REST DSL Component

Since Camel 2.16

Apache Camel offers a REST styled DSL which can be used with Java or XML. The intention is to allow end users to define REST services using a REST style with verbs such as get, post, delete etc.

How it works

The Rest DSL is a facade that builds Rest endpoints as consumers for Camel routes. The actual REST transport is leveraged by using Camel REST components such as Netty HTTP, Servlet, and others that has native REST integration.

Components supporting Rest DSL

The following Camel components supports the Rest DSL. See the bottom of this page for how to integrate a component with the Rest DSL.

Rest DSL with Java

To use the Rest DSL in Java then just do as with regular Camel routes by extending the RouteBuilder and define the routes in the configure method.

A simple REST service can be define as follows, where we use rest() to define the services as shown below:

protected RouteBuilder createRouteBuilder() throws Exception {
    return new RouteBuilder() {
        @Override
        public void configure() throws Exception {
            rest("/say")
                .get("/hello").to("direct:hello")
                .get("/bye").consumes("application/json").to("direct:bye")
                .post("/bye").to("mock:update");

            from("direct:hello")
                .transform().constant("Hello World");
            from("direct:bye")
                .transform().constant("Bye World");
        }
    };
}

This defines a REST service with the following url mappings:

Base Path Uri template Verb Consumes

/say

/hello

get

all

/say

/bye

get

application/json

/say

/bye

post

all

Notice that in the REST service we route directly to a Camel endpoint using the to(). This is because the Rest DSL has a short-hand for routing directly to an endpoint using to(). An alternative is to embed a Camel route directly using route() - there is such an example further below.

Rest DSL with XML

The REST DSL supports the XML DSL also using either Spring or Blueprint. The example above can be define in XML as shown below:

<camelContext xmlns="http://camel.apache.org/schema/spring">
  <rest path="/say">
    <get uri="/hello">
      <to uri="direct:hello"/>
    </get>
    <get uri="/bye" consumes="application/json">
      <to uri="direct:bye"/>
    </get>
    <post uri="/bye">
      <to uri="mock:update"/>
    </post>
  </rest>
  <route>
    <from uri="direct:hello"/>
    <transform>
      <constant>Hello World</constant>
    </transform>
  </route>
  <route>
    <from uri="direct:bye"/>
    <transform>
      <constant>Bye World</constant>
    </transform>
  </route>
</camelContext>

Using base path

The REST DSL allows to define base path to make the DSL a bit more DRY. For example to define a customer path, we can set the base path in rest("/customer") and then provide the uri templates in the verbs, as shown below:

rest("/customers/")
    .get("/{id}").to("direct:customerDetail")
    .get("/{id}/orders").to("direct:customerOrders")
    .post("/neworder").to("direct:customerNewOrder");

And using XML DSL it becomes:

<rest path="/customers/">
  <get uri="/{id}">
    <to uri="direct:customerDetail"/>
  </get>
  <get uri="/{id}/orders">
    <to uri="direct:customerOrders"/>
  </get>
  <post uri="/neworder">
    <to uri="direct:customerNewOrder"/>
  </post>
</rest>
The REST DSL will take care of duplicate path separators when using base path and uri templates. In the example above the rest base path ends with a slash ( / ) and the verb starts with a slash ( / ). But Apache Camel will take care of this and remove the duplicated slash.

It is not required to use both base path and uri templates. You can omit the bast path and define the base path and uri template in the verbs only. The example above can be defined as:

<rest>
  <get uri="/customers/{id}">
    <to uri="direct:customerDetail"/>
  </get>
  <get uri="/customers/{id}/orders">
    <to uri="direct:customerOrders"/>
  </get>
  <post uri="/customers/neworder">
    <to uri="direct:customerNewOrder"/>
  </post>
</rest>
You can combine path parameters to build complex expressions. For example: 
  rest("items/")
      .get("{id}/{filename}.{content-type}")
      .to("direct:item")

Using Dynamic To in Rest DSL

Since Camel 2.16

The Rest DSL supports the new .toD <toD> as dynamic to in the rest-dsl. For example to do a request/reply over JMS where the queue name is dynamic defined

 public void configure() throws Exception {
   rest("/say")
     .get("/hello/{language}").toD("jms:queue:hello-${header.language}");
}

And in XML DSL

<rest uri="/say">
  <get uri="/hello//{language}">
    <toD uri="jms:queue:hello-${header.language}"/>
  </get>
<rest>

See more details at Message Endpoint about the dynamic to, and what syntax it supports. By default it uses the Simple language, but it has more power than so.

Embedding Camel routes

Each of the rest services becomes a Camel route, so in the first example we have 2 x get and 1 x post REST service, which each become a Camel route. And we have 2 regular Camel routes, meaning we have 3 + 2 = 5 routes in total.

There are two route modes with the Rest DSL

  • mini using a singular to

  • embedding a Camel route using route

The first example is using the former with a singular to. And that is why we end up with 3 + 2 = 5 total routes.

The same example could use embedded Camel routes, which is shown below:

protected RouteBuilder createRouteBuilder() throws Exception {
    return new RouteBuilder() {
        @Override
        public void configure() throws Exception {
            rest("/say/hello")
                .get().route().transform().constant("Hello World");
            rest("/say/bye")
                .get().consumes("application/json").route().transform().constant("Bye World").endRest()
                .post().to("mock:update");
    };
}

In the example above, we are embedding routes directly in the rest service using .route(). Notice we need to use .endRest() to tell Camel where the route ends, so we can go back to the Rest DSL and continue defining REST services.

Configuring route options

In the embedded route you can configure the route settings such as routeId, autoStartup and various other options you can set on routes today.

.get()
  .route().routeId("myRestRoute").autoStartup(false)
  .transform().constant("Hello World");

Managing Rest services

Each of the rest services becomes a Camel route, so in the first example we have 2 x get and 1 x post REST service, which each become a Camel route. This makes it the same from Camel to manage and run these services - as they are just Camel routes. This means any tooling and API today that deals with Camel routes, also work with the REST services.

This means you can use JMX to stop/start routes, and also get the JMX metrics about the routes, such as number of message processed, and their performance statistics.

There is also a Rest Registry JMX MBean that contains a registry of all REST services which has been defined.

Binding to POJOs using

The Rest DSL supports automatic binding json/xml contents to/from POJOs using Camels Data Format. By default the binding mode is off, meaning there is no automatic binding happening for incoming and outgoing messages.

You may want to use binding if you develop POJOs that maps to your REST services request and response types. This allows you as a developer to work with the POJOs in Java code.

The binding modes are:

Binding Mode Description

off

Binding is turned off. This is the default option.

auto

Binding is enabled and Camel is relaxed and support json, xml or both if the needed data formats are included in the classpath. Notice that if for example camel-jaxb is not on the classpath, then XML binding is not enabled.

json

Binding to/from json is enabled, and requires a json capabile data format on the classpath. By default Camel will use json-jackson as the data format. See the INFO box below for more details.

xml

Binding to/from xml is enabled, and requires camel-jaxb on the classpath. See the INFO box below for more details.

json_xml

Binding to/from json and xml is enabled and requires both data formats to be on the classpath. See the INFO box below for more details.
From Camel 2.14.1 onwards when using camel-jaxb for xml bindings, then you can use the option mustBeJAXBElement to relax the output message body must be a class with JAXB annotations. You can use this in situations where the message body is already in XML format, and you want to use the message body as-is as the output type. If that is the case, then set the dataFormatProperty option mustBeJAXBElement to false value.
From Camel 2.16.3 onwards the binding from POJO to JSon/JAXB will only happen if the content-type header includes the word json or xml representatively. This allows you to specify a custom content-type if the message body should not attempt to be marshalled using the binding. For example if the message body is a custom binary payload etc.

To use binding you must include the necessary data formats on the classpath, such as camel-jaxb and/or camel-jackson. And then enable the binding mode. You can configure the binding mode globally on the rest configuration, and then override per rest service as well.

To enable binding you configure this in Java DSL as shown below

restConfiguration().component("netty-http").host("localhost").port(portNum).bindingMode(RestBindingMode.auto);

And in XML DSL

<restConfiguration bindingMode="auto" component="netty-http" port="8080"/>

When binding is enabled Camel will bind the incoming and outgoing messages automatic, accordingly to the content type of the message. If the message is json, then json binding happens; and so if the message is xml then xml binding happens. The binding happens for incoming and reply messages. The table below summaries what binding occurs for incoming and reply messages.

Message Body Direction Binding Mode Message Body

XML

Incoming

auto, xml, json_xml

POJO

POJO

Outgoing

auto, xml, json_xml

XML

JSON

Incoming

auto, json, json_xml

POJO

POJO

Outgoing

auto, json, json_xml

JSON

When using binding you must also configure what POJO type to map to. This is mandatory for incoming messages, and optional for outgoing.

For example to map from xml/json to a pojo class UserPojo you do this in Java DSL as shown below:

// configure to use netty-http on localhost with the given port
// and enable auto binding mode
restConfiguration().component("netty-http").host("localhost").port(portNum).bindingMode(RestBindingMode.auto);

// use the rest DSL to define the rest services
rest("/users/")
    .post().type(UserPojo.class)
        .to("direct:newUser");

Notice we use type to define the incoming type. We can optionally define an outgoing type (which can be a good idea, to make it known from the DSL and also for tooling and JMX APIs to know both the incoming and outgoing types of the REST services.). To define the outgoing type, we use outType as shown below:

// configure to use netty-http on localhost with the given port
// and enable auto binding mode
restConfiguration().component("netty-http").host("localhost").port(portNum).bindingMode(RestBindingMode.auto);

// use the rest DSL to define the rest services
rest("/users/")
    .post().type(UserPojo.class).outType(CountryPojo.class)
        .to("direct:newUser");

And in XML DSL

<rest uri="/users/">
  <post type="UserPojo" outType="CountryPojo">
    <to uri="direct:newUser"/>
  </post>
<rest>

To specify input and/or output using an array, append [] to the end of the canonical class name as shown in the following Java DSL:

// configure to use netty-http on localhost with the given port
// and enable auto binding mode
restConfiguration().component("netty-http").host("localhost").port(portNum).bindingMode(RestBindingMode.auto);

// use the rest DSL to define the rest services
rest("/users/")
    .post().type(UserPojo[].class).outType(CountryPojo[].class)
        .to("direct:newUser");

The UserPojo is just a plain pojo with getter/setter as shown:

public class UserPojo {
    private int id;
    private String name;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

The UserPojo only supports json, as XML requires to use JAXB annotations, so we can add those annotations if we want to support XML also

@XmlRootElement(name = "user")
@XmlAccessorType(XmlAccessType.FIELD)
public class UserPojo {
    @XmlAttribute
    private int id;
    @XmlAttribute
    private String name;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

By having the JAXB annotations the POJO supports both json and xml bindings.

Configuring Rest DSL

Option Default Description

component

-

The Camel Rest component to use for the REST transport, such as spark-rest.

If no component has been explicit configured, then Camel will lookup if there is a Camel component that integrates with the Rest DSL, or if a org.apache.camel.spi.RestConsumerFactory is registered in the registry. If either one is found, then that is being used.

apiComponent

-

The Camel component to use as the REST API (such as swagger)

producerComponent

-

The Camel component to use as the REST producer.

producerApiDoc

-

The location of the api document (swagger api) the REST producer will use to validate the REST uri and query parameters are valid accordingly to the api document.

This requires adding camel-swagger-java to the classpath, and any miss configuration will let Camel fail on startup and report the error(s).

The location of the api document is loaded from classpath by default, but you can use file: or \http: to refer to resources to load from file or http url.

scheme

http

The scheme to use for exposing the REST service. Usually http or https is supported

host

-

The hostname to use for exposing the REST service.

useXForwardHeaders

true

Whether to use X-Forwarded-Host (or Host) from incoming HTTP Header to set the hostname

apiHost

-

Specific hostname for the API documentation (eg swagger)

This can be used to override the generated host with this configured hostname

port

-

The port number to use for exposing the REST service.

NOTE: if you use servlet component then the port number configured here does not apply, as the port number in use is the actual port number the servlet component is using, e.g., if using Apache Tomcat its the tomcat HTTP port, if using Apache Karaf it’s the HTTP service in Karaf that uses port 8181 by default etc. Though in those situations setting the port number here, allows tooling and JMX to know the port number, so its recommended to set the port number to the number that the servlet engine uses.`

contextPath

-

Leading context-path the REST services will be using. This can be used when using components such as SERVLET where the deployed web application is deployed using a context-path. Or for components such as camel-jetty or camel-netty-http that includes a HTTP server.

apiContextPath

-

A leading API context-path the REST API services will be using.

This can be used when using components such as camel-servlet where the deployed web application is deployed using a context-path.

apiContextRouteId

-

Route id to use for the route that services the REST API. The route will by default use an auto assigned route id.

apiContextIdPattern

-

Optional CamelContext id pattern to only allow Rest APIs from rest services within CamelContext’s which name matches the pattern.

The pattern #name# refers to the CamelContext name, to match on the current CamelContext only. For any other value, the pattern uses the rules from {@link org.apache.camel.util. EndpointHelper#matchPattern(String, String)}

apiContextListing

-

Sets whether listing of all available CamelContext’s with REST services in the JVM is enabled. If enabled it allows to discover these contexts, if <tt>false</tt> then only the current CamelContext is in use.

apiVendorExtension

-

Whether vendor extension is enabled in the Rest APIs. If enabled then Camel will include additional information as vendor extension (eg keys starting with x-) such as route ids, class names etc.

Not all 3rd party API gateways and tools supports vendor-extensions when importing your API docs.

hostNameResolver

-

From Camel 2.20 If no hostname has been explicit configured, then this resolver is used to compute the hostname the REST service will be using.

The resolver supports:

allLocalIp (from Camel 2.17) localHostName localIp For Camel 2.16.x or older: localHostName

From Camel 2.17: allLocalIp

restHostNameResolver

-

Camel 2.19 and before (now called "hostNameResolver")

bindingMode

off

Whether binding is in use. See further above for more details.

skipBindingOnErrorCode

true

Camel 2.14.1: Whether to skip binding on output if there is a custom HTTP error code header.

This allows to build custom error messages that do not bind to JSON/XML etc, as success messages otherwise will do.

See below for an example.

clientRequestValidation

false

From Camel 2.22 Whether to enable validation of the client request to check whether the Content-Type and Accept headers from the client is supported by the Rest-DSL configuration of its consumes/produces settings.

This can be turned on, to enable this check. In case of validation error, then HTTP Status codes 415 or 406 is returned.

enableCORS

false

Camel 2.14.1: Whether to enable CORS headers in the HTTP response.

jsonDataFormat

-

Name of specific JSON data format to use. By default json-jackson will be used.

Important: This option is only for setting a custom name of the data format, not to refer to an existing data format instance.

Note: Currently Jackson is what we recommend and are using for testing.

xmlDataFormat

-

Name of specific XML data format to use. By default jaxb will be used.

Important: This option is only for setting a custom name of the data format, not to refer to an existing data format instance.

Note: Currently only jaxb is supported.

componentProperty

-

Allows to configure as many additional properties. This is used to configure component specific options such as for netty-http, jetty, undertow etc. The options value can use the # notation to refer to a bean to lookup in the Registry

endpointProperty

-

Allows to configure as many additional properties. This is used to configure endpoint specific options for netty-http, jetty, undertow. The options value can use the # notation to refer to a bean to lookup in the Registry

consumerProperty

-

Allows to configure as many additional properties. This is used to configure consumer specific options for netty-http, jetty, undertow. The options value can use the # notation to refer to a bean to lookup in the Registry

dataFormatProperty

-

Allows to configure as many additional properties. This is used to configure the data format specific options.

For example set property prettyPrint=true to have JSON outputted in pretty mode.

From Camel 2.14.1: the keys can be prefixed with either:

*json.in.

*json.out.

* xml.in.

* xml.out.

to denote that the option is only for either JSON or XML data format, and only for either the in or the out going. For example a key with value xml.out.mustBeJAXBElement is only for the XML data format for the outgoing.

A key without a prefix is a common key for all situations.

From Camel 2.17: the options value can use the # notation to refer to a bean to lookup in the Registry

apiProperty

-

Sets additional options on api level.

corsHeaders

-

Allows to configure custom CORS headers.

For example to configure to use the spark-rest component on port 9091, then we can do as follows:

restConfiguration().component("spark-rest").port(9091).componentProperty("foo", "123");

And with XML DSL

<restConfiguration component="spark-rest" port="9091">
  <componentProperty key="foo" value="123"/>
</restConfiguration>

If no component has been explicit configured, then Camel will lookup if there is a Camel component that integrates with the Rest DSL, or if a org.apache.camel.spi.RestConsumerFactory is registered in the registry. If either one is found, then that is being used.

You can configure properties on these levels.

  • component - Is used to set any options on the Component class. You can also configure these directly on the component.

  • endpoint - Is used set any option on the endpoint level. Many of the Camel components has many options you can set on endpoint level.

  • consumer - Is used to set any option on the consumer level.

  • data format - Is used to set any option on the data formats. For example to enable pretty print in the json data format.

  • cors headers - If cors is enabled, then custom CORS headers can be set. See below for the default values which are in used. If a custom header is set then that value takes precedence over the default value.

You can set multiple options of the same level, so you can can for example configure 2 component options, and 3 endpoint options etc.

Enabling or disabling Jackson JSON features

Since Camel 2.15

When using JSON binding you may want to turn specific Jackson features on or off. For example to disable failing on unknown properties (eg json input has a property which cannot be mapped to a POJO) then configure this using the dataFormatProperty as shown below:

restConfiguration().component("jetty").host("localhost").port(getPort()).bindingMode(RestBindingMode.json)
   .dataFormatProperty("json.in.disableFeatures", "FAIL_ON_UNKNOWN_PROPERTIES");

You can disable more features by separating the values using comma, such as:

.dataFormatProperty("json.in.disableFeatures", "FAIL_ON_UNKNOWN_PROPERTIES,ADJUST_DATES_TO_CONTEXT_TIME_ZONE");

Likewise you can enable features using the enableFeatures such as:

restConfiguration().component("jetty").host("localhost").port(getPort()).bindingMode(RestBindingMode.json)
   .dataFormatProperty("json.in.disableFeatures", "FAIL_ON_UNKNOWN_PROPERTIES,ADJUST_DATES_TO_CONTEXT_TIME_ZONE")
   .dataFormatProperty("json.in.enableFeatures", "FAIL_ON_NUMBERS_FOR_ENUMS,USE_BIG_DECIMAL_FOR_FLOATS");

The values that can be used for enabling and disabling features on Jackson are the names of the enums from the following three Jackson classes

  • com.fasterxml.jackson.databind.SerializationFeature

  • com.fasterxml.jackson.databind.DeserializationFeature

  • com.fasterxml.jackson.databind.MapperFeature

The rest configuration is of course also possible using XML DSL

<restConfiguration component="jetty" host="localhost" port="9090" bindingMode="json">
  <dataFormatProperty key="json.in.disableFeatures" value="FAIL_ON_UNKNOWN_PROPERTIES,ADJUST_DATES_TO_CONTEXT_TIME_ZONE"/>
  <dataFormatProperty key="json.in.enableFeatures" value="FAIL_ON_NUMBERS_FOR_ENUMS,USE_BIG_DECIMAL_FOR_FLOATS"/>
</restConfiguration>

Default CORS headers

Since Camel 2.14.1

If CORS is enabled then the follow headers is in use by default. You can configure custom CORS headers which takes precedence over the default value.

Key Value

Access-Control-Allow-Origin

*

Access-Control-Allow-Methods

GET, HEAD, POST, PUT, DELETE, TRACE, OPTIONS, CONNECT, PATCH

Access-Control-Allow-Headers

Origin, Accept, X-Requested-With, Content-Type, Access-Control-Request-Method, Access-Control-Request-Headers

Access-Control-Max-Age

3600

Defining a custom error message as-is

If you want to define custom error messages to be sent back to the client with a HTTP error code (eg such as 400, 404 etc.) then from Camel 2.14.1 onwards you just set a header with the key Exchange.HTTP_RESPONSE_CODE to the error code (must be 300+) such as 404. And then the message body with any reply message, and optionally set the content-type header as well. There is a little example shown below:

restConfiguration().component("netty-http").host("localhost").port(portNum).bindingMode(RestBindingMode.json);
// use the rest DSL to define the rest services
rest("/users/")
    .post("lives").type(UserPojo.class).outType(CountryPojo.class)
        .route()
            .choice()
                .when().simple("${body.id} < 100")
                    .bean(new UserErrorService(), "idToLowError")
                .otherwise()
                    .bean(new UserService(), "livesWhere");

In this example if the input id is a number that is below 100, we want to send back a custom error message, using the UserErrorService bean, which is implemented as shown:

public class UserErrorService {
    public void idToLowError(Exchange exchange) {
        exchange.getIn().setBody("id value is too low");
        exchange.getIn().setHeader(Exchange.CONTENT_TYPE, "text/plain");
        exchange.getIn().setHeader(Exchange.HTTP_RESPONSE_CODE, 400);
    }
}

In the UserErrorService bean we build our custom error message, and set the HTTP error code to 400. This is important, as that tells rest-dsl that this is a custom error message, and the message should not use the output pojo binding (eg would otherwise bind to CountryPojo).

Catching JsonParserException and returning a custom error message

From Camel 2.14.1 onwards you return a custom message as-is (see previous section). So we can leverage this with Camel error handler to catch JsonParserException, handle that exception and build our custom response message. For example to return a HTTP error code 400 with a hardcoded message, we can do as shown below:

onException(JsonParseException.class)
    .handled(true)
    .setHeader(Exchange.HTTP_RESPONSE_CODE, constant(400))
    .setHeader(Exchange.CONTENT_TYPE, constant("text/plain"))
    .setBody().constant("Invalid json data");

Query Parameter default Values

You can specify default values for parameters in the rest-dsl, such as the verbose parameter below:

  rest("/customers/")
      .get("/{id}").to("direct:customerDetail")
      .get("/{id}/orders")
        .param().name("verbose").type(RestParamType.query).defaultValue("false").description("Verbose order details").endParam()
          .to("direct:customerOrders")
      .post("/neworder").to("direct:customerNewOrder");

From Camel 2.17 onwards then the default value is automatic set as header on the incoming Camel Message. So if the call the /customers/id/orders do not include a query parameter with key verbose then Camel will now include a header with key verbose and the value false because it was declared as the default value. This functionality is only applicable for query parameters.

Client Request Validation

From Camel 2.22 onwards its possible to enable validation of the incoming client request. The validation checks for the following:

  • Content-Type header matches what the Rest DSL consumes. (Returns HTTP Status 415)

  • Accept header matches what the Rest DSL produces. (Returns HTTP Status 406)

  • Missing required data (query parameters, HTTP headers, body). (Returns HTTP Status 400)

If the validation fails then Rest DSL will return back an empty response with a HTTP error code.

The validation is by default turned off (to be backwards compatible). It can be turned on via clientRequestValidation as shown below:

restConfiguration().component("jetty").host("localhost")
    .clientRequestValidation(true);

Integrating a Camel component with Rest DSL

Any Apache Camel component can integrate with the Rest DSL if they can be used as a REST service (eg as a REST consumer in Camel lingo). To integrate with the Rest DSL, then the component should implement the org.apache.camel.spi.RestConsumerFactory. The Rest DSL will then invoke the createConsumer method when it setup the Camel routes from the defined DSL. The component should then implement logic to create a Camel consumer that exposes the REST services based on the given parameters, such as path, verb, and other options. For example see the source code for camel-netty-http, camel-jetty, camel-undertow, camel-spark-rest.

Swagger API

The Rest DSL supports Swagger Java by the camel-swagger-java module. See more details at Swagger and the camel-swagger-java example from the Apache Camel distribution.

From Camel 2.16 onwards you can define each parameter fine grained with details such as name, description, data type, parameter type and so on, using the <param>. For example to define the id path parameter you can do as shown below:

<!-- this is a rest GET to view an user by the given id -->
<get uri="/{id}" outType="org.apache.camel.example.rest.User">
  <description>Find user by id</description>
  <param name="id" type="path" description="The id of the user to get" dataType="int"/>
  <to uri="bean:userService?method=getUser(${header.id})"/>
</get>

And in Java DSL

.get("/{id}").description("Find user by id").outType(User.class)
    .param().name("id").type(path).description("The id of the user to get").dataType("int").endParam()
    .to("bean:userService?method=getUser(${header.id})")

The body parameter type requires to use body as well for the name. For example a REST PUT operation to create/update an user could be done as:

<!-- this is a rest PUT to create/update an user -->
<put type="org.apache.camel.example.rest.User">
  <description>Updates or create a user</description>
  <param name="body" type="body" description="The user to update or create"/>
  <to uri="bean:userService?method=updateUser"/>
</put>

And in Java DSL

.put().description("Updates or create a user").type(User.class)
    .param().name("body").type(body).description("The user to update or create").endParam()
    .to("bean:userService?method=updateUser")

Vendor Extensions

The generated API documentation can be configured to include vendor extensions (https://swagger.io/specification/#specificationExtensions) which document the operations and definitions with additional information, such as class name of model classes, camel context id and route id’s. This information can aid developers and during trouble shooting. However at production usage you may wish to not have this turned on to avoid leaking implementation details into your API docs.

The vendor extension information is stored in the API documentation with keys starting with x-.

Not all 3rd party API gateways and tools supports vendor-extensions when importing your API docs.

The vendor extensions can be turned on RestConfiguration via the apiVendorExtension option:

restConfiguration()
    .component("servlet")
    .bindingMode(RestBindingMode.json)
    .dataFormatProperty("prettyPrint", "true")
    .apiContextPath("api-doc")
    .apiVendorExtension(true)
        .apiProperty("api.title", "User API").apiProperty("api.version", "1.0.0")
        .apiProperty("cors", "true");

And in XML DSL:

 <restConfiguration component="servlet" bindingMode="json"
                       apiContextPath="api-docs"
                       apiVendorExtension="true">

      <!-- we want json output in pretty mode -->
      <dataFormatProperty key="prettyPrint" value="true"/>

      <!-- setup swagger api descriptions -->
      <apiProperty key="api.version" value="1.0.0"/>
      <apiProperty key="api.title" value="User API"/>

</restConfiguration>

Supported API properties

The following table lists supported API properties and explains their effect. To set them use apiProperty(String, String) in the Java DSL or <apiProperty> when defining the REST API via XML configuration. Properties in bold are required by the OpenAPI 2.0 specification. Most of the properties affect the OpenAPI Info object, License object or Contact object.

Property

Description

api.version

Version of the API

api.title

Title of the API

api.description

Description of the API

api.termsOfService

API Terms of Service of the API

api.license.name

License information of the API

api.license.url

URL for the License of the API

api.contact.name

The identifying name of the contact person/organization

api.contact.url

The URL pointing to the contact information

api.contact.email

The email address of the contact person/organization

api.specification.contentType.json

The Content-Type of the served OpenAPI JSON specification, application/json by default

api.specification.contentType.yaml

The Content-Type of the served OpenAPI YAML specification, text/yaml by default