PHP is filling json with duplicates of last item

Question

I am working on a web app using php. I am trying to pull from a database and fill an array with the information then encode it to json.

Here is what I have so far:

$result = mysqli_query($db, $query);
$row = mysqli_fetch_array($result);

$frats = array();
while ($row = mysqli_fetch_array($result)) {
    $frat->name = $row['name'];
    $frat->description = $row['description'];
    $frat->chapter = $row['chapter'];
    $frat->members = $row['members'];
    $frat->cover_image = $row['cover_image'];
    $frat->profile_image = $row['profile_image'];
    $frat->calendar_image = $row['calendar_image'];
    $frat->preview_image = $row['preview_image'];
    $frat->address = $row['address'];
    $frats[] = $frat;
}

echo json_encode($frats);

What I get in return is in the correct json format I want with the correct keys and everything, but every item in the json is the same. All of them are the last one. I believe this is because I might just be referencing the values, but I am not sure how to actually copy them in php.

Any suggestions?

Where is $frat exactly being initialized and setup? Do you have that code? — IncredibleHat
– IncredibleHat, Commented Oct 30, 2017 at 21:43

atoms · Accepted Answer · 2017-10-30 21:49:14Z

you need to create a new instance of $frat inside the loop. Otherwise you are just updating the original $frat each time the loop runs and adding a reference to it in the array.

Assuming its not a static class you could use:

$frats = array();
while ($row = mysqli_fetch_array($result)) {
    $frat = new frat();
    $frat->name = $row['name'];
    $frat->description = $row['description'];
    $frat->chapter = $row['chapter'];
    $frat->members = $row['members'];
    $frat->cover_image = $row['cover_image'];
    $frat->profile_image = $row['profile_image'];
    $frat->calendar_image = $row['calendar_image'];
    $frat->preview_image = $row['preview_image'];
    $frat->address = $row['address'];
    $frats[] = $frat;
}

echo json_encode($frats);

Even better would be to modify the constructor or create a method to consume the data. If you used the class's constructor then you could do something like this:

$frats = array();
while ($row = mysqli_fetch_array($result)) {
    $frats[] &= new frat($row['name'], $row['description'], $row['chapter']);
}

echo json_encode($frats);

Dave Goodchild · Accepted Answer · 2017-10-30 21:51:41Z

1

In the first line inside your while loop, you simply need the following line:

$frat = new \stdClass();

answered Oct 30, 2017 at 21:51

Dave Goodchild

3726 silver badges9 bronze badges

2 Comments

IncredibleHat Over a year ago

(could be disastrous if $frat is not a stdClass object to begin with ... but the question is unclear where $frat even came from)

Dave Goodchild Over a year ago

@Randall yep, there's no indication as to if $frat was anything before, who knows

Eduardo Escobar · Accepted Answer · 2017-10-30 21:52:57Z

0

You need to properly declare your variables $frats (array) and $frat (object):

$frats = array();
while ($row = mysqli_fetch_array($result)) {
  $frat = (object) array();
  $frat->name = $row['name'];
  $frat->description = $row['description'];
  $frat->chapter = $row['chapter'];
  $frat->members = $row['members'];
  $frat->cover_image = $row['cover_image'];
  $frat->profile_image = $row['profile_image'];
  $frat->calendar_image = $row['calendar_image'];
  $frat->preview_image = $row['preview_image'];
  $frat->address = $row['address'];
  array_push($frats, $frat); // For backward compatiblity
}

echo json_encode($frats);

edited Oct 30, 2017 at 21:52

answered Oct 30, 2017 at 21:46

Eduardo Escobar

3,4192 gold badges20 silver badges17 bronze badges

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