HTTPsys

HTTPsys, also known as the HTTP Server API, is a kernel-mode component within the Windows operating system that facilitates the processing of HTTP requests. It acts as a foundational layer for web servers and other applications that need to communicate over the HTTP protocol. Instead of each application having to implement its own low-level HTTP parsing and network handling, HTTPsys provides a standardized and efficient mechanism.

Developers can leverage HTTPsys by registering specific URL prefixes with it. When an HTTP request arrives that matches a registered prefix, HTTPsys directs the request to the corresponding application. This allows multiple applications to share a single IP address and port, with HTTPsys managing the routing based on the requested URL. This approach offers several advantages, including improved security, performance, and resource utilization.

Key features of HTTPsys include its ability to handle connection management, request queuing, and the parsing of HTTP headers. It operates at a lower level than user-mode web server software, meaning it can process requests more quickly and efficiently. Windows operating system components like Internet Information Services (IIS) and Windows Communication Foundation (WCF) utilize HTTPsys extensively. Developers writing custom web services or HTTP-based applications on Windows can also directly interact with the HTTPsys API to build their solutions.