im facing a trouble with send RSSI to the host server
And what might that trouble be?
If you succeed in connecting to the server, why do you connect again?
The Host field contains the name of a server, NOT a protocol and not a script to be executed. The script to be executed is supposed to be part of the POST request. It currently isn't.
You are using the WiFi library, which is ONLY for the Arduino WiFi shield, but apparently are using a ESP device.
int getStrength(int points){
long rssi = 0;
//long averageRSSI=0;
for (int i=0;i < points;i++){
rssi += WiFi.RSSI();
delay(20);
}
return WiFi.RSSI();
}
Get the RSSI value 7 times. Then ignore those 7 values, and get the value again and return it. What is magic about the 8th value?
What is so secret about this value that you need the obscurity, and complexity, of a POST request? A GET request is far simpler, and doesn't require pissing away resources on the String class.