WordPress Lies About Image Sizes / Dimensions

JS Morisset WordPress

There are a few functions available to retrieve the URL and size of an image in the WordPress Media Library, but few people know that these functions will often lie about an image’s dimensions.

As an example, let’s define a custom image size of 1000 x 1000 cropped, and use image_downsize() to retrieve the URL and size of an image ID (this example can be used with wp_get_attachment_image_src() as well). I’ll use list() in the example, instead of an array variable for the return values, to keep the code more readable. ;-)

add_image_size( 'my-custom-size', 1000, 1000, true );

list( $img_url, $img_width, $img_height, $img_is_intermediate ) = image_downsize( $id, 'my-custom-size' );

WordPress will return a URL for the image and the values of $width / $height may be 1000 / 1000 – it all depends on several factors.

Continue reading

Remove MultiArch / i386 in Ubuntu with Puppet

JS Morisset Puppet, Ubuntu

Here’s a little snippet I use to remove multiarch / i386 support from Ubuntu with Puppet.

if versioncmp( $::lsbdistrelease, "12.04" ) > 0 {
    exec { "remove-architecture i386":
        command => "/usr/bin/dpkg --remove-architecture i386",
        onlyif => "/usr/bin/dpkg --print-foreign-architectures | /bin/grep -q i386",
    }
} else {
    file { "/etc/dpkg/dpkg.cfg.d/multiarch": ensure => absent, }
}

Continue reading

Multiple MongoDB Instances with Ubuntu’s Upstart

JS Morisset Ubuntu, Upstart

Recently a client asked me to setup multiple instances of MongoDB on a Linux Ubuntu server. Ubuntu does not use standard /etc/init.d/ scripts, instead it uses upstart, an event-based replacement for the /sbin/init daemon, that handles starting of tasks and services during boot, stopping them during shutdown and supervising them while the system is running. Upstart uses it’s own limited syntax to describe a service or task. I tried launching several processes from a single upstart config, but upstart could not track the service properly. Instead, I broke-up the upstart script into two — one master to define the instances, and another to start each one independently.

Continue reading

Shell Script to Route Multiple Public/Private Interfaces

JS Morisset Bash, Linux

If you have a server with multiple interfaces – either public and/or private – your routing table might look something like this:

sh# ip route list
default via 17.10.20.1 dev eth1  metric 100 
192.168.0.0/24 dev eth0  proto kernel  scope link  src 192.168.0.51 
17.10.20.0/23 dev eth1  proto kernel  scope link  src 17.10.20.51 
105.104.72.16/28 dev eth2  proto kernel  scope link  src 105.104.72.23

This example shows one private interface with IP 192.168.0.51, two public interfaces with IPs 17.10.20.51 and 105.104.72.23, and a default route to 17.10.20.1. This means that any traffic to/from an IP outside the interface’s subnets is sent to 17.10.20.1 — and this is where problems occur (and probably why you’re reading this article). ;-)

Continue reading

Read Adobe XMP / XML in PHP

JS Morisset PHP, WordPress

I’ve found a few snippets of PHP code to read XMP / XML meta data from an image file, but none that I would call very robust or efficient. I ended up writing my own for Underwater Focus, and I’m quite pleased with the result. In fact, after adding support for a shortcode, I packaged it as an Adobe XMP plugin for WordPress.

The first part of using XMP meta data is reading the XMP information from the image. I’ve seen a few solutions that read the whole file into memory, and others that read-in just a small part. If the XMP / XML contains a lot of information, that small part may be incomplete. And each time the XMP meta data is required, the original (and sometimes quite large) image file must be re-read. Since the XMP doesn’t change unless the original image is updated, there’s no reason to keep re-reading the same large file time and time again.

Continue reading

Encode Small Images in Stylesheets

JS Morisset CSS

Continuing the earlier theme of Optimizing Images to Save Bandwidth and Speed Page Load, you can also encode small (background) images directly in your stylesheets. For each image / page element encoded within a stylesheet, it means one less HTTP connection for content, which in turn means pages finish loading faster. These images should generally be small and downloadable quickly — what you want to save is the HTTP connection overhead, not the download time (both images and stylesheets are generally cached after downloading). The images should also be encoded within sourced stylesheet files, so the stylesheet files can be cached by the browser. If you encode images within your content (using `<style></style>` tags for example), the encoded image will have to be downloaded for every page view, so although you’re saving HTTP connections, your page size has increased. By encoding images in sourced stylesheet files instead, the browser (and content delivery services) can cache the whole stylesheet, including the encoded image(s).

Continue reading