how to retrieve Schema Validation error result in mule-esb - mule

Question

In Mule, am trying to validate a XML against XSD.
In my flow am using schema-validation-filter component nested with in message-filter component and working as expected.
but my question is, if XML fails, how do I capture the error details in logger component and based on results in need to navigate the flow.
Basically am looking for a MEL to print the error description on the console
Note: "returnResult" is set to false, because i need, to do further operations on the XML.
here is my configuration Flow:
<?xml version="1.0" encoding="UTF-8"?>
<mule xmlns:http="http://www.mulesoft.org/schema/mule/http" xmlns:file="http://www.mulesoft.org/schema/mule/file" xmlns:jms="http://www.mulesoft.org/schema/mule/jms" xmlns:tracking="http://www.mulesoft.org/schema/mule/ee/tracking" xmlns:mulexml="http://www.mulesoft.org/schema/mule/xml" xmlns:vm="http://www.mulesoft.org/schema/mule/vm" xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:doc="http://www.mulesoft.org/schema/mule/documentation" xmlns:spring="http://www.springframework.org/schema/beans" version="EE-3.4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-current.xsd
http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd
http://www.mulesoft.org/schema/mule/vm http://www.mulesoft.org/schema/mule/vm/current/mule-vm.xsd
http://www.mulesoft.org/schema/mule/xml http://www.mulesoft.org/schema/mule/xml/current/mule-xml.xsd
http://www.mulesoft.org/schema/mule/ee/tracking http://www.mulesoft.org/schema/mule/ee/tracking/current/mule-tracking-ee.xsd
http://www.mulesoft.org/schema/mule/jms http://www.mulesoft.org/schema/mule/jms/current/mule-jms.xsd
http://www.mulesoft.org/schema/mule/file http://www.mulesoft.org/schema/mule/file/current/mule-file.xsd
http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd">
<mulexml:schema-validation-filter schemaLocations="D:\MuleStudio\workspace\exceptiontest\src\test\resources\sample.xsd" returnResult="false" name="Schema_Validation" doc:name="Schema Validation"/>
<flow name="ExceptionTestFlow2" doc:name="ExceptionTestFlow2">
<http:inbound-endpoint exchange-pattern="one-way" host="localhost" port="8081" path="dataQ" doc:name="HTTP"/>
<expression-filter expression="#[message.payload != '/favicon.ico' ]" doc:name="Expression does't allow /favicon.ico"/>
<set-payload value="<data>
<books>
<book edition='1.0'>
<auth> auth</auth>
<title>title</title>
<pulbisher>pub</pulbisher>
</book>
</books>
</data>
" doc:name="XML is set as payload tp the current flow"/>
<logger message="::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Actual Flow Started :::::::::::::::::::::::::::::::::::::::::::::::::" level="INFO" doc:name="indicates Actual Flow Started Logger"/>
<logger message="paylad is :::: #[payload] :::::" level="INFO" doc:name="Prints current Payload"/>
<vm:outbound-endpoint exchange-pattern="one-way" path="dataQ" doc:name="VMQ_stores current xml which needs to be validated_senderQ"/>
</flow>
<flow name="ExceptionTestFlow1" doc:name="ExceptionTestFlow1">
<vm:inbound-endpoint exchange-pattern="one-way" path="dataQ" doc:name="VMQ_stores current xml which needs to be validated_receiverQ"/>
<logger message="::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Flow Started :::::::::::::::::::::::::::::::::::::::::::::::::" level="DEBUG" doc:name="indicates Flow Started Logger"/>
<message-filter doc:name="filter to validate xml against xsd" throwOnUnaccepted="true">
<filter ref="Schema_Validation"/>
</message-filter>
<logger message=" validation is true and the payload is :::: #[payload]" level="INFO" doc:name="current Payload"/>
<logger message="::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: End of Actual Flow:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::" level="INFO" doc:name="indicates Flow End Logger"/>
<choice-exception-strategy doc:name="Choice Exception Strategy">
<catch-exception-strategy when="exception.causedBy(org.mule.api.routing.filter.FilterUnacceptedException)" enableNotifications="false" doc:name="FilterUnacceptedException">
<logger message="::::::::::::::::::::::::::::::::::: in FilterUnacceptedException :::::::::::::::::::::::::" level="ERROR" doc:name="indicates FilterUnacceptedException Flow Started Logger"/>
<set-payload value="The request cannot be processed, the error is #[exception.getMessage()]" doc:name="Set Payload"/> <!-- [1] -->
<set-property propertyName="http.status" value="500" doc:name="Property"/>
<logger message=":::::::::::: end of FilterUnacceptedException with a payload as #[message.payload] ::::::::::::" level="INFO" doc:name="indicates FilterUnacceptedException End Logger"/> <!-- [2] -->
</catch-exception-strategy>
<catch-exception-strategy enableNotifications="false" doc:name="default">
<logger message=":::::::::::::::::::::: in default::::::::::::::::::::::::::::" level="ERROR" doc:name="indicates defaultException Flow Started Logger"/>
<set-payload value="The request cannot be processed, the error is #[exception.getSummaryMessage()]" doc:name="Set Payload"/>
<logger message="::::::::::::::::::::::::::::::::::::::::::::: END of Default Exception :::::::::::::::::::::::::::::::::::" level="INFO" doc:name="indicates DefaultException End Logger"/> <!-- [1] -->
<!-- [2] -->
</catch-exception-strategy>
</choice-exception-strategy>
</flow>
<flow name="Flow_If_XML_not_valid" doc:name="Flow_If_XML_not_valid">
<logger message=":::::::::::::::::::::::::::: #[payload] :::::::::::::: onThrow ::::::" level="INFO" doc:name="Should Print error description"/>
</flow>
</mule>
Have added an exception strategy that gives the following output:
Message has been rejected by filter. Message payload is of type: String
Code : MULE_ERROR--2
Exception stack is:
1. Message has been rejected by filter. Message payload is of type: String (org.mule.api.routing.filter.FilterUnacceptedException)
... http://www.mulesoft.org/docs/site/current3/apidocs/org/mule/api/routing/filter/FilterUnacceptedException.html)..
I need to be able to pinpoint which field is causing the problem.

Answer 1

Since the filter is configured to throw on unaccepted, you need to have an exception strategy in place in order to deal with the error.
Read: http://www.mulesoft.org/documentation/display/current/Error+Handling

Answer 2

You don't, see the SchemaValidationFilter source file. The SAXException is just catch and log (in debug). I think you need make your own SchemaValidationFilter. (Inherit Mule Validator)

Answer 3

package what.the.fuck.customFilter;
import java.io.IOException;
import javax.xml.transform.Source;
import javax.xml.transform.dom.DOMResult;
import org.mule.api.MuleMessage;
import org.mule.api.transport.PropertyScope;
import org.mule.module.xml.filters.SchemaValidationFilter;
import org.xml.sax.SAXException;
public class SchemaValidationFilterWithTrace extends SchemaValidationFilter {
public final static String SAX_ERROR_PROPERTIES = "SAX_ERROR_PROPERTIES";
public final static boolean RETURN_RESULT = false;
public final static String SCHEMA_LOCATION = "what.the.fuck.xsd";
public SchemaValidationFilterWithTrace(){
super();
super.setReturnResult(false);
super.setSchemaLocations(SCHEMA_LOCATION);
}
/**
* Accepts the message if schema validation passes.
*
* #param message The message.
* #return Whether the message passes schema validation.
*/
#Override
public boolean accept(MuleMessage message)
{
Source source;
try
{
source = loadSource(message);
}
catch (Exception e)
{
if (e instanceof RuntimeException)
{
throw (RuntimeException) e;
}
if (logger.isInfoEnabled())
{
logger.info("SchemaValidationFilter rejected a message because there was a problem interpreting the payload as XML.", e);
}
return false;
}
if (source == null)
{
if (logger.isInfoEnabled())
{
logger.info("SchemaValidationFilter rejected a message because the XML source was null.");
}
return false;
}
DOMResult result = null;
try
{
if (super.isReturnResult())
{
result = new DOMResult();
createValidator().validate(source, result);
}
else
{
createValidator().validate(source);
}
}
catch (SAXException e)
{
message.setProperty(SAX_ERROR_PROPERTIES, e.getMessage(), PropertyScope.OUTBOUND);
if (logger.isDebugEnabled())
{
logger.debug(
"SchemaValidationFilter rejected a message because it apparently failed to validate against the schema.",
e);
}
return false;
}
catch (IOException e)
{
if (logger.isInfoEnabled())
{
logger.info(
"SchemaValidationFilter rejected a message because there was a problem reading the XML.",
e);
}
return false;
}
finally
{
if (result != null && result.getNode() != null)
{
message.setPayload(result.getNode());
}
}
if (logger.isDebugEnabled())
{
logger.debug("SchemaValidationFilter accepted the message.");
}
return true;
}
}