[[AHC-AsyncHttpClientComponent]]
Async Http Client Component
~~~~~~~~~~~~~~~~~~~~~~~~~~~

*Available as of Camel 2.8*

The *ahc:* component provides HTTP based link:endpoint.html[endpoints]
for consuming external HTTP resources (as a client to call external
servers using HTTP). +
 The component uses the
https://github.com/AsyncHttpClient/async-http-client[Async Http Client]
library.

Maven users will need to add the following dependency to their `pom.xml`
for this component:

[source,xml]
------------------------------------------------------------
<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-ahc</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>
------------------------------------------------------------

[[AHC-URIformat]]
URI format
^^^^^^^^^^

[source,java]
---------------------------------------------------
ahc:http://hostname[:port][/resourceUri][?options]
ahc:https://hostname[:port][/resourceUri][?options]
---------------------------------------------------

Will by default use port 80 for HTTP and 443 for HTTPS.

You can append query options to the URI in the following format,
`?option=value&option=value&...`

[[AHC-AhcEndpointOptions]]
AhcEndpoint Options
^^^^^^^^^^^^^^^^^^^





// endpoint options: START
The AHC component supports 12 endpoint options which are listed below:

[width="100%",cols="2s,1,1m,1m,5",options="header"]
|=======================================================================
| Name | Group | Default | Java Type | Description
| httpUri | producer |  | URI | *Required* The URI to use such as http://hostname:port/path
| binding | producer |  | AhcBinding | To use a custom AhcBinding which allows to control how to bind between AHC and Camel.
| bridgeEndpoint | producer | false | boolean | If the option is true then the Exchange.HTTP_URI header is ignored and use the endpoint's URI for request. You may also set the throwExceptionOnFailure to be false to let the AhcProducer send all the fault response back.
| bufferSize | producer | 4096 | int | The initial in-memory buffer size used when transferring data between Camel and AHC Client.
| headerFilterStrategy | producer |  | HeaderFilterStrategy | To use a custom HeaderFilterStrategy to filter header to and from Camel message.
| throwExceptionOnFailure | producer | true | boolean | Option to disable throwing the AhcOperationFailedException in case of failed responses from the remote server. This allows you to get all responses regardless of the HTTP status code.
| transferException | producer | false | boolean | If enabled and an Exchange failed processing on the consumer side and if the caused Exception was send back serialized in the response as a application/x-java-serialized-object content type (for example using Jetty or Servlet Camel components). On the producer side the exception will be deserialized and thrown as is instead of the AhcOperationFailedException. The caused exception is required to be serialized. This is by default turned off. If you enable this then be aware that Java will deserialize the incoming data from the request to Java and that can be a potential security risk.
| clientConfig | advanced |  | AsyncHttpClientConfig | To configure the AsyncHttpClient to use a custom com.ning.http.client.AsyncHttpClientConfig instance.
| clientConfigOptions | advanced |  | Map | To configure the AsyncHttpClientConfig using the key/values from the Map.
| exchangePattern | advanced | InOnly | ExchangePattern | Sets the default exchange pattern when creating an exchange
| synchronous | advanced | false | boolean | Sets whether synchronous processing should be strictly used or Camel is allowed to use asynchronous processing (if supported).
| sslContextParameters | security |  | SSLContextParameters | Reference to a org.apache.camel.util.jsse.SSLContextParameters in the Registry. This reference overrides any configured SSLContextParameters at the component level. See Using the JSSE Configuration Utility. Note that configuring this option will override any SSL/TLS configuration options provided through the clientConfig option at the endpoint or component level.
|=======================================================================
// endpoint options: END






[[AHC-AhcComponentOptions]]
AhcComponent Options
^^^^^^^^^^^^^^^^^^^^







// component options: START
The AHC component supports 6 options which are listed below.



[width="100%",cols="2s,1m,8",options="header"]
|=======================================================================
| Name | Java Type | Description
| client | AsyncHttpClient | To use a custom AsyncHttpClient
| binding | AhcBinding | To use a custom AhcBinding which allows to control how to bind between AHC and Camel.
| clientConfig | AsyncHttpClientConfig | To configure the AsyncHttpClient to use a custom com.ning.http.client.AsyncHttpClientConfig instance.
| sslContextParameters | SSLContextParameters | Reference to a org.apache.camel.util.jsse.SSLContextParameters in the Registry. Note that configuring this option will override any SSL/TLS configuration options provided through the clientConfig option at the endpoint or component level.
| allowJavaSerializedObject | boolean | Whether to allow java serialization when a request uses context-type=application/x-java-serialized-object This is by default turned off. If you enable this then be aware that Java will deserialize the incoming data from the request to Java and that can be a potential security risk.
| headerFilterStrategy | HeaderFilterStrategy | To use a custom HeaderFilterStrategy to filter header to and from Camel message.
|=======================================================================
// component options: END







Notice that setting any of the options on the `AhcComponent` will
propagate those options to
`AhcEndpoints` being created. However the `AhcEndpoint` can also
configure/override a custom option. Options set on endpoints will always
take precedence over options from the `AhcComponent`.

[[AHC-MessageHeaders]]
Message Headers
^^^^^^^^^^^^^^^

[width="100%",cols="10%,10%,80%",options="header",]
|=======================================================================
|Name |Type |Description
|`Exchange.HTTP_URI` |`String` |URI to call. Will override existing URI set directly on the endpoint.

|`Exchange.HTTP_PATH` |`String` |Request URI's path, the header will be used to build the request URI
with the HTTP_URI. If the path is start with "/", http producer will try
to find the relative path based on the Exchange.HTTP_BASE_URI header or
the `exchange.getFromEndpoint().getEndpointUri();`

|`Exchange.HTTP_QUERY` |`String` |*Camel 2.11 onwards:* URI parameters. Will override existing URI
parameters set directly on the endpoint.

|`Exchange.HTTP_RESPONSE_CODE` |`int` |The HTTP response code from the external server. Is 200 for OK.

|`Exchange.HTTP_CHARACTER_ENCODING` |`String` |Character encoding.

|`Exchange.CONTENT_TYPE` |`String` |The HTTP content type. Is set on both the IN and OUT message to provide
a content type, such as `text/html`.

|`Exchange.CONTENT_ENCODING` |`String` |The HTTP content encoding. Is set on both the IN and OUT message to
provide a content encoding, such as `gzip`.
|=======================================================================

[[AHC-MessageBody]]
Message Body
^^^^^^^^^^^^

Camel will store the HTTP response from the external server on the OUT
body. All headers from the IN message will be copied to the OUT message,
so headers are preserved during routing. Additionally Camel will add the
HTTP response headers as well to the OUT message headers.

[[AHC-Responsecode]]
Response code
^^^^^^^^^^^^^

Camel will handle according to the HTTP response code:

* Response code is in the range 100..299, Camel regards it as a success
response.
* Response code is in the range 300..399, Camel regards it as a
redirection response and will throw a `AhcOperationFailedException` with
the information.
* Response code is 400+, Camel regards it as an external server failure
and will throw a `AhcOperationFailedException` with the information.
+
throwExceptionOnFailure
+
The option, `throwExceptionOnFailure`, can be set to `false` to prevent
the `AhcOperationFailedException` from being thrown for failed response
codes. This allows you to get any response from the remote server.

[[AHC-AhcOperationFailedException]]
AhcOperationFailedException
^^^^^^^^^^^^^^^^^^^^^^^^^^^

This exception contains the following information:

* The HTTP status code
* The HTTP status line (text of the status code)
* Redirect location, if server returned a redirect
* Response body as a `java.lang.String`, if server provided a body as
response

[[AHC-CallingusingGETorPOST]]
Calling using GET or POST
^^^^^^^^^^^^^^^^^^^^^^^^^

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` if 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.

[[AHC-ConfiguringURItocall]]
Configuring URI to call
^^^^^^^^^^^^^^^^^^^^^^^

You can set the HTTP producer's URI directly form the endpoint URI. In
the route below, Camel will call out to the external server, `oldhost`,
using HTTP.

[source,java]
----------------------------------
from("direct:start")
        .to("ahc:http://oldhost");
----------------------------------

And the equivalent Spring sample:

[source,xml]
---------------------------------------------------------------------
<camelContext xmlns="http://activemq.apache.org/camel/schema/spring">
  <route>
    <from uri="direct:start"/>
    <to uri="ahc:http://oldhost"/>
  </route>
</camelContext>
---------------------------------------------------------------------

You can override the HTTP endpoint URI by adding a header with the key,
`Exchange.HTTP_URI`, on the message.

[source,java]
-------------------------------------------------------------
from("direct:start")
    .setHeader(Exchange.HTTP_URI, constant("http://newhost"))
    .to("ahc:http://oldhost");
-------------------------------------------------------------

[[AHC-ConfiguringURIParameters]]
Configuring URI Parameters
^^^^^^^^^^^^^^^^^^^^^^^^^^

The *ahc* 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 `Exchange.HTTP_QUERY` on the message.

[source,java]
---------------------------------------------------------
from("direct:start")
        .to("ahc:http://oldhost?order=123&detail=short");
---------------------------------------------------------

Or options provided in a header:

[source,java]
-------------------------------------------------------------------------------
from("direct:start")
            .setHeader(Exchange.HTTP_QUERY, constant("order=123&detail=short"))
        .to("ahc:http://oldhost");
-------------------------------------------------------------------------------

[[AHC-HowtosetthehttpmethodtotheHTTPproducer]]
How to set the http method 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;

[source,java]
--------------------------------------------------------------
from("direct:start")
            .setHeader(Exchange.HTTP_METHOD, constant("POST"))
        .to("ahc:http://www.google.com")
            .to("mock:results");
--------------------------------------------------------------

And the equivalent Spring sample:

[source,xml]
---------------------------------------------------------------------
<camelContext xmlns="http://activemq.apache.org/camel/schema/spring">
  <route>
    <from uri="direct:start"/>
    <setHeader headerName="CamelHttpMethod">
        <constant>POST</constant>
    </setHeader>
    <to uri="ahc:http://www.google.com"/>
    <to uri="mock:results"/>
  </route>
</camelContext>
---------------------------------------------------------------------

[[AHC-Configuringcharset]]
Configuring charset
^^^^^^^^^^^^^^^^^^^

If you are using `POST` to send data you can configure the `charset`
using the `Exchange` property:

[source,java]
----------------------------------------------------------
exchange.setProperty(Exchange.CHARSET_NAME, "iso-8859-1");
----------------------------------------------------------

[[AHC-URIParametersfromtheendpointURI]]
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 `&` character as separator, just as you would in the
web browser. Camel does no tricks here.

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

[[AHC-URIParametersfromtheMessage]]
URI Parameters from the Message
+++++++++++++++++++++++++++++++

[source,java]
---------------------------------------------------------------------
Map headers = new HashMap();
headers.put(Exchange.HTTP_QUERY, "q=Camel&lr=lang_en");
// we query for Camel and English language at Google
template.sendBody("ahc: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.

[[AHC-GettingtheResponseCode]]
Getting the Response Code
+++++++++++++++++++++++++

You can get the HTTP response code from the AHC component by getting the
value from the Out message header with `Exchange.HTTP_RESPONSE_CODE`.

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

[[AHC-ConfiguringAsyncHttpClient]]
Configuring AsyncHttpClient
^^^^^^^^^^^^^^^^^^^^^^^^^^^

The `AsyncHttpClient` client uses a `AsyncHttpClientConfig` to configure
the client. See the documentation at +
 http://github.com/sonatype/async-http-client[Async Http Client] for
more details.

In Camel *2.8*, configuration is limited to using the builder pattern
provided by `AsyncHttpClientConfig.Builder`. In Camel 2.8, the
`AsyncHttpClientConfig` doesn't support getters/setters so its not easy
to create/configure using a Spring bean style (eg the <bean> tag in the
XML file).

The example below shows how to use a builder to create the
`AsyncHttpClientConfig` which we configure on the `AhcComponent`.

In Camel *2.9*, the AHC component uses Async HTTP library 1.6.4. This
newer version provides added support for plain bean style configuration.
The `AsyncHttpClientConfigBean` class provides getters and setters for
the configuration options available in `AsyncHttpClientConfig`. An
instance of `AsyncHttpClientConfigBean` may be passed directly to the
AHC component or referenced in an endpoint URI using the `clientConfig`
URI parameter.

Also available in Camel *2.9* is the ability to set configuration
options directly in the URI. URI parameters starting with
"clientConfig." can be used to set the various configurable properties
of `AsyncHttpClientConfig`. The properties specified in the endpoint URI
are merged with those specified in the configuration referenced by the
"clientConfig" URI parameter with those being set using the
"clientConfig." parameter taking priority. The `AsyncHttpClientConfig`
instance referenced is always copied for each endpoint such that
settings on one endpoint will remain independent of settings on any
previously created endpoints. The example below shows how to configure
the AHC component using the "clientConfig." type URI parameters.

[source,java]
---------------------------------------------------------------------------------------------------------
from("direct:start")
    .to("ahc:http://localhost:8080/foo?clientConfig.maxRequestRetry=3&clientConfig.followRedirects=true")
---------------------------------------------------------------------------------------------------------

[[AHC-SSLSupport]]
SSL Support (HTTPS)
^^^^^^^^^^^^^^^^^^^

[[AHC-UsingtheJSSEConfigurationUtility]]
Using the JSSE Configuration Utility

As of Camel 2.9, the AHC component supports SSL/TLS configuration
through the link:camel-configuration-utilities.html[Camel JSSE
Configuration Utility].  This utility greatly decreases the amount of
component specific code you need to write and is configurable at the
endpoint and component levels.  The following examples demonstrate how
to use the utility with the AHC component.

[[AHC-Programmaticconfigurationofthecomponent]]
Programmatic configuration of the component

[source,java]
-------------------------------------------------------------------------
KeyStoreParameters ksp = new KeyStoreParameters();
ksp.setResource("/users/home/server/keystore.jks");
ksp.setPassword("keystorePassword");

KeyManagersParameters kmp = new KeyManagersParameters();
kmp.setKeyStore(ksp);
kmp.setKeyPassword("keyPassword");

SSLContextParameters scp = new SSLContextParameters();
scp.setKeyManagers(kmp);

AhcComponent component = context.getComponent("ahc", AhcComponent.class);
component.setSslContextParameters(scp));
-------------------------------------------------------------------------

[[AHC-SpringDSLbasedconfigurationofendpoint]]
Spring DSL based configuration of endpoint

[source,xml]
----------------------------------------------------------------------------------
...
  <camel:sslContextParameters
      id="sslContextParameters">
    <camel:keyManagers
        keyPassword="keyPassword">
      <camel:keyStore
          resource="/users/home/server/keystore.jks"
          password="keystorePassword"/>
    </camel:keyManagers>
  </camel:sslContextParameters>...
...
  <to uri="ahc:https://localhost/foo?sslContextParameters=#sslContextParameters"/>
...
----------------------------------------------------------------------------------

[[AHC-SeeAlso]]
See Also
^^^^^^^^

* link:configuring-camel.html[Configuring Camel]
* link:component.html[Component]
* link:endpoint.html[Endpoint]
* link:getting-started.html[Getting Started]

* link:jetty.html[Jetty]
* link:http.html[HTTP]
* link:http4.html[HTTP4]

