Hyrax - Apache Integration
The problem of linking Tomcat with Apache has been greatly reduced as of Apache 2.2. In previous incarnations of Apache & Tomcat, it was fairly complex. To see how to solve the problem for older versions of Apace, see the old Apache Integration instructions. What follows are the instructions for Apache 2.2 and Tomcat 6.x.
- Apace 2.2 or greater
- Tomcat 6.x or greater
- mod_proxy_ajp installed in Apache (typically this is present in 2.2+)
You have to create the AJP connector in the conf/server.xml file:
<Connector port="8009" enableLookups="false" redirectPort="8443" protocol="AJP/1.3" />
This line will enable AJP connections to the 8009 port of your tomcat server (localhost for example).
In the example below, pay special attention to the protocol part of the proxy URL - it uses ajp:// and not 'http://'.
Add this to Apache's httpd.conf file:
<Proxy *> AddDefaultCharset Off Order deny,allow Allow from all </Proxy> ProxyPass / ajp://localhost:8009/ ProxyPassReverse / ajp://localhost:8009/
NB: It's possible to embed these in a VirtualHost directive.
ProxyPass and ProxyPassReverse are classic reverse proxy directives used to forward the stream to another location. ajp://... is the AJP connector location (your tomcat's server host/port)
A web client will connect through HTTP to http://localhost/ (supposing your apache2 server is running on localhost), the mod_proxy_ajp will forward you request transparently using the AJP protocol to the tomcat application server on localhost:8009.
Apache Compressed Responses
Many OPeNDAP clients accept compressed responses. This can greatly increase the efficiency of the client/server interaction by diminishing the number of bytes actually transmitted over "the wire". Compression can reduce the number of bytes transmitted by an order of magnitude for many datasets!
Tomcat provides native compression support for the GZIP compression mechanism, however it is NOT turned on by default. More perversely, even if you have configured Tomcat to provide compressed responses, if you are using AJP to proxy Tomcat through the Apache web server compression will not be enabled unless you configure the Apache web server to compress responses. This is because Tomcat NEVER compresses responses sent over AJP.
When you configure your Apache web server to provide compressed responses you will probably want to make sure that Apache doesn't apply compression to images (In general images are already compressed and there is little to gain by attempting to compress them and a lot of CPU cycles to burn if you try)
You will need to add (something like) the following to your Apache web server's httpd.conf file:
# # Compress everything except images. # <Location /> # Insert filter SetOutputFilter DEFLATE # Netscape 4.x has some problems... BrowserMatch ^Mozilla/4 gzip-only-text/html # Netscape 4.06-4.08 have some more problems BrowserMatch ^Mozilla/4\.0 no-gzip # MSIE masquerades as Netscape, but it is fine # BrowserMatch \bMSIE !no-gzip !gzip-only-text/html # NOTE: Due to a bug in mod_setenvif up to Apache 2.0.48 # the above regex won't work. You can use the following # workaround to get the desired effect: BrowserMatch \bMSI[E] !no-gzip !gzip-only-text/html # Don't compress images SetEnvIfNoCase Request_URI \ \.(?:gif|jpe?g|png)$ no-gzip dont-vary # Make sure proxies don't deliver the wrong content Header append Vary User-Agent env=!dont-vary </Location>