components/camel-http/src/main/docs/http-component.adoc

= HTTP Component
:doctitle: HTTP
:shortname: http
:artifactid: camel-http
:description: Send requests to external HTTP servers using Apache HTTP Client 5.x.
:since: 2.3
:supportlevel: Stable
:tabs-sync-option:
:component-header: Only producer is supported
//Manually maintained attributes
:camel-spring-boot-name: http

*Since Camel {since}*

*{component-header}*

The HTTP component provides HTTP based endpoints
for calling external HTTP resources (as a client to call external
servers using HTTP).

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-http</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>
------------------------------------------------------------

== URI format

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

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


// component-configure options: START

// component-configure options: END

// component options: START
include::partial$component-configure-options.adoc[]
include::partial$component-endpoint-options.adoc[]
// component options: END

// endpoint options: START

// endpoint options: END

// component headers: START
include::partial$component-endpoint-headers.adoc[]
// component headers: END

== 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.

== Using System Properties

When setting useSystemProperties to true, the HTTP Client will look for
the following System Properties, and it will use it:

* ssl.TrustManagerFactory.algorithm
* http://javax.net/[javax.net].ssl.trustStoreType
* http://javax.net/[javax.net].ssl.trustStore
* http://javax.net/[javax.net].ssl.trustStoreProvider
* http://javax.net/[javax.net].ssl.trustStorePassword
* java.home
* ssl.KeyManagerFactory.algorithm
* http://javax.net/[javax.net].ssl.keyStoreType
* http://javax.net/[javax.net].ssl.keyStore
* http://javax.net/[javax.net].ssl.keyStoreProvider
* http://javax.net/[javax.net].ssl.keyStorePassword
* http.proxyHost
* http.proxyPort
* http.nonProxyHosts
* http.keepAlive
* http.maxConnections

== 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 `HttpOperationFailedException`
with the information.
* Response code is 400+, Camel regards it as an external server failure
and will throw a `HttpOperationFailedException` with the information.

*throwExceptionOnFailure*

The option, `throwExceptionOnFailure`, can be set to `false` to prevent
the `HttpOperationFailedException` from being thrown for failed response
codes. This allows you to get any response from the remote server.

== Exceptions

`HttpOperationFailedException` 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

== Which HTTP method will be used

The following algorithm is used to determine what HTTP method should be used: +
 1. Use method provided as endpoint configuration (`httpMethod`). +
 2. Use method provided in header (`Exchange.HTTP_METHOD`). +
 3. `GET` if query string is provided in header. +
 4. `GET` if endpoint is configured with a query string. +
 5. `POST` if there is data to send (body is not `null`). +
 6. `GET` otherwise.

== Configuring URI to call

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

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

And the equivalent XML DSL:

[source,xml]
---------------------------------------------------------------------
<route>
  <from uri="direct:start"/>
  <to uri="http://oldhost"/>
</route>
---------------------------------------------------------------------

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("http://oldhost");
-----------------------------------------------------------

In the sample above Camel will call the http://newhost despite the
endpoint is configured with http://oldhost. +
If the http endpoint is working in bridge mode, it will ignore the
message header of `Exchange.HTTP_URI`.

== Configuring 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 `Exchange.HTTP_QUERY` on the message.

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

== How to set the http method (GET/PATCH/POST/PUT/DELETE/HEAD/OPTIONS/TRACE) 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(org.apache.camel.component.http.HttpMethods.POST))
  .to("http://www.google.com")
  .to("mock:results");
-----------------------------------------------------------------------------------------------

The method can be written a bit shorter using the string constants:

[source,java]
-----------------------------------------------
.setHeader("CamelHttpMethod", constant("POST"))
-----------------------------------------------

And the equivalent XML DSL:

[source,xml]
---------------------------------------------------------------------
<route>
  <from uri="direct:start"/>
  <setHeader name="CamelHttpMethod">
      <constant>POST</constant>
  </setHeader>
  <to uri="http://www.google.com"/>
  <to uri="mock:results"/>
</route>
---------------------------------------------------------------------

== Using client timeout - SO_TIMEOUT

See the
https://github.com/apache/camel/blob/main/components/camel-http/src/test/java/org/apache/camel/component/http/HttpSOTimeoutTest.java[HttpSOTimeoutTest]
unit test.

== Configuring a Proxy

The HTTP component provides a way to configure a proxy.

[source,java]
------------------------------------------------------------------------
from("direct:start")
  .to("http://oldhost?proxyAuthHost=www.myproxy.com&proxyAuthPort=80");
------------------------------------------------------------------------

There is also support for proxy authentication via the
`proxyAuthUsername` and `proxyAuthPassword` options.

=== Using proxy settings outside of URI

To avoid System properties conflicts, you can set proxy configuration
only from the CamelContext or URI. +
 Java DSL :

[source,java]
---------------------------------------------------------------
context.getGlobalOptions().put("http.proxyHost", "172.168.18.9");
context.getGlobalOptions().put("http.proxyPort", "8080");
---------------------------------------------------------------

Spring XML

[source,xml]
----------------------------------------------------------------
<camelContext>
    <properties>
        <property key="http.proxyHost" value="172.168.18.9"/>
        <property key="http.proxyPort" value="8080"/>
   </properties>
</camelContext>
----------------------------------------------------------------

Camel will first set the settings from Java System or CamelContext
Properties and then the endpoint proxy options if provided.
So you can override the system properties with the endpoint options.

There is also a `http.proxyScheme` property you
can set to explicit configure the scheme to use.

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

=== Sample with scheduled poll

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

[source,java]
------------------------------------------------------------
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 `&` 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("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("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 HTTP component by getting
the value from the Out message header with
`Exchange.HTTP_RESPONSE_CODE`.

[source,java]
------------------------------------------------------------------------------------
Exchange exchange = template.send("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);
------------------------------------------------------------------------------------

== Disabling Cookies

To disable cookies in the CookieStore you can set the HTTP Client to ignore cookies by
adding this URI option: `httpClient.cookieSpec=ignore`. This doesn't affect cookies manually set in the `Cookie` header

== Basic auth with the streaming message body

In order to avoid the `NonRepeatableRequestException`, you need to do the
Preemptive Basic Authentication by adding the option: `authenticationPreemptive=true`

== OAuth2 Support

In order to get a access token from a Authorization Server and fill that in Authorization header to do requests to protected services, you will need to use `oauth2ClientId`, `oauth2ClientSecret` and  `oauth2TokenEndpoint` properties, and those should be defined as specified at RFC 6749 and provided by your Authorization Server.

In below example camel will do a underlying request to `https://localhost:8080/realms/master/protocol/openid-connect/token` using provided credentials (client id and client secret), then will get `access_token` from response and lastly will fill it at `Authorization` header of request which will be done to `https://localhost:9090`.

[source,java]
------------------------------------------------------------------------------------
String clientId = "my-client-id";
String clientSecret = "my-client-secret";
String tokenEndpoint = "https://localhost:8080/realms/master/protocol/openid-connect/token";

from("direct:start")
  .to("https://localhost:9090/?oauth2ClientId=" + clientId + "&oauth2ClientSecret=" + clientSecret + "&oauth2TokenEndpoint=" + tokenEndpoint);
------------------------------------------------------------------------------------

NOTE: Camel only provide support for OAuth2 client credentials flow

Important: Camel does not perform any validation in access token. It's up to the underlying service to validate it.

== Advanced Usage

If you need more control over the HTTP producer you should use the
`HttpComponent` where you can set various classes to give you custom
behavior.

=== Setting up SSL for HTTP Client

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

The HTTP 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 HTTP component.

[[HTTP-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);

HttpComponent httpComponent = getContext().getComponent("https", HttpComponent.class);
httpComponent.setSslContextParameters(scp);
---------------------------------------------------------------------------------------

[[HTTP-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="https://127.0.0.1/mail/?sslContextParameters=#sslContextParameters"/>
--------------------------------------------------------------------------------------

[[HTTP-ConfiguringApacheHTTPClientDirectly]]
Configuring Apache HTTP Client Directly

Basically camel-http component is built on the top of
https://hc.apache.org/httpcomponents-client-5.1.x/[Apache HttpClient].
Please refer to
https://hc.apache.org/httpcomponents-client-4.5.x/current/tutorial/html/connmgmt.html[SSL/TLS
customization] (even if the link is referring to an article about version 4, it is still more or less relevant moreover there is no equivalent for version 5) for details or have a look into the
`org.apache.camel.component.http.HttpsServerTestSupport` unit test base
class. +
 You can also implement a custom
`org.apache.camel.component.http.HttpClientConfigurer` to do some
configuration on the http client if you need full control of it.

However, if you _just_ want to specify the keystore and truststore you
can do this with Apache HTTP `HttpClientConfigurer`, for example:

[source,java]
------------------------------------------------------------------------------------------------------
KeyStore keystore = ...;
KeyStore truststore = ...;

SchemeRegistry registry = new SchemeRegistry();
registry.register(new Scheme("https", 443, new SSLSocketFactory(keystore, "mypassword", truststore)));
------------------------------------------------------------------------------------------------------

And then you need to create a class that implements
`HttpClientConfigurer`, and registers https protocol providing a
keystore or truststore per example above. Then, from your camel route
builder class you can hook it up like so:

[source,java]
--------------------------------------------------------------------------------------
HttpComponent httpComponent = getContext().getComponent("http", HttpComponent.class);
httpComponent.setHttpClientConfigurer(new MyHttpClientConfigurer());
--------------------------------------------------------------------------------------

If you are doing this using the Spring DSL, you can specify your
`HttpClientConfigurer` using the URI. For example:

[source,xml]
-----------------------------------------------------------------------------------------
<bean id="myHttpClientConfigurer"
 class="my.https.HttpClientConfigurer">
</bean>

<to uri="https://myhostname.com:443/myURL?httpClientConfigurer=myHttpClientConfigurer"/>
-----------------------------------------------------------------------------------------

As long as you implement the `HttpClientConfigurer` and configure your
keystore and truststore as described above, it will work fine.

[[HTTP-UsingHTTPStoauthenticategotchas]]
Using HTTPS to authenticate gotchas

An end user reported that he had problem with authenticating with HTTPS.
The problem was eventually resolved by providing a custom configured
`org.apache.hc.core5.http.protocol.HttpContext`:

* 1. Create a (Spring) factory for HttpContexts:

[source,java]
------------------------------------------------------------------
public class HttpContextFactory {

  private String httpHost = "localhost";
  private String httpPort = 9001;
  private String user = "some-user";
  private String password = "my-secret";

  private HttpClientContext context = HttpClientContext.create();
  private BasicAuthCache authCache = new BasicAuthCache();
  private BasicScheme basicAuth = new BasicScheme();

  public HttpContext getObject() {
    UsernamePasswordCredentials credentials = new UsernamePasswordCredentials(user, password.toCharArray());
    BasicCredentialsProvider provider = new BasicCredentialsProvider();
    HttpHost host = new HttpHost(httpHost, httpPort);
    provider.setCredentials(host, credentials);

    authCache.put(host, basicAuth);

    httpContext.setAuthCache(authCache);
    httpContext.setCredentialsProvider(provider);

    return httpContext;
  }

  // getter and setter
}
------------------------------------------------------------------

* 2. Declare an` HttpContext` in the Spring application context file:

[source,xml]
---------------------------------------------------------------------------------------
<bean id="myHttpContext" factory-bean="httpContextFactory" factory-method="getObject"/>
---------------------------------------------------------------------------------------

* 3. Reference the context in the http URL:

[source,xml]
-----------------------------------------------------------------------
<to uri="https://myhostname.com:443/myURL?httpContext=myHttpContext"/>
-----------------------------------------------------------------------

[[HTTP-UsingdifferentSSLContextParameters]]
Using different SSLContextParameters

The xref:http-component.adoc[HTTP] component only support one instance of
`org.apache.camel.support.jsse.SSLContextParameters` per component. If you
need to use 2 or more different instances, then you need to setup
multiple xref:http-component.adoc[HTTP] components as shown below. Where we have
2 components, each using their own instance of `sslContextParameters`
property.

[source,xml]
----------------------------------------------------------------------------
<bean id="http-foo" class="org.apache.camel.component.http.HttpComponent">
   <property name="sslContextParameters" ref="sslContextParams1"/>
   <property name="x509HostnameVerifier" ref="hostnameVerifier"/>
</bean>

<bean id="http-bar" class="org.apache.camel.component.http.HttpComponent">
   <property name="sslContextParameters" ref="sslContextParams2"/>
   <property name="x509HostnameVerifier" ref="hostnameVerifier"/>
</bean>
----------------------------------------------------------------------------


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