Question

I have an Apache Tomcat server running. If I have something like:

webapp/
    image1.png

Then, I can simply access it using:

example.com/image1.png

Which is perfect, except that I don’t have any control over what headers are being sent. I wish to send specific Expires header for certain MIME-types (like, for image/png). These headers will be static, so I don’t really mind if I have to specify this in some XML file and cannot be dynamic.

Is it possible with Apache Tomcat? The other obvious way is to read from the file and output it to the browser with the appropriate headers, but I think that it might be an overkill.

Answer 1

Use Tomcat Filters for applying this headers.

<web-app ...>
    ...
    <filter>
       <filter-name>ExpiresFilter</filter-name>
       <filter-class>org.apache.catalina.filters.ExpiresFilter</filter-class>
       <init-param>
          <param-name>ExpiresByType image</param-name>
          <param-value>access plus 10 minutes</param-value>
       </init-param>
       <init-param>
          <param-name>ExpiresByType text/css</param-name>
          <param-value>access plus 10 minutes</param-value>
       </init-param>
       <init-param>
          <param-name>ExpiresByType application/javascript</param-name>
          <param-value>access plus 10 minutes</param-value>
       </init-param>
    </filter>
    ...
    <filter-mapping>
       <filter-name>ExpiresFilter</filter-name>
       <url-pattern>/*</url-pattern>
       <dispatcher>REQUEST</dispatcher>
    </filter-mapping>
    ...
 </web-app>

More Info at Tomcat Filter Documentation