Retire or Update the Viewers code in the OLFS

[ndp-opendap]

In the OLFS catalog pages:

• http://test.opendap.org:8080/opendap/data/nc/

We can see that the OLFS produces a viewers link for each dataset. The "returned page" contains a list of Web Start links and a list of Web Service links.

• Web Start applications can be used to read and display data. The Web Start links return a Java WebStart JNLP file that provides a recipe to retrieve the application from some distant repo., and then launch it in such a way that the client finds the dataset in question. Under the hood, template JNLP files and configuration are the order of the day. Known issues: The lack of signing of the returned JNLP files causes the OS-X systems to baulk at launching them. The returned JNLP does not appear to be compatible with the JVM on my dev system with the message: The operation couldn’t be completed. Unable to locate a Java Runtime that supports javaws. Java Web Start was deprecated in Java 9 by Oracle so I think it's safe to say that this part needs to go. Replacement? Research...

• A Web Service link points to the HTML encoded endpoint for the web service. For DAP2 and DAP4 that's the HTML Data Request Form page. For WCS that's the page for the coverage info or whatever they call it.

All of this is plumbed up in the olfs/src/opendap/viewers/ViewersServlet.java" class. which uses an XSLT, cannily named olfs/resources/hyrax/xsl/webStartDataset.xsl`, to build the viewers response page.

Basically the rest of this is an elaborate configuration driven link factory that gets used by the ViewersServlet to make a web page using the xslt.

Java Code

• olfs/src/opendap/webstart/**
• olfs/src/opendap/viewers/**

Resources

• olfs/resources/hyrax/WebStart
• olfs/resources/hyrax/xsl/webStartDataset.xsl

References
Keep these in the code base but remove, carefully, the viewers stuff.

• olfs/resources/hyrax/xsl/node_Contents.xsl
• olfs/resources/hyrax/xsl/dap4Contents.xsl

Here's the service in action:

http://test.opendap.org:8080/opendap/viewers/viewers?dapService=/opendap/hyrax&datasetID=/data/nc/coads_climatology.nc

You can see that test.o.o has a WCS configuration for that dataset, and so the WCS service shows up in the list of Web Services.

We might consider keeping the list of Web Services I suppose, but, :shrugs:, is it worth the added complexity? Once WCS and w10n are retired we only have dap2 and dap4. And given that dap2 is headed into the sunset...

I'm at remove the whole viewers ecosystem from the OLFS.

[jgallagher59701]

At this point I think we should retire this feature and its implementation.