# cpp-httplib — Header-Only C++ HTTP/HTTPS Server and Client Library

> cpp-httplib is a single-header C++11 library for building HTTP and HTTPS servers and clients with minimal setup. It supports SSL/TLS, WebSockets, server-sent events, and compression out of the box.

## Install

Save as a script file and run:

# cpp-httplib — Header-Only C++ HTTP/HTTPS Server and Client Library

## Quick Use
```cpp
#include "httplib.h"

int main() {
    httplib::Server svr;
    svr.Get("/hello", [](const httplib::Request&, httplib::Response& res) {
        res.set_content("Hello World!", "text/plain");
    });
    svr.listen("0.0.0.0", 8080);
}
// Compile: g++ -std=c++11 -o server main.cpp -lpthread
```

## Introduction
cpp-httplib is a cross-platform, header-only C++ library that makes building HTTP/HTTPS servers and clients as simple as including a single file. It targets developers who need straightforward HTTP functionality without pulling in heavyweight frameworks or complex build dependencies.

## What cpp-httplib Does
- Creates HTTP/HTTPS servers with route handlers using lambda callbacks and path pattern matching
- Provides an HTTP client for making GET, POST, PUT, DELETE, and other standard requests
- Supports SSL/TLS via OpenSSL, MbedTLS, or wolfSSL backends for encrypted connections
- Handles multipart form data, file uploads, and chunked transfer encoding automatically
- Includes built-in WebSocket support and Server-Sent Events (SSE) for real-time communication

## Architecture Overview
The library is contained entirely in a single header file (`httplib.h`). It uses blocking socket I/O with a thread-per-connection model managed by an internal thread pool. Request routing is handled through a pattern-matching system that maps URL paths to user-defined handlers. TLS support is compiled in conditionally based on preprocessor definitions, keeping the library lightweight when encryption is not needed.

## Self-Hosting & Configuration
- Include `httplib.h` in your project — no build system integration required
- Define `CPPHTTPLIB_OPENSSL_SUPPORT` and link OpenSSL for HTTPS support
- Define `CPPHTTPLIB_ZLIB_SUPPORT` to enable gzip compression on responses
- Thread pool size is configurable via `svr.new_task_queue` for tuning concurrency
- Supports both IPv4 and IPv6 binding with configurable listen backlog

## Key Features
- True single-header design with zero mandatory dependencies
- Built-in support for gzip, Brotli, and Zstandard response compression
- Stream API for handling large file downloads without buffering entire responses in memory
- Regex-based URL routing with path parameter capture
- Cross-platform compatibility across Linux, macOS, and Windows (MSVC, GCC, Clang)

## Comparison with Similar Tools
- **Crow** — also header-only but uses async I/O; cpp-httplib is simpler with blocking sockets
- **Drogon** — full async framework with ORM and WebSocket; cpp-httplib is lighter and easier to embed
- **Boost.Beast** — lower-level HTTP/WebSocket on Boost.Asio; cpp-httplib abstracts away all networking details
- **Pistache** — REST-focused with async design; cpp-httplib covers more protocols with less setup
- **cpr** — client-only wrapper around libcurl; cpp-httplib provides both server and client

## FAQ
**Q: Is cpp-httplib suitable for high-concurrency production servers?**
A: It uses blocking I/O and a thread pool, so it works well for moderate concurrency. For tens of thousands of simultaneous connections, consider an async framework.

**Q: How do I enable HTTPS?**
A: Define `CPPHTTPLIB_OPENSSL_SUPPORT`, link OpenSSL, and use `httplib::SSLServer` with your certificate and key paths.

**Q: Does it support HTTP/2?**
A: No. cpp-httplib implements HTTP/1.1 only. Use a reverse proxy like Nginx for HTTP/2 termination.

**Q: Can I serve static files?**
A: Yes. Use `svr.set_mount_point("/", "/path/to/www")` to serve a directory of static files.

## Sources
- https://github.com/yhirose/cpp-httplib
- https://github.com/yhirose/cpp-httplib#readme

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Source: https://tokrepo.com/en/workflows/asset-bc4eb453
Author: Script Depot