How to Extract Apache Camel URI parameters - apache-camel

Question

Does anyone know how to extract parameter from camel URI?
I have a route defined like this
from("SOME_URI")
.to("SOME_URI")
.to("bean:myBean?method=myMethod&myParameter1=val1&myParameter2=val2")
I want to extract parameter1 and parameter2 in "myMethod" like this (I'm implementing camel in Grails)
def myMethod(def inBody, Exchange exchange){
String parameter1 = extractParameter('myParameter1')
String parameter2 = extractParameter('myParameter2')
...//rest of code
return something
}
Thank's in advance!

Answer 1

Main Answer
You can get what you're looking for out of the exchange:
exchange.getFromEndpoint()
Will return the Endpoint defined by "SOME_URI" and:
exchange.getFromEndpoint().getEndpointUri()
will return the String value of "SOME_URI"
Meaning your code could become:
def myMethod(def inBody, Exchange exchange){
def uri = exchange?.fromEndpoint?.endpointUri
if(uri) {
String parameter1 = extractParameter(uri, 'myParameter1')
String parameter2 = extractParameter(uri, 'myParameter2')
//...rest of code
}
return something
}
/*
* do any kind of processing you want here to manipulate the string
* and return the parameter. This code should work just fine in grails
*/
def extractParameter(String uri, String parameterName) {
def m = uri =~ "${parameterName}=([^&]+)"
return m.find() ? m[0][1] : null
}
If a Java equivalent is preferred, this should do the same:
private static String extractParameter(String uri, String parameterName) {
Matcher m = Pattern.compile(parameterName + "=([^&]+)").matcher(uri);
return m.find() ? m.group(1) : null
}
Alternative
Also note that, depending on what exactly you're trying to accomplish, a better approach might be to use the fromF DSL to supply parameters directly to your route. That way, you have the parameters available in code and you don't have to worry about extracting them, afterward.
The code snippet below is taken from the Camel Documentation of FromF.
fromF("file://%s?include=%s", path, pattern).toF("mock:%s", result);

Answer 2

Are val1 and val2 hardcoded values, or should they be some kind of dynamic value, maybe from the message itself?
The Camel bean component allows you to define the binding, and pass in values from the message or fixed values. See more details at: http://camel.apache.org/bean-binding.html
And you would also need to look at the number of parameters in your method signature, and the number of parameters you define in the Camel bean binding uri. They should match up.

Answer 3

If I understand correctly, you are trying to pass parameters into a method that is going to be invoked. The usual way to do this is to modify the Exchange object as it's flowing through the route.
from("SOME_URI")
.to("SOME_URI")
.setHeader("myParameter1", constant("val1"))
.setHeader("myParameter2", constant("val2"))
.to("bean:myBean?method=myMethod")
In your method, you just access the headers of the Exchange.
def myMethod(Exchange exchange) {
String parameter1 = exchange.getHeader("myParameter1", String.class)
String parameter2 = exchange.getHeader("myParameter2", String.class)
//...rest of code
}
Or if you want to get fancy and use Camel's bean binding,
def myMethod(Exchange exchange,
#Header("myParameter1") String parameter1,
#Header("myParameter2") String parameter2) {
//...rest of code
}
Please remember to vote up if this helps.