Retrieve the URL for an attachment.

Signature

wp_get_attachment_url( $attachment_id = 0 )
attachment_id
 (int) Optional. Attachment post ID. Defaults to global $post.
Default: 0

Return

(string|false) Attachment URL, otherwise false.

Source

function wp_get_attachment_url( $attachment_id = 0 ) {
	$attachment_id = (int) $attachment_id;
	if ( ! $post = get_post( $attachment_id ) ) {
		return false;
	}

	if ( 'attachment' != $post->post_type )
		return false;

	$url = '';
	// Get attached file.
	if ( $file = get_post_meta( $post->ID, '_wp_attached_file', true ) ) {
		// Get upload directory.
		if ( ( $uploads = wp_get_upload_dir() ) && false === $uploads['error'] ) {
			// Check that the upload base exists in the file location.
			if ( 0 === strpos( $file, $uploads['basedir'] ) ) {
				// Replace file location with url location.
				$url = str_replace($uploads['basedir'], $uploads['baseurl'], $file);
			} elseif ( false !== strpos($file, 'wp-content/uploads') ) {
				// Get the directory name relative to the basedir (back compat for pre-2.7 uploads)
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