How do namespace work in PHP - php

I'm trying to instantiate a class that use namespace.
<?php
namespace CFPropertyList;
require_once('CFPropertyList/CFPropertyList.php');
$plist = new CFPropertyList();
?>
That's working!
But when I try put that code into my class I get syntax errors. I can't use "namespace CFPropertyList;" in a class?
<?php
class Plist{
public function test(){
namespace CFPropertyList;
require_once('CFPropertyList/CFPropertyList.php');
$plist = new CFPropertyList();
}
}
?>
UPDATE:
Thanks to all I got this working.
<?php
namespace CFPropertyList;
require_once('CFPropertyList/CFPropertyList.php');
class Plist{
public function test(){
//some code
}
}
}
But is my own class in a namespace now? Sorry for the noob questions.
I can't do.
$plist = new Plist;
$plist->test();

Your namespace should be declared before your class, so the class would then belong to that namespace:
plist.php
<?php
namespace CFPropertyList;
class Plist{
public function test() {
echo 'Test';
}
}
?>
other.php
<?php
require_once('plist.php');
$plist = new CFPropertyList::Plist();
$plist.test();
?>

You have to put the namespace definition outside the class definition.
(Besides that your class definition seems to be pretty messed up. Don't you have any class methods?)

From Defining namespaces
Namespaces are declared using the namespace keyword. A file containing
a namespace must declare the namespace at the top of the file before
any other code - with one exception: the declare keyword.
So you must declare it at the top of the file.

Related

Is there a PHP namespace extension that allows you to import/use/alias functions as if it was extended?

Is there a PHP namespace extension that allows you to import/use/alias functions as if it was extended directly into the class rather your typical namespace'd silo?
main.php
<?php
namespace api;
class main extends core{
print $this->whoami; // prints computer
}
core.php i.e. class core holding basic functions / standards:
<?php
namespace api;
class core{
function __construct(){
$this->whoami = "computer";
}
}
I want to add modular like classes and or functions that can be directly access from the class i.e.,
function-addon.php:
<?php
namespace api;
function abc($a){
print $a;
}
function-class.php
<?php
namespace api;
class tools{
function tool_a( $a ){
return $a;
}
}
with main.php looking like this (non working sample below):
<?php
namespace api;
use function api\abc as abc;
use api\tools as tools;
class main extends core{
print $this->whoami; // prints computer
print $this->abc(5); // print 5 (desired access)
print tools::tool_a(10); //print 10
}
The goal is "$this->abc" access and not i.e., tools:tool_a.
As I experiment I have a working solution, but I'm not a huge fan of yet as it doesn't use namespaces / aliases.
<?php
namespace api;
require("function-addon.php");
class main extends core{
}
function-addon.php:
<?php
function abc($a){
print $a;
}
Which would then allow the following to work:
<?php
namespace api;
require("function-addon.php");
class main extends core{
function __call( $func, $arg ){
return $this->func($arg);
}
}
The above allows the magic __call function access the locally referenced function-addon.php file.
The solution here is PHP Traits (https://www.php.net/manual/en/language.oop5.traits.php)
Per #nice_dev reference, a PHP trait implements a way to reuse code.
function-addon.php:
<?php
namespace api;
trait tools{
function abc($a;){
return $a;
}
}
Which would then allow the following to work:
<?php
namespace api;
require("function-addon.php");
class main extends core{
use tools;
function __construct(){
$this->abc(5); //returns 5
}
}
Make sure you use namespace in your traits!
Since you're working all within in the same namespace, you don't actually need any imports.
Assuming you're using composer, note that psr-4 doesn't work on autoloading functions. But you can specify "files" to be autoloaded in your composer.json file.
For example you can use:
{
"autoload": {
"psr-4": {
"api\\": "api"
},
"files": ["api/abc.php"]
}
}
Now that we got that out of the way,
Let's say your main file is /index.php:
<?php
use api\main;
require __DIR__ . '/vendor/autoload.php';
echo main::abc(5); // 5
$main = new main();
$main->abc(6); // 6
echo $main->whoami; // computer
The main file would look something like this /api/main.php:
<?php
namespace api;
class main extends core {
public function __call($name, $arguments)
{
if(function_exists(__NAMESPACE__.'\\'.$name)) {
return call_user_func_array(__NAMESPACE__.'\\'.$name, $arguments);
}
}
public static function __callStatic($name, $arguments)
{
if(function_exists(__NAMESPACE__.'\\'.$name)) {
return call_user_func_array(__NAMESPACE__.'\\'.$name, $arguments);
}
}
}
core would look like this: /api/core.php:
<?php
namespace api;
class core{
function __construct(){
$this->whoami = "computer";
}
}
abc.php like this /api/abc.php:
<?php
namespace api;
function abc($a){
print $a;
}
But note that if you need to "import" from another namespace, then you'll probably run into trouble since you need a way to specify which namespace to import from. The imports list, to the best of my knowledge, is a shorthand to save you from typing out the full namespace of whatever you're "importing". But at runtime, the imports list no longer exists, and you can't, for example, use eval in order to take advantage of the import to turn a string like "abc" into "api\abc". You'd need another way to do this.
I'm not much of a fan of __call, and __callStatic, I'd sooner define the methods you're importing.
A good way to do this is through a trait.
Then when you import, you can use a trait, and it will be part of the class.
For example:
/api/xyz.php:
<?php
namespace api;
trait xyz
{
function xyz($a)
{
print $a;
}
}
Then you'd use it like so /api/main.php:
<?php
namespace api;
class main extends core {
use xyz;
}
Then index.php: /index.php
<?php
use api\main;
require __DIR__ . '/vendor/autoload.php';
$main = new main();
$main->xyz(7); // 7

PHP: Namespace and calling one class into other

I have two classes, Class1 and Class2 which are under namespace myNameSpace.
I want to create an instance of Class2 in classand I am getting an error in implementing fileClass 'myNameSpace\Class2' not found in.. `. Code given below:
Class1.php
namespace myNameSpace {
use myNameSpace\Class2;
class Class1
{
public function myMethod()
{
$obj = new Class2();
}
}
call.php
namespace myNameSpace {
include 'Class1.php';
error_reporting(E_ALL);
ini_set('display_errors',1);
use myNameSpace\Class1;
$o = new Class1();
$o->myMethod();
}
If they're both in the same namespace you should not have to use a "use" statement. Seems more likely that you're not simply includeing both files.
Maybe what you're looking for is autoloading? http://php.net/manual/en/language.oop5.autoload.php

PHP: How to import sub-namespace in main namespace?

I am trying to find answer of following question:
Function world() is defined in the namespace 'myapp\utils\hello.' Your code is in namespace 'myapp'
What is the correct way to import the hello namespace so you can use the world() function?
Following is my code which I am trying but I am getting this error:
Fatal error: Call to undefined function myapp\world()
My Code:
<?php
namespace myapp;
use myapp\utils\hello;
world();
namespace myapp\utils\hello;
function world()
{
echo 'yes world';
}
You may do this:
<?php
namespace myapp;
\myapp\utils\hello\world();
namespace myapp\utils\hello;
function world()
{
echo 'yes world';
}
Also, read more here Using namespaces.
This is intresting:
All versions of PHP that support namespaces support three kinds of
aliasing or importing: aliasing a class name, aliasing an interface
name, and aliasing a namespace name. PHP 5.6+ also allows aliasing or
importing function and constant names.
Simply, before PHP 5.6, you can not use use to import a function. It has to be in a class. But with PHP5.6+, you can do this:
<?php
namespace myapp;
use function myapp\utils\hello\world;
world();
namespace myapp\utils\hello;
function world()
{
echo 'yes world';
}
<?php
namespace myapp;
use myapp\utils\hello\world;
But you miss the class name:
<?php
namespace myapp;
use myapp\utils\hello\world; // now, you can create an instance of world
class foo
{
public function bar()
{
return (new world())->yourMethod();
}
}
And your world class:
<?php
namespace myapp;
class world
{
public function yourMethod()
{
return 'It works';
}
}
Be sure that you've (auto)loaded the required classes!

Call function from different class and namespace

I'm having some trouble to call a function from a namespaced class in a different namespaced class. In the dummy example below I would like to know how to use Class2 within Class1. I'm getting the error:
Trait 'name1\name2\Class2' not found in class1.php
The code:
#file index.php
require "class1.php";
require "class2.php";
$class1 = new name1\Class1();
$class1->sayHello();
#file class1.php
namespace name1{
class Class1{
use name2\Class2;
public function sayHello(){
echo Class2::staticFunction();
}
}
}
#file class2.php
namespace name2{
class Class2{
public static function staticFunction(){
return "hello!";
}
}
}
Thank you for any advice.
Ok, so you've got several errors which I have fixed.
Here's the working code you need:
# index.php
include "class1.php";
include "class2.php";
$class1 = new name1\Class1();
$class1->sayHello();
# class1.php
namespace name1;
use name2\Class2;
class Class1{
public function sayHello(){
echo Class2::staticFunction();
}
}
# class2.php
namespace name2;
class Class2{
public static function staticFunction(){
return "hello!";
}
}
Some explanations:
When in class definition the use is used for using traits and not namespace
In PHP namespace need not be enclosed in curly brackets
In PHP you include files with include, include_once, require, or require_once, and not import
Inside your first class, your trait is calling class2 as use name2\Class2 but, you are still within the name1{} namespace, so in reality you are calling it as: use name1\name2\Class2
So, you need to change
use name2\Class2; to use \name2\Class2
Try this.
namespace name1{
use \name2\Class2;
class Class1{
public function sayHello(){
echo Class2::staticFunction();
}
}
}
#file class2.php
namespace name2{
class Class2{
public static staticFunction(){
return "hello!";
}
}
}
Also, another tip: If you are separating your classes in separate files, you do not need to separate them as in they way you have done. Just call the namespace simple as:
// file1.php
namespace person;
class name{}
//file2.php
namespace address;
class name{}
Why not drop the static method and just inject the class? Seems like going through extra work for something so simple. That's what function arguments are made for.
namespace name1{
use \name2\Class2;
class Class1{
public function sayHello($Class2){
echo $Class2->someFunction();
}
}
}
namespace name2{
class Class2{
public function someFunction(){
return "hello!";
}
}
}
#index.php
include "class1.php";
include "class2.php";
$Class1 = new name1\Class1();
$Class2 = new name2\Class2();
$Class1->sayHello($Class2);
//hello!

How to resolve fatal error when using namespace in a class

I have a PHP class that I would like to add a namespace to it.
I am using PHP Version 5.5.12 on Windows Server 2008 R2 and Apache 2.4
My Permissions class in located in /classes/Permissions.php
class Permissions
{
private $db;
public function __construct(){
}
public function sayHello(){
echo 'Hello';
}
private function _test(){
}
}
?>
When I want to start a new instance of the class, I do this in a file located "/test.php"
require_once 'classes/Permissions.php';
$r = new Permissions();
$r->sayHello();
And this is working fine.
Now I am trying to add namespace "which I never used before"
I changed my code to implement namespace like so
<?php
namespace classes\Permissions;
class Permissions
{
private $db;
public function __construct(){
}
public function sayHello(){
echo 'Hello';
}
private function _test(){
}
}
?>
and when staring a new instance of the class I do this
require_once 'classes/Permissions.php';
$r = new classes\Permissions();
$r->sayHello();
But with this I get a fatal error
Fatal error: Class 'Permissions' not found
What am I doing wrong? and how to correct it?
If you're going to require the file manually with require_once you're free to put the class under any namespace you like. So you can go:
namespace Foo;
class Permissions {}
You can instantiate this class with:
require_once 'path.to.classfile.php';
$r = Foo\Permissions(); //if you're in global namespace
docs: http://php.net/manual/en/language.namespaces.php
So when you have a class like this:
namespace classes\Permissions;
class Permissions {}
The way to create an object after you include it is with new classes\Permissions\Permissions(); again assuming you're in global namespace.
You should call classes with backslash at begin of namespace.
Try like this:
$r = new \classes\Permissions();
Is not it \classes\Permissions\Permissions()? You have a class Permissions in \classes\Permissions namespace

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