Is it possible to read a file after receiving an event? - apache-camel

Question

I'm using a ActiveMQ Broker with built-in Camel Routes. I want to read a file after an Event received.
<pseudo>
from Event A
read File XY
to Event B with Body from File XY
</pseuod>
I simple tried moving files from a temporary directory based on an event but only event B is written. In the Log file are no Exceptions or Error messages.
<camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">
<!-- You can use Spring XML syntax to define the routes here using the <route> element -->
<route>
<description>Example Camel Route</description>
<from uri="activemq:example.A"/>
<from uri="file://tmp/a?delete=true"/>
<to uri="file://tmp/b?overruleFile=copy-of-${file:name}"/>
<to uri="activemq:example.B"/>
</route>
</camelContext>
Update with working solution for single file:
<camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">
<!-- You can use Spring XML syntax to define the routes here using the <route> element -->
<route>
<description>Example Camel Route</description>
<from uri="activemq:example.A"/>
<pollEnrich>
<constant>file:///tmp/a?fileName=file1</constant>
</pollEnrich>
<log message="file content ${body}"/>
<to uri="activemq:example.B"/>
</route>
</camelContext>

Answer 1

You need to use Content Enrichers for this. This is exactly what you are looking for.
<route>
<from uri="activemq:example.A"/>
<pollEnrich>
<constant>file://tmp/a?delete=true</constant>
</pollEnrich>
<to uri="activemq:example.B"/>
</route>
Please be aware that for camel version 2.15 or older
pollEnrich does not access any data from the current Exchange which
means when polling it cannot use any of the existing headers you may
have set on the Exchange. For example you cannot set a filename in the
Exchange.FILE_NAME header and use pollEnrich to consume only that
file. For that you must set the filename in the endpoint URI.