CAP

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# CAP 　　　　　　　　　　　　　　　　　　　　[中文](https://github.com/dotnetcore/CAP/blob/master/README.zh-cn.md)

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CAP is a .NET library that provides a lightweight, easy-to-use, and efficient solution for distributed transactions and event bus integration.

When building SOA or Microservice-based systems, services often need to be integrated via events. However, simply using a message queue cannot guarantee reliability. CAP leverages a local message table, integrated with your current database, to solve exceptions that can occur during distributed system communications. This ensures that event messages are never lost.

You can also use CAP as a standalone EventBus. It offers a simplified approach to event publishing and subscribing without requiring you to inherit or implement any specific interfaces.

## Key Features

*   **Core Functionality**
    *   **Distributed Transactions**: Guarantees data consistency across microservices using a local message table (Outbox Pattern).
    *   **Event Bus**: High-performance, lightweight event bus for decoupled communication.
    *   **Guaranteed Delivery**: Ensures messages are never lost, with automatic retries for failed messages.

*   **Advanced Messaging**
    *   **Delayed Messages**: Native support for publishing messages with a delay, without relying on message queue features.
    *   **Flexible Subscriptions**: Supports attribute-based, wildcard (`*`, `#`), and partial topic subscriptions.
    *   **Consumer Groups & Fan-Out**: Easily implement competing consumer or fan-out patterns for load balancing or broadcasting.
    *   **Parallel & Serial Processing**: Configure consumers for high-throughput parallel processing or ordered sequential execution.
    *   **Backpressure Mechanism**: Automatically manages processing speed to prevent memory overload (OOM) under high load.

*   **Extensibility & Integration**
    *   **Pluggable Architecture**: Supports a wide range of message queue