How to use a File-proxy custom plugin in Lua for Apache APISIX

This repo includes a source code of a new custom plugin called file-proxy for APISIX using Lua. This plugin will be used to expose the static files through API and fetch a file from a specified URL.

When using this plugin

Often, we want to expose a static file (Yaml, JSON, JavaScript, CSS, or image files) through API. Read the full tutorial to understand when and why to use this plugin.

https://api7.ai/blog/plugin-development-with-lua-and-chatgpt

How to use this plugin

You can easily add the file-proxy.lua plugin ****implementation file to your APISIX project. In this repo, you can see a simple example of using it in APISIX project running on Docker.

It has a quite similar structure to the existing Apisix docker example repo, only we removed unnecessary files to keep the demo simple. The project has 3 folders, docker-compose.yml, and sample openapi.yaml files.

• docker-compose.yml defines two containers one for APISIX and another for etcd (which is configuration storage for APISIX).
• custom-plugins folder has the implementation of the file-proxy plugin in Lua.
• openapi.yaml is just a sample OpenAPI specification .yaml file we expose. Basically, we want to place a file openapi.yaml to http://localhost:9080/openapi.yaml path.

Prerequisites

• Before you start, it is good to have a basic understanding of APISIX. Familiarity with API gateway, and its key concepts such as routes, upstream, Admin API, plugins, and HTTP protocol will also be beneficial.
• Docker is used to installing the containerized etcd and APISIX.
• curl is used to send requests to APISIX Admin API. You can also use tools such as Postman to interact with the API.

How to use the plugin demo project

You can easily install the apisix-file-proxy-plugin-demo project by running docker compose up from the project root folder after you fork/clone the project.

Create a route with the file-proxy plugin

To use and test our new file-proxy plugin we need to create a route in APISIX that uses the plugin:

curl "http://127.0.0.1:9180/apisix/admin/routes/open-api-definition" -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
   "name":"OpenAPI Definition",
   "desc":"Route for OpenAPI Definition file",
   "uri":"/openapi.yaml",
   "plugins":{
      "file-proxy":{
         "path":"/usr/local/apisix/conf/openapi.yaml"
      }
   }
}'

Test the plugin

Then, you can send a cURL request to the route or open the link http://127.0.0.1:9080/openapi.yaml in your browser. The response should be the content of the file openapi.yamlat the specified URL.

curl -i http://127.0.0.1:9080/openapi.yaml

The plugin works as we expected. With this plugin configuration, you can now access any files using the specified route.

About the author

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