json_encode
Json_encode is a php inbuilt function used for Encoding purpose to to achieve data usability. It encode passed php values into corresponding json format.
Syntax:
json_encode ( mixed $param , int $flags = 0 , int $depth = 512 )
Input Params:
- $param : Required
- $flags : Optional (Default: 0). This is JSON constants . Example : JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, JSON_INVALID_UTF8_IGNORE..
- $depth : Optional param and must be greater than zero. Example : Depth one is considered for one Dimensional array. Depth N is considered for N Dimensional array. Default depth 512. we can set maximum depth. Json_encode will return false if specified depth is less than size of input array. Please refer below example for more understanding.
Return Value:
- On Success : Json Encoded String
- On Failure : False
Let's Explore some Example below
Case 1: Json encode Value for One Dimensional Array with Depth 1
$employee1 = array("John", "Denis", "Peter");
var_dump (json_encode($employee1, 0, 1));
//Return value: string(24) "["John","Denis","Peter"]"
Case 2: Json encoded Value for Two Dimensional Array with Depth less than input array size
$employee2 = array( "John" => array("Account"), "Denis" => array("Finance"), "Peter" => array("Hr"));
var_dump( json_encode($employee2, 0, 1));
//Return value: bool(false)
Case 3: Json encode Value for Two Dimensional Array with Depth more than size of array (Ex. 3)
$employee3 = array( "John" => array("Account"), "Denis" => array("Finance"), "Peter" => array("Hr"));
var_dump( json_encode($employee3, 0, 3));
//Return value: string(55) "{"John":["Account"],"Denis":["Finance"],"Peter":["Hr"]}"
Scroll for More Useful Information and Relevant FAQs
How to find root cause and solve if json_encode returning false?
There can be various reasons behind false return from json_encode. Let's see some of most common error as below
| JSON error codes | Error message | Available on PHP version |
|---|---|---|
| JSON_ERROR_DEPTH | The maximum exceeded. (Please refer example below.) | PHP 5.3.0 |
| JSON_ERROR_SYNTAX | Syntax error in provided input data | PHP 5.3.0 |
Sometimes we can't predict what is the issue in input data. No issues, we can use following json in built method to know actual cause
- json_last_error() return int value.
- Json_last_error_msg() returns the error string for last call of json encode/decode function.
Let see by an example below
Get Json encode Value for Two Dimensional Array with given depth less than input array size
$employee2 = array( "John" => array("Account"), "Denis" => array("Finance"), "Peter" => array("Hr"));
var_dump( json_encode($employee2, 0, 1));
//output : bool(false)
var_dump(json_last_error() == JSON_ERROR_DEPTH);
//output : bool(true)
var_dump("Error Message:" . json_last_error_msg());
//output : Error Message: Maximum stack depth exceeded
How to get the json encoded value as an original string then \uXXXX for special chars/foreign language?
Let's understand with following example
Case 1: Json_encode foreign language
$language = array("hindi" => "??????", "chinese" => "??", "japanese"=> "?????", "vietnamese"=> "xin chào");
echo json_encode($language);
Output : {"hindi":"\u0928\u092e\u0938\u094d\u0924\u0947","chinese":"\u4f60\u597d","japanese":"\u3053\u3093\u306b\u3061\u306f","vietnamese":"xin ch\u00e0o"}
$language = array("hindi" => "??????", "chinese" => "??", "japanese"=> "?????", "vietnamese"=> "xin chào");
echo json_encode($language, JSON_UNESCAPED_UNICODE);
Output: {"hindi":"??????","chinese":"??","japanese":"?????","vietnamese":"xin chào"}
