Tomcat8 Gzip Compression for CSS, JS

Question

I am using tomcat8 and trying to simulate GZIP compression of CSS and JS. I have added the entry in server.xml and follows

 <Connector port="8088" protocol="HTTP/1.1"
           connectionTimeout="20000"
           redirectPort="8443" compression="on"
     compressionMinSize="2048"
     noCompressionUserAgents="gozilla, traviata"
     compressableMimeType="text/html,text/xml,text/plain,text/css,text/javascript,text/json,application/x-javascript,application/javascript,application/json" />

And in my html page i have included the script as follows

<script type="text/javascript" src="extjs/ext-all-debug.js"></script> 

But while accessing the page, compression is not happening and resposne header received as follows.

Remote Address:[::1]:8088
Request URL:http://localhost:8088/test/extjs/ext-all-debug.js
Request Method:GET
Status Code:200 OK

Response Headers

view source
Accept-Ranges:bytes
Content-Length:4585183
Content-Type:application/javascript
Date:Wed, 03 Jun 2015 00:34:12 GMT
ETag:W/"4585183-1427778288000"
Last-Modified:Tue, 31 Mar 2015 05:04:48 GMT
Server:Apache-Coyote/1.1

Request Headers

view source
Accept:*/*
Accept-Encoding:gzip, deflate, sdch
Accept-Language:en-US,en;q=0.8
Connection:keep-alive
Host:localhost:8088
Referer:http://localhost:8088/test/index.html
User-Agent:Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.81 Safari/537.36

Please help me to find what went wrong here. The same is happening when i do this setting in remote server.

Answer 1

I added attribute useSendfile with value false.

The manual says:

(bool)Use this attribute to enable or disable sendfile capability. The default value is true. Note that the use of sendfile will disable any compression that Tomcat may otherwise have performed on the response.

My tomcat8 is now compressing a large html-file.

My connector:

<Connector port="8080" protocol="HTTP/1.1"
           connectionTimeout="20000"
            useSendfile="false"
            compression="on"
            compressionMinSize="2048"
            noCompressionUserAgents="gozilla, traviata"
            compressableMimeType="text/html,text/xml,text/plain,text/css"
           redirectPort="8443" />

Fiddler info:

HTTP/1.1 200 OK
Server: Apache-Coyote/1.1
Accept-Ranges: bytes
ETag: W/"560012-1444044890000"
Last-Modified: Mon, 05 Oct 2015 11:34:50 GMT
Content-Type: text/html
Transfer-Encoding: chunked
Content-Encoding: gzip
Vary: Accept-Encoding
Date: Tue, 06 Oct 2015 08:53:53 GMT

Answer 2

I came across the same problem while working on an angularjs application with tomcat8. It had some large js files.Setting useSendfile to 'false' helped partially, in the sense some files got compressed but not all of them. On further research I found that it is necessary to add 'application/javascript' also in the compressableMimeType. That worked for all the javascript files.

From tomcat8 documentation

The value is a comma separated list of MIME types for which HTTP compression may be used. The default value is text/html,text/xml,text/plain,text/css,text/javascript,application/javascript .

Answer 3

FYI for anyone attempting to use compression="force" attribute on the Connector. "force" is only force if the client supports compression.

Note the force is after the "Content-Encoding" header check...

 /**
 * Check if the resource could be compressed, if the client supports it.
 */
private boolean isCompressible() {

    // Check if content is not already compressed
    MessageBytes contentEncodingMB = response.getMimeHeaders().getValue("Content-Encoding");

    if ((contentEncodingMB != null) &&
            (contentEncodingMB.indexOf("gzip") != -1 ||
                    contentEncodingMB.indexOf("br") != -1)) {
        return false;
    }

    // If force mode, always compress (test purposes only)
    if (compressionLevel == 2) {
        return true;
    }
    ...

Source