Why Is This PHP Call to Json_Encode Silently Failing - Inability to Handle Single Quotes

Why is this PHP call to json_encode silently failing - inability to handle single quotes?

You need to set the connection encoding before executing queries. How this is done depends on the API you are using to connect:

• call mysql_set_charset("utf8") if you use the old, deprecated API.
• call mysqli_set_charset("utf8") if you use mysqli
• add the charset parameter to the connection string if you use PDO and PHP >= 5.3.6. In earlier versions you need to execute SET NAMES utf8.

When you obtain data from MySQL any text will be encoded in "client encoding", which is likely windows-1252 if you don't configure it otherwise. The character that is causing your problem is the "curly quote", seen as 92 in the hex dump, which confirms that the mysql client is encoding text in windows-1252.

Another thing you might consider is pass all text through utf8_encode, but in this case it wouldn't produce the correct result. PHP's utf8_encode converts iso-8859-1-encoded text. In this encoding \x92 is a non-printable control character, which would be converted into a non-printable control character in utf-8. You could use str_replace("\x92", "'", $input) to fix the problem for this particular character, but if there's any chance there will be any other non-ascii characters in the database you'll want to have the client use UTF-8.

PHP: json_encode() doesn't show anything with multidimensional array

User @Joni led me to the solution.

Adding mysql_set_charset("utf8") fixed my issue.

As mentioned in this post: Why is this PHP call to json_encode silently failing - inability to handle single quotes?.

Why would json_encode return false in this case?

From PHP's manpage for json_last_error():

JSON_ERROR_UTF8 Malformed UTF-8 characters, possibly incorrectly encoded (PHP 5.3.3)

You have to ensure that the data given to json_encode() is UTF8, you should try using iconv to convert your strings to a proper format.

Php array from query to json is not working

My recollection is that php's json encode is sensitive to character sets, and in particular enforces the (standard for JSON) that chars are in UTF-8.
You may have to re-encode your text into UTF-8 before you encode it.

It is possible that doing this on the serialize() string, then unserializing, then json encode, is the fastest way.

PHP: json_encode() doesn't show anything with multidimensional array

User @Joni led me to the solution.

Adding mysql_set_charset("utf8") fixed my issue.

As mentioned in this post: Why is this PHP call to json_encode silently failing - inability to handle single quotes?.

json_encode returns false when dealing with multibyte substring

Simply pass the utf-8 encoding as the fourth parameter of the mb_substr() and you are good to go.

$a = mb_substr($s, 0, 10,'utf-8');
echo $a; // に搭載されるようにな
echo json_encode($a); // "\u306b\u642d\u8f09\u3055\u308c\u308b\u3088\u3046\u306b\u306a"

Demonstration

json_decode fails on godaddy hosting

For whatever reason, on godaddy hosting only (maybe in some other places too, but not in other places I tested), when I was submitting the form, the server was escaping quotes - and that's what was causing the issue. The solution to the problem was quite simple: instead of doing

$data = json_decode($_POST['logdata'], true);

I did

$data = json_decode(stripslashes($_POST['logdata']), true);

and everything worked perfectly.

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