Add a custom field in WP Form Master

The following code creates a custom post selection field for the WP Form Master plugin, allowing users to select a post from a drop-down list in a form. This field also checks whether a valid selection has been made (if required), saves the ID or title of the selected post, and allows it to be added to forms using a shortcode.

Code

PHP

<?php
if (!defined('ABSPATH'))
    exit;

class WP_FormMaster_AddCustomField_PostSelect {
    private $fieldname = "select-post";
    private $isRequired = true;

    public function __construct() {
        add_filter("allowed_block_types_all", array($this, "setBlocks"), 11, 2);
        add_shortcode("wpformmaster-form-post-select", [$this, "postSelectCallback"]);
        add_filter("wpfmaster_form_extractfields", array($this, "extractFields"), 10, 4);
        add_filter("wpformmaster_field_value", array($this, "getFieldValue"), 10, 7);
        add_filter("wpfmaster_form_validate_field", array($this, "addRequiredError"), 10, 8);
    }

    public function addRequiredError($error, $formID, $key, $type, $field, $errors, $posts, $files) {
        if (!$error) {
            if ($key && $key === $this->fieldname) {
                if ($this->isRequired) {
                    if (isset($posts[$key])) {
                        $post = get_post($posts[$key]);
                        if (!$post || $post->post_type != "post") {
                            $error = __("Please select an item", "my-domain");
                        }
                    }
                }
            }
        }
        return $error;
    }

    public function getFieldValue($value, $key, $type, $attrs, $posts, $files, $getInterpretValue) {
        if ($key && $key === $this->fieldname) {
            if ($getInterpretValue) {
                if (isset($posts[$key]) && $posts[$key]) {
                    $post = get_post($posts[$key]);
                    if ($post) {
                        return sanitize_text_field($post->post_title);
                    }
                }
            } else {
                if (isset($posts[$key]) && $posts[$key]) {
                    return intval($posts[$key]);
                }
            }
        }
        return $value;
    }

    public function extractFields($fields, $formID, $posts, $files) {
        return array_merge($fields, [
            [
                "attrs" => [
                    "type" => "custom-select",
                    "name" => $this->fieldname
                ]
            ]
        ]);
    }

    public function postSelectCallback($atts) {
        ob_start();
        extract(
            shortcode_atts(
                array(
                    'title' => __("Article", "my-domain"),
                ),
                $atts
            )
        );
        ?>
        <div class="formmaster-field" datatype="select" dataname="<?= $this->fieldname; ?>">
            <div class="formmaster-select">
                <select name="<?= $this->fieldname; ?>">
                    <option value=""><?= $title . ($this->isRequired ? "*" : ""); ?></option>
                    <?php
                    $posts = get_posts([
                        'post_type' => array("post"),
                        'post_status' => 'publish',
                        'suppress_filters' => false,
                        'posts_per_page' => -1,
                        "orderby" => array(
                            "title" => "ASC"
                        )
                    ]);
                    foreach ($posts as $post) {
                        ?>
                        <option value="<?= $post->ID; ?>"><?= $post->post_title; ?></option>
                        <?php
                    }
                    ?>
                </select>
            </div>
        </div>
        <?php
        return ob_get_clean();
    }

    public function setBlocks($allowed_blocks, $editor_context) {
        if ($editor_context->post && $editor_context->post->post_type === "fmaster_form") {
            return array_merge($allowed_blocks, [
                'core/shortcode'
            ]);
        }
        return $allowed_blocks;
    }
}

new WP_FormMaster_AddCustomField_PostSelect();
?>

​x
 
<?php
if (!defined('ABSPATH'))
    exit;
​
class WP_FormMaster_AddCustomField_PostSelect {
    private $fieldname = "select-post";
    private $isRequired = true;
​
    public function __construct() {
        add_filter("allowed_block_types_all", array($this, "setBlocks"), 11, 2);
        add_shortcode("wpformmaster-form-post-select", [$this, "postSelectCallback"]);
        add_filter("wpfmaster_form_extractfields", array($this, "extractFields"), 10, 4);
        add_filter("wpformmaster_field_value", array($this, "getFieldValue"), 10, 7);
        add_filter("wpfmaster_form_validate_field", array($this, "addRequiredError"), 10, 8);
    }
​
    public function addRequiredError($error, $formID, $key, $type, $field, $errors, $posts, $files) {
        if (!$error) {
            if ($key && $key === $this->fieldname) {
                if ($this->isRequired) {
                    if (isset($posts[$key])) {
                        $post = get_post($posts[$key]);
                        if (!$post || $post->post_type != "post") {
                            $error = __("Please select an item", "my-domain");
                        }
                    }
                }
            }
        }
        return $error;
    }
​
    public function getFieldValue($value, $key, $type, $attrs, $posts, $files, $getInterpretValue) {
        if ($key && $key === $this->fieldname) {
            if ($getInterpretValue) {
                if (isset($posts[$key]) && $posts[$key]) {
                    $post = get_post($posts[$key]);
                    if ($post) {
                        return sanitize_text_field($post->post_title);
                    }
                }
            } else {
                if (isset($posts[$key]) && $posts[$key]) {
                    return intval($posts[$key]);
                }
            }
        }
        return $value;
    }
​
    public function extractFields($fields, $formID, $posts, $files) {
        return array_merge($fields, [
            [
                "attrs" => [
                    "type" => "custom-select",
                    "name" => $this->fieldname
                ]
            ]
        ]);
    }
​
    public function postSelectCallback($atts) {
        ob_start();
        extract(
            shortcode_atts(
                array(
                    'title' => __("Article", "my-domain"),
                ),
                $atts
            )
        );
        ?>
        <div class="formmaster-field" datatype="select" dataname="<?= $this->fieldname; ?>">
            <div class="formmaster-select">
                <select name="<?= $this->fieldname; ?>">
                    <option value=""><?= $title . ($this->isRequired ? "*" : ""); ?></option>
                    <?php
                    $posts = get_posts([
                        'post_type' => array("post"),
                        'post_status' => 'publish',
                        'suppress_filters' => false,
                        'posts_per_page' => -1,
                        "orderby" => array(
                            "title" => "ASC"
                        )
                    ]);
                    foreach ($posts as $post) {
                        ?>
                        <option value="<?= $post->ID; ?>"><?= $post->post_title; ?></option>
                        <?php
                    }
                    ?>
                </select>
            </div>
        </div>
        <?php
        return ob_get_clean();
    }
​
    public function setBlocks($allowed_blocks, $editor_context) {
        if ($editor_context->post && $editor_context->post->post_type === "fmaster_form") {
            return array_merge($allowed_blocks, [
                'core/shortcode'
            ]);
        }
        return $allowed_blocks;
    }
}
​
new WP_FormMaster_AddCustomField_PostSelect();
?>

Explanations

Overall class structure

The WP_FormMaster_AddCustomField_PostSelect class defines and registers a new custom field that displays a drop-down list of posts. This field uses several WordPress filters and shortcuts to integrate with the form, control display, and manage validation.

Class variables

$fieldname: Stores the field name, here “select-post”.
$isRequired: Indicates whether the field is required, here set to true.

Class constructor

The class constructor adds several filters and a shortcode to integrate the custom field into the form:

allowed_block_types_all: Used to define which blocks are allowed in the WordPress form.
wpformmaster-form-post-select: Creates a shortcode to display the drop-down list of posts in the form.
wpfmaster_form_extractfields: Adds custom field attributes to the form.
wpformmaster_field_value: Extracts and interprets the value selected in the field for data recording.
wpfmaster_form_validate_field: Manages field validation to ensure that a post has been selected if the field is required.

Class methods

1. `addRequiredError`

This method is used to add an error message if the user does not select a post in the required field:

Parameters: It receives several parameters such as $formID, $key (field name), $type, $field, $errors, $posts, and $files.
How it works:
- First, it checks whether the field is mandatory.
- Then it checks whether a valid post is selected (existing and of type post).
- If the field is empty or contains an invalid selection, it returns an error message: “Please select an item”.

2. `getFieldValue`

This method determines the value of the field to be saved in the form:

Parameters: In addition to $value, $key, $type, $attrs, $posts, $files, it also takes $getInterpretValue to indicate whether the value should be interpreted.
How it works:
- If $getInterpretValue is true, it returns the title of the selected post.
- Otherwise, it simply returns the post ID (as an integer).
- If the field is empty, it returns the default value of $value.

3. `extractFields`

This method adds this field to the table of fields extracted by WP Form Master :

How it works:
- It adds a new field with a custom-select attribute and the name defined in $fieldname.
- This field will then be available for the form, with the appropriate name to be identified when sending.

4. `postSelectCallback`

This method defines the HTML display of the selection field in the form:

Parameters: It takes $atts to accept custom attributes passed to the shortcode.
How it works:
- Uses get_posts to retrieve all published posts.
- Creates an HTML drop-down list where each option represents a post, displaying its title and storing its ID as a value.
- If $isRequired is true, the field title will be marked with an asterisk to indicate that it is mandatory.

5. `setBlocks`

This method authorizes certain blocks for the WordPress block editor (Gutenberg) when the form is modified:

How it works:
- If the editor is in the context of a WP Form Master form (here identified by the post type fmaster_form), it authorizes the core/shortcode block.
- This allows you to use the shortcode to add this specific field in the block editor.

Class instantiation

The line new WP_FormMaster_AddCustomField_PostSelect(); creates a new instance of the class and activates the custom field when the code is executed.

Back-office

Wypo Wp Form Master Exemples Ajout Champ Personnalise

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