json_last_error
(PHP 5 >= 5.3.0, PHP 7, PHP 8)
Returns the last error occurred
Description
Returns the last error (if any) occurred during the last JSON validation/encoding/decoding, which did not specify JSON_THROW_ON_ERROR.
Parameters Parameters
Return Values
Returns an integer, the value can be one of the following constants:
JSON_ERROR_NONENo error has occurred
JSON_ERROR_DEPTHThe maximum stack depth has been exceeded
JSON_ERROR_STATE_MISMATCHInvalid or malformed JSON
JSON_ERROR_CTRL_CHARControl character error, possibly incorrectly encoded
JSON_ERROR_SYNTAXSyntax error
JSON_ERROR_UTF8Malformed UTF-8 characters, possibly incorrectly encoded
JSON_ERROR_RECURSIONOne or more recursive references in the value to be encoded
JSON_ERROR_INF_OR_NANJSON_ERROR_UNSUPPORTED_TYPEA value of a type that cannot be encoded was given
JSON_ERROR_INVALID_PROPERTY_NAMEA property name that cannot be encoded was given
JSON_ERROR_UTF16Malformed UTF-16 characters, possibly incorrectly encoded
JSON_ERROR_NON_BACKED_ENUMValue contains a non-backed enum which cannot be serialized
Changelog
| Version | Description |
|---|---|
| 8.1.0 | JSON_ERROR_NON_BACKED_ENUM was added. |
Examples
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 JSONjson_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)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)