Camel Spring DSL Route: set http query parameter

Question

I'm new to camel and in my opinion the documentation is large but could be structured better. So it's hard to find what you are looking for.

My problem: I've defined a camel route in spring DSL for redirection from the camel servlet to another http endpoint. On redirecting, some http query parameter like PARAM1 should be set:

<route id="bridge">
    <from uri="servlet:bridge" />
    <setHeader headerName="HTTP_QUERY">
        <constant>PARAM1=value1</constant>
    </setHeader>
    <to uri="http://127.0.0.1:8081/actions.do?bridgeEndpoint=true" />
</route>

The redirection works, but the "TO" endpoint doesn't gets the parameter PARAM1. Where is my mistake?

regards jundl

Answer 1

To send query parameters to an http end point you can use HTTP_QUERY header as below

   <route>
    <from uri="servlet:bridge" />
    <setHeader headerName="HTTP_QUERY">
     <constant>param1=value1&param2=value2</constant>        
    </setHeader>
    <to uri="http://127.0.0.1:8081/actions.do?bridgeEndpoint=true" />
   </route>

and if you want some dynamic values like a header value as value1 you must use camel simple tag as below

  <route>
    <from uri="servlet:bridge" />
    <setHeader headerName="HTTP_QUERY">
     <simple>param1=${headerNameOfValue1}&param2=value2</simple>        
    </setHeader>
    <to uri="http://127.0.0.1:8081/actions.do?bridgeEndpoint=true" />
   </route>

Hope it helps!

Answer 2

try this http://camel.apache.org/constant.html

<route>
   <from uri="servlet:bridge" />
  <setHeader headerName="PARAM1">
    <constant>value1</constant>        
  </setHeader>
  <to uri="http://127.0.0.1:8081/actions.do?bridgeEndpoint=true" />
</route>

Answer 3

You are using a wrong headerName. If you want to use in a DSL route the Exchange.HTTP_QUERY constant, you need to write its value. That is, instead of write "HTTP_QUERY", you have to write "CamelHttpQuery". Take a look to https://camel.apache.org/maven/current/camel-core/apidocs/constant-values.html.

If you change your code in this way, it will work:

<route id="bridge">
    <from uri="servlet:bridge" />
    <setHeader headerName="CamelHttpQuery">
        <constant>PARAM1=value1</constant>
    </setHeader>
    <to uri="http://127.0.0.1:8081/actions.do?bridgeEndpoint=true" />
</route>