tomcat-notes.md

• Unidata Science Gateway Notes on Tomcat
  • 301 Redirection
    • server.xml Connector Element
    • server.xml Engine Element
    • rewrite.config file

Unidata Science Gateway Notes on Tomcat

We use Tomcat quite a bit on the Unidata Science Gateway (USG) in a few different capacities via the Unidata Tomcat Docker container:

• THREDDS Server
• NEXRAD THREDDS Server
• RAMADDA

This document is a loose collection of notes concerning the use of Tomcat on the USG.

301 Redirection

In order to get redirection to work in Tomcat (e.g., thredds-aws.unidata.ucar.edu -> tds-nexrad.scigw.unidata.ucar.edu), there are a few details that have to be taken into account in keystore.jks and server.xml. First, the valid certificates for the old and new URLs must be present in the .jks keystore file and referenced in server.xml in roughly the following manner (I've omitted a number of Connector element details for the sake of clarity).

server.xml Connector Element

<Connector port="8443"
           defaultSSLHostConfigName="_default_">
  <SSLHostConfig honorCipherOrder="true"
                 hostName="_default_"
                 disableSessionTickets="true">
    <Certificate certificateKeystoreFile="${catalina.base}/conf/keystore.jks"
                 certificateKeystorePassword="xxx"
                 certificateKeyAlias="tds-nexrad.scigw.unidata.ucar.edu"/>
  </SSLHostConfig>
  <SSLHostConfig honorCipherOrder="true"
                 hostName="thredds-aws.unidata.ucar.edu"
                 disableSessionTickets="true">
    <Certificate certificateKeystoreFile="${catalina.base}/conf/keystore.jks"
                 certificateKeystorePassword="xxx"
                 certificateKeyAlias="thredds-aws.unidata.ucar.edu"/>
  </SSLHostConfig>
</Connector>

server.xml Engine Element

Additionally, you'll need to augment the Engine element with the old and new host as well as localhost and the RewriteValve in the following manner (again omitting some details, e.g., logging for the sake of clarity):

<Engine name="Catalina" defaultHost="localhost">
  <Host name="thredds-aws.unidata.ucar.edu" appBase="webapps" createDirs="false"
        unpackWARs="true" autoDeploy="true">
    <Valve className="org.apache.catalina.valves.rewrite.RewriteValve" />
  </Host>
  <Host name="tds-nexrad.scigw.unidata.ucar.edu"  appBase="webapps"  createDirs="false"
        unpackWARs="true" autoDeploy="true">
  </Host>
  <Host name="localhost"  appBase="webapps"  createDirs="false"
        unpackWARs="true" autoDeploy="true">
  </Host>
</Engine>

rewrite.config file

Finally, you will need a rewrite.config file that is co-located to the server.xml:

RewriteCond %{HTTP_HOST} ^thredds-aws.unidata.ucar.edu$
RewriteRule ^/(.*)$ https://tds-nexrad.scigw.unidata.ucar.edu/$1 [R=301,L]