JSON acronimo di JavaScript Object Notation.
Funzioni native PHP:
- json_encode() = PHP -> json
- json_decode() = json -> PHP
UTF-8
Per entrambe le funzioni bisogna prima codificare il dato in utf-8, pertanto utilizzare la funzion utf8_encode().
1 json_encode()
json_encode(mixed $value, int $options = 0);
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// Returns: ["Apple","Banana","Pear"] json_encode(array("Apple", "Banana", "Pear")); // Returns: {"4":"four","8":"eight"} json_encode(array(4 => "four", 8 => "eight")); // Returns: {"apples":true,"bananas":null} json_encode(array("apples" => true, "bananas" => null)); // PHP OGGETTO TO JSON class User { public $firstname = "Mario"; public $lastname = ""; public $birthdate = ""; protected $pro = "hidden"; private $priv = "hidden too"; public $func; public $notUsed; /** Constructor */ public function __construct() { $this->func = function() { return "Foo"; }; } } $user = new User(); $user->lastname = "Rossi"; $user->birthdate = new DateTime(); /* Returns: { "firstname":"Mario", "lastname":"Rossi", "birthdate": { "date":"2012-06-06 08:46:58", "timezone_type":3, "timezone":"Europe\/Berlin" }, "func":{}, "notUsed":null } */ json_encode($user); |
Notare che boolean e NULL non vengono trasformati in stringhe.
Options
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// Returns: {"0":"Starsky & Hutch","1":123456} json_encode(array("Starsky & Hutch", "123456"), JSON_NUMERIC_CHECK | JSON_FORCE_OBJECT); |
Vedi lista qui: http://php.net/manual/en/json.constants.php
UTF-8
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1 |
echo utf8_encode(json_encode($payload)); |
2 json_decode
Data la seguente stringa JSON: $string = '{"foo": "bar", "cool": "attr"}'; posso trasformarla in oggetto PHP $result = json_decode($string); oppure in array PHP se setto il secondo parametro della funzione a TRUE $result = json_decode($string, true);.
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$string = '{"foo": "bar", "cool": "attr"}'; $result = json_decode($string); var_dump($result);// Result: object(stdClass)#1 (2) { ["foo"]=> string(3) "bar" ["cool"]=> string(4) "attr" } echo $result->foo;// Prints "bar" echo $result->cool;// Prints "attr" |
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$string = '{"foo": "bar", "cool": "attr"}'; $result = json_decode($string, true); var_dump($result);// Result: array(2) { ["foo"]=> string(3) "bar" ["cool"]=> string(4) "attr" } echo $result['foo'];// Prints "bar" echo $result['cool'];// Prints "attr" |
Con il terzo parametro controllo la profondità che mi aspetto di ottenere e se la supera interrompe la conversione e torna NULL
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1 2 3 |
$string = '{"foo": {"bar": {"cool": "value"}}}';// profondità 3 $result = json_decode($string, true, 2);// profondità 2 var_dump($result);// Result: null |
Errori
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class JsonHandler { protected static $_messages = array( JSON_ERROR_NONE => 'No error has occurred', JSON_ERROR_DEPTH => 'The maximum stack depth has been exceeded', JSON_ERROR_STATE_MISMATCH => 'Invalid or malformed JSON', JSON_ERROR_CTRL_CHAR => 'Control character error, possibly incorrectly encoded', JSON_ERROR_SYNTAX => 'Syntax error', JSON_ERROR_UTF8 => 'Malformed UTF-8 characters, possibly incorrectly encoded' ); public static function encode($value, $options = 0) { $result = json_encode($value, $options); if($result) { return $result; } throw new RuntimeException(static::$_messages[json_last_error()]); } public static function decode($json, $assoc = false) { $result = json_decode($json, $assoc); if($result) { return $result; } throw new RuntimeException(static::$_messages[json_last_error()]); } } // Returns "Correctly thrown" assertException("Syntax error", function() { $string = '{"foo": {"bar": {"cool": NONUMBER}}}'; $result = JsonHandler::decode($string); }); |
Snippet code
Normalizza JSON I/O
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/** * Serialize format transforming an input (Array or String) in output (JSON) * <br> and viceversa an input (JSON) in an output (Array) * @param mixed $param ARRAY or JSON or even a String * @param boolean $prepare_for_db (default)FALSE, * <br>if TRUE return right format to be written in the DB, * <br>independently the input type (as far as possible) * @return mixed * <br> FALSE: return output opposite input es.: (JSON --> Array) || (Array --> JSON) * <br> TRUE: return anyhow JSON es.: (* --> JSON) */ function _convertIdTags($param,$prepare_for_db=FALSE) { if ( $prepare_for_db ) { // return anyhow JSON // (* --> JSON) // case n,n,n,n, // showld be a string but could be if (is_string($param) && !is_array(json_decode($param,JSON_NUMERIC_CHECK)) ){ // echo 'A1'; $param = str_replace(';', ',', $param);// cambia ; con , $param = str_replace('-', ',', $param);// cambia - con , $param = str_replace('"', '', $param); // elimina " $param = str_replace('\'', '', $param);// elimina ' $array_param = explode(',', $param); // trasforma in array return json_encode($array_param,JSON_NUMERIC_CHECK); } // case array(n,n,n,n) elseif ( is_array($param) ) { // echo 'A2'; return json_encode($param,JSON_NUMERIC_CHECK); } // case [n,n,n,n] // showld be a json but could be ["n",n] or ['n',n] elseif ( is_array(json_decode($param,JSON_NUMERIC_CHECK)) ) { // echo 'A3'; $param = str_replace('"', '', $param); $param = str_replace('\'', '', $param); //$param = preg_replace('/[^A-Za-z0-9\-]/', '', $param); return $param; } } else { // echo 'B'; // return output opposite input // (JSON --> Array) || (Array --> JSON) return ( is_array($param) ) ? json_encode($param,JSON_NUMERIC_CHECK) : json_decode($param,JSON_NUMERIC_CHECK) ; // JSON Array } } |
Criticità
(sicurezza) – JSONP e le richieste cross-domain
Tecnica per ovviare alla restrizione di non poter usufruire di contenuti (javascript?) richiamati da pagine non appartenenti allo stesso host domain. – vedi jsonp
fonte: http://nitschinger.at/Handling-JSON-like-a-boss-in-PHP/