Flowable HTTP Client

Flowable uses an instance of FlowableHttpClient in the platform to perform HTTP requests. This Flowable HTTP Client is used in the HTTP Task and the Service Registry REST models.

Flowable has 3 types of implementations:

• Based on Spring WebClient
• Based on Apache HTTP 5
• Based on Apache HTTP 4

Based on what is available on the classpath that would take precedence. e.g. Spring WebClient has precedence over Apache HTTP 5, which has a precedence over Apache HTTP 4.

The http client can be configured using the properties with prefix flowable.http. The properties are defined here.

Depending on which client is being used there are other customizations options.

Customizing Spring WebClient

The available configuration properties for the Spring WebClient are defined here.

v3.14.0+

A bean of type FlowableHttpClientWebClientCustomizer can be used to provide more complex customization of the WebClient.Builder

e.g.

@Configuration(proxyBeanMethods = false)
public class CustomConfiguration {

    @Bean
    public FlowableHttpClientWebClientCustomizer httpClientCustomizer() {
        return webClientBuilder -> {
            // Customization
        };
    }
    
}

Customizing Apache HTTP Client 5

The available configuration properties for the Apache HTTP Client 5 are defined here.

v3.14.0+

A bean of type FlowableHttpClientApacheHttpClient5Customizer can be used to provide more complex customization of the HttpAsyncClientBuilder

e.g.

@Configuration(proxyBeanMethods = false)
public class CustomConfiguration {

    @Bean
    public FlowableHttpClientApacheHttpClient5Customizer httpClientCustomizer() {
        return clientBuilder -> {
            // Customization
        };
    }
    
}

note

If you want to customize the HTTP proxy you can set flowable.http.use-system-properties to true and then configure the default Java HTTP proxy properties

Customizing Apache HTTP Client 4

v3.14.5+

A bean of type FlowableHttpClientApacheHttpClient4Customizer can be used to provide more complex customization of the HttpClientBuilder

e.g.

@Configuration(proxyBeanMethods = false)
public class CustomConfiguration {

    @Bean
    public FlowableHttpClientApacheHttpClient4Customizer httpClientCustomizer() {
        return clientBuilder -> {
            // Customization
        };
    }
    
}

note

If you want to customize the HTTP proxy you can set flowable.http.use-system-properties to true and then configure the default Java HTTP proxy properties

Multiple FlowableHttpClient(s)

In case multiple FlowableHttpClient(s) are needed, e.g. a custom one for a specific Service Registry Service Definition Model, then the FlowableHttpClientBuilder can be used to provide an instance of the default implementation (see here for an example).

e.g.

@Configuration(proxyBeanMethods = false)
public class CustomConfiguration {

    @Bean
    public FlowableHttpClient customFlowableHttpClient(FlowableHttpClientBuilder<HttpAsyncClientBuilder> flowableHttpBuilder) {
        // Replace HttpAsyncClientBuilder with the appropriate builder
        return flowableHttpBuilder
                .addCustomizer(builder -> {
                    // Provide customizations
                })
                .build();
    }

    @Bean
    @Primary
    public FlowableHttpClient defaultFlowableHttpClient(FlowableHttpClientBuilder<?> builder) {
        return builder.build();
    }
    
}

note

The use of the HttpAsyncClientBuilder is an example. Depending on which client type is the generic should be the appropriate type. e.g. WebClient.Builder when using the Spring WebClient, HttpAsyncClientBuilder when using the Apache HTTP Client 5 and HttpClientBuilder when using the Apache HTTP Client 4.