What is the use of remove-module & IgnoreUrlPrefixes in bundling

Question

I have followed the steps from this document, to setup bundling & minification in my local instance.

It works with & without executing the last two steps, which are:

Adding the remove attribute for the bundle

<system.webServer>
   ...
   <remove name="BundleModule"/> 
   <add type="System.Web.Optimization.BundleModule" name="BundleModule"/>
 </system.webServer>

Adding a setting to ignore url prefixes:

<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <settings>
      <setting name="IgnoreUrlPrefixes" value="(all other sitecore paths here)|/bundles"/>
    </settings>
  </sitecore>
 </configuration>

Please help me understand what do they do and if they are mandatory.

Answer 1

Adding the remove attribute for the bundle

Modules from the <modules> section of web config are processed and combined in top-down order (starting from the server-specific modules). Some modules may possible be already configured on a higher level, so it's a place for potential conflicts.

It's a recommended practice to remove modules before adding your own to avoid conflicts.

Adding a setting to ignore url prefixes:

IgnoreUrlPrefixes can be used to prevent Sitecore from processing specific requests. There is absulutely no point in Sitecore trying to e.g. resolve item from a bundle url. That's why you should add you custom bundle url to IgnoreUrlPrefixes