WordPress的get_the_excerpt而不是$ post-> post_excerpt

Question

I'm trying to replace $post->post_content in the function below with get_the_excerpt that simply deducts an excerpt from the_content on the fly .

Original function:

function getExcerpt($post) {
    $summary = apply_filters('the_content', $post->post_content);
    return apply_filters("mc-message", $summary);
}

I could have replaced $post->post_content with $post->post_excerpt but that would return nothing as there is no hard-corded excerpt entered in the Wordpress editor's excerpt meta box. Read that get_the_excerpt creates a summary out of the post content. But it didn't pass any value

function getExcerpt($post) {
    $deducted_excerpt = get_the_excerpt();
    $summary = apply_filters('the_content', $deducted_excerpt);
    return apply_filters("mc-message", $summary);
}

Answer 1

Yes, you are right. get_the_excerpt generates word-counted trimmed-down version of the full post content, when there is no user-supplied excerpt. But here, you are not using get_the_excerpt inside the loop. So, you will need to pass a post object or post ID as parameter to fetch the excerpt.

From codex:

If this function is used outside The Loop and the post doesn't have a custom excerpt, this function will use wp_trim_excerpt() to generate an excerpt. That function uses get_the_content() , which must be used with The Loop and will cause problems if get_the_excerpt() is being used outside The Loop. In order to avoid the issues, use setup_postdata() prior to calling get_the_excerpt() to set up the global $post object.

Your code should be:

function getExcerpt($post) {
    $deducted_excerpt = get_the_excerpt($post);//<==== see here. $post object is passed as parameter.
    $summary = apply_filters('the_content', $deducted_excerpt);
    return apply_filters("mc-message", $summary);
}

More details on get_the_excerpt() function

Answer 2

I had initially passed the post id to it and still didn't return the truncated content excerpt I was hoping for. Since the Codex suggests using the seup_postdata , I preceded my function with that. And solved the issue:

function getExcerpt($post) {
    setup_postdata($post);
    $deducted_excerpt = custom_excerpt($post);
    $summary = apply_filters('the_content', $deducted_excerpt);
    return apply_filters("mc-message", $summary);
}