json_encode
While this can obviously change between versions, the current error codes are as follows:
0 = JSON_ERROR_NONE
1 = JSON_ERROR_DEPTH
2 = JSON_ERROR_STATE_MISMATCH
3 = JSON_ERROR_CTRL_CHAR
4 = JSON_ERROR_SYNTAX
5 = JSON_ERROR_UTF8
I'm only posting these for people who may be trying to understand why specific JSON files are not being decoded. Please do not hard-code these numbers into an error handler routine.
json_last_error
(PHP 5 >= 5.3.0)
json_last_error — Returns the last error occurred
Description
int json_last_error
( void
)
Returns the last error (if any) occurred during the last JSON encoding/decoding.
Parameters
This function has no parameters.
Return Values
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 |
Examples
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, $error === JSON_ERROR_UTF8);
?>
The above example will output:
string(4) "null" bool(true)
See Also
- json_decode() - Decodes a JSON string
- json_encode() - Returns the JSON representation of a value
add a note
User Contributed Notes
json_last_error - [2 notes]
jimmetry at gmail dot com ¶
1 year ago
lior at mytopia dot com ¶
4 years ago
For those of you who prefer a more object oriented approach (as I do), here is a fairly simple wrapper that handles errors using exceptions:
<?php
class JSON
{
public static function Encode($obj)
{
return json_encode($obj);
}
public static function Decode($json, $toAssoc = false)
{
$result = json_decode($json, $toAssoc);
switch(json_last_error())
{
case JSON_ERROR_DEPTH:
$error = ' - Maximum stack depth exceeded';
break;
case JSON_ERROR_CTRL_CHAR:
$error = ' - Unexpected control character found';
break;
case JSON_ERROR_SYNTAX:
$error = ' - Syntax error, malformed JSON';
break;
case JSON_ERROR_NONE:
default:
$error = '';
}
if (!empty($error))
throw new Exception('JSON Error: '.$error);
return $result;
}
}
?>