Acl -- Advanced Cross-Platform C/C++ Network Communication Library and Server Framework

0. About Acl Project

Acl (Advanced C/C++ Library) is a powerful cross-platform network communication library and server programming framework that supports Linux, Windows, Solaris, FreeBSD, macOS, Android, iOS, and HarmonyOS. Numerous applications developed with Acl run on various devices, providing stable and reliable services to hundreds of millions of users.

The Acl project includes a rich set of functional modules: network communication, server framework, application protocols, various codecs, and more. It has built-in implementations of common network protocols such as HTTP/SMTP/ICMP/MQTT/Redis/Memcached/Beanstalk/Handler Socket, as well as complete codec libraries including XML/JSON/MIME/BASE64/UUCODE/QPCODE/RFC2047/RFC1035, etc. Additionally, Acl provides a unified abstract interface for mainstream databases (MySQL, PostgreSQL, SQLite), enabling developers to write database applications more easily, quickly, and securely.

Software Architecture

Overall Architecture

<hr>

0. About Acl Project
1. Six Core Modules
2. Other Important Modules
3. Platform Support and Compilation
- 3.1. Compiling Acl on Different Platforms
- 3.2. Notes on Windows Compilation
4. Quick Start
5. More Information
6. Appendix
- 6.1. Software Layered Architecture
- 6.2. Project Directory Structure

<hr>

1. Six Core Modules

As a fully-featured C/C++ foundation library, Acl provides rich and practical functionality for application development. The six core modules include: Network Communication, Coroutine, HTTP, Redis Client, MQTT, and Server Framework.

1.1. Basic Network Module

Stream Processing Module
This module is the cornerstone of Acl's network communication, providing a unified streaming communication interface that supports both network streams and file streams. Main features include:

Read data line by line, automatically compatible with \r\n on Windows and \n on UNIX
Read data line by line with automatic removal of trailing newline characters (\n or \r\n)
Read data with custom string delimiters
Read data of specified length
Try to read a line or specified length of data
Detect network IO status
Write a line of data
Formatted data writing (similar to fprintf)
File stream positioning operations (similar to fseek)
Batch write data (similar to UNIX writev)
Truncate files (similar to ftruncate)
Get file size and current file stream pointer position (similar to ftell)
Get local and remote addresses of network streams

Network Operation Module
This module provides complete network operation functionality, including:

Network server listening (supports TCP/UDP/UNIX domain sockets)
Network client connection (supports TCP/UNIX domain sockets)
DNS domain name query and result caching (supports both system API calls and direct DNS protocol)
Socket operations and local network interface information retrieval

Non-blocking Network Stream
Comprehensive support for non-blocking network operations, including non-blocking connections, reads (line reads, specified length reads), writes (line writes, specified length writes, batch writes), etc.

Common Network Application Protocol Library
Built-in implementations of common network application protocols such as HTTP, SMTP, ICMP, etc. The HTTP and ICMP modules support both blocking and non-blocking communication modes. The HTTP protocol in the C++ version of lib_acl_cpp provides both server and client modes:

Server Mode: Provides a Java HttpServlet-like interface, supports Cookie, Session, HTTP MIME file upload, etc.
Client Mode: Supports connection pool and cluster management, chunked transfer, automatic character set conversion, automatic decompression, resume download, and other rich features

Common Network Communication Library
Provides client communication libraries for Memcached, Beanstalk, Handler Socket, etc., all supporting connection pool mode.

1.2. Coroutine

Acl's coroutine module is a mature and stable cross-platform coroutine library that has been widely used and validated in many important projects.

Platform Support

Supports mainstream operating systems including Linux, macOS, Windows, iOS, and Android
Supports multiple CPU architectures including x86, ARM, etc.
Supports multiple event engines including select/poll/epoll/kqueue/iocp/win32 GUI messages

Core Features

Complete DNS Protocol Implementation: DNS protocol is natively implemented in coroutines, DNS API can be used directly in coroutines
System API Hook: Automatically hooks system IO APIs on Unix and Windows platforms to enable coroutine support
- Read APIs: read/readv/recv/recvfrom/recvmsg
- Write APIs: write/writev/send/sendto/sendmsg/sendfile64
- Socket APIs: socket/listen/accept/connect/setsockopt
- Event APIs: select/poll/epoll_create/epoll_ctl/epoll_wait
- DNS APIs: gethostbyname/gethostbyname_r/getaddrinfo/freeaddrinfo
Shared Stack Mode: Supports shared stack mode to significantly reduce memory usage

Synchronization Primitives

Coroutine Mutex and Semaphore: For synchronization between coroutines
Coroutine Event: Supports synchronous communication between coroutines and threads

For more details, see Using Acl Coroutine Library

1.3. HTTP Module

Complete implementation of HTTP/1.1 protocol, supporting both client and server application development.

Main Features

Java HttpServlet-like Interface (server side): Provides familiar programming interface, reducing learning curve
Connection Pool Mode (client side): Efficiently manages connection resources, improves performance
Chunked Transfer: Supports streaming data transfer
Compression: Built-in Gzip compression/decompression support
SSL/TLS Encryption: Supports secure encrypted transmission
Resume Download: Supports resume download for large files
Cookie Management: Complete cookie setting and retrieval functionality
Session Management (server side): Built-in session management mechanism
WebSocket Support: Supports WebSocket protocol
HTTP MIME Format: Supports MIME multipart data format
Sync/Async Mode: Flexible choice of communication modes

1.4. Redis Client

Acl's Redis client module is powerful, high-performance, and easy to use, making it an ideal choice for production environments.

Features

Rich Command Support: Supports Redis data types and commands including Bitmap/String/Hash/List/Set/Sorted Set/PubSub/HyperLogLog/Geo/Script/Stream/Server/Cluster
STL-style Interface: Provides STL-like C++ interface for each Redis command, conforming to C++ programming conventions
Smart Cluster Management: Client automatically caches and adapts to changes in Redis cluster hash slots without manual intervention
Multiple Communication Modes: Supports standalone, cluster, and pipeline modes with unified interface
Connection Pool Support: Built-in connection pool supporting standalone and cluster modes, improving resource utilization
High Performance: Excellent performance in cluster and pipeline modes
Automatic Retry: Automatically retries on network errors, improving reliability
Coroutine Friendly: Can be used in shared stack coroutine mode

For more details, see Using Acl Redis Client

1.5. MQTT Module

Acl fully implements the MQTT 3.1.1 protocol with a streaming parser design that can flexibly adapt to various IO modes.