是否可以覆盖自定义类的 var_dump 输出？我想要这样的东西：
class MyClass{
public $foo;
public $bar;
//pseudo-code
public function __dump($foo, $bar)
{
return 'Foo:$foo, bar:$bar';
}
}
var_dump(array($instanceOfMyClass));
//it should output this:
array(1) {
[0] =>
class MyClass#1 (2) {
Foo:valueOfFoo, bar:valueOfBar
}
}
我知道我可以使用一些第 3 方 var_dump 替代品，但我想在我的库项目中自定义 var_dump 的行为。
谢谢。
在PHP 5.6.0+中，您可以使用__debugInfo()魔术函数自定义var_dump().
array __debugInfo ( void )
var_dump()在转储对象以获取应显示的属性时调用此方法。如果该方法未在对象上定义，则将显示所有公共、受保护和私有属性。此功能是在 PHP 5.6.0 中添加的。
class MyDateTime{
public $year, $month, $day, $hour, $minute, $second;
public function __debugInfo() {
return array(
'date' => $this->year . "-" . $this->month . "-" . $this->day,
'time' => sprintf("%02d:%02d:%02d", $this->hour, $this->minute, $this->second),
);
}
}
$dt = new MyDateTime();
$dt->year = 2014; $dt->month = 9; $dt->day = 20;
$dt->hour = 16; $dt->minute = 2; $dt->second = 41;
var_dump($dt);
object(MyDateTime)#1 (2) {
["date"]=>
string(9) "2014-9-20"
["time"]=>
string(8) "16:02:41"
}
object(MyDateTime)#1 (6) {
["year"]=>
int(2014)
["month"]=>
int(9)
["day"]=>
int(20)
["hour"]=>
int(16)
["minute"]=>
int(2)
["second"]=>
int(41)
}
__debugInfo()必须返回一个array. 我在 PHP 5.6.0 上遇到错误，因为返回 a string：
致命错误：__debuginfo() 必须在第 15 行的 /somepath/somefile.php 中返回一个数组
print_r()，尽管这似乎没有在任何地方记录。为此，您可以使用 ReflectionClass 函数并构建自己的函数来获取所需的信息。
http://php.net/manual/de/reflectionclass.tostring.php
http://php.net/manual/en/book.reflection.php
您不能覆盖核心 PHP 函数。
您可以在对象中添加函数 __toString()：
class myClass {
public function __toString(){
// custom var_dump() content here then output it
}
}
$myClass = new myClass();
echo $myClass;
没有意义覆盖 var_dump 结果，您可以使用 toString() 魔术方法
class MyClass{
public $foo;
public $bar;
public function test(){}
public function __toString()
{
$vars="Variables:";
foreach(get_class_vars(__CLASS__) as $name => $value) $vars.="<br> $name : {$this->{$name}}".gettype($this->{$name});
return __CLASS__.':<br>'.$vars.'<br>Methods:<br>'.implode('<br>',get_class_methods(__CLASS__));
}
}
$lol = new MyClass();
$lol->foo = 10;
$lol->bar = 'asd';
echo $lol;
例子在这里
如果您正在寻找更具可读性（主观上）的 var_dump，我前段时间写过类似的东西，也许它会对您有用:)
我想打印每个对象，就好像它是一个数组一样。代码的质量不是最好的，但是当我不能使用 XDebug 时它帮助了我。
class XDump
{
private static array $object_hash = []; //workaround for cyclic dependencies
public static function dump($var, bool $withContent = true, ?int $maxDepth = null): void
{
$dumpVar = self::convertToArray($var, $withContent, $maxDepth);
print_r($dumpVar);
exit();
}
private static function convertToArray($var, bool $withContent, ?int $maxDepth)
{
self::$object_hash = [];
if (!$withContent) {
return self::getArrayStructure($var, $maxDepth);
}
return self::getArray($var, $maxDepth);
}
private static function getArray($obj, ?int $maxDepth, $mainKey = '', int $depth = 0)
{
$simpleReturn = self::getSimpleReturn($obj, $mainKey);
if (null !== $simpleReturn) {
return $simpleReturn;
}
$result = [];
$objectArray = (array)$obj;
foreach ($objectArray as $key => $item) {
if (!$maxDepth || $depth <= $maxDepth) {
$result[$key] = self::getArray($item, $maxDepth, $key, $depth + 1);
}
}
return self::shortenArray($result);
}
private static function getArrayStructure($obj, ?int $maxDepth, $mainKey = '', int $depth = 0)
{
$simpleReturn = self::getSimpleReturn($obj, $mainKey);
if (null !== $simpleReturn) {
return $simpleReturn;
}
$result = [];
$objectArray = (array)$obj;
foreach ($objectArray as $key => $item) {
if (self::hasChildren($item)) {
if (!$maxDepth || $depth <= $maxDepth) {
$result[$key] = self::getArrayStructure($item, $maxDepth, (string)$key, $depth + 1);
}
} else {
self::throwErrorIfNotPrintable($key, $mainKey);
$result['elements'][] = $key;
}
}
if (isset($result['elements'])) {
$elements = implode(' | ', $result['elements']);
if (1 === \count($result)) {
return $elements;
}
$result['elements'] = $elements;
}
return self::shortenArray($result);
}
private static function hasChildren($obj): bool
{
return \is_object($obj) || \is_array($obj);
}
private static function getHashIfAlreadyHashed($obj): ?string
{
$hash = self::getObjectHash($obj);
$existingHash = self::$object_hash[$hash] ?? null;
self::$object_hash[$hash] = $hash;
return $existingHash;
}
private static function throwErrorIfNotPrintable($obj, string $name = 'object'): void
{
if (!self::isPrintable($obj)) {
$type = \gettype($obj);
throw new ServerException("Value of {$name} with type {$type} is not handled!");
}
}
private static function isPrintable($obj): bool
{
return is_scalar($obj) || null === $obj;
}
private static function getSimpleReturn($obj, $mainKey)
{
if (\is_object($obj)) {
if (is_subclass_of($obj, \DateTimeInterface::class)) {
return TimeHelper::toDateTimeString($obj);
}
if (\Closure::class === \get_class($obj)) {
return 'Closure';
}
$existingHash = self::getHashIfAlreadyHashed($obj);
if (null !== $existingHash) {
return "Already hashed somewhere else as {$existingHash}!";
}
}
if (\is_string($obj)) {
$jsonData = json_decode($obj, true);
if ($jsonData) {
$jsonData['XDump_IS_JSON_STRING'] = true;
return $jsonData;
}
}
if (\is_resource($obj)) {
$type = get_resource_type($obj);
return "PHP resource with type: {$type} in {$mainKey}";
}
if (!self::hasChildren($obj)) {
self::throwErrorIfNotPrintable($obj);
return $obj;
}
return null;
}
private static function shortenArray(array $retArray): array
{
$shortenRet = [];
foreach ($retArray as $key => $item) {
$shortKey = self::shortenKey((string)$key);
$shortenRet[$shortKey] = $item;
}
return $shortenRet;
}
private static function shortenKey($key): string
{
try {
$parts = explode("\0", $key);
$shortKey = end($parts);
} catch (\Throwable $e) {
$shortKey = $key;
}
return $shortKey;
}
private static function getObjectHash($obj): string
{
return \get_class($obj).'|'.spl_object_hash($obj);
}
}