Skip to main content

RequireJS - Busting the browser cache with every deployment using Grunt targethtml plugin

The projects that I work on have deployments to the QA very often; testing out the bug fixes and new features. Every time after the deployment, I ask the QA to clear the cache, since all JavaScript files are cached by the browser. This is really frustrating to QA and I needed someway to clear the cache with every deployment. This would be same in a continuous delivery project, wherein the client would be required to clear the browser cache.

I use RequireJS to bind the dependencies between various modules. Also, I use Grunt to manage the deployment workflow. The JavaScript code is optimized using RequireJS optimizer, which minifies and combines all the dependencies.

I referred to the RequireJS documentation and found that one can use 'urlArgs' property to bust the browser cache. If you refer to that example code, it uses the JavaScript Date object and assigns the time-stamp value to the  urlArgs parameter. This works fine if you never want the Require modules to be cached by the browser. However, in a workflow where you would like these files to cleared from the cache only when there is a deployment then you can use a Grunt plugin - grunt-targethtml.

The target-html plugin parses the source html file and generates the content accordingly. In your source html file, you need to specify target tags that will be processed when Grunt is run:

Here, the target html code that will be processed by the Grunt plugin is included in a comment. It has an 'If statement' which declares that if the grunt build is being run with 'dist' as an option then include the below code. Notice that the script block also specifies a template variable - 'bustVersion'. When the html content is being generated this would be treated as string that needs to be replaced with a value.

In your target html configuration (in Gruntfile.js) you need to provide the value that will be assigned to this variable:

Here, the 'curlyTags' configuration includes a template string 'bustVersion' whose value is a scriptlet '<%= grunt.template.today("yyyymmdd") %>'. Also, the files configuration includes the mapping between the destination file and the source file. Here 'dist/index.html' is the destination file and 'dev/index.html' is the source file that will be processed.

 When 'grunt dist' is run, the template string {{bustVersion}} is replaced with today's date (in 'yyyymmdd' format). The destination file will now have script tag specifying the RequireJS configuration - 'urlArgs' with the date generated using the scriptlet.
Labels:

Comments

Post a Comment

Popular posts from this blog

How to use the APP_INITIALIZER token to hook into the Angular bootstrap process

I've been building applications using Angular as a framework of choice for more than a year and this post is not about another React vs Angular or the quirks of each framework. Honestly, I like Angular and every day I discover something new which makes development easier and makes me look like a guy who built something very complex in a matter of hours which would've taken a long time to put the correct architecture in place if I had chosen a different framework. The first thing that I learned in Angular is the use of the APP_INITIALIZER token.
Post a Comment
Read more

File upload and Progress events with HTML5 XmlHttpRequest Level 2

The XmlHttpRequest Level 2 specification adds several enhancements to the XmlHttpRequest object. Last week I had blogged about cross-origin-requests and how it is different from Flash\Silverlight's approach .  With Level 2 specification one can upload the file to the server by passing the file object to the send method. In this post I'll try to explore uploading file using XmlHttpRequest 2 in conjunction with the progress events. I'll also provide a description on the new HTML5 tag -  progress which can be updated while the file is being uploaded to the server. And of course, some ColdFusion code that will show how the file is accepted and stored on the server directory.
18 comments
Read more

On GraphQL and building an application using React Apollo

When I visualize building an application, I would think of using React and Redux on the front-end which talks to a set of RESTful services built with Node and Hapi (or Express). However, over a period of time, I've realized that this approach does not scale well when you add new features to the front-end. For example, consider a page that displays user information along with courses that a user has enrolled in. At a later point, you decide to add a section that displays popular book titles that one can view and purchase. If every entity is considered as a microservice then to get data from three different microservices would require three http  requests to be sent by the front-end app. The performance of the app would degrade with the increase in the number of http requests. I read about GraphQL and knew that it is an ideal way of building an app and I need not look forward to anything else. The GraphQL layer can be viewed as a facade which sits on top of your RESTful services o...
Post a Comment
Read more