esp8266helper.c

/*
 * Commands
 * - Wifi commands
 * - MQTT commands
 * Whenever a command is not recognized, a response of "?" is given
 * --------------------------------------------------------------------------------
 * 
 * Wifi Commands
 * 
 * Set IP
 * WI<ip byte[4]><gateway byte[4]><subnet byte[4]><dns byte[4]>
 * Replies with
 * - WI: Set successfully
 * 
 * Connect to Wifi (not blocking)
 * WC<ssid length byte><password length byte><ssid string, not 0 terminated><password string, not 0 terminated>
 * password length may be 0, subsequently the password string may have no content
 * Replies with
 * - WCF Internal failure or parameter failure
 * - WCS Successfully initiated the wifi connection
 * 
 * Disconnect from Wifi
 * WD
 * Replies with
 * - WD Called disconnect
 * 
 * Get Wifi status
 * WS
 * Replies with
 * - WS<status int32>
 * Copied from the documentation, the status int should be one of the following values
 * 0 : WL_IDLE_STATUS when Wi-Fi is in process of changing between statuses
 * 1 : WL_NO_SSID_AVAIL in case configured SSID cannot be reached
 * 3 : WL_CONNECTED after successful connection is established
 * 4 : WL_CONNECT_FAILED if password is incorrect
 * 6 : WL_DISCONNECTED if module is not configured in station mode
 * 
 * --------------------------------------------------------------------------------
 * 
 * Configure MQTT
 * MI<server length byte><port uint16><server string, not 0 terminated>
 * Replies with
 * - MI
 * 
 * Connect MQTT (blocking)
 * MC<device id length byte><user length byte><password length byte><device id string, not 0 terminated><user string, not 0 terminated><password string, not 0 terminated>
 * Replies with
 * - MCF Internal failure or bad input
 * - MCS Success
 * user length may be 0, subsequently the user string may have no content
 * password length may be 0, subsequently the password string may have no conent
 * 
 * Disconnect MQTT
 * MD
 * Replies with
 * - MD
 * 
 * Subscribe to MQTT topic (blocking)
 * MB<topic length byte><topic string, not 0 terminated>
 * Replies with
 * - MBF on internal failure, bad input, or on bad MQTT response
 * - MBS on success
 * 
 * TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO 
 * Unsubscribe to MQTT topic (blocking)
 * MU<topic length byte><topic string, not 0 terminated>
 * Replies with
 * - MUF on internal failure, bad input, or bad MQTT response
 * - MUS on success
 * 
 * Get MQTT Status
 * MS
 * Replies with
 * - MS<status int32>
 * Copied from the source of PubSubClient
 * -4 MQTT_CONNECTION_TIMEOUT
 * -3 MQTT_CONNECTION_LOST
 * -2 MQTT_CONNECT_FAILED
 * -1 MQTT_DISCONNECTED
 * +0 MQTT_CONNECTED
 * +1 MQTT_CONNECT_BAD_PROTOCOL
 * +2 MQTT_CONNECT_BAD_CLIENT_ID
 * +3 MQTT_CONNECT_UNAVAILABLE
 * +4 MQTT_CONNECT_BAD_CREDENTIALS
 * +5 MQTT_CONNECT_UNAUTHORIZED
 * 
 * TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO
 * Publish
 * MP<topic length><content length><topic string, not 0 terminated><content bytes>
 * Replies with
 * - MPF on internal failure, bad input, or bad MQTT response
 * - MPS on success
 */