Streams are a way of generalising file, network, compression resources and a few other things in a way that allows them to share a common set of features. I stream is a resource object that has streamable behaviour. It can be read or written to in a linear fashion, but not necessarily from the beginning of the stream.

Streams have been available in PHP for quite a while (at least since version 4.3.0) and are used pretty transparently by most PHP programmers. They can be used to access files, network resources, command line arguments, pretty much anything that goes through the input/output stream in PHP.

I was recently looking at ReactPHP and found that the use of streams was a requirement in order to prevent blocking the input/output stream. Although, I had seen streams being used in PHP applications, I wasn't entirely certain how to use them myself. As a result I thought I'd put together a post about them.

Drupal's hook system allows modules to interact with various parts of a Drupal application and is part of the power of the application.

One common issue I have found is altering things that have been added by other modules during the hooks process. For example, a hook might be called that involves gathering data from one or more modules. If you need to intercept this configuration there is no guarantee that your module will be called after the module you are trying to intercept.

Another (more concrete) example is when altering forms. The code below shows a hook_form_alter() being run on all node edit forms on a site.

Since my last visit to this subject I have been thinking about how to represent a collection of random colors so that it looks sorted and that no information is lost during that process. I quickly realised that I needed to use all three aspects of the color space, which lends itself to generating 3D objects. Indeed, the red, green, blue color space is built around a cube so it can often be represented as a cube.

The hue, saturation, and value color space is built around the concept of a cylinder, which means that 2 of the axis lend themselves to a circumference of a circle (the hue) and the diameter of a circle (the saturation). This is an example of the polar coordinate system. We can therefore draw a circle using hue and saturation and the value can be used to represent a different aspect of the color space.

Since my last post, where I talked about drawling a line with pixels in PHP, I have been looking at drawing circles. As it turns out, there are a few different ways to draw a circle, so I'll go through a few options here.

To start with, there are some built in functions in PHP that can be used to draw an arc, circle or ellipse as a filled in shape or a line. The built in function in PHP called imageellipse() that can be used to draw a circle. This is part of the GD library.

Whilst working on a project recently I hit upon a PHP error that I've never seen before. During a process where a soap service was calling an API the connection would fail and the program would fatal error and stop.

I had protection mechanisms in place to catch this kind of connection error, but the fatal error was caused when the program tried to throw the exception I had put in place to indicate a failed connection.

Here is the error message (with some of the detail removed). This is a Drupal site but that detail is irrelevant to the problem.

This problem came out of a recent project I was working on. I had to perform a bunch of API lookups on behalf of a user that could take a minute or so to complete. The results of the API lookups were cached and so once it was done the site would be very quick, unfortunately the initial API lookup slowed down the page load quite considerably so this created a problem.

Rather than just doing the API loading in the page load process and making the user sit through it I created a batch process to load the API results in a more manageable manner. This created another problem as although the batch runner in Drupal is really good, it is perhaps a little too much just to show to users and expect them to understand what is going on. This led me to think if I could run a batch process via an AJAX callback from the page they were trying to load.

Drupal's cache system is robust, feature full and extensible. It can be used to cache small blocks of rendered output or the results of more complex calculations. The cache can be stored in a for the page request, in a database or in a different cache system.

I recently needed to store a decent amount of data that was pulled from an API. Getting the data from the API took a few seconds so it was important to cache this within the site for quick retrieval. Even just storing the cache in the database was many times quicker than the API so it made sense to cache the results within the site. Having the user sat there waiting for the page to load every time they do anything isn't great.

To this end I created a small Drupal service that would manage this cache for me. Here is the record from the services YAML file within the module.

From the pages of 'crazy things you can do with Drupal 8' comes this idea that I recently had to implement on a site. This was on a site that had implemented translations, but they needed something a little extra. The central idea was that if you visited a page on the site in a particular language, and that language didn't exist, then to try and give the user a similar language.

If you weren't already aware, Drupal's default behaviour is to return the default language version of a page if the language requested doesn't exist. If the Path Auto module is installed (which is usually the case on most Drupal sites) then Drupal will not be able to translate the path alias correctly and will issue a 404 if the requested translation doesn't exist. Drupal can't take the path for the French page /fr/about-us and find the original node because as far as it's concerned /fr/about-us doesn't exist.