Proper use of Output Buffer

I’m attempting to use actions to override function calls I currently have throughout a template (to make updating certain replicated sections easier). For example, in archives.php I have the following:

<?php get_header(); ?>

    <?php roots_content_before(); ?>
    <?php $page_for_posts = get_option( 'page_for_posts' ); if ($page_for_posts) { echo '<h1>' . get_the_title($page_for_posts) . '</h1>'; } ?>
    <h3>
        <?php
            $term = get_term_by('slug', get_query_var('term'), get_query_var('taxonomy'));
            if ($term) {
                echo $term->name;
            } elseif (is_day()) {
                printf(__('Daily Archives: %s', 'roots'), get_the_date());
            } elseif (is_month()) {
                printf(__('Monthly Archives: %s', 'roots'), get_the_date('F Y'));
            } elseif (is_year()) {
                printf(__('Yearly Archives: %s', 'roots'), get_the_date('Y'));
            } elseif (is_author()) {
                global $post;
                $author_id = $post->post_author;
                printf(__('Author Archives: %s', 'roots'), get_the_author_meta('user_nicename', $author_id));
            } else {
                single_cat_title();
            }
        ?>
    </h3>
    <?php echo category_description(); ?>
    <?php roots_loop_before(); ?>
    <?php get_template_part('loop', 'category'); ?>
    <?php roots_loop_after(); ?>
    <?php roots_content_after(); ?>

<?php get_footer(); ?>

You can see a few of the functions, like roots_content_before(); In a separate file, I have the following:

function roots_content_before() { do_action('roots_content_before'); }

and use it as follows:

<?php

    add_action('roots_content_before', 'roots_bootstrap_content_before');

    function roots_bootstrap_content_before() { ?>

        this is some text

    <?php }

?>

From what I’ve read, especially if I’m going to have large chunks of code, I should be using the output buffer, but when I try to do this, I’m getting diddly squat:

<?php

    add_action('roots_content_before', 'roots_bootstrap_content_before');

    function roots_bootstrap_content_before() { ob_start(); ?> 

        this is some text

       <?php return ob_get_clean();

    }

?>

Am I thinking of this completely wrong? I am still learning, but have been trying for a bit without any success. Any pointers in the right direction would really be appreciated. Thanks!

Answers:

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Method 1

No, you don’t need output buffering in this case. As a rule of thumb: Don’t use output buffering unless you really have to.

Just imagine what happens if someone else uses output buffering too from a plugin and it crosses with yours:

// plugin
ob_start();

// later, you in your theme
ob_start();

// you call a function where the plugin author hooked in to call:
print ob_get_clean();

// you call *your*:
return ob_get_clean();

// is is empty!

This is really hard to debug. Avoid it.

You don’t need a separate function to cover a plain do_action(). Just write do_action('roots_content_before'); in your theme.

Method 2

@toscho’s answer is totally wrong.

• Output buffering can be nested, there’s no need to worry about other Plugins.
• In this post from 2009 there’s a very elegant way to fetch and manipulate the final output of WordPress.

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0