do the trick.
function setBackTrace(){
$backTraceData = debug_backtrace();
$traceObject = array_reduce($backTraceData, function ($str, $val2) {
if (trim($str) === "") {
return $val2['function'];
}
return $str . " -> " . $val2['function'];
});
return $traceObject;
}
function getfunctionDo1(){
return setBackTrace();
}
function getfunctionDo2(){
return setBackTrace();
}
class DoSomething {
static function callfunctionTodo($type){
return (($type === 1) ? getfunctionDo1() : getfunctionDo2());
}
}
echo DoSomething::callfunctionTodo(1);
echo "<br/>";
echo DoSomething::callfunctionTodo(2);
/*Output
setBackTrace -> getfunctionDo1 -> callfunctionTodo
setBackTrace -> getfunctionDo2 -> callfunctionTodo
*/
The above function would output the which function returned the response
Im not so experienced in php , Im using codeigniter to write my application , I have my own library and within my library there are three functions/methods that passes there arguments in one function which is in one of my models , my question is how will i manipulate/trick the method in my model to know exactly which function among the three in my library has passed the value and return the correct value ..
1st function
public function id_exist ($id) {
if(empty($id)) {
return FALSE;
}
return $this->library_model->this_exist($id);
}
2nd function
public function group_exist($group) {
if(empty($group)){
return FALSE;
}
return $this->library_model->this_exist($group);
}
with the 3rd same as the above 2
in my model
public function this_exist ($item) {
if(empty($item) || !isset($item)) {
return FALSE;
}
// here is where i need to know which function has passed the argument so that i can work with it and return the correct value from the database
}
Might be dirty, might be not sophisticated, but why not passing another argument which tells exactly the origin?
public function id_exist ($id) {
if(empty($id)) {
return FALSE;
}
return $this->library_model->this_exist('id', $id);
}
public function group_exist($group) {
if(empty($group)){
return FALSE;
}
return $this->library_model->this_exist('group', $group);
}
Model:
public function this_exist ($origin, $item) {
if(empty($item) || !isset($item)) {
return FALSE;
}
if($origin == 'id'){
// do something
}
elseif($origin == 'group') {
// do something else
}
}
I know that you can use nested functions in PHP.
Here is the question:
I have this code:
class ClassName
{
private $data;
function __construct()
{
}
public function myFunction()
{
if($condition1 != NULL)
{
if(!empty($condition2) && $this->data->condition3 == NULL)
{
$this->do1($condition2);
$this->do3($condition2);
$this->do3($condition2);
$this->doBLAH();
}
elseif(empty($checkoutItem->rebillCheckoutItemId))
{
$this->do1($condition2);
$this->do3($condition2);
$this->do3($condition2);
$this->doSomethingElse();
}
}
}
}
As you can see, this part is redundant:
$this->do1($condition2);
$this->do3($condition2);
$this->do3($condition2);
So get rid off redundancy i could create a new method:
private function doSomething($condition2)
{
$this->do1($condition2);
$this->do3($condition2);
$this->do3($condition2);
}
But i don't want to. It might really mess my code up.
Just wondering if its possible to do something like:
public function myFunction()
{
if($condition1 != NULL)
{
if(!empty($condition2) && $this->data->condition3 == NULL)
{
$this->doSomething($condition2);
$this->doBLAH();
}
elseif(empty($checkoutItem->rebillCheckoutItemId))
{
$this->doSomething($condition2);
$this->doSomethingElse();
}
}
function doSomething($condition2)
{
$this->do1($condition2);
$this->do3($condition2);
$this->do3($condition2);
}
}
I tried it but it throws a Fatal error: Call to undefined function doSomething(). Are there any tricks? Am i doing something wrong?
UPDATE
I'm working in YII framework and it gives me an exception: BlahWidget and its behaviors do not have a method or closure named "doSomething"
You can define an anonymous function in your local scope instead. Otherwise, the function will still be defined in the global scope or namespace.
This should work from PHP 5.4 because $this is used within the closure. In 5.3, you will need to do additional gymnastics. See below.
public function myFunction()
{
$do = function ($condition2) {
$this->do1($condition2);
$this->do3($condition2);
$this->do3($condition2);
};
if($condition1 != NULL)
{
if(!empty($condition2) && $this->data->condition3 == NULL)
{
$do($condition2);
$this->doBLAH();
}
elseif(empty($checkoutItem->rebillCheckoutItemId))
{
$do($condition2);
$this->doSomethingElse();
}
}
}
And now the 5.3 version. Note that the functions called need to be public.
public function myFunction()
{
$that = $this;
$do = function ($condition2) use ($that) {
$that->do1($condition2);
$that->do3($condition2);
$that->do3($condition2);
};
if($condition1 != NULL)
{
if(!empty($condition2) && $this->data->condition3 == NULL)
{
$do($condition2);
$this->doBLAH();
}
elseif(empty($checkoutItem->rebillCheckoutItemId))
{
$do($condition2);
$this->doSomethingElse();
}
}
}
In an example like this, for 5.3, I would rather create a private method on the class.
First of all, you can't have a function called do(). It is reserved.
So let's change your do() to do_somthing(). Then you need to call it with $this->do_something() wherever you want to make use of it.
I have a validation class which uses method chaining. I would like to be able to do single checks with TRUE/FALSE like this:
if ($obj->checkSomething()) {}
But also chain methods like this:
if ($obj->checkSomething()->checkSomethingElse()) {}
The problem however is that if one method returns FALSE, it will not send back an object and thus breaks the method chaining which ends with this error:
Fatal error: Call to a member function checkSomething() on a non-object in ...
Do I have to pick either single method return calls or method chaining or is there a workaround?
One idea would be to set an internal flag to indicate success or failure, and access it via another method, while checking that flag in each method and not doing anything if it's set. E.g.:
class A {
private $valid = true;
public function check1() {
if (!$this->valid) {
return $this;
}
if (!/* do actual checking here */) {
$this->valid = false;
}
return $this;
}
public function check2() {
if (!$this->valid) {
return $this;
}
if (!/* do actual checking here */) {
$this->valid = false;
}
return $this;
}
public function isValid() {
return $this->valid;
}
}
// usage:
$a = new A();
if (!$a->check1()->check2()->isValid()) {
echo "error";
}
To minimize the boilerplate checking in each function, you could also use the magic method __call(). E.g.:
class A {
private $valid;
public function __call($name, $args) {
if ($this->valid) {
$this->valid = call_user_func_array("do" . $name, $args);
}
return $this;
}
private function docheck1() {
return /* do actual checking here, return true or false */;
}
private function docheck2() {
return /* do actual checking here, return true or false */;
}
public isValid() {
return $this->valid;
}
}
The usage would be same as above:
$a = new A();
if (!$a->check1()->check2()->isValid()) {
echo "error";
}
I believe you're looking to have an instance evaluate as true/false based on the outcome of validation.
While some languages allow you to override the boolean value of an instance, php does not (except for casting to string, that is. See PHP's Magic Methods).
Also, the booleans page in the PHP Manual has a list of things that evaluate to false, but it doesn't give any method of overriding the behavior either.
That being said, I'd suggest going with JRL's idea, and construct a chain of validation rules, then 'execute' it with a function that returns the boolean needed in your if statement.
You could wrap them up in a subclass, perhaps.
e.g. if you have
class Validate {
public function checkSomething($data) {
if ($data === $valid) {
return true;
}
return false;
}
public function checkSomethingElse($data) {
if ($data === $valid) {
return true;
}
return false;
}
}
You could do this:
class ValidateChain extends Validate {
protected $valid = true;
public function checkSomething($data) {
if (false === parent::checkSomething($data)) {
$this->valid = false;
}
return $this;
}
public function checkSomethingElse($data) {
if (false === parent::checkSomethingElse($data)) {
$this->valid = false;
}
return $this;
}
public function getIsValid() {
return $this->valid;
}
}
$v = new ValidationChain();
$valid = $v->checkSomething()->checkSomethingElse()->getIsValid();
Quick and dirty, E&OE. And you'd probably need to add a way to find out which bits weren't valid, etc.
Consider the following PHP snippet:
<?php
class Is
{
function __get($key)
{
$class = __CLASS__ . '_' . $key;
if (class_exists($class) === true)
{
return $this->$key = new $class();
}
return false;
}
function Domain($string)
{
if (preg_match('~^[0-9a-z\-]{1,63}\.[a-z]{2,6}$~i', $string) > 0)
{
return true;
}
return false;
}
}
class Is_Domain
{
function Available($domain)
{
if (gethostbynamel($domain) !== false)
{
return true;
}
return false;
}
}
$Is = new Is();
var_dump($Is->Domain('google.com')); // true
var_dump($Is->Domain->Available('google.com')); // false
?>
Is it possible to call the Available() method like this (and still return solely true or false if the Available method is not called)?
var_dump($Is->Domain('google.com')->Available()); // false
If yes, how?
EDIT: Would this do the trick?
class Is
{
function __get($key)
{
// same as before
}
function Domain($string)
{
if (preg_match('~^[0-9a-z\-]{1,63}\.[a-z]{2,6}$~i', $string) > 0)
{
return (bool) $this->Domain;
}
return false;
}
}
class Is_Domain
{
function __toString()
{
return true;
}
function Available($domain)
{
if (gethostbynamel($domain) !== false)
{
return true;
}
return false;
}
}
Thanks in Advance!
PS: This snippet is truncated, so don't expect it to make it a lot of sense just by its own.
Essentially you want a method to return either a bool or an object based on whether a subsequent method call to the result is going to occur. I don't think this will be possible without some massive hack (e.g. reading the PHP file in yourself and looking ahead), and it shouldn't be because your objects shouldn't be worrying about the context in which they are used.
Instead you could get the first call to return an object which is relevant in both cases, e.g. DomainLookupResult, which has two methods e.g. Exists() and IsAvailable(). You could then do:
$result = $Is->Domain('google.com');
$isValid = $result->Exists();
$isAvaliable = $result->IsAvailable();
//or chaining:
$isValid = $Is->Domain('google.com')->Exists();
$isAvailable = $Is->Domain('google.com')->IsAvailable();
You can only chain method calls if they return an object!
This is because you can only call methods on objects.
The problem with your code is that the methods return a non object value, either true or false. And the problem is not in any way solved better by chaining methods. You should use that where its applicable. Like chaining many setters, NOT getters which the methods you want to use essentially is.
var_dump($Is->Domain->Available('google.com')); // false
//is the same as
$res = $Is->Domain;
$res = $res->Available('google.com'));
var_dump($res);
So you see the first res is a boolean true or false, and you can not call a method on that.
edit
This might be a "solution". Not a good solution though since this is better without chaining.
class Domain
{
public $domain;
function setDomain($domain) {
$this->domain = $domain;
return $this;
}
function isDomain($domain = null) {
if (is_string($domain)) {
$this->setDomain($domain);
}
$result = gethostbynamel($this->domain) !== false;
return new Result($this, $result);
}
function isValid() {
$result = (bool) preg_match('', $this->domain);
return new Result($this, $result)
}
}
class Result
{
public $result;
public $object;
public function __construct($object, $result)
{
$this->result = $result;
$this->object = $object;
}
public function __call($method, $arguments)
{
if (is_object($this->result)) {
return call_user_func_array(array($this->result, $method), $arguments);
}
if (!$this->result) {
return $this;
}
return call_user_func_array(array($this->object, $method), $arguments);
}
}
$domain = new Domain();
var_dump($domain->isValid('google.com')->isAvailable()->result);
/edit
This will solve your problem above.
var_dump($Is->Domain('validandfreedomain.com') && $Is_Domain->Available('validandfreedomain.com')); // true
If you desperately want to chain a method for this problem you could make it more like this.
class Domain
{
public $domain;
function setDomain($domain) {
$this->domain = $domain;
return $this;
}
function isAvailable() {
return gethostbynamel($this->domain) !== false;
}
function isValid() {
return (bool) preg_match('', $this->domain);
}
}
$domain = new Domain();
$result = $domain->setDomain('validandfreedomain.com')->isValid() && $domain->isAvailable();
It is possible, if your function returns an object, you can call its method, and so on (see method chaining). The only limitation is - as far as a I know - is that you cannot chain calls from an object created by new ( new Object()->method1()->method2() ).
As for your example, I see no point in using either the dynamic class, or method chaining stuff.