Opcache is one of PHP's most powerful tools when it comes to performance. With the release of PHP 7 it received a new feature which has gone largely un-noticed: the file cache. Depending on your hosting environment and/or traffic levels the file cache may be able to help squeeze even more performance out of PHP.
PHP apps can easily begin to slow down over time as they grow, and with the recent patches for the Meltdown vulnerability adding a performance penalty to many workloads this slowdown can be amplified. Often there are some simple changes that can be made in order to see a measurable performance improvement for production workloads.
Chrome, along with Edge, Opera and Safari, has built in support for detecting and preventing Cross Site Scripting (XSS) attacks. This works well as a safety net to protect users when websites fail to protect themselves from such attacks, but can cause issues with applications which allow users to post HTML in forms. This shows in chrome as an error page with the text "ERR_BLOCKED_BY_XSS_AUDITOR" and can be quite intimidating for users trying to perform a legitimate operation.
Recently I've been trying to make some improvements to sites that I'm ivolved with, particularly converting images to SVG format and implementing HTTP Content Security Policy (more to come on those later). While doing so I ran into a strange issue to do with how Microsoft Edge handles the combination of these two technologies which only seems to be documented in an Edge bug report.
Unit tests are a crucial part of the software development process. When used well they give you the confidence and sense of security needed to make changes without introducing bugs or regressions. When used badly they become a hindrance, slowing down development and encouraging bad practice. One common mistake is to write unit tests which reach too far and introduce fragility to your test suite.