Why Does the PHP Json_Encode Function Convert Utf-8 Strings to Hexadecimal Entities

Why does the PHP json_encode function convert UTF-8 strings to hexadecimal entities?

Since PHP/5.4.0, there is an option called JSON_UNESCAPED_UNICODE. Check it out:

https://php.net/function.json-encode

Therefore you should try:

json_encode( $text, JSON_UNESCAPED_UNICODE );

json_encode return encoded utf-8 string

Just use the JSON_UNESCAPED_UNICODE flag:

echo json_encode($str, JSON_UNESCAPED_UNICODE);

Any way to return PHP `json_encode` with encode UTF-8 and not Unicode?

{"a":"\u00e1"} and {"a":"á"} are different ways to write the same JSON document; The JSON decoder will decode the unicode escape.

In php 5.4+, php's json_encode does have the JSON_UNESCAPED_UNICODE option for plain output. On older php versions, you can roll out your own JSON encoder that does not encode non-ASCII characters, or use Pear's JSON encoder and remove line 349 to 433.

json_encode returns JSON_ERROR_UTF8 when converting array to JSON

"If I try to connect to the database using charset=utf8 or charset=utf8mb4, it retrieves Cartão(bad codification), instead of Cartão (good codification)"

You are using latin1 as the display encoding, so that UTF-8 encoded, correct, text is displayed incorrectly.

Add charset=utf8 to the connection string and also set the response charset to UTF-8:

header('Content-Type: text/html;charset=utf-8');

How to keep json_encode() from dropping strings with invalid characters

php does try to spew an error, but only if you turn display_errors off. This is odd because the display_errors setting is only meant to control whether or not errors are printed to standard output, not whether or not an error is triggered. I want to emphasize that when you have display_errors on, even though you may see all kinds of other php errors, php doesn't just hide this error, it will not even trigger it. That means it will not show up in any error logs, nor will any custom error_handlers get called. The error just never occurs.

Here's some code that demonstrates this:

error_reporting(-1);//report all errors
$invalid_utf8_char = chr(193);

ini_set('display_errors', 1);//display errors to standard output
var_dump(json_encode($invalid_utf8_char));
var_dump(error_get_last());//nothing

ini_set('display_errors', 0);//do not display errors to standard output
var_dump(json_encode($invalid_utf8_char));
var_dump(error_get_last());// json_encode(): Invalid UTF-8 sequence in argument

That bizarre and unfortunate behavior is related to this bug https://bugs.php.net/bug.php?id=47494 and a few others, and doesn't look like it will ever be fixed.

workaround:

Cleaning the string before passing it to json_encode may be a workable solution.

$stripped_of_invalid_utf8_chars_string = iconv('UTF-8', 'UTF-8//IGNORE', $orig_string);
if ($stripped_of_invalid_utf8_chars_string !== $orig_string) {
    // one or more chars were invalid, and so they were stripped out.
    // if you need to know where in the string the first stripped character was, 
    // then see http://stackoverflow.com/questions/7475437/find-first-character-that-is-different-between-two-strings
}
$json = json_encode($stripped_of_invalid_utf8_chars_string);

http://php.net/manual/en/function.iconv.php

The manual says

//IGNORE silently discards characters that are illegal in the target
charset.

So by first removing the problematic characters, in theory json_encode() shouldnt get anything it will choke on and fail with. I haven't verified that the output of iconv with the //IGNORE flag is perfectly compatible with json_encodes notion of what valid utf8 characters are, so buyer beware...as there may be edge cases where it still fails. ugh, I hate character set issues.

Edit

in php 7.2+, there seems to be some new flags for json_encode:
JSON_INVALID_UTF8_IGNORE and JSON_INVALID_UTF8_SUBSTITUTE

There's not much documentation yet, but for now, this test should help you understand expected behavior:
https://github.com/php/php-src/blob/master/ext/json/tests/json_encode_invalid_utf8.phpt

And, in php 7.3+ there's the new flag JSON_THROW_ON_ERROR. See http://php.net/manual/en/class.jsonexception.php

Æøå in returned JSON result - the data doesn't look like it's supposed to

What you receive in $result is an utf-8 string that seems to represent an url of some sort. Anyhow, json_encode will escape any unicode character to \u008E strings.

If you don't want to escape utf-8 character, this question is relevent to you : Why does the PHP json_encode function convert UTF-8 strings to hexadecimal entities?

Everything seems to work fine from what I see. Although, the string you have provided us seem to be troncated but I guess this is an error on your part.

difficulty passing Japanese characters(UTF-8) via json_encode

\u611b\u77e5\u770c = 愛知県　(Aichi Prefecture)

\u611b\u5a9b\u770c = 愛媛県 (Ehime Prefecture)

Both are correct Japanese Prefecture name.
So string conversion part has no problem.

The perp is hiding in the later phase.

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