Covert all tables from MyISAM to InnoDB

Here’s a quick one liner to convert all tables on in a specified database from MyISAM to InnoDB:

mysql -Bse "SELECT CONCAT('ALTER TABLE ',table_schema,'.',table_name,' engine=InnoDB;') FROM information_schema.tables WHERE engine = 'MyISAM' and table_schema = 'your_database_name';" | xargs -I {} mysql -e {}

Boom! You’re welcome.

Hide WordPress Post from All Queries

Problem: you want to create a variation of a page but you don’t want it to show up on the home page or in any archives or anything. You just need a direct link so you can share it with someone.

Solution:

add_action('pre_get_posts', 'hide_hidden_posts');
function hide_hidden_posts($query) {
  if ( is_admin() ) {
    return $query;
  }

  if ( is_single() AND $query->is_main_query() ) {
    return $query;
  }
  $ids = wp_cache_get('hidden_posts', 'posts');
  if ( !$ids ) {
    global $wpdb;
    $ids = $wpdb->get_col("SELECT post_id FROM {$wpdb->prefix}postmeta WHERE meta_key = 'hide_post'");
    wp_cache_set('hidden_posts', $ids, 'posts');
  }
  $query->set('post__not_in', $ids);
  return $query;
}

This function will modify all WordPress’ frontend queries to exclude any posts with a custom field “hide_post”, except in the case that the query is the main query on a single post page.

Caveat: This will only be functional for plugins and themes using the WP_Query api. Custom queries will not be modified.

Meta Tag Titles and Descriptions for Your WordPress site.

There are many good plugins out there the help you easily add meta tags to your site. All-in-one-SEO is probably the most popular of all the options. But there several reason why you may want to manually add this code to your template.

For one, you may be a template designer and want your templates to come pre-installed with this SEO friend feature.

Second, you may be having issues with Facebook link sharing not working. WordPress plugins use the wp_head() hook to access your template. But you have no control over the order. If you are using more than a dozen plugins your meta tags can get buried under tons of other code. This can prevent some bots from finding them. Indeed on several of my site Facebook’s bot was not finding them.

Third, it is just always good to do things without plugins if possible. Call it Occum’s Razor of web site building, the less code you use, the better.

Luck for us, it is extremely simple to add code for meta tags and descriptions without knowing much about wordpress or PHP.

Open the header.php file in your theme and paste in the following code:

<?php if(is_singular()) { ?>
<?php
global $post;
?>
<?php $recent = new WP_query('p='.$post->ID);
while($recent->have_posts()) : $recent->the_post(); ?>
<meta name="title" content="<?php the_title(); ?>">
<meta name="description" content="<?php the_content_rss('', TRUE, '', 50); ?>">
<?php endwhile; ?>
<?php } else { ?>
<meta name="title" content="<?php bloginfo('title'); ?>">
<meta name="description" content="<?php bloginfo('description'); ?>">
<?php } ?>

So what’s going on here? First, we’re checking to see if the post is a single post using the WordPress Conditional tag <?php if(is_singular()); ?> because we’ll to pull the title and the description of the individual post for our meta tags. But to do this, we need to get some information about the post, which is why we use the call global $post. This will give us information about the current post. Particularly it allows us access to $post->ID to query information about the post using WP_query.

The query we us looks like this:

$recent = new WP_query('p='.$post->ID); 

Once we have the query we put it into the standard wordpress loop:

while($recent->have_posts()) : $recent->the_post();

Then we use the standard WordPress tag <?php the_title(); ?> to pull in the META TITLE and <? the_content_rss() ?> to get the description. Notice, we are not using <?php the_excerpt(); ?>. This is because this WordPress tag prints the excerpt with a “read more” link in it. This will seriously screw up your theme. Using <?php the_content_rss(); ?> allows us to specify how many words of the content to pull in. But the second parameter has to be set to TRUE to avoid pulling in a “read more” link.