HTTP

HTTP Component

The http: component provides HTTP based endpoints for consuming external HTTP resources.

URI format

http:hostname[:port][/resourceUri][?options]

Usage

You can only produce to endpoints generated by the HTTP component. Therefore it should never be used aas input into your camel Routes. To bind/expose an HTTP endpoint via an http server as input to a camel route, you can use the Jetty Component

GET or POST

In Camel 1.5 the following algorithm is used to determine if either GET or POST http method should be used:
1. Use method provided in header
2. GET is query string is provided in header
3. GET if endpoint is configured with a query string
4. POST if there is data to send (body is not null)
5. GET otherwise

URI Parameters

The http producer supports URI parameters to be sent to the HTTP server. The URI parameters can either be set directly on the endpoint URI or as a header with the key HttpProducer.QUERY on the message. See samples below.

How to set the POST/PUT/INFO/DELETE/GET to the HTTP producer

The HTTP component provides a way to set the HTTP request method by setting the message header. Here is an example;

 new RouteBuilder() {
    public void configure() {
        from("direct:start")
            .setHeader(org.apache.camel.component.http.HttpMethods.HTTP_METHOD, constant(org.apache.camel.component.http.HttpMethods.POST))
	    .to("http://www.google.com")
            .to("mock:results");
    }            
};

And the equivalent spring sample:

<camelContext xmlns="http://activemq.apache.org/camel/schema/spring">
  <route>
    <from uri="direct:start"/>
    <setHeader headerName="http.requestMethod">
        <constant>POST</constant>
    </setHeader>
    <to uri="http://www.google.com"/>
    <to uri="mock:results"/>
  </route>
</camelContext>

Sample with scheduled poll

The sample polls the Google homepage every 10 seconds and write the page to the file message.html

from("timer://foo?fixedRate=true&delay=0&period=10000")
    .to("http://www.google.com")
    .setHeader(FileComponent.HEADER_FILE_NAME, "message.html").to("file:target/google");

URI Parameters from the endpoint URI

In this sample we have the complete URI endpoint that is just what you would have typed in a web browser. Multiple URI parameters can of course be set using the & as separator, just as you would in the web browser. Camel does no tricks here.

// we query for Camel at the Google page
template.sendBody("http://www.google.com/search?q=Camel", null);

URI Parameters from the Message

Map headers = new HashMap();
headers.put(HttpProducer.QUERY, "q=Camel&lr=lang_en");
// we query for Camel and English language at Google
template.sendBody("http://www.google.com/search", null, headers);

In the header value above notice that it should not be prefixed with ? and you can separate parameters as usual with the & char.

Response Code

You can get the http response code from the http component by getting the value from out message header with HttpProducer.HTTP_RESPONSE_CODE.

   Exchange exchange = template.send("http://www.google.com/search", new Processor() {
            public void process(Exchange exchange) throws Exception {
                exchange.getIn().setHeader(HttpProducer.QUERY, constant("hl=en&q=activemq"));
            }
   });
   Message out = exchange.getOut();
   int responseCode = out.getHeader(HttpProducer.HTTP_RESPONSE_CODE, Integer.class);

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