PHP JSON String, escape Double Quotes for JS output

Question

I'm creating a JSON string from a PHP array. I've encoded it using json_encode().

$data = array(
    'title' => 'Example string\'s with "special" characters'
);

$data = json_encode( $data );

$data is localized using wp_localize_script() and is accessible via a global data variable.

In the JS file I can access the information by the following:

var data     = data.replace( /"/g, '"' ),
    jsonData = jQuery.parseJSON( data );

console.log( jsonData );

This results in an output of:

{ "title":"Example string's with "special" characters" }

Entering that result into http://jsonlint.com/ returns an error. Removing the double quotes around "special" validates the string.

What is the best way to create a JSON string from PHP and properly escape it for use in a JS file?

Answer 1

From http://www.php.net/manual/en/function.json-encode.php#100565

That said, quotes " will produce invalid JSON, but this is only an issue if you're using json_encode() and just expect PHP to magically escape your quotes. You need to do the escaping yourself.

Answer 2

Another way would be to encode the quotes using htmlspecialchars:

$json_array = array(
    'title' => 'Example string\'s with "special" characters'
);

$json_decode = htmlspecialchars(json_encode($json_array), ENT_QUOTES, 'UTF-8');

Answer 3

I succefully just did this :

$json = str_replace("\u0022","\\\\\"",json_encode( $phpArray,JSON_HEX_QUOT)); 

json_encode() by default will escape " to \" . But it's still wrong JSON for json.PARSE(). So by adding option JSON_HEX_QUOT, json_encode() will replace " with \u0022. json.PARSE() still will not like \u0022. So then we need to replace \u0022 with \\". The \\\\\" is escaped \\".

NOTE : you can add option JSON_HEX_APOS to replace single quote with unicode HEX value if you have javascript single quote issue.

ex: json_encode( $phpArray, JSON_HEX_APOS|JSON_HEX_QUOT ));

Answer 4

Use json_encode($json_array, JSON_HEX_QUOT); since php 5.3: http://php.net/manual/en/json.constants.php

Answer 5

This is a solutions that takes care of single and double quotes:

<?php
$php_data = array("title"=>"Example string's with \"special\" characters");

$escaped_data = json_encode( $php_data, JSON_HEX_QUOT|JSON_HEX_APOS );
$escaped_data = str_replace("\u0022", "\\\"", $escaped_data );
$escaped_data = str_replace("\u0027", "\\'",  $escaped_data );
?>
<script>
// no need to use JSON.parse()...
var js_data = <?= $escaped_data ?>;
alert(js_data.title); // should alert `Example string's with "special" characters`
</script>

Answer 6

I just ran into this problem and the actual issue was that I forgot to add a proper application/json header before spitting out the actual JSON data.

header('Content-Type: application/json');

Answer 7

I had challenge with users innocently entering € and some using double quotes to define their content. I tweaked a couple of answers from this page and others to finally define my small little work-around

$products = array($ofDirtyArray);
if($products !=null) {
    header("Content-type: application/json");
    header('Content-Type: charset=utf-8');
    array_walk_recursive($products, function(&$val) {
        $val = html_entity_decode(htmlentities($val, ENT_QUOTES, "UTF-8"));
    });
    echo json_encode($products,  JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES | JSON_NUMERIC_CHECK);
}

I hope it helps someone/someone improves it.