README.md 2.3 KB

nodemcu-httpserver

A (very) simple web server written in Lua for the ESP8266 firmware NodeMCU.

Features

  • GET
  • Multiple MIME types
  • Error pages (404 and others)
  • Remote execution of Lua scripts

How to use

  1. Upload httpserver.lua using luatool.py or equivalent. Add the following to your init.lua in order to start the server:

     require("httpserver")
     server = httpserver.start(80, 10)
    

80 is the port your server is listening to, and 10 is the timeout (in seconds) for clients.

  1. Upload the files you want to serve. Again, use luatool.py or similar and upload the HTML and other files.

All the files you upload must be prefixed with «http/». Wait, what?

Yes: NodeMCU’s filesystem does not support folders, but filenames can contain slashes.

  1. Visit your server from a web browser.

Example: Say the IP for your ESP8266 is 2.2.2.2 and the server is running in the default port 80. Go to http://2.2.2.2/index.html using your web browser. The ESP8266 will serve you with the contents of the file «http/myPage.html» (if it exists). If you visit the root (/) then index.html is server. By the way, the URLs are case-sensitive.

How to create dynamic Lua scripts

Similar to static files, upload a Lua script called «http/[name].lua where you replace [name] with the script’s name. The script should return a function that takes two parameters:

  return function (connection, args)
     -- code goes here
  end

Use the connection parameter to send the response back to the client. Note that you are in charge of sending the HTTP header. The args parameter is a Lua table that contains any arguments sent by the client in the GET request.

For example, if the client requests http://2.2.2.2/foo.lua?color=red then the server will execute the function in your Lua script foo.lua and pass in connection and args, where args.color == «red».

Not supported

  • Other methods: HEAD, POST, PUT, DELETE, TRACE, OPTIONS, CONNECT, PATCH
  • Server side scripting.

Open issues

  • File system doesn’t like long names, need to protect:

    PANIC: unprotected error in call to Lua API (httpserver.lua:78: filename too long)
    
  • System is very, very memory constrained. Remote execution of Lua scripts only works with trivial scripts.