1. Introduction to Lua
Lua is a lightweight, efficient scripting programming language originally developed and released by a research group at the Catholic University of Rio de Janeiro, Brazil. The design goal of Lua is to provide a simple, embeddable, and extensible scripting language. The official implementation is completely written in ANSI C and can be embedded into other applications in the form of a C library.
As a procedural dynamic language, Lua has the following characteristics:
- Simplicity and lightweight : Lua's syntax is simple and clear, and it has a small code base and memory footprint, making it very suitable for use in embedded systems and resource-constrained environments.
- Efficiency : Lua's interpreter is built based on virtual machine technology and has fast execution speed. It uses a series of optimization measures, such as just-in-time compilation and lightweight coroutines, to improve execution efficiency and concurrency performance.
- Embeddability : Lua is designed to be embedded into other applications. Its interpreter is provided as a library and can be easily integrated with other programming languages such as C/C++ to provide scripting extension capabilities to applications.
- Extensibility : Lua provides a powerful extension mechanism, allowing developers to extend Lua's functions by writing C/C++ extension modules. This allows Lua to interact with other programming languages and integrate with existing code bases.
- Dynamic typing : Lua is a dynamically typed language, and the types of variables are determined at runtime. This makes it more flexible and can be dynamically typed and manipulated as needed.
- Automatic memory management and garbage collection : Lua has automatic memory management and garbage collection mechanisms, so developers do not need to manually manage memory, reducing the burden on programmers.
- Powerful table : Lua's table is a general data structure that can be used to represent arrays, dictionaries, objects, etc. It has flexible access and operation methods and is one of the important data structures in Lua.
- Multi-paradigm programming : Lua supports multiple programming paradigms, including procedural programming, functional programming, and object-oriented programming. Developers can choose the appropriate programming style according to their needs
2. Environment setup
- Download the corresponding platform version at https://openresty.org/cn/download.html
- Install plug-in EmmyLua in IDEA
3. Using Lua with OpenResty
In OpenResty, you can extend the functionality of Nginx by writing Lua code. Here are some common uses:
- Handle HTTP requests : You can use Lua to handle HTTP requests and perform corresponding logical processing based on the content of the request. For example, you can write Lua functions to parse request parameters, authenticate users, etc.
- Modifying requests and responses : Using Lua, you can modify the content of HTTP requests and responses. You can modify request headers, add response headers, redirect requests, etc. by writing Lua code.
- Caching and proxies : By writing Lua code, you can implement efficient caching and proxy functions. You can use Lua scripts to control cache policies, update cache content, etc.
4. Application examples
We find the newly installed openresty-1.21.4.2-win64\conf\nginx.conf. After adding the response to hello, click nginx.exe to start it.
# nginx.conf
http {
server {
listen 90;
location /hello {
default_type 'text/plain';
content_by_lua_block {
ngx.say("Hello, OpenResty!")
}
}
}
}
The access result is as shown in the figure. If it cannot be accessed, the process can kill the nginx service and execute it start nginx.
Welcome to follow the public account algorithm niche