JSON return with special characters in URL

Question

I’m having a problem with the return of a JSON, I made a query to fetch some images from the database, some URL users registered the images with special characters like -> (ç ã) the texts that contain these characters are returning right, no problems.

Some Urls that are in the bank:

media/upload/revista/capa_edição_810.jpg
media/upload/revista/capa_edição_806.jpg

On the return of JSON are coming like this:

media/upload/revista/capa_edi/u00c3/u00a7/u00c3/u00a3o_810.jpg
media/upload/revista/capa_edi/u00c3/u00a7/u00c3/u00a3o_806.jpg

My code in PHP:

<?php

require_once('conexao.php');

$query = " SELECT CONCAT('http://www.meusite.com.br/media/', imagem) as imagem, \n" 
    ." concat('edicao_', rr.edicao) as edicao, rr.edicao as numedicao, ei.id as Id_revista  \n"
    ." FROM `revistas_revista` rr   \n"
    ." inner join edicao_impressa_edicaoanterior ei on ei.revista_anterior_id = rr.id   \n"
    ."  where ei.ativo = 1 and year(rr.data) = '".$_GET['Ano']."' \n"
    ." order by edicao desc ";

$result = mysql_query($query) or die("Erro ao buscar dados");

mysql_close();  

$linhas = array();   

while ($r = mysql_fetch_assoc($result)){
   $linhas[] = $r;
}

echo json_encode($linhas); 

?>

A solution to this problem?

Answer 1

Quick fix.

Just copy and paste.
You don’t have to use your brain very much.

while ($r = mysql_fetch_assoc($result)){
   $linhas[] = $r;
}

echo json_encode($linhas); 

Trade it in and it’s all quiet!

while ($r = mysql_fetch_assoc($result)){
   $linhas[] = utf8_decode($r);
}

echo json_encode($linhas, JSON_UNESCAPED_UNICODE);

The rest of the answer is in case you want to understand what’s been done.
Continue reading if you want to fix the problem correctly.

Detailed answer.

_{Note: It takes a little brain to continue reading. Texts with more than 3 lines give sleep. Good luck.}

Concerning the issue

I don’t really understand what you really want, but I understand that you want to display in the return of json, the characters in their original form.

The function json_encode() automatically encodes special characters and applies escape characters. So you get the result as uxxxx.

Simple solution (PHP5.4+)

One simple way to solve is to define the second function parameter json_encode(). There is a constant call JSON_UNESCAPED_UNICODE, which can be used like this:

echo json_encode(array('acentuação'), JSON_UNESCAPED_UNICODE);
// retorna 
// ["acentuação"]

echo json_encode(array('acentuação'));
// retorna 
// ["acentua\u00e7\u00e3o"]

Backward compatibility

To ensure greater compatibility, below is an example of how to create backward compatibility with PHP versions below 5.4:

The reason for this is that this feature of the function json_encode() is available from PHP5.4. Currently it is still common to find servers with PHP below version 5.4, so it is still valid to apply this technique.

function JsonEncode($val, $option = null)
    {

        if (empty($option)) {
            return json_encode($val);
        }

        if (PHP_VERSION >= 5.4) {
            return json_encode($val, JSON_UNESCAPED_UNICODE);
        } else {
            // $option == JSON_UNESCAPED_UNICODE
            $encoded = json_encode($val);
            //$unescaped = preg_replace_callback('/\\\\u(\w{4})/', function ($matches) {
            $unescaped = preg_replace_callback(
                '/(?<!\\\\)\\\\u(\w{4})/',
                function ($matches) {
                    return html_entity_decode('&#x' . $matches[1] . ';', ENT_COMPAT, 'UTF-8');
                },
                $encoded
            );
            return $unescaped;
        }
    }

// Usage sample
echo JsonEncode(array('acentuação'));
// retorna 
// ["acentuação"]

Double condification

According to @Bacco’s observations, its original code is probably applying double coding, so it generates a wrong code.

The Unicode format of the string ção is \u00e7\u00e3o. However, the code presented in the question displays \u00c3\u00a7\u00c3\u00a3o

In a simple test, I simulated double encoding and hit 100% with the result of the question:

$str = 'acentuação';
$str_utf8 = utf8_encode($str);
echo PHP_EOL.$str_utf8;
echo PHP_EOL.json_encode($str_utf8);
// retorna
//u00c3/u00a7/u00c3/u00a3o_810

// Esse aqui é o correto como deveria retornar
echo PHP_EOL.json_encode(array($str));

To solve your specific case, there is an easy and dumb option which is to sweep the dirt under the rug:

utf8_decode(json_encode($val, JSON_UNESCAPED_UNICODE));

The second option is to do it "the right way", eliminating the problem at the root. Look for where you are applying the double encoding and fix it. Thus eliminating the unnecessary use of utf8_encode() and utf8_decode().

_{The complete code of the test: https://ideone.com/kHyBVf}

_{Note: The use of utf8_encode() and utf8_decode() is unnecessary in the context of the question. It does not mean that it is totally unnecessary, but rather that it is being misused.}