HTTP Component
The http: component provides HTTP based endpoints for consuming 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, you can use the Jetty Component
HttpEndpoint Options
Name |
Default Value |
Description |
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Camel 2.0: Option to disable throwing the |
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Camel 2.1: 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 throwExcpetionOnFailure to be false to let the HttpProducer send all the fault response back. |
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Reference to a |
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Camel 2.3: Reference to a |
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Reference to a |
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Camel 2.3: Reference to a |
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Setting options on the HttpClientParams. For instance |
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Camel 2.3: To use a custom |
Camel 2.2 or older: Setting Authentication and Proxy
Name |
Default Value |
Description |
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Username for authentication. |
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Password for authentication. |
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Camel 2.1: Domain for NTML Authentication. This option must be used to force NTML authentication. |
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Camel 1.6.2: The proxy host name |
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Camel 1.6.2: The proxy port number |
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Camel 1.6.2: Username for proxy authentication |
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Camel 1.6.2: Password for proxy authentication |
Camel 2.3 or newer: Setting Authentication and Proxy
Name |
Default Value |
Description |
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Authentication method, either as |
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Username for authentication |
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Password for authentication |
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Domain for NTML authentication |
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Optional host for NTML authentication |
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The proxy host name |
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The proxy port number |
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Authentication method for proxy, either as |
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Username for proxy authentication |
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Password for proxy authentication |
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Domain for proxy NTML authentication |
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Optional host for proxy NTML authentication |
When using authentication you must provide the choice of method for 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
will take precedence over HttpComponent
. Its most likely best to configure this on the HttpComponent
which allows you to do this once.
HttpComponent Options
Name |
Default Value |
Description |
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To use a custom |
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To use a custom |
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To use a custom |
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Camel 2.3: To use a custom |
Notice that in Camel 2.3 the options on org.apache.camel.component.http.HttpConfiguration
is all provided as delegates on HttpComponent
so you easily can configure proxy and authentication details.
Message Headers
Camel 1.x
Name |
Type |
Description |
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Camel 1.6.0: URI to call. Will override existing URI set directly on the endpoint. Is set on the In message. |
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The HTTP response code from the external server. Is 200 for OK. Is set on the Out message. |
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URI parameters. Will override existing URI parameters set directly on the endpoint. Is set on the In message. |
Camel 2.x
Name |
Type |
Description |
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URI to call. Will override existing URI set directly on the endpoint. |
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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(); |
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URI parameters. Will override existing URI parameters set directly on the endpoint. |
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The HTTP response code from the external server. Is 200 for OK. |
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Character encoding. |
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The HTTP content type. Is set on both the IN and OUT message to provide a content type, such as |
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The HTTP content encoding. Is set on both the IN and OUT message to provide a content encoding, such as |
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Camel 2.3: The |
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Camel 2.3: The |
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
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 tofalse
to prevent theHttpOperationFailedException
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.
HttpOperationFailedException
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.io.InputStream
, if server provided a body as response
Calling using GET or POST
In Camel 1.5 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.
How to get access to HttpServletRequest and HttpServletResponse
Available as of Camel 2.0
You can get access to these two using the Camel type converter system using
NOTE from Camel 2.3.0 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>
In Camel 1.5.1 you can override the HTTP endpoint URI by adding a header with the key, HttpProducer.HTTP_URI
, on the message.
from("direct:start") .setHeader(org.apache.camel.component.http.HttpProducer.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.
And the same code in Camel 2.0:
from("direct:start") .setHeader(HttpConstants.HTTP_URI, constant("http://newhost")) .to("http://oldhost");
Where Constants is the class, org.apache.camel.component.http.Constants
.
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 HttpProducer.QUERY
on the message.
from("direct:start") .to("http://oldhost?order=123&detail=short");
Or options provided in a header:
from("direct:start") .setHeader(HttpConstants.HTTP_QUERY, constant("order=123&detail=short")) .to("http://oldhost");
How to set the http method (GET/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;
Camel 1.x
from("direct:start") .setHeader(HttpConstants.HTTP_METHOD, constant(org.apache.camel.component.http.HttpMethods.POST)) .to("http://www.google.com") .to("mock:results");
Camel 2.x
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 headerName="CamelHttpMethod"> <constant>POST</constant> </setHeader> <to uri="http://www.google.com"/> <to uri="mock:results"/> </route> </camelContext>
Using client tineout - SO_TIMEOUT
See the unit test in this link
Configuring a Proxy
Only for >= Camel 1.6.2
The HTTP component provides a way to configure a proxy.
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.
Using proxy settings outside of URI
*Only for >= Camel 1.6.2 and < Camel 2.2.0 *
The HTTP component will detect Java System Properties for http.proxyHost
and http.proxyPort
and use them if provided.
See more at SUN http proxy documentation.
To avoid the System properties conflicts, from Camel 2.2.0 you can only set the proxy configure from CameContext 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.
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
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");
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(HttpProducer.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 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(HttpProducer.QUERY, constant("hl=en&q=activemq")); } }); Message out = exchange.getOut(); int responseCode = out.getHeader(HttpProducer.HTTP_RESPONSE_CODE, Integer.class);
Using throwExceptionOnFailure=false
to get any response back
Available as of Camel 2.0
In 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.
Disabling Cookies
To disable cookies you can set the HTTP Client to ignore cookies by adding this URI option:
httpClient.cookiePolicy=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 MaxConnectionsPerHost
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.
And then we can just use it as we normally do in our routes:
Using HTTPS to authenticate gotchas
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
Accepting self signed certifications from remote server
See this link from a mailing list discussion with some code to outline how to do this with the Apache Commons HTTP API.
Setting up SSL for HTTP Client
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.