HTTP — provides endpoints for consuming external HTTP resources
The HTTP component provides HTTP based endpoints for consuming external HTTP resources as a client to call external servers using HTTP.
The HTTP component can only send messages to external resources. It should never be used as input into a route. To expose an HTTP endpoint via a HTTP server as input to a route, you can use the Jetty Component.
The URI format for an HTTP endpoint is:
http:hostname[:port][/resourceUri][?param1=value1][¶m2=value2]
By default the port is set to 80
for HTTP and to 443
for
HTTPS.
![]() | Important |
---|---|
You can produce only 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, you can use the Jetty Component or the Servlet component. |
Maven users will need to add a dependency on camel-http
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>
Call the url with the body using POST and return response as out message. If body is null call URL using GET and return response as out message
Java DSL | Spring DSL |
---|---|
from("direct:start") .to("http://myhost/mypath"); |
<from uri="direct:start"/> <to uri="http://oldhost"/> |
You can override the HTTP endpoint URI by adding a header. Camel will call the http://newhost. This is very handy for e.g. REST urls.
Java DSL |
---|
from("direct:start") .setHeader(Exchange.HTTP_URI, simple("http://myserver/orders/${header.orderId}")) .to("http://dummyhost"); |
URI parameters can either be set directly on the endpoint URI or as a header
Java DSL |
---|
from("direct:start") .to("http://oldhost?order=123&detail=short"); from("direct:start") .setHeader(Exchange.HTTP_QUERY, constant("order=123&detail=short")) .to("http://oldhost"); |
Set the HTTP request method to POST
Java DSL | Spring DSL |
---|---|
from("direct:start") .setHeader(Exchange.HTTP_METHOD, constant("POST")) .to("http://www.google.com"); |
<from uri="direct:start"/> <setHeader headerName="CamelHttpMethod"> <constant>POST</constant> </setHeader> <to uri="http://www.google.com"/> <to uri="mock:results"/> |
Table 23, “HTTP endpoint options” lists the options for an HTTP endpoint.
Table 23. HTTP endpoint options
Name | Default | Description |
---|---|---|
throwExceptionOnFailure
|
true
| 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. |
bridgeEndpoint
|
false
|
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 throwExceptionOnFailure to be false to let the HttpProducer send all the fault response back. Camel 2.3: If the option is true, HttpProducer and CamelServlet will skip the gzip processing if the content-encoding is "gzip". |
disableStreamCache
|
false
| DefaultHttpBinding will copy the request input stream into a stream cache and put it into message body if this option is false to support read it twice, otherwise DefaultHttpBinding will set the request input stream direct into the message body. |
httpBindingRef
|
null
|
Deprecated and will be removed in Camel
3.0: Reference to a
org.apache.camel.component.http.HttpBinding in
the Registry. Use the
httpBinding option instead. |
httpBinding
|
null
| Reference to a
org.apache.camel.component.http.HttpBinding in
the Registry. |
httpClientConfigurerRef
|
null
|
Deprecated and will be removed in Camel
3.0: Reference to a
org.apache.camel.component.http.HttpClientConfigurer
in the Registry. Use the
httpClientConfigurer option instead. |
httpClientConfigurer
|
null
| Reference to a
org.apache.camel.component.http.HttpClientConfigurer
in the Registry. |
httpClient.XXX
|
null
| Setting options on the HttpClientParams. For instance
httpClient.soTimeout=5000 will set the
SO_TIMEOUT to 5 seconds. |
clientConnectionManager
|
null
| To use a custom
org.apache.http.conn.ClientConnectionManager .
|
transferException
|
false
| Camel 2.6: 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 HttpOperationFailedException . The
caused exception is required to be serialized. |
headerFilterStrategy
|
null
| Camel 2.11: Reference to a instance
of org.apache.camel.spi.HeaderFilterStrategy in the
Registry. It will be used to apply
the custom headerFilterStrategy on the new create HttpEndpoint. |
urlRewrite
|
null
| Camel 2.11:Producer only 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 UrlRewrite and
How to use Camel as a HTTP proxy between a client and
server. |
The following authentication options can also be set on the HTTP endpoint:
Table 24. HTTP authentication options
Name | Description |
---|---|
authMethod
|
Specifies the authentication method to use. Supported methods are:
|
authMethodPriority
| Specifies the priority of the authentication methods using a comma seperated list. |
authUsername
| Specifies the username for authentication. |
authPassword
| Specifies the password for authentication. |
authDomain
| Specifies the domain for NTML authentication. |
authHost
| Specifies an optional host for NTML authentication. |
proxyHost
| Specifies the proxy host name. |
proxyPort
| Specifies the proxy port number. |
proxyAuthMethod
|
Specifies the authentication method to use for connecting to the proxy. Supported methods are:
|
proxyAuthUsername
| Specifies the username for proxy authentication. |
proxyAuthPassword
| Specifies the password for proxy authentication. |
proxyAuthDomain
| Specifies the domain for proxy NTML authentication. |
proxyAuthHost
| Specifies the optional host for proxy NTML authentication. |
When using authentication you must provide a value for either the
authMethod
or authProxyMethod
options. You can
configure the proxy and authentication details on either the
HttpComponent
or the HttpEndoint
. Values
provided on the HttpEndpoint
take precedence over
HttpComponent
. It's probably best to configure this on the
HttpComponent
, which allows you to do it just once.
The HTTP component uses convention over
configuration, which means that, if you have not explicitly set an
authMethodPriority
, it will fallback to using the select(ed)
authMethod
as priority as well. So, if you use
authMethod.Basic
, the auhtMethodPriority
will
be Basic
too.
Table 25. HTTP component options
Name | Default | Description |
---|---|---|
httpBinding
|
null
| To use a custom
org.apache.camel.component.http.HttpBinding .
|
httpClientConfigurer
|
null
| To use a custom
org.apache.camel.component.http.HttpClientConfigurer .
|
httpConnectionManager
|
null
| To use a custom
org.apache.commons.httpclient.HttpConnectionManager .
|
httpConfiguration
|
null
| To use a custom
org.apache.camel.component.http.HttpConfiguration
|
The following Exchange
properties are recognized by HTTP
endpoints:
Table 26. HTTP Exchange properties
Name | Type | Description |
---|---|---|
Exchange.HTTP_URI
|
String
| URI to call. Will override existing URI set directly on the endpoint. |
Exchange.HTTP_METHOD
|
String
| HTTP Method / Verb to use (GET/POST/PUT/DELETE/HEAD/OPTIONS/TRACE) |
Exchange.HTTP_PATH
|
String
| Request URI's path, the header will be used to build the request URI with the HTTP_URI. Camel 2.3.0: 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
| 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 . |
Exchange.HTTP_SERVLET_REQUEST
|
HttpServletRequest
| The HttpServletRequest object. |
Exchange.HTTP_SERVLET_RESPONSE
|
HttpServletResponse
| The HttpServletResponse object. |
Exchange.HTTP_PROTOCOL_VERSION
|
String
| Camel 2.5: You can set the http protocol version with this header, eg. "HTTP/1.0". If you didn't specify the header, HttpProducer will use the default value "HTTP/1.1" |
Apache 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, Apache Camel will add the HTTP response headers as well to the OUT message headers.
Apache Camel will handle according to the HTTP response code:
Response code is in the range 100..299, Apache Camel regards it as a success response.
Response code is in the range 300..399, Apache Camel regards it as a
redirection response and will throw a
HttpOperationFailedException
with the information.
Response code is 400+, Apache Camel regards it as an external server failure
and will throw a HttpOperationFailedException
with the information. 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.
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
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.
You can get access to these two using the Camel type converter system using
HttpServletRequest request = exchange.getIn().getBody(HttpServletRequest.class); HttpServletRequest response = exchange.getIn().getBody(HttpServletResponse.class);
Java DSL |
---|
from("direct:start") .to("http://oldhost?proxyHost=www.myproxy.com&proxyPort=80"); |
There is also support for proxy authentication via the
proxyUsername
and proxyPassword
options.
Java DSL |
---|
context.getProperties().put("http.proxyHost", "172.168.18.9"); context.getProperties().put("http.proxyPort" "8080"); |
Spring DSL |
---|
<camelContext> <properties> <property key="http.proxyHost" value="172.168.18.9"/> <property key="http.proxyPort" value="8080"/> </properties> </camelContext> |
Options on Endpoint will override options on the context.
If you are using POST
to send data you can configure the
charset
setProperty(Exchange.CHARSET_NAME, "iso-8859-1");
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");
You can get the HTTP response code from the HTTP component by getting the value from
the 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(Exchange.HTTP_QUERY, constant("hl=en&q=activemq")); } }); Message out = exchange.getOut(); int responseCode = out.getHeader(HttpProducer.HTTP_RESPONSE_CODE, Integer.class);
throwExceptionOnFailure=false
to get any response
backIn the route below we want to route a message that we enrich with data returned from a
remote HTTP call. As we want any response from the remote server, we set the
throwExceptionOnFailure
option to false
so we
get any response in the AggregationStrategy
. As the code is based on
a unit test that simulates a HTTP status code 404, there is some assertion code
etc.
// We set throwExceptionOnFailure to false to let Camel return any response from the remove HTTP server without thrown // HttpOperationFailedException in case of failures. // This allows us to handle all responses in the aggregation strategy where we can check the HTTP response code // and decide what to do. As this is based on an unit test we assert the code is 404 from("direct:start").enrich("http://localhost:{{port}}/myserver?throwExceptionOnFailure=false&user=Camel", new AggregationStrategy() { public Exchange aggregate(Exchange original, Exchange resource) { // get the response code Integer code = resource.getIn().getHeader(Exchange.HTTP_RESPONSE_CODE, Integer.class); assertEquals(404, code.intValue()); return resource; } }).to("mock:result"); // this is our jetty server where we simulate the 404 from("jetty://http://localhost:{{port}}/myserver") .process(new Processor() { public void process(Exchange exchange) throws Exception { exchange.getOut().setBody("Page not found"); exchange.getOut().setHeader(Exchange.HTTP_RESPONSE_CODE, 404); } });
To disable cookies you can set the HTTP Client to ignore cookies by adding this URI
option: httpClient.cookiePolicy=ignoreCookies
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.
The HTTP Component has a
org.apache.commons.httpclient.HttpConnectionManager
where you can
configure various global configuration for the given component. By global, we mean that
any endpoint the component creates has the same shared
HttpConnectionManager
. So, if we want to set a different value
for the max connection per host, we need to define it on the HTTP component and
not on the endpoint URI that we usually use. So
here comes:
First, we define the http
component in Spring XML. Yes, we use the
same scheme name, http
, because otherwise Camel will auto-discover
and create the component with default settings. What we need is to overrule this so we
can set our options. In the sample below we set the max connection to 5 instead of the
default of 2.
<bean id="http" class="org.apache.camel.component.http.HttpComponent"> <property name="camelContext" ref="camel"/> <property name="httpConnectionManager" ref="myHttpConnectionManager"/> </bean> <bean id="myHttpConnectionManager" class="org.apache.commons.httpclient.MultiThreadedHttpConnectionManager"> <property name="params" ref="myHttpConnectionManagerParams"/> </bean> <bean id="myHttpConnectionManagerParams" class="org.apache.commons.httpclient.params.HttpConnectionManagerParams"> <property name="defaultMaxConnectionsPerHost" value="5"/> </bean>
And then we can just use it as we normally do in our routes:
<camelContext id="camel" xmlns="http://camel.apache.org/schema/spring" trace="true"> <route> <from uri="direct:start"/> <to uri="http://www.google.com"/> <to uri="mock:result"/> </route> </camelContext>
An end user reported that he had problem with authenticating with HTTPS. The problem
was eventually resolved when he discovered the HTTPS server did not return a HTTP code
401 Authorization Required. The solution was to set the following URI option:
httpClient.authenticationPreemptive=true
See this link from a mailing list discussion with some code to outline how to do this with the Apache Commons HTTP API.
As of Camel 2.8, the HTTP4 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 HTTP4 component.
The version of the Apache HTTP client used in this component resolves SSL/TLS
information from a global "protocol" registry. This component provides an
implementation,
org.apache.camel.component.http.SSLContextParametersSecureProtocolSocketFactory
,
of the HTTP client's protocol socket factory in order to support the use of the Camel
JSSE Configuration utility. The following example demonstrates how to configure the
protocol registry and use the registered protocol information in a route.
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); ProtocolSocketFactory factory = new SSLContextParametersSecureProtocolSocketFactory(scp); Protocol.registerProtocol("https", new Protocol( "https", factory, 443)); from("direct:start") .to("https://mail.google.com/mail/").to("mock:results");
Basically camel-http component is built on the top of Apache HTTP client, and you can
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:
Protocol authhttps = new Protocol("https", new AuthSSLProtocolSocketFactory( new URL("file:my.keystore"), "mypassword", new URL("file:my.truststore"), "mypassword"), 443); Protocol.registerProtocol("https", authhttps);
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="https://myhostname.com:443/myURL?httpClientConfigurerRef=myHttpClientConfigurer"/>
As long as you implement the HttpClientConfigurer and configure your keystore and truststore as described above, it will work fine.
Jetty