Add default image to custom post type to be used as images in news article schema

[bonakor]

Hello, On some of my custom posts, I have no featured image nor images in the content. I'd like to have a default image added automatically to the schema news article, how can I do it, please?

Is it the same process than modifying the output of default description or title?

[sybrew]

Hello!

Changing how the image generator works is different from the title and description generators. This is because the description is a string (there may only be one), whereas images are an array of strings (Open Graph and Schema.org allow multiple images). So, instead of assigning a value directly, we assign a generator (which yields a value).

Depending on the queue position of your generator (assigned before or after), it may influence whether the image is used under certain conditions. We recommend users to only set one image for Open Graph, so only the first good image will be used, and the other images won't even be looked up. This means that only the first few generators could be called, and all following won't be called. This is the beauty of generators; code can be halted remotely -- almost naturally.

Generators must always yield a value and may optionally return a value. Hence, the syntax is a little different.

The snippet below may do. Two things before it works:

1. Set $post_type's value to your custom post type.
2. Set 'url' to your image URL in my_custom_tsf_image_generator(). Also set 'id' to the attachment's ID so dimensions can be obtained.

add_filter( 'the_seo_framework_image_generation_params', 'my_tsf_custom_image_generation_args', 10, 3 );
/**
 * Adjusts image generation parameters.
 *
 * @link https://theseoframework.com/docs/api/filters/#append-image-generators-for-social-images
 * @param array      $params  : [
 *    string  size:     The image size to use.
 *    boolean multi:    Whether to allow multiple images to be returned. This may be overwritten by generators to 'false'.
 *    array   cbs:      The callbacks to parse. Ideally be generators, so we can halt remotely.
 *    array   fallback: The callbacks to parse. Ideally be generators, so we can halt remotely.
 * ];
 * @param array|null $args    The query arguments. Contains 'id', 'taxonomy', and 'pta'.
 *                            Is null when the query is auto-determined.
 * @param string     $context The filter context. Default 'social'.
 *                            May be (for example) 'breadcrumb' or 'article' for structured data.
 * @return array $params
 */
function my_tsf_custom_image_generation_args( $params, $args = null, $context = 'social' ) {

    switch ( $context ) {
        case 'sitemap':
        case 'schema':
            // Filter only sitemap and schema.
            break;
        default:
            // Do not filter the rest
            return $params;
    }

    // Set this to your post type name:
    $post_type = 'my_post_type';

    if ( null === $args ) {
        $is_my_post_type = is_singular( $post_type );
    } else {
        // Out the loop. Use $args to evaluate the query...
        if ( ! $args['taxonomy'] && ! $args['pta'] ) {
            $is_my_post_type = get_post_type( $args['id'] ) === $post_type;
        }
    }

    if ( ! empty( $is_my_post_type ) ) {
        $params['cbs'] = array_merge(
            [ 'custom' => 'my_custom_tsf_image_generator' ], // prepend to regular callbacks.
            $params['cbs'],
        );
    }

    return $params;
}

/**
 * Generates image URL and ID via my_get_image_value.
 *
 * @generator
 *
 * @param array|null $args The query arguments. Accepts 'id' and 'taxonomy'.
 *                         Leave null to autodetermine query.
 * @param string     $size The size of the image to get.
 * @yield array : {
 *    string url: The image URL location,
 *    int    id:  The image ID,
 * }
 */
function my_custom_tsf_image_generator( $args = null, $size = 'full' ) {
    // Yield the image...
    yield [
        'url' => 'https://example.com/path/to/image.jpg',
        'id'  => 0, // Optional image ID. But required to fetch image dimensions.
    ];
}

[bonakor]

Hello @sybrew, Thank you for this detailed answer (as always).

Sorry for the delay in mine, I was enjoying a summer break.

I'll implement this next week and get back to you if needed.

Thanks!