Wednesday, June 8, 2016

HTTP Compression and Performance tuning

With the advancement of technology and exceeding expectations of users, one has to be very careful designing a website. Performance is one of the key elements for success of an application. Even if, you have designed the application with uttermost care and rock solid architecture, there are few key areas in which you have to be really vigilant. HTTP Compression is one of those pivotal spaces.

HTTP compression is the technique to compress static and dynamic content which improves the transfer speed and performance of a website.

Steps to keep the compression ON for a website. Here the demonstration is given for IIS based website.
1. Open IIS (inetmgr)
2. Goto website. Right side will show all components of that website
3. Click on 'Compression' module and verify that both the checkboxes are checked if you need static and dynamic content to be compressed.




4. Click 'Mime Types' and check 'application/x-javascript' is added in the existing mime types. If not, add it.
5. Reset IIS, browse website and verify that JS is getting compressed now.

Web.Config Settings
Here are all the mime types and gzip information which should exist for a website if compression needed, either in IIS settings or in web.config.
Note: Include it in web.config if configuration file also get deployed with every build.

Section to include in <system.webserver></system.webserver>
<system.webServer>
<httpCompression> 
  <staticTypes> 
    <add mimeType="text/*" enabled="true" /> 
    <add mimeType="message/*" enabled="true" /> 
    <add mimeType="application/javascript" enabled="true" /> 
    <add mimeType="application/x-javascript" enabled="true" /> 
    <add mimeType="image/jpeg" enabled="true" /> 
    <add mimeType="*/*" enabled="false" /> 
  </staticTypes> 
  <dynamicTypes> 
    <add mimeType="text/*" enabled="true" /> 
    <add mimeType="message/*" enabled="true" /> 
    <add mimeType="application/javascript" enabled="true" /> 
    <add mimeType="application/x-javascript" enabled="true" /> 
    <add mimeType="image/jpeg" enabled="true" /> 
    <add mimeType="*/*" enabled="false" /> 
  </dynamicTypes> 
  <scheme name="gzip" dll="%Windir%\system32\inetsrv\gzip.dll" dynamicCompressionLevel="4" /> 
</httpCompression>
</system.webServer>

After compression is ON:
Response header of a JS file being loaded in website. 'Content-Encoding: gzip' shows that it is compressed.



Useful tools
There are several webistes which can help you detect, if your website/CSS/JS is compressed or not. You should check css/js or website seperately to make sure that all static medias are compressed. One of the examples website is given here.
Check Compression

For further detail, you can contact me www.bajajsumit.com. Please share your feedback if you find the article useful.