|Marcos Kirsch dfb2dbecdf Smaller GIF, but animated||6 years ago|
|http||6 years ago|
|LICENSE||6 years ago|
|README.md||6 years ago|
|b64.lua||6 years ago|
|b64.py||6 years ago|
|httpserver-error.lua||6 years ago|
|httpserver-static.lua||6 years ago|
|httpserver.lua||6 years ago|
|init.lua||6 years ago|
|makefile||6 years ago|
A (very) simple web server written in Lua for the ESP8266 firmware NodeMCU.
Upload server files using luatool.py or equivalent. Or, even better, use GNU Make with the bundled makefile. Type the following to upload server code, init.lua (which you may want to modify), and some example files.
Compile the server files so that it uses less memory. This needs free memory so I suggest you do it after a fresh node.restart().
node.compile("httpserver.lua") node.compile("httpserver-static.lua") node.compile("httpserver-error.lua")
If this is not in init.lua, then start the server by typing:
In this example, 80 is the port your server is listening at but you can change it.
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.
Example: Say the IP for your ESP8266 is 22.214.171.124 and the server is running in the default port 80. Go to http://126.96.36.199/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 served. By the way, unlike some http servers, the URLs are case-sensitive.
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://188.8.131.52/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».
If you are going to be sending lots (as in over a KB) of data, you should yield the thread/coroutine every now and then in order to avoid overflowing the buffer in the microcontroller. Use:
Look at the included example scripts for more ideas.
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 a garage door. This is a very simple example that doesn’t even use arguments passed in the request (see example args.lua for that).
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.
This example assumes that GPIO2 on the ESP8266 is connected 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 relay is controlled by the microcontroller and acts as the button, and can actually be connected in parallel with the existing mechanical button.
This example consists of the following files:
Be careful permanently installing something like this in your home. The scripts use no authentication and no encryption. Your only layer of security is your 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.
File system doesn’t like long names, need to protect:
PANIC: unprotected error in call to Lua API (httpserver.lua:78: filename too long)
nodemcu firmware with floating point doesn’t have enough memory to compile nor run the server. See below.
luatool.py which is used by the makefile, doesn’t support uploading binary files (yet?). But I’ve successfully used nodemcu-uploader. The only thing to know is that after uploading a file, you need to file.rename() it to add the http/ prefix.
The chip is very, very memory constrained. You must use a recent build of nodemcu-firmware that supports node.compile() since the server expects the helper scripts to be compiled.
If you can’t compile the server code without error even after a fresh restart, then you may need a build of the firmware without floating point. In file nodemcu-firmware/app/lua/luaconf.h right around line 572 (line number may change in the future) add
Then rebuild and re-flash the firmware.
Any help reducing the memory needs of the server without crippling its features are appreciated!