nodemcu-httpserver

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

Features

GET, POST, PUT and minor changes to support other methods
Multiple MIME types
Error pages (404 and others)
Server-side execution of Lua scripts
Query string argument parsing with decoding of arguments
Serving .gz compressed files
HTTP Basic Authentication
Decoding of request bodies in both application/x-www-form-urlencoded and application/json (if cjson is available)

How to use

Upload server files using nodemcu-uploader. The easiest is to use GNU Make with the bundled Makefile. Open the Makefile and modify the user configuration to point to your nodemcu-uploader script and your serial port. Type the following to upload the server code, init.lua (which you may want to modify), and some example files:
```
  make upload_all
```
If you only want to upload the server code, then type:
```
  make upload_server
```
And if you only want to upload the http files:
```
  make upload_http
```
Restart the server. This will execute init.lua which will compile the server code. Then, assuming init.lua doesn't have it, start the server yourself by typing:
```
  dofile("httpserver.lc")(80)
```
In this example, 80 is the port your server is listening at, but you can change it.
Want to upload your own files? Move them to the http/ folder. Be careful though, the flash memory seems to fill up quickly and get corrupted.

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. Only files that begin with "http/" will be accessible through the server.
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)[http://2.2.2.2/index.html] using your web browser. The ESP8266 will serve you with the contents of the file "http/index.html" (if it exists). If you visit the root (/) then index.html is served. By the way, unlike most HTTP servers, nodemcu_httpserver treats the URLs in a case-sensitive manner.
How to use HTTP Basic Authentication.

Enable and configure HTTP Basic Authentication by editing "httpserver-conf.lua" file.

When enabled, HTTP Basic Authentication is global to every file served by the server.

Remember that HTTP Basic Authentication is a very basic authentication protocol, and should not be considered secure if the server is not using encryption, as your username and password travel in plain text.

How to create dynamic Lua scripts

Similar to static files, upload a Lua script called "http/[name].lua where you replace [name] with your 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".

Look at the included example scripts for more ideas.

Example: Garage door opener

Purpose

This is a bundled example that shows how to use nodemcu-httpserver together with server-side scripting to control something with the ESP8266. In this example, we will pretend to open one of two garage doors.

Your typical garage door opener has a wired remote with a single button. The button simply connects to two terminals on the electric motor and when pushed, the terminals are shorted. This causes the motor to open or close.

Hardware description

This example assumes that GPIO1 and GPIO2 on the ESP8266 are connected each to a relay that can be controlled. How to wire such thing is outside of the scope of this document but information is easily found online. The relays are controlled by the microcontroller and act as the push button, and can actually be connected in parallel with the existing mechanical button.

Software description

This example consists of the following files:

garage_door_opener.html: Static HTML displays a button with a link to the garage_door_opener.lua script. That's it!
garage_door_opener.css: Provides styling for garage_door_opener.html just so it looks pretty.
garage_door_opener.lua: Does the actual work. The script first sends a little javascript snippet to redirect the client back to garage_door_opener.html and then toggles the GPIO2 line for a short amount of time (roughly equivalent to the typical button press for opening a garage door) and then toggles it back.
apple-touch-icon.png: This is optional. Provides an icon that will be used if you "Add to Home Screen" the demo on an iPhone. Now it looks like an app!

Security implications

Be careful permanently installing something like this in your home. The server provides no encryption. Your only layer of security is the WiFi network and anyone with access to it could open or close your garage, enter your home, and steal your flatscreen TV.

This script is provided simply as an educational example and you should treat accordingly.

Not supported

~~Other methods: HEAD, POST, PUT, DELETE, TRACE, OPTIONS, CONNECT, PATCH~~
Encryption
Multiple users (HTTP Basic Authentication)
Only protect certain directories (HTTP Basic Authentication)

Notes on memory usage.

The chip is very, very memory constrained.

Use nodemcu-firmware dev096 or newer with as few optional modules as possible. Older versions have very little free RAM.
Use a firmware build without floating point support. This takes up a good chunk of RAM as well. In the (nodemcu-firmware releases page)[https://github.com/nodemcu/nodemcu-firmware/releases] these would be the ones with the term "integer" in them. If you are building it yourself then we'll assume you know what you're doing.
Any help reducing the memory needs of the server without crippling its functionality is appreciated!
Compile your Lua scripts in order to reduce their memory usage. The server knows to serve and treat both .lua and .lc files as scripts.

KillerGoldFisch/nodemcu-httpserver