How to Enable Request Scope in Asynchronous Task Execution?

Enabling Request Scope in Asynchronous Task Execution

Problem:

Asynchronous web services need to access request-scoped beans within their asynchronous processing, particularly those annotated with @Scope(value = WebApplicationContext.SCOPE_REQUEST). However, SimpleAsyncTaskExecutor does not preserve thread-bound request attributes, leading to exceptions.

Solution:

To enable request scope in asynchronous task execution, a custom TaskPoolExecutor is created along with a special Callable that stores and clears the request context for the background thread.

Implementation:

Custom Executor:

<code class="java">public class ContextAwarePoolExecutor extends ThreadPoolTaskExecutor {
    @Override
    public <T> Future<T> submit(Callable<T> task) {
        return super.submit(new ContextAwareCallable(task, RequestContextHolder.currentRequestAttributes()));
    }
}</code>

Context-Aware Callable:

<code class="java">public class ContextAwareCallable<T> implements Callable<T> {
    private Callable<T> task;
    private RequestAttributes context;

    public ContextAwareCallable(Callable<T> task, RequestAttributes context) {
        this.task = task;
        this.context = context;
    }

    @Override
    public T call() throws Exception {
        if (context != null) {
            RequestContextHolder.setRequestAttributes(context);
        }

        try {
            return task.call();
        } finally {
            RequestContextHolder.resetRequestAttributes();
        }
    }
}</code>

Configuration Override:

<code class="java">@Configuration
public class ExecutorConfig extends AsyncConfigurerSupport {
    @Override
    @Bean
    public Executor getAsyncExecutor() {
        return new ContextAwarePoolExecutor();
    }
}</code>

Usage:

<code class="java">taskExecutor.execute(new ContextAwareCallable(new Runnable() {
    @Override
    public void run() {
        asyncRequest(request);
    }
}), RequestContextHolder.currentRequestAttributes());</code>

Notes:

• This method only supports request and session scopes, not security contexts.
• It is compatible with both Callable and Runnable interfaces.

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