使用 Java DSL 从 WSO2 转换为骆驼：如何使用 URI 模式转发

Question

I'm removing WSO2 from our stack and I have to write in Camel Java DSL the endpoints that were implemented in WSO2.

In WSO2 we had an endpoint as below:

<resource methods="OPTIONS GET" uri-template="/request/{data}" inSequence="requestreset"/>
<http method="GET" uri-template="http://127.0.0.1/index.php?_q=requestreset&amp;data={uri.var.data}"/>

My code in Java Camel's Router is:

public class DefaultRouteBuilder extends RouteBuilder {

    private HashMap<String, String> routeCorresponding = new HashMap();

    @Override
    public void configure() throws Exception {

        routeCorresponding.put("reset/request/{data}", "http://127.0.0.1/index.php?_q=requestreset&data={data}");

        for (Map.Entry<String, String> pair : routeCorresponding.entrySet()) {
            String url = pair.getKey();
            String target = pair.getValue();

            String resultTarget = target.contains("?") ? target + "&bridgeEndpoint=true" : target + "?bridgeEndpoint=true";

            fromF("servlet:"+ url +"?matchOnUriPrefix=true")
                    .log("Request: ${in.header."+ Exchange.HTTP_METHOD +"} to ${in.header."+ Exchange.HTTP_URI +"}")
                    .toF(resultTarget);
        }

    }

}

But it doesn't work as I would want it because when I make a request to tomcat.myserver.com:8080/camel-example-servlet/reset/request/blablablablabla I get a response this: org.apache.camel.http.common.HttpOperationFailedException: HTTP operation failed invoking http://127.0.0.1/index.php/reset/request/blablablablabla?_q=requestreset&data=%7Bdata%7D with statusCode: 404

Instead of http://127.0.0.1/index.php/reset/request/blablablablabla?_q=requestreset&data=%7Bdata%7D , I would like the following request to be on http://127.0.0.1/index.php?_q=requestreset&data=blablablablabla

Is it possible to achieve in Camel/Java DSL that? Basically what WSO2 was implementing with the URI template and the curly brackets around fields?

Answer 1

You can absolutely achieve that - but your {data} block is stored as a header, so you need to refer to it as ${header.data} in your target URI .

Here's an example using the REST DSL :

restConfiguration().component("servlet");

rest("/reset/request/{data}")
    .get()
    .route()
    .log("Received request...")
    .setHeader(Exchange.HTTP_PATH, simple("/index.php"))
    .setHeader(Exchange.HTTP_QUERY, simple("_q=requestreset&data=${header.data}"))
    .to("http://localhost:8080?bridgeEndpoint=true");

Edit based on your question below. Alternatively, if you need to proxy hundreds of URLs, instead of creating hundreds of routes, you could just create one single route which proxies them all and implement your routing logic in a Processor , eg:

from("servlet:?matchOnUriPrefix=true")
    .process(new Processor() {
        public void process(Exchange exchange) throws Exception { 
            // set your target URI here, look it up from the HashMap, etc.
        }
    })
    .to("http://localhost:8080?bridgeEndpoint=true");