[CAMEL-19257] camel-jslt: Exception when using camel-jslt in Tomcat Servlet

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.20.3, 4.0-M2
• Fix Version/s: 3.20.4, 3.21.0, 4.0-M3, 4.0.0
• Estimated Complexity: Unknown
• Assignee: Unassigned
• Reporter: Jacek Szymański
• Created: 07/Apr/23 06:19
• Updated: 09/Apr/23 07:53
• Resolved: 09/Apr/23 07:53

Description

When a JSLT transformation is used in a route which is called from a Tomcat Servlet in Spring Boot, an exception is thrown after the Exchange is completely processed and the response is being returned to the client:

java.lang.IllegalStateException: getWriter() has already been called for this response
at org.apache.catalina.connector.Response.getOutputStream(Response.java:552) ~[tomcat-embed-core-9.0.70.jar:9.0.70]
at org.apache.catalina.connector.ResponseFacade.getOutputStream(ResponseFacade.java:210) ~[tomcat-embed-core-9.0.70.jar:9.0.70]
at org.apache.camel.http.common.DefaultHttpBinding.doWriteDirectResponse(DefaultHttpBinding.java:537) ~[camel-http-common-3.20.3.jar:3.20.3]
at org.apache.camel.http.common.DefaultHttpBinding.doWriteResponse(DefaultHttpBinding.java:439) ~[camel-http-common-3.20.3.jar:3.20.3]
at org.apache.camel.http.common.DefaultHttpBinding.writeResponse(DefaultHttpBinding.java:362) ~[camel-http-common-3.20.3.jar:3.20.3]
at org.apache.camel.http.common.CamelServlet.afterProcess(CamelServlet.java:349) ~[camel-http-common-3.20.3.jar:3.20.3]

This happens because the Response object is held in a header and getWriter() gets prematurely called when the headers are serialized in JsltEndpoint.extractVariables().

Issue Links

• links to: GitHub Pull Request #9830