1. Checking the Server

2. Location of Server Files on the Virtual Machine
On your virtual machine:
We’ll use the root directory of the shrew/hyrax checkout often and refer to it as $prefix
The value of $prefix on you VM is /home/opendap/src/hyrax-1.9
The Tomcat servlet engine is in $prefix/tomcat
The BES, data handlers and related source files are in $prefix/src. The BES has been built and installed in $prefix/{bin,lib,…}
The OLFS web archive file is $prefix/tomcat/webapps/opendap.war
BES: bes.conf, found at $prefix/etc/bes/bes.conf
OLFS: olfs.xml and catalog.xml, found at $prefix/tomcat/content/opendap

3. Background: Starting the Server
Start the BES (back-end data processing component)
Use bescmdln to verify it’s working
Start Tomcat: This automatically starts all installed servlets
Servlets are installed by copying the .war file to the servlet’s webapps directory
Verify it’s working using a web browser

4. Start the BES

5. Verify the BES is running

6. Start Tomcat & the OLFS Typical steps:
Unpack the olfs jar-file
Copy the opendap.war file to Tomcat’s webapps directory
Start Tomcat
Since all but the last step has been done already, start Tomcat:
/usr/local/javadev/apache-tomcat /bin/startup.sh

7. …terminal view

8. Verify Tomcat is running

9. …and Hyrax

10. Troubleshooting The getdap command line client
Can request any of the DAP response objects
Can act as a simple, generic web client
When even getdap cannot diagnose a problem, use telnet!

11. Troubleshooting with getdap
Use getdap to get
The DAS, DDS, Data, DDX
Version information
Use telnet to view the raw HTTP response
If the server times out too quickly, use expect to control telnet

12. Use the ‘-a’ option to get a DAS response
Also provide a valid URL

13. Use the ‘-d’ option to get a DDS response

14. …or drop the -d option and append the ‘.dds’ suffix

15. Use the ‘-D’ (data) and ‘-c’ (constraint)
options to get a data response.
A constraint expression with just one
variable. We got this from the DDS above

16. This constraint is asking for the values of
‘time’ between indexes 2 and 6 (every
second value).

17. Appending the string ‘version’ to the server
root name requests version information. It
comes back in an XML document.

18. Telnet reveals all
Use telnet to pass HTTP commands directly to the ‘opendap’ web application
Open the connection using the host name and port number
Use the ‘GET’ command, the pathname part of the URL including the DAP request extension and ‘HTTP/1.1’ or ‘HTTP/1.0’
Often you will need to supply a ‘Host: <name>’ header
A blank line.

19. Connect to the Tomcat or Apache server
GET <pathname> HTTP/1.1 (or 1.0) - hit
return quickly!
Host: header is important for a virtual server
Here’s the payoff - we can see all of the
headers set by both the web app and
the server, plus the response. Be cautious
with data responses because they are
binary and will mess up your terminal
session. Note the HTTP 1.1 chunking
counts (c5 and 0)