json_encode only working on some php arrays and not importing the data for others

Question

I am trying to import three arrays from php into js using json_encode

Here is the code:

<?php
    $query2 = "SELECT * FROM all_data";

    $result2 = $conn->query($query2);

    $bu = [];
    $rank = [];
    $id = [];

    if ($result2->num_rows > 0) {

        while($row2 = $result2->fetch_assoc()) {
            $bu[] = $row2["bu"];
            $rank[] = $row2["rank"];
            $id[] = $row2["id"];
            echo "<tr class='dn' id='u-" . $row2["rank"] . "'>";
            echo "<td>" . $row2["rank"] . "</td>";
            echo "<td>" . $row2["bu"] . "</td>";
            echo "<td>" . $row2["tokens"] . "</td>";
            echo "</tr>";
        }

    }


    ?>

    var users = <?php echo json_encode($bu); ?>;
    var ranks = <?php echo json_encode($rank); ?>;
    var identifier = <?php echo json_encode($id); ?>;

Problem is, the arrays ranks and identifier are getting imported correctly, but users is not. This script was working the last few times I used it. Recently however, I changed the table all_data, by dropping it and then importing it from csv again. However the charset was utf8 when I imported, so I don't understand what the problem might be here.

Even if I am just doing <?php echo json_encode($bu) ?> it is not working. However <?php print_r($bu) ?> shows me that the array is not actually empty and it actually contains the query results.

You never do anything with `$result1`. And using `LIMIT` without `ORDER BY` means the 10 selected rows are unpredictable. — Barmar, Mar 26 '18 at 23:39
I have actually not posted the full code here, which is very long. I will remove the useless bits — Yuki.kuroshita, Mar 26 '18 at 23:41
what you mean by not imported correctly. does the console show errors ? — Mohd Alomar, Mar 26 '18 at 23:42
Yes, the console shows errors. Specifically "Unexpected token ;" atthe line where I define users. When I am checking the js generated, it shows that nothing is being assigned to users variable — Yuki.kuroshita, Mar 26 '18 at 23:47
Just show us the `echo json_encode($bu);` without assing to some var — kip, Mar 26 '18 at 23:51
@kip That is the problem. Even in PHP, json_encode is giving me no output at all — Yuki.kuroshita, Mar 26 '18 at 23:52
@Yuki.kuroshita use `print_r($bu)` to show the array, I think that the problem is related to some unicode char, but first check the output from `print_r` — kip, Mar 26 '18 at 23:56
There is one entry in the table which contains some special characters. Might that be a problem? — Yuki.kuroshita, Mar 27 '18 at 00:00
And if I want to keep that entry somehow, is there a way to do that? Since the entry is not in the utf8 charset (This is the entry: Hró╨ólfr), is there a non utf8 way to do this? — Yuki.kuroshita, Mar 27 '18 at 00:06
If you set the correct charset in the database connection try this: `echo json_encode($bu, JSON_UNESCAPED_UNICODE);`, do you have a correct charset rigth ? — kip, Mar 27 '18 at 00:07
@Yuki.kuroshita [this](https://stackoverflow.com/a/10829891/6591929) — kip, Mar 27 '18 at 00:20
Well, my database, table, everything has been set to utf8 already — Yuki.kuroshita, Mar 27 '18 at 00:25

score 2 · Accepted Answer · answered Mar 26 '18 at 23:41

2

json_encode turns the array into a string; if you want to have access to the array again in Javascript, parse the string back to an array again, such as:

var users = JSON.parse('<?php echo json_encode($bu); ?>');

But it's quite bad practice to create JS on the fly like this - if you want the script to have information served from your PHP, either insert the object into a element which gets parsed by the Javascript, or use data- attributes.

answered Mar 26 '18 at 23:41

CertainPerformance

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Even if I don't want to use it in javascript, at least json_encode should work right? Problem is json_encode is working for everything except $bu – Yuki.kuroshita Mar 26 '18 at 23:51

score 0 · Answer 2 · answered Sep 14 '18 at 16:58

As @kip points out in the comments, the most likely cause of the failure is the conversion of a unicode character, or other special characters that is causing the json_encode to fail to encode the array.

Most likely, you will need to use one of the json_encode predefined constants such as @kip recommended:
json_encode($bu, JSON_UNESCAPED_UNICODE);

I would actually take this a step further and use:
json_encode($bu, JSON_UNESCAPED_UNICODE, JSON_PARTIAL_OUTPUT_ON_ERROR)

Finally, since you know you are getting a json_encode error of some kind, after running your line
var users = < ? php echo json_encode($bu); ?>;

You can add the line:
json_last_error()

This will tell you exactly what the problem is, and should allow you to adjust the parameters of the json_encode to work with your $bu array.

json_encode only working on some php arrays and not importing the data for others

2 Answers2