Get an attachment ID by URL in WordPress

We all know you can use wp_get_attachment_url() to return an attachment’s URL by passing in the ID, but what about the reverse scenario?

There are a lot of long-winded examples of how to get an attachment ID by URL floating around the interwebs. Most of them limit results to only returning images or use expensive DB queries. Really, there should be a function for this in core, but there isn’t.

Needless to say, I wasn’t really happy with any of the solutions I found people using, so I decided to take a stab at it.

Below is the most lightweight method I’ve come up with (so far) to get an attachment ID by passing through an attachment URL.

Example usage

Just as an example, this would echo the attachment ID integer of test-image.jpg onto the page:

<?php echo fjarrett_get_attachment_id_by_url( 'http://frankiejarrett.com/wp-content/uploads/2013/05/test-image.jpg' ) ?>

This would echo the same result as above because we are ignoring www usage in the URL being passed through:

<?php echo fjarrett_get_attachment_id_by_url( 'http://www.frankiejarrett.com/wp-content/uploads/2013/05/test-image.jpg' ) ?>

This would echo nothing, because the image doesn’t exist in the WordPress uploads directory:

<?php echo fjarrett_get_attachment_id_by_url( 'http://frankiejarrett.com/foo/test-image.jpg' ) ?>

And finally, this would also echo nothing because the URL of the file is pointing to an external domain:

<?php echo fjarrett_get_attachment_id_by_url( 'http://www.anotherdomain.com/wp-content/uploads/2013/05/test-image.jpg' ) ?>

Conclusion

We managed to fetch an attachment ID in just a few lines of code with no expensive DB queries! Awesome 8-)

Now you can do cool things like turn a URL into an absolute path:

<?php
$url = 'http://frankiejarrett.com/wp-content/uploads/2013/05/test-image.jpg';
$attachment_id = fjarrett_get_attachment_id_by_url( $url );
$path = ( $attachment_id ) ? get_attached_file( $attachment_id ) : null;
echo $path;
?>

For more information about what was used in this function, please see:
http://php.net/manual/en/function.explode.php
http://php.net/manual/en/function.parse-url.php
http://php.net/manual/en/function.str-ireplace.php
http://codex.wordpress.org/Function_Reference/home_url
http://codex.wordpress.org/Determining_Plugin_and_Content_Directories#Constants
http://codex.wordpress.org/Class_Reference/wpdb#SELECT_a_Column

Was this code helpful to you? Let me know in the comments!

Remove specific menu items from the WordPress Admin

Sometimes it’s best – especially when you’re using WordPress as a CMS – to remove those unwanted admin menus that create clutter for clients. They are never going to use them so why confuse their admin experience? For example: if the client isn’t going to blog, why include Posts or Comments in the menu at all?

Just insert this code into the functions.php file of your WordPress theme and *bam!* no more clutter. Please note that we are not going to restrict the Administrator user experience, this will just affect logged in users who can’t manage options.

(Make sure to edit the $restricted array with the items you want to hide, this is just an example so you can see what’s possible) Enjoy!

Add prefixes to WordPress post types when a theme is activated

Recently, I had a real problem on my hands.

I had neglected to prefix the post type names in some of my themes, and as it turns out, so did another popular WordPress plugin. Long story short: this plugin became unusable when running my themes, and this did not make my users very happy.

It became clear that I needed to bust out some ninja moves to overcome this dilema.

The code below is the solution I drafted – maybe it will help you too. It’s a function that runs when the theme is in use, and rewrites the post type names in the database with any prefix you choose.

After the theme is activated the specified post types will be renamed to: fjarrett_acme, fjarrett_foo and fjarrett_bar.

Sadly, there is not yet a hook that will fire only when themes are activated/updated. The after_setup_theme action is a little misleading in that it fires when WordPress sets up the current theme, not when an admin activates and/or updates the current theme.

So, it’s basically firing with every load of WordPress when the theme is active. Someone first made a patch for this 3 years ago and it looks like it’s finally being revisited.

For that reason, this is by no means the most resource-friendly solution, but we are killing the script if the prefixed post type already exists – which requires an additional query – but this is crucial for two reasons:

  1. So we’re not attempting to update the database with every page load – after the original post types are given prefixes the database update will never run again.
  2. So other plugins/themes (like the one I was in conflict with) can be installed later, creating their blasphemous post type names, and we won’t attempt to rewrite them.

Hopefully this is helpful to you and your project in some way. If so, please tell me about it the comments!

How to hide your WordPress version number…completely

Did you know that your WordPress version number is visible to everyone?

As Matt Mullenweg rightly pointed out several years ago, simply hiding your WordPress version number is not enough by itself to stay protected from potential threats (you should always be keeping your WordPress installation up-to-date).

But perhaps you have a client who has specifically requested its removal or maybe you just like keeping things on the safe side, either way there are a lot of tutorials out there on how to remove it from various areas but none that I’ve found showing how to remove it from every area at the same time.

The WordPress version number appears in three areas:

1. Generator Meta Tag in the Header

<meta name="generator" content="WordPress 3.3.2" />

2. Generator Tag in RSS Feeds

<generator>http://wordpress.org/?v=3.3.2</generator>

3. Query Strings on Scripts & Styles

If a script or style does not specify a version number when enqueued, the current version of WordPress is used.

foo.js?ver=3.3.2

One Block of Code to Rule Them All

Just enter this into your functions.php file and your WordPress version will be safely hidden from the public.

However, there is one small caveat to be aware of when using this method: This function will check to see if the ver query string matches the WordPress version number, so if the version of the enqueued script happens to be the exact same as the WordPress version then its version string will be removed as well.

This will occur rarely (if ever), especially when the current WordPress version is a point release, such as 3.3.2.

I’ve been HEROized as The Solution!

Last night was a very memorable night for me as my friends at X-Team unveiled my inner superhero, dubbing me as The Solution!

The Solution

When Frankie Jarrett isn’t living his passion for working in WordPress or making music, he’s the problem solving hero known as, The Solution!

He was born with the amazing cerebral super power to solve any problem. Frankie can always figure out a way to communicate clearly with anyone. He is often there to listen and offer support to others, no matter how difficult their situation. Often Frankie only needs to say, “I’ll have to think about this problem a little”, and soon he has an exciting solution!

No situation is too big or too small and there is no danger too great for him to face. Whether you are having a tough time remembering trigonometry for your math test, or you are stranded on the roof of a burning building, The Solution can always figure out the best way to rescue someone.

Our hero also has the natural ability to inspire others, whether leading musical worship in his church or jamming with friends, Frankie uses his voice and musical talents to uplift and inspire those around him.

When not saving the innocent, Frankie spends his time watching the History channel with his wife, whom he absolutely adores.

Being HEROized is a true honor, and I am grateful to Dave and the rest of the team for recognizing me in this way.

Now to create more solutions! :)

Add first and last classes to your loop without using JavaScript

So you’re a pixel-perfect designer who wants to keep control over your WordPress loop styles? Hell yeah! You’re already pretty cool in my book.

You’ve probably got a fancy post separator, or a brilliant doodle to fit between your last post and the comments. Whatever the reason, you don’t have CSS class selectors for targeting the first or last posts in your archive – and you really need them.

There are a lot of tutorials on how to achieve this with jQuery. But it’s not worth relying on JavaScript for something that can easily be done with a little PHP magic.

First, insert this function into your functions.php file.

Now, open up loop.php and replace post_class() with the newly created fjarrett_post_class().

This new function accepts the same parameters as the original function, so you can use it the exact same way. The only difference will be that the first and last posts will be marked automatically with an appropriate class name. Enjoy total control. :)

If this helped you in any way I’d love to hear about it in the comments!

The simplest way to require/include wp-load.php

If you want to use WordPress functionality in a PHP file that exists outside of your WordPress installation then you need to include wp-load.php. Perhaps you could call this “hooking into WordPress”.

Maybe you’re already using some sort of relative path method, like:

<?php include '../../../wp-load.php'; ?>

But this can create problems if directories change. You need a clean, dynamic way to get wp-load.php. So here is the simplest way to do it, with just two lines of code (place it at the very top of your file):

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<?php
 
$parse_uri = explode( 'wp-content', $_SERVER['SCRIPT_FILENAME'] );
require_once( $parse_uri[0] . 'wp-load.php' );
 
?>

Short and sweet :)

Disclaimer: This is intended for experimental and development purposes only. It is not advised to redundantly load WordPress on live production environments. But, why?