JSON output from MySQL works, but then white screen appears? - php

Question

I've used the below code to generate JSON from a MySQL table. It works great when I'm only generating 2 arrays, but for some reason when I try and generate 3 or 4 arrays, I get the "white screen of death". I thought it was happening because I needed to bump up my PHP Memory Limit, but I've done that and still get the same problem. See below:
The code that works is:
<?php
//Create Database connection
$db = mysql_connect("localhost","user","dbpassword");
if (!$db) {
die('Could not connect to db: ' . mysql_error());
}
//Select the Database
mysql_select_db("dbname",$db);
//Replace * in the query with the column names.
$result = mysql_query("select * from customer", $db);
//Create an array
$json_response = array();
while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
$row_array['customerfname'] = $row['customerfname'];
$row_array['customerlname'] = $row['customerlname'];
//push the values in the array
array_push($json_response,$row_array);
}
echo json_encode($json_response);
//Close the database connection
fclose($db);
?>
But when I attempt to call more values, this is where I get the blank screen:
<?php
//Create Database connection
$db = mysql_connect("localhost","user","dbpassword");
if (!$db) {
die('Could not connect to db: ' . mysql_error());
}
//Select the Database
mysql_select_db("dbname",$db);
//Replace * in the query with the column names.
$result = mysql_query("select * from customer", $db);
//Create an array
$json_response = array();
while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
$row_array['customerfname'] = $row['customerfname'];
$row_array['customerlname'] = $row['customerlname'];
$row_array['customeremail'] = $row['customeremail'];
$row_array['customertel'] = $row['customertel'];
//push the values in the array
array_push($json_response,$row_array);
}
var_dump($json_response);
echo json_encode($json_response);
?>
Update**
The error appears to be with my last line (echo json_encode ($json_response);
The following output is generated when I add print_r($row) before that last line.
Array ( [id] => 1 [customerfname] => First [customerlname] => Last [customeremail] => test#test.com [customerphone] => 000-000-0000
Update 2
Adding var_dump($json_response); before the echo json_encode line results in the blank screen.

Answer 1

For future reference: If someone else is visiting this question due to having a similar problem, the error with the blank page occurred since the query returned too many rows and json_encode() did not seem to be able to handle it.
Try the following, and share with us your result,
<?php
ini_set('display_errors', 1);
error_reporting(E_ALL);
//Create Database connection
$db = mysql_connect("localhost","user","dbpassword");
if (!$db)
die('Could not connect to db: ' . mysql_error());
mysql_select_db("dbname",$db);
mysql_query('SET CHARACTER SET utf8');
$result = mysql_query("select `customerfname`, `customerlname`, `customeremail`, `customertel` from customer", $db) or die("Error: ".mysql_error());
$json_response = array();
while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
$json_response[] = $row;
}
var_dump($json_response);
/* If the var_dump works, you can try and uncomment this section
if (function_exists('json_encode'))
{
echo json_encode($json_response);
echo "JSON Error: ".json_last_error();
}
else { echo "json_encode() is not supported"; }
*/
?>

Answer 2

When you use flcose($db) that is going to cause some trouble. remove that line.
flcose is used to close ressources such as writing to text files.
to close connection use mysql_close():
mysql_close($db);
and also Your loop can be reduce to this:
//Create an array
$json_response = array();
while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
//push the values in the array
array_push($json_response,$row);
}
//Close the database connection
mysql_close($db);
echo json_encode($json_response);
and I would probably echo the json after closing the connection but thats no biggie.
And I find white screen of death very funny :D