(PHP 5 >= 5.3.0, PHP 7)
json_last_error — Returns the last error occurred
Returns the last error (if any) occurred during the last JSON encoding/decoding,
which did not specify JSON_THROW_ON_ERROR.
This function has no parameters.
Returns an integer, the value can be one of the following constants:
| Constant | Meaning | Availability |
|---|---|---|
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 | PHP 5.3.3 |
JSON_ERROR_RECURSION |
One or more recursive references in the value to be encoded | PHP 5.5.0 |
JSON_ERROR_INF_OR_NAN |
One or more
NAN
or INF
values in the value to be encoded
|
PHP 5.5.0 |
JSON_ERROR_UNSUPPORTED_TYPE |
A value of a type that cannot be encoded was given | PHP 5.5.0 |
JSON_ERROR_INVALID_PROPERTY_NAME |
A property name that cannot be encoded was given | PHP 7.0.0 |
JSON_ERROR_UTF16 |
Malformed UTF-16 characters, possibly incorrectly encoded | PHP 7.0.0 |
Example #1 json_last_error() example
<?php
// A valid json string
$json[] = '{"Organization": "PHP Documentation Team"}';
// An invalid json string which will cause an syntax
// error, in this case we used ' instead of " for quotation
$json[] = "{'Organization': 'PHP Documentation Team'}";
foreach ($json as $string) {
echo 'Decoding: ' . $string;
json_decode($string);
switch (json_last_error()) {
case JSON_ERROR_NONE:
echo ' - No errors';
break;
case JSON_ERROR_DEPTH:
echo ' - Maximum stack depth exceeded';
break;
case JSON_ERROR_STATE_MISMATCH:
echo ' - Underflow or the modes mismatch';
break;
case JSON_ERROR_CTRL_CHAR:
echo ' - Unexpected control character found';
break;
case JSON_ERROR_SYNTAX:
echo ' - Syntax error, malformed JSON';
break;
case JSON_ERROR_UTF8:
echo ' - Malformed UTF-8 characters, possibly incorrectly encoded';
break;
default:
echo ' - Unknown error';
break;
}
echo PHP_EOL;
}
?>
The above example will output:
Decoding: {"Organization": "PHP Documentation Team"} - No errors
Decoding: {'Organization': 'PHP Documentation Team'} - Syntax error, malformed JSON
Example #2 json_last_error() with json_encode()
<?php
// An invalid UTF8 sequence
$text = "\xB1\x31";
$json = json_encode($text);
$error = json_last_error();
var_dump($json, $error === JSON_ERROR_UTF8);
?>
The above example will output:
string(4) "null" bool(true)
Example #3 json_last_error() and JSON_THROW_ON_ERROR
<?php
// An invalid UTF8 sequence which causes JSON_ERROR_UTF8
json_encode("\xB1\x31");
// The following does not cause a JSON error
json_encode('okay', JSON_THROW_ON_ERROR);
// The global error state has not been changed by the former json_encode()
var_dump(json_last_error() === JSON_ERROR_UTF8);
?>
The above example will output:
bool(true)