This is the demonstration project for the small but powerful libesphttpd webserver for LinkNode D1. It is an example of how to make a module that can have the AP it connects to configured over a webbrowser. It also illustrates multiple flash layouts and some OTA update functionality.

1. About the webserver

• Supports multiple connections, for eg simultaneous html/css/js/images downloading
• Static files stored in flash, in an (optionally compressed) RO filesystem
• Pluggable using external cgi routines
• Simple template engine for mixed c and html things
• Usable as an embedded library – should be easy to drop into your existing projects
• Includes websocket support

2. Source code

The official esphttpd repo lives at http://git.spritesserver.nl/esphttpd.git/ and http://git.spritesserver.nl/libesphttpd.git/ .

If you’re a fan of Github, you can also peruse the official mirror at https://github.com/Spritetm/esphttpd andhttps://github.com/Spritetm/libesphttpd . If you want to discuss this code, there is a subforum at esp8266.com:http://www.esp8266.com/viewforum.php?f=34 .

3. About the example

When you flash the example into an ESP8266(EX) module, you get a small webserver with a few example pages. If you’ve already connected your module to your WLAN before, it’ll keep those settings. When you haven’t or the settings are wrong, keep GPIO0 for >5 seconds. The module will reboot into its STA+AP mode. Connect a computer to the newly formed access point and browse to http://192.168.4.1/wifi in order to connect the module to your WiFi network. The example also allows you to control a LED that’s connected to GPIO2.

4. Build everything

Required

• toolchain for ESP8266
• esptool for flash ESP8266
• esp-open-sdk

For this, you need an environment that can compile ESP8266 firmware. Environments for this still are in flux at the moment, but I’m using esp-open-sdk: https://github.com/pfalcon/esp-open-sdk .

You probably also need an UNIX-like system; I’m working on Debian Linux myself.

To manage the paths to all this, you can source a small shell fragment into your current session. For example, I source a file with these contents:

export PATH=${PWD}/esp-open-sdk/xtensa-lx106-elf/bin:$PATH
export SDK_BASE=${PWD}/esp-open-sdk/sdk
export ESPTOOL=${PWD}/esptool/esptool.py
export ESPPORT=/dev/ttyUSB0
export ESPBAUD=460800

Actual setup of the SDK and toolchain is out of the scope of this document, so I hope this helps you enough to set up your own if you haven’t already.

If you have that, you can clone out the source code:

git clone http://git.spritesserver.nl/esphttpd.git/

This project makes use of heatshrink, which is a git submodule.

• To fetch the code:

  cd esphttpd 
  git submodule init 
  git submodule update

Configure the flash mode as DIO:

vim Makefile

#0: QIO, 1: QOUT, 2: DIO, 3: DOUT
ESP_FLASH_MODE=2

Now, build the code:

make USE_OPENSDK=yes

Note: You can also edit the Makefile to change this more permanently.

• Download the program:

make flash

Pages of webserver

You should have a working webserver now.

If LinkNode D1 have not access WiFi hotpot, it will generated a WiFi hotpot which is called ESP_XXXXXX.

Use your mobile phone or PC to connect this hotpot, then  open your browser and enter 192.168.4.1, and you will get the following webpages.

• Main page of this webserver

• Update firmware via WiFi

• STA+AP mode, configure the WiFi.

• Turn on or off Build-in LED on LinkNodeD1