PHP code to encode DB data in JSON not working - php

Question

I'm currently stuck with some PHP code. I want to access a table in my database and retrieve the data in a JSON format. Therefore, I tried the following code :
<?php
$con = mysqli_connect("......","username","pwd","DBName");
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$sql = "SELECT * FROM users";
if ($result = mysql_query($con, $sql))
{
$resultArray = array();
$tempArray = array();
while($row = $result->fetch_object())
{
$tempArray = $row;
array_push($resultArray, $tempArray);
}
echo json_encode($resultArray);
}
mysqli_close($con);
?>
However, it's getting me an empty page. It worked once but only with a special number of row in the table, so not very efficient as you might guess.
Does anybody have an idea why i'm getting those weird results?
EDIT 1 :
I Just tried to add this to my code :
echo json_encode($resultArray);
echo json_last_error();
And it's returning me 5. It seems to be an error from the data encoding in my table. Therefore I added that code :
$tempArray = array_map('utf8_encode', $row)
array_push($resultArray, $tempArray);
And I got the following output : [null,null,null]0 (The zero comes from the echo json_last_error();)
So here I am, can anybody help me with this ?

Answer 1

I would start by changing if ($result = mysql_query($con, $sql)) to if ($result = mysqli_query($con, $sql)) because they are different database extensions
Another thing would be to change while($row = $result->fetch_object()) to while ($row = mysqli_fetch_object($result)) { (Procedural style vs. Object oriented style)
If you still see blank screen, try adding error_reporting(E_ALL); at the top of your script, and you'll be able to know exactly where the bug is

Answer 2

<?php
$con = mysqli_connect("......","username","pwd","DBName")
or die("Failed to connect to MySQL: " . mysqli_connect_error());
$sql = "SELECT * FROM users";
$query = mysqli_query($con, $sql) or die ("Failed to execute query")
if ($result = $query)
{
$resultArray = array();
while($row = $result->fetch_object())
{
array_push($resultArray, $row);
}
$result->close()
echo json_encode($resultArray);
}
mysqli_close($con);
?>

Answer 3

This code works for me, try it out:
<?php
$con = mysqli_connect("......","username","pwd","DBName");
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$sql = "SELECT * FROM users";
if ($result = mysqli_query($con, $sql))
{
while($row = $result->fetch_object())
{
$resultArray[] = $row;
}
echo json_encode($resultArray);
}
mysqli_close($con);
?>
EDIT 1:
As a test replace this code:
while($row = $result->fetch_object())
{
$resultArray[] = $row;
}
echo json_encode($resultArray);
with this code:
while($row = $result->fetch_assoc())
{
print_r($row);
}
What output do you get?

Answer 4

I finally found a solution ! That was indeed an encoding problem, the json_encode() function accepts only strings encoded in utf8. I changed the interclassement of my table to utf8_general_ci and I modified my code as follows :
<?php
//Create Database connection
$db = mysql_connect(".....","username","pwd");
if (!$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 users", $db);
//Create an array
$json_response = array();
while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
$row_array['id'] = $row['id'];
$row_array['name'] = utf8_encode($row['name']);
$row_array['lastName'] = utf8_encode($row['lastName']);
//push the values in the array
array_push($json_response,$row_array);
}
echo json_encode($json_response);
//Close the database connection
fclose($db);
?>
And I got the expected output.