How can print a json response with php - php

Question

I'm building a simil web-service in php. This web service can read all record from a table of database and return a list of it in json format.
This is the code of my getArticoli.php file:
<?php
require_once('lib/connection.php');
$query_Articolo = "SELECT CodArticolo,NomeArticolo,Quantita,CodiceBarre, PrezzoAttuale, PrezzoRivenditore,PrezzoIngrosso
FROM VistaArticoli ";
$result_Articoli = $connectiondb->query($query_Articolo);
$answer = array ();
while ($row_Articoli = $result_Articoli->fetch_assoc()) {
$answer[] = ["id" => $row_Articoli['CodArticolo'],
"nome" => '"' . $row_Articoli['NomeArticolo'] . '"',
"quantita" => $row_Articoli['Quantita'],
"codiceBarre" => $row_Articoli['CodiceBarre'],
"codartFornitore" => $row_Articoli['CodiceBarre'],
"PrezzoAttuale" => $row_Articoli['PrezzoAttuale'],
"prezzoRivenditore" => $row_Articoli['prezzoRivenditore'],
"prezzoIngrosso" => $row_Articoli['prezzoIngrosso']];
}
//echo "fine";
echo json_encode($answer);
?>
Now, if I try to open this page, with this url: http://localhost/easyOrdine/getArticoli.php
I don't get the json_response.
In the table of database, there are 1200 records. If I try to insert an echo message in while cycle, I see it.
I have noticed that the problem lays with this field:
"nome"=>'"'.$row_Articoli['NomeArticolo'].'"'
If I remove this field from the response, I can correctly see the json response.
In this field there are any character from a-z/0-9 and special character like "/ * ? - and other".
It is possible that these special character can cause any error of the json answer?
EDIT
I have limit at 5 my query and this is the response:
[{"id":"878","0":"ACCESSORIO PULIZIA PUNTE DISSALDANTE 3 MISURE","quantita":"1","codiceBarre":"DN-705100","codartFornitore":"DN-705100","PrezzoAttuale":"14.39","prezzoRivenditore":null,"prezzoIngrosso":null},
{"id":"318","0":"ACCOPPIANTORE RJ11 TELEFONICO VALUELINE VLTP90920W","quantita":"20","codiceBarre":"5412810196043","codartFornitore":"5412810196043","PrezzoAttuale":"0.68","prezzoRivenditore":null,"prezzoIngrosso":null},
{"id":"320","0":"ACCOPPIATORE AUDIO RCA VALUELINE VLAB24950B","quantita":"5","codiceBarre":"5412810214136","codartFornitore":"5412810214136","PrezzoAttuale":"1.29","prezzoRivenditore":null,"prezzoIngrosso":null},
{"id":"310","0":"ACCOPPIATORE RJ45 VALUELINE VLCP89005W","quantita":"8","codiceBarre":"5412810228843","codartFornitore":"5412810228843","PrezzoAttuale":"0.38","prezzoRivenditore":null,"prezzoIngrosso":null},
{"id":"311","0":"ACCOPPIATORE USB2 VALUELINE VLCP60900B","quantita":"5","codiceBarre":"5412810179596","codartFornitore":"5412810179596","PrezzoAttuale":"1.80","prezzoRivenditore":null,"prezzoIngrosso":null}]

Answer 1

First, remove those extraneous quote characters. You don't need them and they could hurt you down the road:
while ($row_Articoli = $result_Articoli->fetch_assoc()) {
$answer[] = [
"id" => $row_Articoli['CodArticolo'],
"nome" => $row_Articoli['NomeArticolo'],
"quantita" => $row_Articoli['Quantita'],
"codiceBarre" => $row_Articoli['CodiceBarre'],
"codartFornitore" => $row_Articoli['CodiceBarre'],
"PrezzoAttuale" => $row_Articoli['PrezzoAttuale'],
"prezzoRivenditore" => $row_Articoli['prezzoRivenditore'],
"prezzoIngrosso" => $row_Articoli['prezzoIngrosso']
];
}
Then, run your query as is (without the LIMIT), and afterwards run echo json_last_error_msg()';, which could give you a hint to what's going on.
Also, being that your DB is in italian, maybe its encoding is not UTF-8. json_encode requires UTF-8 encoded data. So you may try to utf8_encode your article names before json_encoding the array:
"nome" => utf8_encode($row_Articoli['NomeArticolo']),
And see what you get.
Changing your DB charset to 'utf8mb4' could do the trick as well, and it is usually recommended.