a9fde73d32daf74780765442de44324061b01d66
markd
  Sun Jan 22 22:13:52 2023 -0800
Add URL resolver plugin functionality to allow an external program to convert
cloud URLs (s3:, gs: drs:, or really any non-HTTP RUL) to http/https URLs.
This can include signed URLs.  The cloud URL is used to index the UDC cache
rather than the resolved URL.  This allows for re-resolving signed URLs
if they time out.

Joint work by Max and Markd

diff --git src/product/ex.hg.conf src/product/ex.hg.conf
index c510e6c..79bdc3e 100644
--- src/product/ex.hg.conf
+++ src/product/ex.hg.conf
@@ -662,15 +662,18 @@
 #
 # Provides support for svgBarCharts in hgc. Needed for certain bar chart hgc images to display
 # svgBarChart=on/off 
 
 # show a link on hgTracks at the top-right
 #survey=http://www.sco.com
 #surveyLabel=Link to some Unix company
 
 # Like the above, but not in yellow and just for a database
 #wuhCor1_TopLink=http://genome.ucsc.edu/goldenPath/help/covidBrowserIntro.html
 #wuhCor1_TopLinkLabel=Quick start guide
 
 # Similar to a survey link, but you can add a piece of html and configure everything yourself
 #hgTracksNoteHtml=<span style="color:yellow">Some text</span>
 
+# Configure a program to resolve cloud URLs to HTTP URLs.  See mirrorManual.txt for details.
+#resolvProts=fs,drs
+#resolvCmd=/var/www/tools/urlResolver /var/www/tools/config