TAKAyukiatkwsk/functions.php

## functions.php
<?php
function my_blog_description() {
    $description = '';
    if ( is_single() ) {
        // 投稿の場合
        $_post = get_post();
        $description = $_post->post_content;
        $description = preg_replace( "/[\n|\r|\n\r|\t|\s]/", '', $description );
        $description = strip_tags( $description );
        $more_str = mb_strlen( $description, 'UTF-8' ) > 100 ? '...' : '';
        $description = htmlspecialchars( mb_substr( $description, 0, 100, 'UTF-8' ) . $more_str );
    } else {
        $description = bloginfo( 'description' );
    }
    return $description;
}

## header.php
<!DOCTYPE html>
<html>
<head>
<?php
    global $page, $paged;

    $title = wp_title( '|', false, 'right' );

    // Add the blog name.
    $title .= get_bloginfo( 'name' );

    // Add a page number if necessary:
    if ( $paged >= 2 || $page >= 2 )
        $title .= ' | ' . sprintf( __( 'Page %s', 'twentyeleven' ), max( $paged, $page ) );

?><title><?php echo $title; ?></title>
<meta property="og:title" content="<?php echo $title; ?>" />
<meta property="og:type" content="<?php echo is_home() ? 'blog' : 'article'; ?>" />
<meta property="og:url" content="<?php echo 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI']; ?>" />
<meta property="og:site_name" content="<?php bloginfo( 'name' ); ?>" />
<meta property="fb:admins" content="" /><!-- facebook IDを設定する -->
<meta property="og:description" content="<?php echo my_blog_description(); ?>" />
</head>
	<?php
	function my_blog_description() {
	$description = '';
	if ( is_single() ) {
	// 投稿の場合
	$_post = get_post();
	$description = $_post->post_content;
	$description = preg_replace( "/[\n\|\r\|\n\r\|\t\|\s]/", '', $description );
	$description = strip_tags( $description );
	$more_str = mb_strlen( $description, 'UTF-8' ) > 100 ? '...' : '';
	$description = htmlspecialchars( mb_substr( $description, 0, 100, 'UTF-8' ) . $more_str );
	} else {
	$description = bloginfo( 'description' );
	}
	return $description;
	}