We use these in our new ESP8266 Sensor Server but will make more generic programming notes here.
The ESP8266 is a low-cost Wi-Fi microchip with full TCP/IP stack and microcontroller capability produced by Shanghai-based manufacturer Espressif. wikipedia
We generate sensor reports from flat files maintained within the SensorServer system with the mksensor script.
* ESP8266 Non-OS SDK, API Reference. pdf