Vert.x Web API Service helps you routing the API requests incoming from a Vert.x Web Router built with Vert.x Web API Contract Router Factory to event bus. It’s based on Vert.x service proxies
Using Vert.x API Service
To use Vert.x API Service, add the following dependency to the dependencies section of your build descriptor:
-
Maven (in your
pom.xml
):
<dependency>
<groupId>io.vertx</groupId>
<artifactId>vertx-web-api-service</artifactId>
<version>3.6.0.CR1</version>
</dependency>
-
Gradle (in your
build.gradle
file):
dependencies {
compile 'io.vertx:vertx-web-api-codegen:3.6.0.CR1'
}
Recap on Vert.x Web API Contract
Vert.x Web API Contract helps you to build a Vert.x Web router compliant to an OpenAPI spec, for example:
routerFactory.addHandlerByOperationId("operationId", routingContext -> {
RequestParameters parameters = routingContext.get("parsedParameters");
// Process the request
});
With Vert.x Web API Service you can define an event bus service that connects automatically to the router factory, allowing automatic request routing to Vert.x Event Bus.
We encourage you to read Service Proxy documentation before going further
Define your Service
First you need to define your service interface. Let’s start with this OpenAPI operation definition:
/api/transactions:
get:
operationId: getTransactionsList
parameters:
- name: from
in: query
style: form
explode: false
required: false
schema:
type: string
- name: to
in: query
style: form
explode: false
required: false
schema:
type: string
responses: ...
put:
operationId: putTransaction
requestBody:
required: true
content:
application/json:
schema:
type: object
properties:
from:
type: string
format: email
to:
type: string
format: email
value:
type: number
format: double
additionalProperties: false
required:
- from
- to
- value
responses: ...
Now we can build the interface that specifies a TransactionService that handles getTransactionsList and putTransaction operations. For each operation you need to write a method with name corresponding to operation id with following parameters:
-
Last parameter must be a
Handler<AsyncResult<OperationResponse>>
-
Second to last parameter must be a
OperationRequest
-
All parameters from first to second to last (excluded) are extracted from
RequestParameter
with specified type automatically, but they need to respect service proxy restrictions
For example:
@WebApiServiceGen
interface TransactionService {
void getTransactionsList(String from, String to, OperationRequest context, Handler<AsyncResult<OperationResponse>> resultHandler);
void putTransaction(JsonObject body, OperationRequest context, Handler<AsyncResult<OperationResponse>> resultHandler);
}
When you receive a request at TransactionService.getTransactionsList()
the generated service handler will automatically extract from
and to
parameter (if present) from OperationRequest
. In putTransaction()
we use the body
parameter name to extract the json body.
The service handler is also capable to translate JsonObject
to Vert.x data objects automatically, for example if you have a Transaction
data object that matches the json schema above, you can rewrite the putTransaction()
signature as:
void putTransaction(Transaction body, OperationRequest context, Handler<AsyncResult<OperationResponse>> resultHandler);
Note that generated service handler matches method parameters with spec’s parameter name and not with the location of parameter, so avoid duplicated parameter names in your spec
We also encourage to extract with RequestParameter
parameters that uses json schema allOf/anyOf/oneOf/not keywords because the extraction can produce undefined behaviours
Implement your service
Now you can implement your service. The OperationRequest
object contains headers and parameters maps.
To write the request you must call the resultHandler
with an OperationResponse
. To construct the OperationResponse
you can use some handy methods like OperationResponse.completedWithJson
or OperationResponse.completedWithPlainText
For example:
resultHandler.handle(
Future.succeededFuture(
OperationResponse.completedWithPlainText(Buffer.buffer("Hello world!"))
)
);
Mount to Router Factory and run the service
Now that your service is ready you need to mount it to OpenAPI3RouterFactory
. When you use one of the methods below, the router factory mounts an handler that routes the request through the event bus to the service at the address specified. Pay attention to specify the correct address to event bus endpoint.
You have four methods to match the service with router operation handlers:
-
Mount manually every operation to a specified address with
mountOperationToEventBus
-
Mount operations matching a tag[https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#operation-object] to a specified address with
mountServiceFromTag
. -
Specify the class interface and the address of the service with
mountServiceInterface
. This method introspects the interface public methods and mounts all matching method names with operation ids -
Specify inside the OpenAPI specification the
x-vertx-event-bus
extension for operations you want to route to your service and scan all operations that contains it withmountServicesFromExtensions
The x-vertx-event-bus
must be one of these two formats:
-
A string containing the address of service
-
An object containing the field
address
and the fieldmethod
that specifies the interface method name
For example if I want to route getTransactionsList to TransactionService
mounted at event bus address transaction_service.my_application
:
/api/transactions:
get:
operationId: getTransactionsList
parameters: ...
responses: ...
x-vertx-event-bus: transaction_service.my_application
Or
/api/transactions:
get:
operationId: getTransactionsList
parameters: ...
responses: ...
x-vertx-event-bus:
address: transaction_service.my_application
method: getTransactionsList
Then you can call mountServicesFromExtensions
that scans entire spec and mounts the handlers that route to your service the requests
Now you can register your service to event bus:
TransactionService service = new TransactionServiceImpl();
final ServiceBinder serviceBinder = new ServiceBinder(vertx).setAddress("address");
MessageConsumer<JsonObject> serviceConsumer = serviceBinder.register(TransactionService.class, service);