Core Concepts

Deep dive into the fundamental building blocks of aspect-rs.

What You’ll Learn

• The Aspect trait and its four advice methods
• JoinPoint context and metadata
• ProceedingJoinPoint for around advice
• Advice types and when to use each
• Error handling with AspectError

The Aspect Trait

Every aspect implements this trait:

#![allow(unused)]
fn main() {
pub trait Aspect: Send + Sync {
    fn before(&self, ctx: &JoinPoint) {}
    fn after(&self, ctx: &JoinPoint, result: &dyn Any) {}
    fn after_throwing(&self, ctx: &JoinPoint, error: &dyn Any) {}
    fn around(&self, pjp: ProceedingJoinPoint) -> Result<Box<dyn Any>, AspectError> {
        pjp.proceed()
    }
}
}

Key points:

• All methods have default implementations
• Must be Send + Sync for thread safety
• Implement only the advice you need

Chapter Sections

• The Aspect Trait - Detailed API reference
• JoinPoint Context - Accessing execution metadata
• Advice Types - Comparison and use cases
• Error Handling - Working with errors and panics

See The Aspect Trait to continue.