wp_get_attachment_url( int $attachment_id = 0 ): string|false

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$attachment_idintoptional

Attachment post ID. Defaults to global $post.Default: 0

Return value

string|false

Attachment URL, otherwise false.

Code examples

Every example is editable and runs in a real WordPress booted in your browser by WordPress Playground. Press Run, then edit the code: clicking away re-runs it. Nothing is sent anywhere until you do.

$attachment_id = get_option( 'wppaste_example_attachment_id' );

$url = wp_get_attachment_url( $attachment_id );

if ( $url ) {
	echo esc_html( 'Attachment URL: ' . $url );
} else {
	echo esc_html( 'No URL could be resolved for this attachment.' );
}

$url = wp_get_attachment_url( 1 );

if ( false === $url ) {
	echo esc_html( 'Post 1 is not an attachment, so wp_get_attachment_url() returned false.' );
} else {
	echo esc_html( $url );
}

Common problems and fixes · 4

• Why does wp_get_attachment_url() return false when I know the ID exists?
• Why does wp_get_attachment_url() give me the GUID instead of a proper uploads URL?
• Why is the URL still http on the front end when my site is over SSL?
• Why does calling wp_get_attachment_url() with no argument return false outside The Loop?

Alternatives and related functions

wp_get_attachment_image_src

When you also need the image width and height alongside the URL, not just the URL string.

wp_get_attachment_image

When you want a ready-made `` tag with srcset and sizes instead of building markup around a bare URL.

get_attached_file

When you need the local filesystem path to the attachment rather than its public URL.

wp_get_original_image_url

When the attachment may have been edited or scaled and you specifically need the URL of the original, unmodified file.

Performance profile

How much work a call to wp_get_attachment_url() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Heavy

Reaches the database via get_post().

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

10–78

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 91.

Plugin surface

1 hook

Third-party callbacks on 'wp_get_attachment_url' run inside this call, and their cost is not bounded by anything here.

Called by

43

43 places in core call this, so the cost is paid more often than your own code shows.

What it touches

• querycontent queryget_post()called directly
• hookthird-party callbacksapply_filters()called directly

Further down the call graph this can also reach cache, serialize, option and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 19 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_get_attachment_url() can have, taken from its control-flow graph on PHP 8.5.

Hooks and filters fired · 1

One hook fires while wp_get_attachment_url() runs, in this order:

1. 1
   apply_filters( wp_get_attachment_url )filterline 7248 (+57 into the body)

   Filters the attachment URL.

Uses · 13

• get_post()Retrieves post data given a post ID or post object.
• get_post_meta()Retrieves a post meta field for the given post ID.
• wp_get_upload_dir()Retrieves uploads directory information.
• str_starts_with()Polyfill for `str_starts_with()` function added in PHP 8.0.
• str_contains()Polyfill for `str_contains()` function added in PHP 8.0.
• trailingslashit()Appends a trailing slash.
• _wp_get_attachment_relative_path()Gets the attachment path relative to the upload directory.
• wp_basename()i18n-friendly version of basename().
• get_the_guid()Retrieves the Post Global Unique Identifier (guid).
• is_ssl()Determines if SSL is used.
• is_admin()Determines whether the current request is for an administrative interface page.
• set_url_scheme()Sets the scheme for a URL.

Used by · 43

• Custom_Image_Header::ajax_header_crop()Gets attachment uploaded by Media Manager, crops it, then saves it as a new object. Returns JSON-encoded object details.
• Custom_Image_Header::create_attachment_object()Creates an attachment 'object'.
• Custom_Image_Header::step_3()Displays third step of custom header image page.
• WP_Customize_Manager::import_theme_starter_content()Imports theme starter content into the customized state.
• WP_Media_List_Table::_get_row_actions()Gets the row actions for a media item.
• WP_REST_Attachments_Controller::prepare_item_for_response()Prepares a single attachment output for response.
• WP_Site_Icon::create_attachment_object()Creates an attachment 'object'.
• WP_Widget_Media_Audio::render_media()Render the media on the frontend.
• WP_Widget_Media_Image::render_media()Render the media on the frontend.
• WP_Widget_Media_Video::render_media()Render the media on the frontend.
• _delete_attachment_theme_mod()Checks an attachment being deleted to see if it's a header or background image.
• _load_image_to_edit_path()Retrieves the path or URL of an attachment's attached file.

Source code

View on Trac ↗View on GitHub ↗

7191function wp_get_attachment_url( $attachment_id = 0 ) {7192	global $pagenow;7193 7194	$attachment_id = (int) $attachment_id;7195 7196	$post = get_post( $attachment_id );7197 7198	if ( ! $post ) {7199		return false;7200	}7201 7202	if ( 'attachment' !== $post->post_type ) {7203		return false;7204	}7205 7206	$url = '';7207	// Get attached file.7208	$file = get_post_meta( $post->ID, '_wp_attached_file', true );7209	if ( $file ) {7210		// Get upload directory.7211		$uploads = wp_get_upload_dir();7212		if ( $uploads && false === $uploads['error'] ) {7213			// Check that the upload base exists in the file location.7214			if ( str_starts_with( $file, $uploads['basedir'] ) ) {7215				// Replace file location with url location.7216				$url = str_replace( $uploads['basedir'], $uploads['baseurl'], $file );7217			} elseif ( str_contains( $file, 'wp-content/uploads' ) ) {7218				// Get the directory name relative to the basedir (back compat for pre-2.7 uploads).7219				$url = trailingslashit( $uploads['baseurl'] . '/' . _wp_get_attachment_relative_path( $file ) ) . wp_basename( $file );7220			} else {7221				// It's a newly-uploaded file, therefore $file is relative to the basedir.7222				$url = $uploads['baseurl'] . "/$file";7223			}7224		}7225	}7226 7227	/*7228	 * If any of the above options failed, Fallback on the GUID as used pre-2.7,7229	 * not recommended to rely upon this.7230	 */7231	if ( ! $url ) {7232		$url = get_the_guid( $post->ID );7233	}7234 7235	// On SSL front end, URLs should be HTTPS.7236	if ( is_ssl() && ! is_admin() && 'wp-login.php' !== $pagenow ) {7237		$url = set_url_scheme( $url );7238	}7239 7240	/**7241	 * Filters the attachment URL.7242	 *7243	 * @since 2.1.07244	 *7245	 * @param string $url           URL for the given attachment.7246	 * @param int    $attachment_id Attachment post ID.7247	 */7248	$url = apply_filters( 'wp_get_attachment_url', $url, $post->ID );7249 7250	if ( ! $url ) {7251		return false;7252	}7253 7254	return $url;7255}

Changelog

Introduced in 2.1.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/post.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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