Appserver - Server Configuration, Dir Structure and Threads

This article explores the Appserver architecture in detail, going beyond the high-level overview in the previous installment. We'll delve into contexts, threading models, and the out-of-the-box features that rival popular PHP frameworks. We'll also configure the web server and examine application structure. By the end, you'll understand Appserver's contexts, threading, and setup. Future parts will cover the servlet engine, persistence container, beans, messaging, and timer modules.

Appserver's Unique Threading Model: Unlike standard web servers, Appserver employs a threading model where threads persist throughout the server's lifespan. This significantly enhances performance by eliminating the overhead of thread creation and destruction for each request.

Contexts and Thread Safety: Contexts in Appserver define the runtime environment for each thread. This allows for thread-safe data sharing and inheritance, simplifying application state and configuration management. Appserver manages this sharing, preventing potential conflicts.

Configuration Methods: Appserver uses annotations and XML configuration files (like web.xml) for easy setup and customization of routing, servlets, and other components, minimizing the need for extensive coding.

Programming Paradigms: Appserver supports Aspect-Oriented Programming (AOP) and Design by Contract, promoting modularity and stricter typing.

Directory Structure: Appserver's directory structure is optimized for application management and deployment. Key directories include:

• /WEB-INF: Client-facing PHP classes (servlets, controllers).
• /META-INF: Backend services, aspects, domain model entry points.
• /common: Shared resources.
• /vendor: Composer libraries (PSR-0 autoloading supported).
• /static: Static assets (JS, CSS, images).

Contexts and Threading in Detail: Appserver's context hierarchy starts with a root context, branching into container and server contexts (hosting the web server). Worker contexts, configurable in number, handle parallel request processing. Child contexts inherit selectively from parents (note: this isn't standard OOP inheritance). This persistent context and data sharing contribute to Appserver's performance gains. Bootstrapping, often a performance bottleneck, is performed only once at startup.

Programming Concepts:

• Annotations: Simplify configuration and reduce coding. XML configuration remains an option.
• AOP (Aspect-Oriented Programming): A core paradigm, similar to Laravel's approach.
• Design by Contract: Enforces stricter typing through commented type annotations, throwing exceptions for type mismatches.

The Web Server: Appserver's built-in PHP web server (HTTP 1.1, with HTTP 2.0 planned) provides functionality found in many PHP frameworks. It uses $request and $response objects (via interfaces like HttpServletRequestInterface). Configuration is similar to Apache, supporting rewrites, virtual hosts, environment variables, and HTTP authentication. Key configuration files are located in /etc/appserver.

Creating a Virtual Host: This section guides you through setting up a virtual host, eliminating the need for port numbers in URLs and demonstrating rewrite rules for handling subdomains (e.g., redirecting www.my-app.com to my-app.com).

Appserver File Structure: The /webapps directory contains applications. The example app structure is shown below:

The Servlet Engine: The servlet engine handles the application logic, eliminating the performance hit of repeated bootstrapping in traditional PHP setups. Communication between the servlet engine (/WEB-INF) and persistence container (/META-INF) uses proxy objects, enabling distributed architectures.

Conclusion: This article provides a comprehensive overview of Appserver's architecture and configuration. Future articles will explore the remaining modules in more detail.

(The Frequently Asked Questions section is omitted as it's a repetition of information already covered in the article.)

The above is the detailed content of Appserver - Server Configuration, Dir Structure and Threads. For more information, please follow other related articles on the PHP Chinese website!