GraphQL Component

Since Camel 3.0

Only producer is supported

The GraphQL component is a GraphQL client that communicates over HTTP and supports queries and mutations, but not subscriptions. It uses the Apache HttpClient library.

Maven users will need to add the following dependency to their pom.xml for this component:

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

GraphQL Endpoint URI

The GraphQL endpoint is configured using URI syntax:

graphql:httpUri

with the following path and query parameters:

Path Parameters (1 parameters):

Name Description Default Type

httpUri

Required The GraphQL server URI.

URI

Query Parameters (11 parameters):

Name Description Default Type

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

operationName (producer)

The query or mutation name.

String

proxyHost (producer)

The proxy host in the format hostname:port.

String

query (producer)

The query text.

String

queryFile (producer)

The query file name located in the classpath.

String

variables (producer)

The JsonObject instance containing the operation variables.

JsonObject

basicPropertyBinding (advanced)

Whether the endpoint should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

boolean

synchronous (advanced)

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

false

boolean

accessToken (security)

The access token sent in the Authorization header.

String

password (security)

The password for Basic authentication.

String

username (security)

The username for Basic authentication.

String

GraphQL Component Options

The GraphQL component supports 3 options, which are listed below.

Name Description Default Type

basicPropertyBinding (advanced)

Whether the component should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

boolean

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

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

The component supports 4 options, which are listed below.

Name Description Default Type

camel.component.graphql.basic-property-binding

Whether the component should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

Boolean

camel.component.graphql.bridge-error-handler

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

Boolean

camel.component.graphql.enabled

Whether to enable auto configuration of the graphql component. This is enabled by default.

Boolean

camel.component.graphql.lazy-start-producer

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

Boolean

Message Body

Camel will store the GraphQL response from the external server on the OUT message 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.

Examples

Queries

Simple queries can be defined directly in the URI:

from("direct:start")
    .to("graphql://http://example.com/graphql?query={books{id name}}")

More complex queries can be stored in a file and referenced in the URI:

# booksQuery.graphql
query Books {
  books {
    id
    name
  }
}

from("direct:start")
    .to("graphql://http://example.com/graphql?queryFile=booksQuery.graphql")

When the query file defines multiple operations, it’s required to specify which one should be executed:

from("direct:start")
    .to("graphql://http://example.com/graphql?queryFile=multipleQueries.graphql&operationName=Books")

Queries with variables need to reference a JsonObject instance from the registry:

@BindToRegistry("bookByIdQueryVariables")
public JsonObject bookByIdQueryVariables() {
    JsonObject variables = new JsonObject();
    variables.put("id", "book-1");
    return variables;
}

from("direct:start")
    .to("graphql://http://example.com/graphql?queryFile=bookByIdQuery.graphql&variables=#bookByIdQueryVariables")

Mutations

Mutations are like queries with variables. They specify a query and a reference to a variables bean:

# addBookMutation.graphql
mutation AddBook($bookInput: BookInput) {
  addBook(bookInput: $bookInput) {
    id
    name
    author {
      name
    }
  }
}

@BindToRegistry("addBookMutationVariables")
public JsonObject addBookMutationVariables() {
    JsonObject bookInput = new JsonObject();
    bookInput.put("name", "Typee");
    bookInput.put("authorId", "author-2");
    JsonObject variables = new JsonObject();
    variables.put("bookInput", bookInput);
    return variables;
}

from("direct:start")
    .to("graphql://http://example.com/graphql?graphql?queryFile=addBookMutation.graphql&variables=#addBookMutationVariables")