Experimental Physics and
Industrial Control System

"Kasemir, Kay via Tech-talk" <tech-talk at aps.anl.gov> · Wed, 14 Apr 2021 13:19:11 +0000

> java.net.MalformedURLException: no protocol: /var/lib/tomcat9/webapps/dbwr/LCPC/ColdBox.bob

Looks like you tried to access

    https://your.server/dbwr/view.jsp?display=/var/lib/tomcat9/webapps/dbwr/LCPC/ColdBox.bob

The display link needs to be a valid URL, for example this to access a file on the server:

   https://your.server/dbwr/view.jsp?display=file://var/lib/tomcat9/webapps/dbwr/LCPC/ColdBox.bob

But you might want to block generic file access for security reasons on either the tomcat level and/or by defining WHITELIST* settings.
So better serve the display files from your web as well and then use

   https://your.server/dbwr/view.jsp?display=http://your.server/displays/LCPC/ColdBox.bob

Search the web for setting up Apache httpd and tomcat so that httpd is used for serving plain files (like .../displays) and redirecting dedicated URLs to tomcat (like dbwr/*).

-Kay

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Vishnu Patel via Tech-talk <tech-talk at aps.anl.gov>
Sent: Wednesday, April 14, 2021 9:07 AM
To: EPICS tech-talk <tech-talk at aps.anl.gov>
Subject: [EXTERNAL] CSS Display builder web runtime. 

Hello,
      I am using display builder web runtime with tomcat9 and java 14.
The below error has been encountered.

HTTP Status 500 – Internal Server Error

Type Exception Report
Message Servlet execution threw an exception
Description The server encountered an unexpected condition that prevented it from fulfilling the request.
Exception
javax.servlet.ServletException: Servlet execution threw an exception
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

Root Cause
java.lang.Error: Cannot create display /var/lib/tomcat9/webapps/dbwr/LCPC/ColdBox.bob {}
	dbwr.servlets.ScreenServlet.createHtml(ScreenServlet.java:60)
	dbwr.servlets.DisplayCache.lambda$getOrCreate$0(DisplayCache.java:32)
	java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1708)
	dbwr.servlets.DisplayCache.getOrCreate(DisplayCache.java:32)
	dbwr.servlets.ScreenServlet.doGet(ScreenServlet.java:109)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

Root Cause
java.net.MalformedURLException: no protocol: /var/lib/tomcat9/webapps/dbwr/LCPC/ColdBox.bob
	java.base/java.net.URL.<init>(URL.java:672)
	java.base/java.net.URL.<init>(URL.java:568)
	java.base/java.net.URL.<init>(URL.java:515)
	dbwr.parser.Resolver.<init>(Resolver.java:65)
	dbwr.servlets.ScreenServlet.createHtml(ScreenServlet.java:48)
	dbwr.servlets.DisplayCache.lambda$getOrCreate$0(DisplayCache.java:32)
	java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1708)
	dbwr.servlets.DisplayCache.getOrCreate(DisplayCache.java:32)
	dbwr.servlets.ScreenServlet.doGet(ScreenServlet.java:109)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

Thanks
Vishnu

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System