[[ahc-component]]
= Async HTTP Client (AHC) Component
:docTitle: Async HTTP Client (AHC)
:shortname: ahc
:artifactId: camel-ahc
:description: Call external HTTP services using Async Http Client.
:since: 2.8
:supportLevel: Stable
:component-header: Only producer is supported
//Manually maintained attributes
:camel-spring-boot-name: ahc

*Since Camel {since}*

*{component-header}*

The AHC component provides HTTP based 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>
------------------------------------------------------------

== 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 Endpoint Options







// endpoint options: START
The Async HTTP Client (AHC) endpoint is configured using URI syntax:

----
ahc:httpUri
----

with the following path and query parameters:

=== Path Parameters (1 parameters):


[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *httpUri* | *Required* The URI to use such as \http://hostname:port/path |  | URI
|===


=== Query Parameters (13 parameters):


[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *bridgeEndpoint* (producer) | 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. | false | boolean
| *bufferSize* (producer) | The initial in-memory buffer size used when transferring data between Camel and AHC Client. | 4096 | int
| *connectionClose* (producer) | Define if the Connection Close header has to be added to HTTP Request. This parameter is false by default | false | boolean
| *cookieHandler* (producer) | Configure a cookie handler to maintain a HTTP session |  | CookieHandler
| *headerFilterStrategy* (producer) | To use a custom HeaderFilterStrategy to filter header to and from Camel message. |  | HeaderFilterStrategy
| *lazyStartProducer* (producer) | Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel's routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. | false | boolean
| *throwExceptionOnFailure* (producer) | 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. | true | boolean
| *transferException* (producer) | 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. | false | boolean
| *binding* (advanced) | To use a custom AhcBinding which allows to control how to bind between AHC and Camel. |  | AhcBinding
| *clientConfig* (advanced) | To configure the AsyncHttpClient to use a custom com.ning.http.client.AsyncHttpClientConfig instance. |  | AsyncHttpClientConfig
| *clientConfigOptions* (advanced) | To configure the AsyncHttpClientConfig using the key/values from the Map. |  | Map
| *clientConfigRealmOptions* (security) | To configure the AsyncHttpClientConfig Realm using the key/values from the Map. |  | Map
| *sslContextParameters* (security) | Reference to a org.apache.camel.support.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. |  | SSLContextParameters
|===
// endpoint options: END









== AhcComponent Options









// component options: START
The Async HTTP Client (AHC) component supports 9 options, which are listed below.



[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *lazyStartProducer* (producer) | Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel's routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. | false | boolean
| *allowJavaSerializedObject* (advanced) | 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. | false | boolean
| *autowiredEnabled* (advanced) | Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc. | true | boolean
| *binding* (advanced) | To use a custom AhcBinding which allows to control how to bind between AHC and Camel. |  | AhcBinding
| *client* (advanced) | To use a custom AsyncHttpClient |  | AsyncHttpClient
| *clientConfig* (advanced) | To configure the AsyncHttpClient to use a custom com.ning.http.client.AsyncHttpClientConfig instance. |  | AsyncHttpClientConfig
| *headerFilterStrategy* (filter) | To use a custom org.apache.camel.spi.HeaderFilterStrategy to filter header to and from Camel message. |  | HeaderFilterStrategy
| *sslContextParameters* (security) | Reference to a org.apache.camel.support.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. |  | SSLContextParameters
| *useGlobalSslContextParameters* (security) | Enable usage of global SSL context parameters. | false | boolean
|===
// 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`.

== 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`.
|=======================================================================

== 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.

== 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.

== 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

== 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.

== 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");
-------------------------------------------------------------

== 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");
-------------------------------------------------------------------------------

== 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 name="CamelHttpMethod">
        <constant>POST</constant>
    </setHeader>
    <to uri="ahc:http://www.google.com"/>
    <to uri="mock:results"/>
  </route>
</camelContext>
---------------------------------------------------------------------

== 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");
----------------------------------------------------------

=== 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);
--------------------------------------------------------------------

=== 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.

=== 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);
----------------------------------------------------------------------------------------------

== 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.

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

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.

There 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")
---------------------------------------------------------------------------------------------------------

== SSL Support (HTTPS)

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

The AHC component supports SSL/TLS configuration
through the xref:manual::camel-configuration-utilities.adoc[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"/>
...
----------------------------------------------------------------------------------


include::spring-boot:partial$starter.adoc[]
