You are viewing the documentation for Blueriq 16. Documentation for other versions is available in our documentation directory.

The AQ_RestServiceClient service makes it possible to call a REST webservice.

Parameters

The following parameters can be set for the service from Encore:

NameDescriptionTypeRequiredDirectionSelect module
restServiceThe name of the REST service along with the module where it is defined.Module ElementYesInputYes
operationThe name of the operation of the REST service that needs to be called.StringYesInputNo
urlThe URL of the REST webservice.String ExpressionNoInputNo
connectionOverride

The name to use when overriding connection in the Runtime configuration files (more about this in the following section).

Not that if the expression returns the value unknown ( ? ) as result, an error is thrown. In this scenario no fallback is used.

String ExpressionNoInputNo
mappingThe name of the data mapping to use along with the module where it can be found.Data mappingNoBiDirectionalNo
usernameThe username to use in the service calling.StringNoInputNo
passwordThe password to use in the service calling.StringNoInputNo

Overriding parameters

The parameters url, username and password can be overridden in the Runtime's configuration files.

To do so, one can use either the name of the service call of type AQ_RestServiceClient in Blueriq Encore or the value given to the connectionOverride field. 

The overriding can be done in the application.properties file by either using the name of the service call in Blueriq Encore (SendRest20) like this:

blueriq.connection.SendRest20.http.url=http://randomUrl:8080
blueriq.connection.SendRest20.http.username=randomUsername
blueriq.connection.SendRest20.http.password=randomPassword

... or by using the connection name (connectionName) like this:

blueriq.connection.connectionName.http.url=http://randomUrl:8080
blueriq.connection.connectionName.http.username=randomUsername
blueriq.connection.connectionName.http.password=randomPassword

In order to illustrate the benefit of using the new connectionOverride parameter a simple example will be presented.

Say there is webservice with 5 operations: add, subtract, multiply, divide and modulo. For each operation there is a corresponding service call and for each of those service calls the url, username and password are overridden in the application.properties file using the name of the service call. This means that even if the services call the same webservice (thus calling the same url with the same credentials) the override data must be specified for each of them. This is where the connectionOverride becomes useful by allowing each of those services to use a common connection name and eliminating the need of duplication.

If the value for one of those parameters is specified in more than one place (for instance if the url parameter is defined in Encore but also overridden using the service name) the following prioritization is used by the Runtime:

  1. If there is a connectionOverride defined in Encore then that connection will be used over the others;
  2. If there is no connectionOverride defined in Encore, the Runtime will look into the configuration files for (and will use if it exists) a property to override parameters using the service's name;
  3. Finally, if there is no connectionOveride value defined in Encore and there is no property to override a parameter in the configuration files then the values defined in the model in Encore for the url, username and password will be used.


Final considerations

One must be consistent in the way it assigns value to the service parameters. Giving value to one parameter in a place and to another parameter in another place might prove faulty. For instance if one overrides the url by using a connection override but keeps the username and password values in Encore, the latter will not be used by the Runtime since it expects them to also be overridden in the configuration files.

Error handling

When the runtime sumbles upon an arror during execution of the AQ_RestServiceClient, there are serveral options to handle this:

  • The exception exit can be used to handle exceptions such as a failing data mapping, or a response body that doesn't match the domain schema.
  • Use the exit events to handle timeouts, client errors (http status code 4xx), and server errors (http status code 5xx).
    • If there is a need to distinguish on a more specific http status code than the aforemantioned ranges, you can use the header in the REST service to map the status code with the name "Status" to the profile.

Exit events

NameDescriptionType
TimeoutWhen the REST request returns a timeout exception.

Continue

ClientError (since 16.7)When the REST request returns a 4xx exception.

Continue

ServerError (since 16.7)When the REST request returns a 5xx exception.

Continue

default exit event

All unmapped events will be redirected to the default exit node of the service call, even errors. Therefore it is recommended to always map all possible expected exit events.

Continue

Authentication options

There are several authentication options, which are configurable per connection with properties:

No authentication

When no username and password are set for the service call (none in Encore and also none in the Connections Properties), then no authentication will be attempted. You should use this when the Rest Endpoint that you are calling is not secured.

Basic authentication

When a username and password are supplied, either in Encore or in the Connections Properties, these credentials will be supplied to the Rest Endpoint.

OpenID Connect authentication

See OpenID Connect for more information.

Oauth2 authentication

OAuth2 describes an authentication scheme. In its specification, it is explained what information should be in requests and responses, but not how this information should be transmitted.

Therefore, we use sensible defaults as described in this section. If you need other behavior, you can develop a custom Blueriq extension, as described below.

When the Rest Endpoint that needs to be called is secured with OAuth2, you can set the property blueriq.connection.<connectionName>.http.authentication to oauth2. You need to fill out some extra properties that should be provided by the maintainer of the endpoint. See Connections Properties for those. Blueriq will request a token from the oauth2-token-endpoint and call the Rest Service with that token.

Since OAuth2 doesn't specify how certain properties are transmitted when requesting a token, we include a set of default behavior:

  • When requesting a token, the grant_type and scope attributes will be sent in the request body, using the application/x-www-form-urlencoded encoding scheme.
  • When requesting a token, the Client ID and the Client Secret will be sent as Basic Authentication.
  • When requesting a token, the POST method is used.

  • In the token response, we expect a JSON structure that at least contains an access_token and a token_type:

    {
  "access_token": "f608a968-b1ef-457a-8d1a-71ee007ac4d2",
  "token_type": "bearer"
}

  • Access tokens are not cached. Each Rest Service call will request a new token.

Customization

If you need different behavior, you can write your own custom Access Token Provider, that needs to implement the com.blueriq.component.api.oauth2.Oauth2AccessTokenProvider interface and you need to define it as a Spring Bean in your application.

Limitations

  • The current implementation is limited to one Access Token Provider per Blueriq Runtime, so all of your OAuth2 enabled Rest Service Calls will use the same scheme.
  • The current implementation does not support the grant type password. We only tested the client_credentials grant type.
  • The current implementation will send the Access Token as Bearer to the Rest Service endpoint.

Didn't find the answer you were looking for? Try the advanced search!