{"id":4251398,"date":"2019-04-25T13:05:33","date_gmt":"2019-04-25T13:05:33","guid":{"rendered":"https:\/\/www.deptagency.com\/insight\/in-search-of-the-best-cache-busting-query-string\/"},"modified":"2019-04-25T13:05:33","modified_gmt":"2019-04-25T13:05:33","slug":"in-search-of-the-best-cache-busting-query-string","status":"publish","type":"article","link":"https:\/\/www.deptagency.com\/en-uki\/insight\/in-search-of-the-best-cache-busting-query-string\/","title":{"rendered":"In search of the best cache busting query string"},"content":{"rendered":"
\n\t\n\t<\/svg>\n\t\t\t\n\t\t\tBack to all articles\t\t<\/span>\n\t\n<\/button>\n\t\tIn search of the best cache busting query string\t<\/h1>\n\n\t\t\t\n\t\t\t\n\t\t\t\n\t\t\t\n\t\t\t\n\t\t<\/picture>\n\t\n\t<\/div>
\n\t\t\t\n\t\n\t
\n\t\tJames Simm\t\t
\n\t\tHead of Engineering\n\t\t\t<\/div>\n<\/div>\n\t
\n\t\t\t\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\tDate\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t\t25 April 2019\t\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t<\/div>\n<\/div>\n\n
\n\t
\n\t\t\n\t\t\t\t\t
\n\t\t\t\t\n\n\t\tIf you aren\u2019t already, you should be cache busting your scripts and styles, and what better way to do that by making the URL unique, clearing both the browser cache and any CDNs that are configured correctly. A good explanation of this can be found\u00a0here<\/a>.\t<\/h2>\n\n\n\t\tBut if we were to take this a step further and automate it, what would this look like, and what are our options?\t<\/p>\n\n\n\t\tBusting the cache based on version\t<\/h2>\n\n\n\t\tIf you\u2019re doing any kind of serious project, you\u2019re going to want some kind of automated versioning. We tend to use\u00a0GitVersion<\/a>\u00a0for most of our projects here, which while it has a few foibles that can need ironing out depending on your continuous integration pipeline, I\u2019d still recommend it as the defacto standard for generating out version numbers automatically.\t<\/p>\n\n\n\t\tOnce you have a version number, it\u2019s a case of reading that version number from somewhere and stamping that into a variable, then outputting your files based on that variable. Here\u2019s a quick example:\t<\/p>\n\n\n\t\tpublic static string\u00a0SiteVersion(this\u00a0HtmlHelper\u00a0helper)
{
return typeof(HTMLExtensions).Assembly.GetName().Version.ToString();
}\t<\/p>\n\n\n\t\tThen in your Razor or wherever you want to use it, you can just call it like this:\t<\/p>\n\n\n\t\t<script\u00a0src=”\/_scripts\/cool-website.js?v=@Html.AppVersion()”>
<\/script>\t<\/p>\n\n\n\t\tThis just gets you the version out of your assembly. This does require your build pipeline to be stamping the build onto your DLLs but apart from that it\u2019s a pretty neat solution to the problem. It\u2019s not my favourite though, for reasons i\u2019ll go into below.\t<\/p>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\n\t\n\t