HTTP

Since Camel 1.0

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:

<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.

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

camel-http vs camel-jetty

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

Http Component Options

The HTTP component supports 8 options, which are listed below.

Name Description Default Type

httpClientConfigurer (advanced)

To use the custom HttpClientConfigurer to perform configuration of the HttpClient that will be used.

HttpClientConfigurer

httpConnectionManager (advanced)

To use a custom HttpConnectionManager to manage connections

HttpConnectionManager

httpBinding (producer)

To use a custom HttpBinding to control the mapping between Camel message and HttpClient.

HttpBinding

httpConfiguration (producer)

To use the shared HttpConfiguration as base configuration.

HttpConfiguration

allowJavaSerialized Object (producer)

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

useGlobalSslContext Parameters (security)

Enable usage of global SSL context parameters.

false

boolean

headerFilterStrategy (filter)

To use a custom org.apache.camel.spi.HeaderFilterStrategy to filter header to and from Camel message.

HeaderFilterStrategy

resolveProperty Placeholders (advanced)

Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders.

true

boolean

The HTTP endpoint is configured using URI syntax:

http:httpUri

with the following path and query parameters:

Path Parameters (1 parameters):

Name Description Default Type

httpUri

Required The url of the HTTP endpoint to call.

URI

Query Parameters (38 parameters):

Name Description Default Type

disableStreamCache (common)

Determines whether or not the raw input stream from Servlet is cached or not (Camel will read the stream into a in memory/overflow to file, Stream caching) cache. By default Camel will cache the Servlet input stream to support reading it multiple times to ensure it Camel can retrieve all data from the stream. However you can set this option to true when you for example need to access the raw stream, such as streaming it directly to a file or other persistent store. DefaultHttpBinding will copy the request input stream into a stream cache and put it into message body if this option is false to support reading the stream multiple times. If you use Servlet to bridge/proxy an endpoint then consider enabling this option to improve performance, in case you do not need to read the message payload multiple times. The http/http4 producer will by default cache the response body stream. If setting this option to true, then the producers will not cache the response body stream but use the response stream as-is as the message body.

false

boolean

headerFilterStrategy (common)

To use a custom HeaderFilterStrategy to filter header to and from Camel message.

HeaderFilterStrategy

httpBinding (common)

To use a custom HttpBinding to control the mapping between Camel message and HttpClient.

HttpBinding

bridgeEndpoint (producer)

If the option is true, HttpProducer will ignore the Exchange.HTTP_URI header, and use the endpoint’s URI for request. You may also set the option throwExceptionOnFailure to be false to let the HttpProducer send all the fault response back.

false

boolean

chunked (producer)

If this option is false the Servlet will disable the HTTP streaming and set the content-length header on the response

true

boolean

connectionClose (producer)

Specifies whether a Connection Close header must be added to HTTP Request. By default connectionClose is false.

false

boolean

copyHeaders (producer)

If this option is true then IN exchange headers will be copied to OUT exchange headers according to copy strategy. Setting this to false, allows to only include the headers from the HTTP response (not propagating IN headers).

true

boolean

httpMethod (producer)

Configure the HTTP method to use. The HttpMethod header cannot override this option if set.

HttpMethods

ignoreResponseBody (producer)

If this option is true, The http producer won’t read response body and cache the input stream

false

boolean

preserveHostHeader (producer)

If the option is true, HttpProducer will set the Host header to the value contained in the current exchange Host header, useful in reverse proxy applications where you want the Host header received by the downstream server to reflect the URL called by the upstream client, this allows applications which use the Host header to generate accurate URL’s for a proxied service

false

boolean

throwExceptionOnFailure (producer)

Option to disable throwing the HttpOperationFailedException 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. On the producer side the exception will be deserialized and thrown as is, instead of the HttpOperationFailedException. 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

cookieHandler (producer)

Configure a cookie handler to maintain a HTTP session

CookieHandler

okStatusCodeRange (producer)

The status codes which are considered a success response. The values are inclusive. Multiple ranges can be defined, separated by comma, e.g. 200-204,209,301-304. Each range must be a single number or from-to with the dash included.

200-299

String

urlRewrite (producer)

Deprecated Refers to a custom org.apache.camel.component.http.UrlRewrite which allows you to rewrite urls when you bridge/proxy endpoints. See more details at http://camel.apache.org/urlrewrite.html

UrlRewrite

httpClientConfigurer (advanced)

Register a custom configuration strategy for new HttpClient instances created by producers or consumers such as to configure authentication mechanisms etc

HttpClientConfigurer

httpClientOptions (advanced)

To configure the HttpClient using the key/values from the Map.

Map

httpConnectionManager (advanced)

To use a custom HttpConnectionManager to manage connections

HttpConnectionManager

httpConnectionManager Options (advanced)

To configure the HttpConnectionManager using the key/values from the Map.

Map

mapHttpMessageBody (advanced)

If this option is true then IN exchange Body of the exchange will be mapped to HTTP body. Setting this to false will avoid the HTTP mapping.

true

boolean

mapHttpMessageFormUrl EncodedBody (advanced)

If this option is true then IN exchange Form Encoded body of the exchange will be mapped to HTTP. Setting this to false will avoid the HTTP Form Encoded body mapping.

true

boolean

mapHttpMessageHeaders (advanced)

If this option is true then IN exchange Headers of the exchange will be mapped to HTTP headers. Setting this to false will avoid the HTTP Headers mapping.

true

boolean

synchronous (advanced)

Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported).

false

boolean

proxyAuthDomain (proxy)

Proxy authentication domain to use with NTML

String

proxyAuthHost (proxy)

Proxy authentication host

String

proxyAuthMethod (proxy)

Proxy authentication method to use

String

proxyAuthPassword (proxy)

Proxy authentication password

String

proxyAuthPort (proxy)

Proxy authentication port

int

proxyAuthScheme (proxy)

Proxy authentication scheme to use

String

proxyAuthUsername (proxy)

Proxy authentication username

String

proxyHost (proxy)

Proxy hostname to use

String

proxyPort (proxy)

Proxy port to use

int

authDomain (security)

Authentication domain to use with NTML

String

authHost (security)

Authentication host to use with NTML

String

authMethod (security)

Authentication methods allowed to use as a comma separated list of values Basic, Digest or NTLM.

String

authMethodPriority (security)

Which authentication method to prioritize to use, either as Basic, Digest or NTLM.

String

authPassword (security)

Authentication password

String

authUsername (security)

Authentication username

String

Spring Boot Auto-Configuration

When using Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-http-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 9 options, which are listed below.

Name Description Default Type

camel.component.http.allow-java-serialized-object

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

camel.component.http.enabled

Enable http component

true

Boolean

camel.component.http.header-filter-strategy

To use a custom org.apache.camel.spi.HeaderFilterStrategy to filter header to and from Camel message. The option is a org.apache.camel.spi.HeaderFilterStrategy type.

String

camel.component.http.http-binding

To use a custom HttpBinding to control the mapping between Camel message and HttpClient. The option is a org.apache.camel.http.common.HttpBinding type.

String

camel.component.http.http-client-configurer

To use the custom HttpClientConfigurer to perform configuration of the HttpClient that will be used. The option is a org.apache.camel.component.http.HttpClientConfigurer type.

String

camel.component.http.http-configuration

To use the shared HttpConfiguration as base configuration. The option is a org.apache.camel.http.common.HttpConfiguration type.

String

camel.component.http.http-connection-manager

To use a custom HttpConnectionManager to manage connections. The option is a org.apache.commons.httpclient.HttpConnectionManager type.

String

camel.component.http.resolve-property-placeholders

Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders.

true

Boolean

camel.component.http.use-global-ssl-context-parameters

Enable usage of global SSL context parameters.

false

Boolean

Message Headers

Name Type Description

Exchange.HTTP_URI

String

URI to call. Will override existing URI set directly on the endpoint. This uri is the uri of the http server to call. Its not the same as the Camel endpoint uri, where you can configure endpoint options such as security etc. This header does not support that, its only the uri of the http server.

Exchange.HTTP_PATH

String

Request URI’s path, the header will be used to build the request URI with the HTTP_URI.

Exchange.HTTP_QUERY

String

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_RESPONSE_TEXT

String

The HTTP response text from the external server.

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.

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

  • javax.net.ssl.trustStoreType

  • javax.net.ssl.trustStore

  • javax.net.ssl.trustStoreProvider

  • javax.net.ssl.trustStorePassword

  • java.home

  • ssl.KeyManagerFactory.algorithm

  • javax.net.ssl.keyStoreType

  • javax.net.ssl.keyStore

  • javax.net.ssl.keyStoreProvider

  • 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.

There is a sample below demonstrating this.

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.

How to get access to HttpServletRequest and HttpServletResponse

You can get access to these two using the Camel type converter system using

 *NOTE* You can get the request and response not just from the processor
after the camel-jetty or camel-cxf endpoint.
HttpServletRequest request = exchange.getIn().getBody(HttpServletRequest.class);
HttpServletRequest response = exchange.getIn().getBody(HttpServletResponse.class);

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.

from("direct:start")
        .to("http://oldhost");

And the equivalent Spring sample:

<camelContext xmlns="http://activemq.apache.org/camel/schema/spring">
  <route>
    <from uri="direct:start"/>
    <to uri="http://oldhost"/>
  </route>
</camelContext>

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

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.

from("direct:start")
  .to("http://oldhost?order=123&detail=short");

Or options provided in a header:

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:

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:

.setHeader("CamelHttpMethod", constant("POST"))

And the equivalent Spring sample:

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

Using client timeout - SO_TIMEOUT

See the HttpSOTimeoutTest unit test.

Configuring a Proxy

The HTTP component provides a way to configure a proxy.

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 :
 context.getProperties().put("http.proxyHost", "172.168.18.9");
 context.getProperties().put("http.proxyPort" "8080");

Spring 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:

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:

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.

// 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(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.

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 you can set the HTTP Client to ignore cookies by adding this URI option:

`httpClient.cookieSpec=ignoreCookies`

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

Using the JSSE Configuration Utility

The HTTP component supports SSL/TLS configuration through the 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.

Programmatic configuration of the component

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("https4", HttpComponent.class);
httpComponent.setSslContextParameters(scp);

Spring DSL based configuration of endpoint

...
  <camel:sslContextParameters
      id="sslContextParameters">
    <camel:keyManagers
        keyPassword="keyPassword">
      <camel:keyStore
          resource="/users/home/server/keystore.jks"
          password="keystorePassword"/>
    </camel:keyManagers>
  </camel:sslContextParameters>...
...
  <to uri="https4://127.0.0.1/mail/?sslContextParameters=#sslContextParameters"/>...

Configuring Apache HTTP Client Directly

Basically camel-http component is built on the top of Apache HttpClient. Please refer to SSL/TLS customization 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:

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:

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:

<bean id="myHttpClientConfigurer"
 class="my.https.HttpClientConfigurer">
</bean>

<to uri="https4://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.

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.http.protocol.HttpContext:

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

public class HttpContextFactory {

  private String httpHost = "localhost";
  private String httpPort = 9001;

  private BasicHttpContext httpContext = new BasicHttpContext();
  private BasicAuthCache authCache = new BasicAuthCache();
  private BasicScheme basicAuth = new BasicScheme();

  public HttpContext getObject() {
    authCache.put(new HttpHost(httpHost, httpPort), basicAuth);

    httpContext.setAttribute(ClientContext.AUTH_CACHE, authCache);

    return httpContext;
  }

  // getter and setter
}

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

<bean id="myHttpContext" factory-bean="httpContextFactory" factory-method="getObject"/>

  • 3. Reference the context in the http URL:

<to uri="https4://myhostname.com:443/myURL?httpContext=myHttpContext"/>

Using different SSLContextParameters

The 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 HTTP components as shown below. Where we have 2 components, each using their own instance of sslContextParameters property.

<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>
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