PHP - json_decode - issues decoding string - php

Question

I'm playing with the API from deepl.com that provides automatic translations. I call the API through cURL and I get a json string in return which appears to be fine but cannot be decoded by PHP for some reason.
Let me show first how I make the cURL call :-
$content = "bonjour <caption>monsieur</caption> madame";
$url = 'https://api.deepl.com/v2/translate';
$fields = array(
'text' => $content,
'target_lang' => $lg,
'tag_handling' => 'xml',
'ignore_tags' => 'caption',
'auth_key' => 'my_api_key');
$fields_string = "";
foreach($fields as $key=>$value)
{
$fields_string .= $key.'='.$value.'&';
}
rtrim($fields_string, '&');
$ch = curl_init();
curl_setopt($ch,CURLOPT_URL, $url);
curl_setopt($ch,CURLOPT_POST, count($fields));
curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/x-www-form-urlencoded','Content-Length: '. strlen($fields_string)));
$result = curl_exec($ch);
curl_close($ch);
If at this stage I do
echo $result;
I get:
{"translations":[{"detected_source_language":"FR","text":"Hola <caption>monsieur</caption> Señora"}]}
Which seems ok to me. Then if I use code below -
echo gettype($result);
I get "string" which is still ok but now, the following code fails:
$result = json_decode($result,true);
print_r($result);
The output is empty!
If I now do something like this:
$test = '{"translations":[{"detected_source_language":"FR","text":"Hola <caption>monsieur</caption> Señora"}]}';
echo gettype($test);
$test = json_decode($test,true);
print_r($test);
I get a perfectly fine array:
(
[translations] => Array
(
[0] => Array
(
[detected_source_language] => FR
[text] => Hola <caption>monsieur</caption> Señora
)
)
)
I did nothing else than copy/pasting the content from the API to a static variable and it works but coming from the API, it doesn't. It's like the data coming from the API is not understood by PHP.
Do you have any idea of what's wrong?
Thanks!
Laurent

Answer 1

I've had very similar issues before and for me the issue was with the encoding of the data returned from an API being unicode. I'm guessing when you do your copy/paste the string you hard-code ends up being a different encoding so it works fine when passed into json_decode.
The PHP docs specify json_decode only works with UTF-8 encoded strings:
http://php.net/manual/en/function.json-decode.php
You may be able to use mb_convert_encoding() to convert to UTF-8:
http://php.net/manual/en/function.mb-convert-encoding.php
Try this before calling json_decode:
$result = mb_convert_encoding($result, "UTF-8");

Answer 2

Make sure to set CURLOPT_RETURNTRANSFER to true. Only then will curl_exec actually return the response, otherwise it will output the response and return a boolean, indicating success or failure.
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$result = curl_exec($ch);
curl_close($ch);
if ($result !== false) {
$response = json_decode($result, true);
// do something with $response
} else {
// handle curl error
}

Answer 3

Like said #Eilert Hjelmeseth you have some special char in your JSON string => "Señora"
Another way to encode a string to UTF8: utf8_encode() :
$result = json_decode(utf8_encode($result),true);