custom field - get_post_meta() unserialize issue - returns boolean(false)

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I'm using a simple custom plugin that parses and saves external XML data as a serialized array in a custom field. This works fine, however, when I update the post, instead of the array I only see a message saying: "bool(false)". I guess it has to with serialize / unserialize but didn't find any clues.

I needed to serialize when I update post meta using update_post_meta($post_id, 'tb_data', serialize($new_value_array)); By omitting serialize like update_post_meta($post_id, 'tb_data', $new_value_array); doesn't store any data in custom field. Furthermore, I have to use maybe_unserialize(get_post_meta($post->ID, 'tb_data', true)); to print the results.

There are 2 custom fields, (1) tb_item_group_id and (2) tb_data. Value of tb_data will be added using the below function,

Function I am using to update post meta is as below.

function parse_file_func($title) {
    // get_tickets_array();exit;
    $language = explode('-', get_bloginfo('language'));
    $language = $language[0];
    $file = file_get_contents('.xml');
    if (!$file) {
        exit;
    }
    $domObj = new xmlToArrayParser($file);
    $domArr = $domObj->array;
    if (($domObj->parse_error)) {
        echo $domObj->get_xml_error();
    } else {
        $first = $domArr['rss']['channel']['item'];
        foreach ($first as $item) {
            if ($item['languageCode'] == $language) {
                $args = array(
                    'meta_key' => 'tb_item_group_id',
                    'meta_value' => $item['g:item_group_id'],
                    'post_type' => 'tickets',
                );
                $post = get_posts($args);
                if (empty($post)) {
                    continue;
                } else {
                    $args = array(
                        'meta_key' => 'tb_item_group_id',
                        'meta_value' => $item['g:item_group_id'],
                        'post_type' => 'tickets',
                    );
                    $post = get_posts($args);
                    $post_id = $post[0]->ID;
                    $meta_values = get_post_meta($post_id, 'tb_data');
                    if (empty($meta_values)) {
                        $new_value_array = array();
                        unset($item['cdata']);
                        $new_value_array['tb_' . $item['g:item_group_id'] . '_' . $item['ticketID']] = $item;
                    }
                    else {
                        $meta_arrays = unserialize($meta_values[0]);
                        $new_value_array = $meta_arrays;
                        foreach ($meta_arrays as $meta_ticketbar => $tb_content) {
                            if ($meta_ticketbar == 'tb_' . $item['g:item_group_id'] . '_' . $item['ticketID']) {
                                unset($item['cdata']);
                                $new_value_array[$meta_ticketbar] = $item;
                            } else {
                                $new_value_array = $meta_arrays;
                                unset($item['cdata']);
                                $new_value_array['tb_' . $item['g:item_group_id'] . '_' . $item['ticketID']] = $item;
                            }
                        }
                    }
                    update_post_meta($post_id, 'tb_data', serialize($new_value_array));
                    // update_post_meta($post_id, 'tb_data', base64_encode($new_value_array));
                }
            } else {
                continue;
            }
        }
    }
}

and displaying on front-end using get_post_meta

<?php
    // $tb_meta = get_post_meta($post->ID, 'tb_data', true);
    $tb_meta = get_post_meta($post->ID, 'tb_data', true);
    $tb_meta_unserialized = maybe_unserialize( $tb_meta );
?>
<pre><?php
    // print_r ($tb_meta_unserialized);
    var_dump($tb_meta_unserialized);
?></pre>

I'm using a simple custom plugin that parses and saves external XML data as a serialized array in a custom field. This works fine, however, when I update the post, instead of the array I only see a message saying: "bool(false)". I guess it has to with serialize / unserialize but didn't find any clues.

I needed to serialize when I update post meta using update_post_meta($post_id, 'tb_data', serialize($new_value_array)); By omitting serialize like update_post_meta($post_id, 'tb_data', $new_value_array); doesn't store any data in custom field. Furthermore, I have to use maybe_unserialize(get_post_meta($post->ID, 'tb_data', true)); to print the results.

There are 2 custom fields, (1) tb_item_group_id and (2) tb_data. Value of tb_data will be added using the below function,

Function I am using to update post meta is as below.

function parse_file_func($title) {
    // get_tickets_array();exit;
    $language = explode('-', get_bloginfo('language'));
    $language = $language[0];
    $file = file_get_contents('https://dl.dropboxusercontent/u/12344450/feed.xml');
    if (!$file) {
        exit;
    }
    $domObj = new xmlToArrayParser($file);
    $domArr = $domObj->array;
    if (($domObj->parse_error)) {
        echo $domObj->get_xml_error();
    } else {
        $first = $domArr['rss']['channel']['item'];
        foreach ($first as $item) {
            if ($item['languageCode'] == $language) {
                $args = array(
                    'meta_key' => 'tb_item_group_id',
                    'meta_value' => $item['g:item_group_id'],
                    'post_type' => 'tickets',
                );
                $post = get_posts($args);
                if (empty($post)) {
                    continue;
                } else {
                    $args = array(
                        'meta_key' => 'tb_item_group_id',
                        'meta_value' => $item['g:item_group_id'],
                        'post_type' => 'tickets',
                    );
                    $post = get_posts($args);
                    $post_id = $post[0]->ID;
                    $meta_values = get_post_meta($post_id, 'tb_data');
                    if (empty($meta_values)) {
                        $new_value_array = array();
                        unset($item['cdata']);
                        $new_value_array['tb_' . $item['g:item_group_id'] . '_' . $item['ticketID']] = $item;
                    }
                    else {
                        $meta_arrays = unserialize($meta_values[0]);
                        $new_value_array = $meta_arrays;
                        foreach ($meta_arrays as $meta_ticketbar => $tb_content) {
                            if ($meta_ticketbar == 'tb_' . $item['g:item_group_id'] . '_' . $item['ticketID']) {
                                unset($item['cdata']);
                                $new_value_array[$meta_ticketbar] = $item;
                            } else {
                                $new_value_array = $meta_arrays;
                                unset($item['cdata']);
                                $new_value_array['tb_' . $item['g:item_group_id'] . '_' . $item['ticketID']] = $item;
                            }
                        }
                    }
                    update_post_meta($post_id, 'tb_data', serialize($new_value_array));
                    // update_post_meta($post_id, 'tb_data', base64_encode($new_value_array));
                }
            } else {
                continue;
            }
        }
    }
}

and displaying on front-end using get_post_meta

<?php
    // $tb_meta = get_post_meta($post->ID, 'tb_data', true);
    $tb_meta = get_post_meta($post->ID, 'tb_data', true);
    $tb_meta_unserialized = maybe_unserialize( $tb_meta );
?>
<pre><?php
    // print_r ($tb_meta_unserialized);
    var_dump($tb_meta_unserialized);
?></pre>

• custom-field
• post-meta

Share Improve this question edited Jan 23, 2018 at 18:54 Nathan Johnson 6,52866 gold badges3030 silver badges4949 bronze badges asked Dec 2, 2014 at 11:53 Dipak G.Dipak G. 22822 silver badges99 bronze badges

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2 Answers 2

Sorted by: Reset to default 3

I have managed to fix it at my own.

I have used following code to update post meta

update_post_meta($post_id, 'tb_data', base64_encode(serialize($new_value_array)));

...and following code to get post meta

$tb_meta = get_post_meta($post->ID, 'tb_data', true);
$tb_meta_unserialized = unserialize(base64_decode($tb_meta));

I hope this will help someone.

You definitely don't need base64_encode/base64_dencode for doing PHP serialization/unserialization.

If the metadata contains a serialized array, it will be automatically processed by unserialize function. So, to get unserialized data you do not need to use unserialize nor maybe_unserialize function on received data when using get_post_meta.

Also, there is no need for using serialize when using add_post_meta or update_post_meta; if we pass something other than a primitive and non-structural data type like an array or an object, then that will be detected and serialized. So, we only useed to serialize the data when we want to explicit serialize primitive data types like strings, integers, etc.

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