Related
I am using php 7.4.9 and have a class which reads information from a file. These informations should be all the time availabe from outside the class and it also should possible to modify that array, so that this class can write back these information on request.
I have looked for a while but could not fined a useful solution.
I got the functions working, but the array loose the values from call to call.
Edit 2020/12/12
This is the uses structure of my code
<?php
.......
function show(){
$id3 = ID3::create();
$mp3 = &ID3::$mp3Array;
if($mode == "manual"){
if($file == ""){
return "";
}
$fName = $dir . "/" . $file;
$id3->open($fName);
.......
}else if($mode == "save"){
$fName = $dir . "/" . $file;
$id3->save($fName);
return "Save done!";
}
} // end of show
class ID3{
public static $mp3Array = array();
public static function create(): self {
static $object;
$object = $object ?? new self();
return $object;
}
function open($fName){
$mp3 = self::$mp3Array;
. // $mp3 will be filled
.........
}
function save($fName) {
$mp3 = &ID3::§mp3Array;
error_log("TagSave: ".var_export($mp3, true),0); // is always empty
foreach($mp3 as $key => $value){
........
}
}
} //end of class>
?>
If I try to save the modified array, it is always empty, if show is called again!
I have also implemented the #Logifire proposal 'create'. I got a valid pointer but the arrayis still empty.
Maybe I should point out, that it is web page. The html code sends information (form) back to the php program.
I figured out, that use of global $id3 = NULL; does not work, because the php grogramm will be always called and set the variable again to NULL each time.
I have also implemented the following code on the beginning
<?php
error_log("PHP call",0);
$id3count = 0;
if(array_key_exists("Test_id3",$GLOBALS)){
error_log("GLOBALS[Test_id3] exist!",0);
}else{
error_log("GLOBALS[Test_id3] does not exist!",0);
$GLOBALS['Test_id3'] = "NEW";
}
The $GLOBAL['Test_id3'] never exist, if the programm will be called!
I got the functions working, but the array loose the values from call to call.
As I understand you, your setup is not a long running app, you can not keep state between requests (calls).
But if you are aware of that, the issue may be you have a new instance of the class each time you call it within the same request flow, you may use a singleton if this is the case. I suggest using accessors in your class.
class MyDataList {
private array $my_array = [];
private function __construct()
{
}
public static function create(): self {
static $object;
$object = $object ?? new self();
return $object;
}
public function setArray(array $new_array): void {
$this->my_array = $new_array;
// open, write, close file..
}
public function getArray(): array {
return $this->my_array;
}
}
$my_data_list = MyDataList::create();
Based on your edited question (2020/12/12), I extended the example code:
class MyDataList {
private array $my_array = [];
private $file_path = '';
private function __construct()
{
}
public static function create(string $file_path): self {
static $object;
if ($object === null) {
$object = new self();
$stringified = file_get_contents($file_path) ?: '';
$array = json_decode($stringified, true) ?: [];
$object->file_path = $file_path;
$object->my_array = $array;
}
return $object;
}
public function setArray(array $new_array): void {
$this->my_array = $new_array;
$stringified = json_encode($new_array);
file_put_contents($this->file_path, $stringified);
}
public function getArray(): array {
return $this->my_array;
}
}
$my_data_list = MyDataList::create('/path/to/file');
Note: Be aware, you need to apply error handling
Comment answers:
Is the filepath connected to the array?
Well, you will write your data as JSON to a file each time you "modify" the array via the setArray()
Does it means, that the array is stored into a file and read out each time I try to connect again?
For each request you call create() it will instantiate the internal state of the array based on the stored data in the file. ATM. The file_get_contents call may have been wrapped and only called if the $object was not instantiated. (Now updated in the example)
So I have to call setArray($array); to save the data. I was looking for a soluting to keep the data without an management to save and read the array. Is this not possible with PHP?
Maybe you want to use a session variable to store your data? But it is individual per user and not long lived data - Link: https://www.php.net/manual/en/reserved.variables.session.php
In a standard PHP setup you can not have data/state between requests, but there are solution like Swoole which makes PHP a long running app: https://www.php.net/manual/en/book.swoole.php
I need a possibility to modify the array directly.
Is it a reference to the array you want? https://3v4l.org/OsBC6
class MyDataList {
private array $my_array = [];
private function __construct()
{
}
public static function create(): self {
static $object;
$object = $object ?? new self();
return $object;
}
public function setArray(array &$new_array): void {
$this->my_array = &$new_array;
}
public function getArray(): array {
return $this->my_array;
}
}
There is no easy way to do with PHP!
Finally I use the proposal from Logifire, but had to modified it to fullfill my requirements.
I needed more than 1 array.
One array can ibclude binary data values, which json can't handle. So I have to use base64 for the binary data values.
Here my code:
public array $mp3Array = array();
public array $findArray = array();
private $file_dir = "";
public static function create(string $fileDir): self {
static $object;
if ($object === null) {
$object = new self();
$stringified1 = file_get_contents($fileDir."/mp3Array.obj") ?: '';
$array1 = json_decode($stringified1, true) ?: [];
$stringified2 = file_get_contents($fileDir."/findArray.obj") ?: '';
$array2 = json_decode($stringified2, true) ?: [];
$object->file_dir = $fileDir;
$object->mp3Array = $object->arrayDecode($array1);
$object->findArray = $array2;
}
return $object;
}
private function arrayEncode($arr){
$tmp = [];
foreach($arr as $key => $val){
if(is_array($val)){
$tmp[$key] = $this->arrayEncode($val);
}else if ($key == "data"){
$tmp[$key] = base64_encode($val);
}else{
$tmp[$key] = $val;
}
}
return $tmp;
}
private function arrayDecode($arr){
$tmp = [];
foreach($arr as $key => $val){
if(is_array($val)){
$tmp[$key] = $this->arrayDecode($val);
}else if ($key == "data"){
$tmp[$key] = base64_decode($val);
}else{
$tmp[$key] = $val;
}
}
return $tmp;
}
public function setMp3(array $new_array): void {
$this->mp3Array = $new_array;
$stringified = json_encode($new_array);
file_put_contents($this->file_dir."/mp3Array.obj", $stringified);
}
public function saveMp3(): void {
$base64 = $this->arrayEncode($this->mp3Array);
$stringified = json_encode($base64);
file_put_contents($this->file_dir."/mp3Array.obj", $stringified);
}
public function setFind(array $new_array): void {
$this->findArray = $new_array;
$stringified = json_encode($new_array);
file_put_contents($this->file_dir."/findArray.obj", $stringified);
}
public function saveFind(): void {
$stringified = json_encode( $this->findArray);
file_put_contents($this->file_dir."/findArray.obj", $stringified);
}
I have a question on how to pass an array to a function in PHP. I have a class called "MyClass" and inside it has functions called rankVal($arr1, $arr2) and processResponse($data, $db, $id, $lat, $lng).
processResponse() will call rankVal() and here is my problem is.
class MyClass{
private function cmpVal($a, $b){
/*do sorting stuff*/
}
function rankVal($arr1, $arr2){
$arrIdx=[];
foreach ($arr1 as $key => $value) {
$n=array_search($value, $arr2);
$newPos = ($key+$n)/2;
$arrNewIdx [$n]=round($newPos,0, PHP_ROUND_HALF_DOWN);
}
}
function processResponse($data, $db, $id, $lat, $lng){
//Do some stuffs here...
$someArr1 = [];
foreach($results as $key => $value){
$newVal = new stdClass();
$newVal->key1 = $value->key1;
$newVal->key2 = $value->key2;
$newVal->key3 = $value->key3;
$newVal->key4 = $value->key4;
$newVal->key5 = $value->key5;
$someArr1 []= $newVal;
}
$someArr2 = $someArr1;
usort($someArr2, array($this, "cmpVal"));
$rankedVal = $this->rankVal($someArr1, $someArr2);
}
}
When I called the processResponse() function I got this error:
array_search() expects parameter 2 to be array, object given
So, I var_dump($arr2) in rankVal(), and the output clearly says that $arr2 is an array. Here's the sample output of the var_dump($arr2):
array(30) {
[0]=>
object(stdClass)#385 (7) {
["key1"]=>
string(24) "something"
["key2"]=>
string(20) "something"
["key3"]=>
string(41) "something"
["key4"]=>
float(1.23455)
["key5"]=>
float(1.19128371983198)
}
What did I do wrong? I tried to pass the array by reference by adding "&" in rankVal(&$arr1, &$arr2), but the error is still there.
To add to the other answer here (which now seems to have gone), if you want your class to behave as an array where appropriate, you need to make it iterable.
All you need to do is implement Iterable. This means that you need to create the necessary methods, but this is all you need in order to have your class behave that way.
Its useful for classes which are designed to hold an array of data, but you want to encapsulate additional tools along with that data.
Heres an example:
class Row implements \Iterator {
protected $data;
protected $position = 0;
public function __construct( array $data = [ ]) {
$this->data = $data;
}
public function addData( $value ) {
$this->data[] = $value;
}
public function replaceData( $index, $value ) {
$this->data[ $index ] = $value;
}
public function getData() {
return $this->data;
}
public function setData( array $data ) {
$this->data = $data;
return $this;
}
/** Required by Iterator */
public function current() {
return $this->data[ $this->position ];
}
/** Required by Iterator */
public function next() {
++$this->position;
}
public function __toArray() {
return $this->data;
}
/** Required by Iterator */
public function key() {
return $this->position;
}
/** Required by Iterator */
public function valid( $index = null ) {
return isset( $this->data[ $index ? $index : $this->position ] );
}
/** Required by Iterator */
public function rewind() {
$this->position = 0;
}
public function count() {
return count( $this->data );
}
}
Once you have this, it can be used anywhere you can use an array.
So after checking my code again, I finally found the problem that causing this weird bug which was not supposed to be there.
The culprit is in the rankVal() function where I called usort() which used rankVal() as the callback function for the sorting process. Then, I changed this callback function to the right one, and voila problem's solved.
Thanks for everyone who had answered and given me some suggestions on how to fix it.
Let's say I have this:
class "classname"
{
....
public function section($id)
{
// variable method name
$this->section->$id = new stdClass();
return $this;
}
public function subsection()
{
// $id is not available here
$this->section->$id->subsection = array();
return $this;
}
....
}
When I call:
$classname->section("test")
->subsection();
It is not working because $id is not global nor set in the second chainlink. Do I have to pass it manually to ->subsection($id) or is there a more generic/cleaner way to get it there?
What I try to accomplish here is to create an (big) object with multiple sections. In these sections objects and/or array's so there are more (chained) methods involved.
You can act like this way:
class Foo
{
protected $section;
private $lastUsedId = null;
public function __construct()
{
$this->section = new StdClass();
}
public function section($id)
{
// variable method name
$this->section->$id = new StdClass();
$this->lastUsedId = $id;
return $this;
}
public function subsection()
{
// $id is not available here
$this->section->{$this->lastUsedId}->subsection = array();
return $this;
}
}
so
$obj = (new Foo())
->section('one')
->subsection()
->section('two')
->subsection();
will produce valid result like
object(Foo)#1 (2) {
["section":protected]=>
object(stdClass)#2 (2) {
["one"]=>
object(stdClass)#3 (1) {
["subsection"]=>
array(0) {
}
}
["two"]=>
object(stdClass)#4 (1) {
["subsection"]=>
array(0) {
}
}
}
["lastUsedId":"Foo":private]=>
string(3) "two"
}
Note, that it isn't a good idea to use chaining like this way - it's difficult to read, and, besides, having method that actually changes data, but looks like getter, is confusing.
The problem you're facing is not because of chaining methods. It occurs either because you haven't declared the property $section or if you've declared it it has no property $id.
One possibility would be to define $section on the fly in the same way you're doing it with $id, i.e.
public function section($id) {
$this->section = new stdClass();
$this->section->id = new stdClass();
return $this;
}
or
class Classname {
private $section;
public function __construct() {
$this->section = new stdClass();
}
public function section($id) {
$this->section->id = new stdClass();
return $this;
}
}
or
class Classname {
private $section;
public function __construct() {
$this->section = new B();
}
public function section($id) {
$this->section->id = new stdClass();
return $this;
}
}
class B {
private $id;
}
Consider using 2 classes to accomplish what you want. Here is an example
class Document
{
private $sections = array();
public function addSection(Section $section)
{
$this->sections[] = $section;
}
public function getSections()
{
print_r($this->sections);
}
}
class Section {
private $id;
private $subsection;
public function setId($id)
{
$this->id = $id;
return $this;
}
public function setSubsection()
{
$this->subsection = array();
return $this;
}
}
$section1 = new Section;
$section1->setId(1)->setSubsection();
$section2 = new Section;
$section2->setId(2)->setSubsection();
$document = new Document;
$document->addSection($section1);
$document->addSection($section2);
$document->getSections();
will output
Array (
[0] => Section Object ([id:protected] => 1 [subsection:protected] => Array( ))
[1] => Section Object ([id:protected] => 2 [subsection:protected] => Array( )))
I have a class implementing ArrayAccess and I'm trying to get it to work with a multidimensional array. exists and get work. set and unset are giving me a problem though.
class ArrayTest implements ArrayAccess {
private $_arr = array(
'test' => array(
'bar' => 1,
'baz' => 2
)
);
public function offsetExists($name) {
return isset($this->_arr[$name]);
}
public function offsetSet($name, $value) {
$this->_arr[$name] = $value;
}
public function offsetGet($name) {
return $this->_arr[$name];
}
public function offsetUnset($name) {
unset($this->_arr[$name]);
}
}
$arrTest = new ArrayTest();
isset($arrTest['test']['bar']); // Returns TRUE
echo $arrTest['test']['baz']; // Echo's 2
unset($arrTest['test']['bar']); // Error
$arrTest['test']['bar'] = 5; // Error
I know $_arr could just be made public so you could access it directly, but for my implementation it's not desired and is private.
The last 2 lines throw an error: Notice: Indirect modification of overloaded element.
I know ArrayAccess just generally doesn't work with multidimensional arrays, but is there anyway around this or any somewhat clean implementation that will allow the desired functionality?
The best idea I could come up with is using a character as a separator and testing for it in set and unset and acting accordingly. Though this gets really ugly really fast if you're dealing with a variable depth.
Does anyone know why exists and get work so as to maybe copy over the functionality?
Thanks for any help anyone can offer.
The problem could be resolved by changing public function offsetGet($name) to public function &offsetGet($name) (by adding return by reference), but it will cause Fatal Error ("Declaration of ArrayTest::offsetGet() must be compatible with that of ArrayAccess::offsetGet()").
PHP authors screwed up with this class some time ago and now they won't change it in sake of backwards compatibility:
We found out that this is not solvable
without blowing up the interface and
creating a BC or providing an
additional interface to support
references and thereby creating an
internal nightmare - actually i don't
see a way we can make that work ever.
Thus we decided to enforce the
original design and disallow
references completley.
Edit: If you still need that functionality, I'd suggest using magic method instead (__get(), __set(), etc.), because __get() returns value by reference. This will change syntax to something like this:
$arrTest->test['bar'] = 5;
Not an ideal solution of course, but I can't think of a better one.
Update: This problem was fixed in PHP 5.3.4 and ArrayAccess now works as expected:
Starting with PHP 5.3.4, the prototype checks were relaxed and it's possible for implementations of this method to return by reference. This makes indirect modifications to the overloaded array dimensions of ArrayAccess objects possible.
This issue is actually solvable, entirely functional how it should be.
From a comment on the ArrayAccess documentation here:
<?php
// sanity and error checking omitted for brevity
// note: it's a good idea to implement arrayaccess + countable + an
// iterator interface (like iteratoraggregate) as a triplet
class RecursiveArrayAccess implements ArrayAccess {
private $data = array();
// necessary for deep copies
public function __clone() {
foreach ($this->data as $key => $value) if ($value instanceof self) $this[$key] = clone $value;
}
public function __construct(array $data = array()) {
foreach ($data as $key => $value) $this[$key] = $value;
}
public function offsetSet($offset, $data) {
if (is_array($data)) $data = new self($data);
if ($offset === null) { // don't forget this!
$this->data[] = $data;
} else {
$this->data[$offset] = $data;
}
}
public function toArray() {
$data = $this->data;
foreach ($data as $key => $value) if ($value instanceof self) $data[$key] = $value->toArray();
return $data;
}
// as normal
public function offsetGet($offset) { return $this->data[$offset]; }
public function offsetExists($offset) { return isset($this->data[$offset]); }
public function offsetUnset($offset) { unset($this->data); }
}
$a = new RecursiveArrayAccess();
$a[0] = array(1=>"foo", 2=>array(3=>"bar", 4=>array(5=>"bz")));
// oops. typo
$a[0][2][4][5] = "baz";
//var_dump($a);
//var_dump($a->toArray());
// isset and unset work too
//var_dump(isset($a[0][2][4][5])); // equivalent to $a[0][2][4]->offsetExists(5)
//unset($a[0][2][4][5]); // equivalent to $a[0][2][4]->offsetUnset(5);
// if __clone wasn't implemented then cloning would produce a shallow copy, and
$b = clone $a;
$b[0][2][4][5] = "xyzzy";
// would affect $a's data too
//echo $a[0][2][4][5]; // still "baz"
?>
You can then extend that class, like so:
<?php
class Example extends RecursiveArrayAccess {
function __construct($data = array()) {
parent::__construct($data);
}
}
$ex = new Example(array('foo' => array('bar' => 'baz')));
print_r($ex);
$ex['foo']['bar'] = 'pong';
print_r($ex);
?>
This will give you an object that can be treated like an array (mostly, see note in code), which supports multi-dimensional array set/get/unset.
EDIT: See the response of Alexander Konstantinov. I was thinking of the __get magic method, which is analogous, but was actually implemented correctly. So you cannot do that without an internal implementation of your class.
EDIT2: Internal implementation:
NOTE: You might argue this is purely masturbatory, but anyway here it goes:
static zend_object_handlers object_handlers;
static zend_object_value ce_create_object(zend_class_entry *class_type TSRMLS_DC)
{
zend_object_value zov;
zend_object *zobj;
zobj = emalloc(sizeof *zobj);
zend_object_std_init(zobj, class_type TSRMLS_CC);
zend_hash_copy(zobj->properties, &(class_type->default_properties),
(copy_ctor_func_t) zval_add_ref, NULL, sizeof(zval*));
zov.handle = zend_objects_store_put(zobj,
(zend_objects_store_dtor_t) zend_objects_destroy_object,
(zend_objects_free_object_storage_t) zend_objects_free_object_storage,
NULL TSRMLS_CC);
zov.handlers = &object_handlers;
return zov;
}
/* modification of zend_std_read_dimension */
zval *read_dimension(zval *object, zval *offset, int type TSRMLS_DC) /* {{{ */
{
zend_class_entry *ce = Z_OBJCE_P(object);
zval *retval;
void *dummy;
if (zend_hash_find(&ce->function_table, "offsetgetref",
sizeof("offsetgetref"), &dummy) == SUCCESS) {
if(offset == NULL) {
/* [] construct */
ALLOC_INIT_ZVAL(offset);
} else {
SEPARATE_ARG_IF_REF(offset);
}
zend_call_method_with_1_params(&object, ce, NULL, "offsetgetref",
&retval, offset);
zval_ptr_dtor(&offset);
if (!retval) {
if (!EG(exception)) {
/* ought to use php_error_docref* instead */
zend_error(E_ERROR,
"Undefined offset for object of type %s used as array",
ce->name);
}
return 0;
}
/* Undo PZVAL_LOCK() */
Z_DELREF_P(retval);
return retval;
} else {
zend_error(E_ERROR, "Cannot use object of type %s as array", ce->name);
return 0;
}
}
ZEND_MODULE_STARTUP_D(testext)
{
zend_class_entry ce;
zend_class_entry *ce_ptr;
memcpy(&object_handlers, zend_get_std_object_handlers(),
sizeof object_handlers);
object_handlers.read_dimension = read_dimension;
INIT_CLASS_ENTRY(ce, "TestClass", NULL);
ce_ptr = zend_register_internal_class(&ce TSRMLS_CC);
ce_ptr->create_object = ce_create_object;
return SUCCESS;
}
now this script:
<?php
class ArrayTest extends TestClass implements ArrayAccess {
private $_arr = array(
'test' => array(
'bar' => 1,
'baz' => 2
)
);
public function offsetExists($name) {
return isset($this->_arr[$name]);
}
public function offsetSet($name, $value) {
$this->_arr[$name] = $value;
}
public function offsetGet($name) {
throw new RuntimeException("This method should never be called");
}
public function &offsetGetRef($name) {
return $this->_arr[$name];
}
public function offsetUnset($name) {
unset($this->_arr[$name]);
}
}
$arrTest = new ArrayTest();
echo (isset($arrTest['test']['bar'])?"test/bar is set":"error") . "\n";
echo $arrTest['test']['baz']; // Echoes 2
echo "\n";
unset($arrTest['test']['baz']);
echo (isset($arrTest['test']['baz'])?"error":"test/baz is not set") . "\n";
$arrTest['test']['baz'] = 5;
echo $arrTest['test']['baz']; // Echoes 5
gives:
test/bar is set
2
test/baz is not set
5
ORIGINAL follows -- this is incorrect:
Your offsetGet implementation must return a reference for it to work.
public function &offsetGet($name) {
return $this->_arr[$name];
}
For the internal equivalent, see here.
Since there's no analogous to get_property_ptr_ptr, you ought to return a reference (in the sense of Z_ISREF) or a proxy object (see the get handler) in write-like contexts (types BP_VAR_W, BP_VAR_RW and BP_VAR_UNSET), though it's not mandatory. If read_dimension is being called in a write-like context such as in $val =& $obj['prop'], and you return neither a reference nor an object, the engine emit a notice. Obviously, returning a reference is not enough for those operations to work correctly, it is necessary that modifying the returned zval actually has some effect. Note that assignments such as $obj['key'] = &$a are still not possible – for that one would need the dimensions to actually be storable as zvals (which may or may not be the case) and two levels of indirection.
In sum, operations that involve writing or unseting a sub-dimension of sub-property call offsetGet, not offsetSet, offsetExists or offsetUnset.
Solution:
<?php
/**
* Cube PHP Framework
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* #author Dillen / Steffen
*/
namespace Library;
/**
* The application
*
* #package Library
*/
class ArrayObject implements \ArrayAccess
{
protected $_storage = array();
// necessary for deep copies
public function __clone()
{
foreach ($this->_storage as $key => $value)
{
if ($value instanceof self)
{
$this->_storage[$key] = clone $value;
}
}
}
public function __construct(array $_storage = array())
{
foreach ($_storage as $key => $value)
{
$this->_storage[$key] = $value;
}
}
public function offsetSet($offset, $_storage)
{
if (is_array($_storage))
{
$_storage = new self($_storage);
}
if ($offset === null)
{
$this->_storage[] = $_storage;
}
else
{
$this->_storage[$offset] = $_storage;
}
}
public function toArray()
{
$_storage = $this -> _storage;
foreach ($_storage as $key => $value)
{
if ($value instanceof self)
{
$_storage[$key] = $value -> toArray();
}
}
return $_storage;
}
// as normal
public function offsetGet($offset)
{
if (isset($this->_storage[$offset]))
{
return $this->_storage[$offset];
}
if (!isset($this->_storage[$offset]))
{
$this->_storage[$offset] = new self;
}
return $this->_storage[$offset];
}
public function offsetExists($offset)
{
return isset($this->_storage[$offset]);
}
public function offsetUnset($offset)
{
unset($this->_storage);
}
}
I solved it using this:
class Colunas implements ArrayAccess {
public $cols = array();
public function offsetSet($offset, $value) {
$coluna = new Coluna($value);
if (!is_array($offset)) {
$this->cols[$offset] = $coluna;
} else {
if (!isset($this->cols[$offset[0]])) $this->cols[$offset[0]] = array();
$col = &$this->cols[$offset[0]];
for ($i = 1; $i < sizeof($offset); $i++) {
if (!isset($col[$offset[$i]])) $col[$offset[$i]] = array();
$col = &$col[$offset[$i]];
}
$col = $coluna;
}
}
public function offsetExists($offset) {
if (!is_array($offset)) {
return isset($this->cols[$offset]);
} else {
$key = array_shift($offset);
if (!isset($this->cols[$key])) return FALSE;
$col = &$this->cols[$key];
while ($key = array_shift($offset)) {
if (!isset($col[$key])) return FALSE;
$col = &$col[$key];
}
return TRUE;
}
}
public function offsetUnset($offset) {
if (!is_array($offset)) {
unset($this->cols[$offset]);
} else {
$col = &$this->cols[array_shift($offset)];
while (sizeof($offset) > 1) $col = &$col[array_shift($offset)];
unset($col[array_shift($offset)]);
}
}
public function offsetGet($offset) {
if (!is_array($offset)) {
return $this->cols[$offset];
} else {
$col = &$this->cols[array_shift($offset)];
while (sizeof($offset) > 0) $col = &$col[array_shift($offset)];
return $col;
}
}
}
So you can use it with:
$colunas = new Colunas();
$colunas['foo'] = 'Foo';
$colunas[array('bar', 'a')] = 'Bar A';
$colunas[array('bar', 'b')] = 'Bar B';
echo $colunas[array('bar', 'a')];
unset($colunas[array('bar', 'a')]);
isset($colunas[array('bar', 'a')]);
unset($colunas['bar']);
Please note that I don't check if offset is null, and if it's an array, it must be of size > 1.
Mainly according to Dakota's solution* I want to share my simplification of it.
*) Dakota's was the most understandable one to me and the outcome is quite great (- the others seem quite similar great).
So, for the ones like me, who have their difficulties in understanding what's going on here:
class DimensionalArrayAccess implements ArrayAccess {
private $_arr;
public function __construct(array $arr = array()) {
foreach ($arr as $key => $value)
{
$this[$key] = $value;
}
}
public function offsetSet($offset, $val) {
if (is_array($val)) $val = new self($val);
if ($offset === null) {
$this->_arr[] = $val;
} else {
$this->_arr[$offset] = $val;
}
}
// as normal
public function offsetGet($offset) {
return $this->_arr[$offset];
}
public function offsetExists($offset) {
return isset($this->_arr[$offset]);
}
public function offsetUnset($offset) {
unset($this->_arr);
}
}
class Example extends DimensionalArrayAccess {
function __construct() {
parent::__construct([[["foo"]]]);
}
}
$ex = new Example();
echo $ex[0][0][0];
$ex[0][0][0] = 'bar';
echo $ex[0][0][0];
I did some changes:
deleted the toArray-function, as it has no immediate purpose as long as you don't want to convert your object into an real (in Dakota's case associative) array.
deleted the clone-thing, as it has no immediate purpose as long as you don't want to clone your object.
renamed the extended class and same vars: seems more understandable to me. especially I want to emphasize, that the DimensionalArrayAccess-class gives array-like access to your object even for 3- or more-dimensional (and of course also non-associative) 'arrays' - at least as long as you instanciate it with an array counting the number of dimensions you need.
last it seems important to me to emphasize, that as you can see the Example-class itself is not dependent on a constructor variable, whereas the DimensionalArrayAccess-class is (as it calls itself in the offsetSet-function recursively.
As I introduced, this post is rather for the not so advanced ones like me.
EDIT: this only works for cells which are set during instantiation, whereas it is not possible to add new cells afterwards.
class Test implements \ArrayAccess {
private
$input = [];
public function __construct () {
$this->input = ['foo' => ['bar' => 'qux']];
}
public function offsetExists ($offset) {}
public function offsetGet ($offset) {}
public function offsetSet ($offset, $value) {}
public function offsetUnset ($offset) {}
}
runkit_method_redefine ('Test', 'offsetGet', '&$offset', 'return $this->input[$offset];');
$ui = new Test;
var_dump($ui['foo']['bar']); // string(3) "qux"
Is there any way to create all instance properties dynamically? For example, I would like to be able to generate all attributes in the constructor and still be able to access them after the class is instantiated like this: $object->property. Note that I want to access the properties separately, and not using an array; here's an example of what I don't want:
class Thing {
public $properties;
function __construct(array $props=array()) {
$this->properties = $props;
}
}
$foo = new Thing(array('bar' => 'baz');
# I don't want to have to do this:
$foo->properties['bar'];
# I want to do this:
//$foo->bar;
To be more specific, when I'm dealing with classes that have a large number of properties, I would like to be able to select all columns in a database (which represent the properties) and create instance properties from them. Each column value should be stored in a separate instance property.
Sort of. There are magic methods that allow you to hook your own code up to implement class behavior at runtime:
class foo {
public function __get($name) {
return('dynamic!');
}
public function __set($name, $value) {
$this->internalData[$name] = $value;
}
}
That's an example for dynamic getter and setter methods, it allows you to execute behavior whenever an object property is accessed. For example
print(new foo()->someProperty);
would print, in this case, "dynamic!" and you could also assign a value to an arbitrarily named property in which case the __set() method is silently invoked. The __call($name, $params) method does the same for object method calls. Very useful in special cases. But most of the time, you'll get by with:
class foo {
public function __construct() {
foreach(getSomeDataArray() as $k => $value)
$this->{$k} = $value;
}
}
...because mostly, all you need is to dump the content of an array into correspondingly named class fields once, or at least at very explicit points in the execution path. So, unless you really need dynamic behavior, use that last example to fill your objects with data.
This is called overloading
http://php.net/manual/en/language.oop5.overloading.php
It depends exactly what you want. Can you modify the class dynamically? Not really. But can you create object properties dynamically, as in one particular instance of that class? Yes.
class Test
{
public function __construct($x)
{
$this->{$x} = "dynamic";
}
}
$a = new Test("bar");
print $a->bar;
Outputs:
dynamic
So an object property named "bar" was created dynamically in the constructor.
Yes, you can.
class test
{
public function __construct()
{
$arr = array
(
'column1',
'column2',
'column3'
);
foreach ($arr as $key => $value)
{
$this->$value = '';
}
}
public function __set($key, $value)
{
$this->$key = $value;
}
public function __get($value)
{
return 'This is __get magic '.$value;
}
}
$test = new test;
// Results from our constructor test.
var_dump($test);
// Using __set
$test->new = 'variable';
var_dump($test);
// Using __get
print $test->hello;
Output
object(test)#1 (3) {
["column1"]=>
string(0) ""
["column2"]=>
string(0) ""
["column3"]=>
string(0) ""
}
object(test)#1 (4) {
["column1"]=>
string(0) ""
["column2"]=>
string(0) ""
["column3"]=>
string(0) ""
["new"]=>
string(8) "variable"
}
This is __get magic hello
This code will set dynamic properties in the constructor which can then be accessed with $this->column. It's also good practice to use the __get and __set magic methods to deal with properties that are not defined within the class. More information them can be found here.
http://www.tuxradar.com/practicalphp/6/14/2
http://www.tuxradar.com/practicalphp/6/14/3
You can use an instance variable to act as a holder for arbitrary values and then use the __get magic method to retrieve them as regular properties:
class My_Class
{
private $_properties = array();
public function __construct(Array $hash)
{
$this->_properties = $hash;
}
public function __get($name)
{
if (array_key_exists($name, $this->_properties)) {
return $this->_properties[$name];
}
return null;
}
}
Why is every example so complicated?
<?php namespace example;
error_reporting(E_ALL | E_STRICT);
class Foo
{
// class completely empty
}
$testcase = new Foo();
$testcase->example = 'Dynamic property';
echo $testcase->example;
Here is simple function to populate object members without making class members public.
It also leaves constructor for your own usage, creating new instance of object without invoking constructor! So, your domain object doesn't depend on database!
/**
* Create new instance of a specified class and populate it with given data.
*
* #param string $className
* #param array $data e.g. array(columnName => value, ..)
* #param array $mappings Map column name to class field name, e.g. array(columnName => fieldName)
* #return object Populated instance of $className
*/
function createEntity($className, array $data, $mappings = array())
{
$reflClass = new ReflectionClass($className);
// Creates a new instance of a given class, without invoking the constructor.
$entity = unserialize(sprintf('O:%d:"%s":0:{}', strlen($className), $className));
foreach ($data as $column => $value)
{
// translate column name to an entity field name
$field = isset($mappings[$column]) ? $mappings[$column] : $column;
if ($reflClass->hasProperty($field))
{
$reflProp = $reflClass->getProperty($field);
$reflProp->setAccessible(true);
$reflProp->setValue($entity, $value);
}
}
return $entity;
}
/******** And here is example ********/
/**
* Your domain class without any database specific code!
*/
class Employee
{
// Class members are not accessible for outside world
protected $id;
protected $name;
protected $email;
// Constructor will not be called by createEntity, it yours!
public function __construct($name, $email)
{
$this->name = $name;
$this->emai = $email;
}
public function getId()
{
return $this->id;
}
public function getName()
{
return $this->name;
}
public function getEmail()
{
return $this->email;
}
}
$row = array('employee_id' => '1', 'name' => 'John Galt', 'email' => 'john.galt#whoisjohngalt.com');
$mappings = array('employee_id' => 'id'); // Employee has id field, so we add translation for it
$john = createEntity('Employee', $row, $mappings);
print $john->getName(); // John Galt
print $john->getEmail(); // john.galt#whoisjohngalt.com
//...
P.S. Retrieving data from object is similar, e.g. use $reflProp->setValue($entity, $value);
P.P.S. This function is heavily inspired by Doctrine2 ORM which is awesome!
class DataStore // Automatically extends stdClass
{
public function __construct($Data) // $Data can be array or stdClass
{
foreach($Data AS $key => $value)
{
$this->$key = $value;
}
}
}
$arr = array('year_start' => 1995, 'year_end' => 2003);
$ds = new DataStore($arr);
$gap = $ds->year_end - $ds->year_start;
echo "Year gap = " . $gap; // Outputs 8
You can:
$variable = 'foo';
$this->$variable = 'bar';
Would set the attribute foo of the object it's called on to bar.
You can also use functions:
$this->{strtolower('FOO')} = 'bar';
This would also set foo (not FOO) to bar.
Extend stdClass.
class MyClass extends stdClass
{
public function __construct()
{
$this->prop=1;
}
}
I hope this is what you need.
This is really complicated way to handle this kind of rapid development. I like answers and magic methods but in my opinion it is better to use code generators like CodeSmith.
I have made template that connect to database, read all columns and their data types and generate whole class accordingly.
This way I have error free (no typos) readable code. And if your database model changes run generator again... it works for me.
If you really really must do it, the best way is to overload an ArrayObject, that allows to maintain iteration support (foreach) that will still loop through all your properties.
I note that you said "without using an array", and I just want to assure you that that while technically an array is being used in the background, you NEVER HAVE TO SEE IT. You access all properties via ->properyname or foreach ($class in $name => $value).
Here is a sample I was working on yesterday, note this is also STRONGLY TYPED. So properties that are marked "integer" will throw an error if you try and supply a "string".
You can remove that of course.
There is also an AddProperty() member function, although it is not demonstrated in the example. That will allow you to add properties later.
Sample usage:
$Action = new StronglyTypedDynamicObject("Action",
new StrongProperty("Player", "ActionPlayer"), // ActionPlayer
new StrongProperty("pos", "integer"),
new StrongProperty("type", "integer"),
new StrongProperty("amount", "double"),
new StrongProperty("toCall", "double"));
$ActionPlayer = new StronglyTypedDynamicObject("ActionPlayer",
new StrongProperty("Seat", "integer"),
new StrongProperty("BankRoll", "double"),
new StrongProperty("Name", "string"));
$ActionPlayer->Seat = 1;
$ActionPlayer->Name = "Doctor Phil";
$Action->pos = 2;
$Action->type = 1;
$Action->amount = 7.0;
$Action->Player = $ActionPlayer;
$newAction = $Action->factory();
$newAction->pos = 4;
print_r($Action);
print_r($newAction);
class StrongProperty {
var $value;
var $type;
function __construct($name, $type) {
$this->name = $name;
$this->type = $type;
}
}
class StronglyTypedDynamicObject extends ModifiedStrictArrayObject {
static $basic_types = array(
"boolean",
"integer",
"double",
"string",
"array",
"object",
"resource",
);
var $properties = array(
"__objectName" => "string"
);
function __construct($objectName /*, [ new StrongProperty("name", "string"), [ new StrongProperty("name", "string"), [ ... ]]] */) {
$this->__objectName = $objectName;
$args = func_get_args();
array_shift($args);
foreach ($args as $arg) {
if ($arg instanceof StrongProperty) {
$this->AddProperty($arg->name, $arg->type);
} else {
throw new Exception("Invalid Argument");
}
}
}
function factory() {
$new = clone $this;
foreach ($new as $key => $value) {
if ($key != "__objectName") {
unset($new[$key]);
}
}
// $new->__objectName = $this->__objectName;
return $new;
}
function AddProperty($name, $type) {
$this->properties[$name] = $type;
return;
if (in_array($short_type, self::$basic_types)) {
$this->properties[$name] = $type;
} else {
throw new Exception("Invalid Type: $type");
}
}
public function __set($name, $value) {
self::sdprintf("%s(%s)\n", __FUNCTION__, $name);
$this->check($name, $value);
$this->offsetSet($name, $value);
}
public function __get($name) {
self::sdprintf("%s(%s)\n", __FUNCTION__, $name);
$this->check($name);
return $this->offsetGet($name);
}
protected function check($name, $value = "r4nd0m") {
if (!array_key_exists($name, $this->properties)) {
throw new Exception("Attempt to access non-existent property '$name'");
}
$value__objectName = "";
if ($value != "r4nd0m") {
if ($value instanceof StronglyTypedDynamicObject) {
$value__objectName = $value->__objectName;
}
if (gettype($value) != $this->properties[$name] && $value__objectName != $this->properties[$name]) {
throw new Exception("Attempt to set {$name} ({$this->properties[$name]}) with type " . gettype($value) . ".$value__objectName");
}
}
}
}
class ModifiedStrictArrayObject extends ArrayObject {
static $debugLevel = 0;
/* Some example properties */
static public function StaticDebug($message) {
if (static::$debugLevel > 1) {
fprintf(STDERR, "%s\n", trim($message));
}
}
static public function sdprintf() {
$args = func_get_args();
$string = call_user_func_array("sprintf", $args);
self::StaticDebug("D " . trim($string));
}
protected function check($name) {
if (!array_key_exists($name, $this->properties)) {
throw new Exception("Attempt to access non-existent property '$name'");
}
}
//static public function sget($name, $default = NULL) {
/******/ public function get ($name, $default = NULL) {
self::sdprintf("%s(%s)\n", __FUNCTION__, $name);
$this->check($name);
if (array_key_exists($name, $this->storage)) {
return $this->storage[$name];
}
return $default;
}
public function offsetGet($name) {
self::sdprintf("%s(%s)\n", __FUNCTION__, implode(",", func_get_args()));
$this->check($name);
return call_user_func_array(array(parent, __FUNCTION__), func_get_args());
}
public function offsetSet($name, $value) {
self::sdprintf("%s(%s)\n", __FUNCTION__, implode(",", func_get_args()));
$this->check($name);
return call_user_func_array(array(parent, __FUNCTION__), func_get_args());
}
public function offsetExists($name) {
self::sdprintf("%s(%s)\n", __FUNCTION__, implode(",", func_get_args()));
$this->check($name);
return call_user_func_array(array(parent, __FUNCTION__), func_get_args());
}
public function offsetUnset($name) {
self::sdprintf("%s(%s)\n", __FUNCTION__, implode(",", func_get_args()));
$this->check($name);
return call_user_func_array(array(parent, __FUNCTION__), func_get_args());
}
public function __toString() {
self::sdprintf("%s(%s)\n", __FUNCTION__, $name);
foreach ($this as $key => $value) {
$output .= "$key: $value\n";
}
return $output;
}
function __construct($array = false, $flags = 0, $iterator_class = "ArrayIterator") {
self::sdprintf("%s(%s)\n", __FUNCTION__, implode(",", func_get_args()));
parent::setFlags(parent::ARRAY_AS_PROPS);
}
}
After reading #Udo 's answer. I've come up with the following pattern, that doesn't bloat a class instance with what-ever items that is in your constructor array argument but still let you type less and easily add new properties to the class.
class DBModelConfig
{
public $host;
public $username;
public $password;
public $db;
public $port = '3306';
public $charset = 'utf8';
public $collation = 'utf8_unicode_ci';
public function __construct($config)
{
foreach ($config as $key => $value) {
if (property_exists($this, $key)) {
$this->{$key} = $value;
}
}
}
}
Then you can pass arrays like:
[
'host' => 'localhost',
'driver' => 'mysql',
'username' => 'myuser',
'password' => '1234',
'charset' => 'utf8',
'collation' => 'utf8_unicode_ci',
'db' => 'key not used in receiving class'
]