Using an Adafruit Huzzah ESP8266 with nRF24L01+ as a (one-way) internet gateway for several nRF24L01+ sensor nodes

ESP8266-nRF24L01.ino

#include <SPI.h>
#include <RF24Network.h>
#include <RF24.h>
#include <ESP8266WiFi.h>

const char* ssid     = "ssid";
const char* password = "password";

const char* host = "coolapp.herokuapp.com";

// SPI pin configuration figured out from here:
// http://d.av.id.au/blog/esp8266-hardware-spi-hspi-general-info-and-pinout/
RF24 radio(2, 15);    // Set up nRF24L01 radio on SPI bus plus pins 2 & 15
RF24Network network(radio);          // Network uses that radio

// TODO: store this in EEPROM
const uint16_t this_node = 0;        // Address of this node (the gateway node)

struct dataStruct{
  uint16_t _salt;           // 2 bytes
  uint16_t clientId;        // 2 bytes
  char location[4];        // 4 bytes
  char room[4];            // 4 bytes
  uint16_t sensorId;        // 2 bytes
  
  int16_t temp;          // 2 bytes
  uint16_t humidity;        // 2 bytes
  uint16_t volt;            // 2 bytes
}sensor_data;

void setup() {
  Serial.begin(115200);
//  Serial.setDebugOutput(true);
  connectToWifi();
  yield();
  Serial.println("starting......");
  restartRadio();                    // turn on and configure radio
  
  // TODO: remove debugging used to fix payload being too large
  Serial.print("Size of salt: ");Serial.println(sizeof(sensor_data._salt));
  Serial.print("Size of clientId: ");Serial.println(sizeof(sensor_data.clientId));
  Serial.print("Size of location: ");Serial.println(sizeof(sensor_data.location));
  Serial.print("Size of room: ");Serial.println(sizeof(sensor_data.room));
  Serial.print("Size of sensorId: ");Serial.println(sizeof(sensor_data.sensorId));
  Serial.print("Size of temp: ");Serial.println(sizeof(sensor_data.temp));
  Serial.print("Size of humidity: ");Serial.println(sizeof(sensor_data.humidity));
  Serial.print("Size of volt: ");Serial.println(sizeof(sensor_data.volt));
  Serial.print("Size of struct: ");Serial.println(sizeof(sensor_data));  
  Serial.println("Listening for sensor values..."); 
}

void loop() {
  network.update();
  
  while (network.available()) {
    yield();  // give wifi functionality some time to do its operations
    RF24NetworkHeader header;        
    //network.read(header, &sensor_data, radio.getDynamicPayloadSize());
    // explicitly set payload size
    network.read(header,&sensor_data,sizeof(sensor_data));
    
    // TODO: remove debug
    Serial.print("Got message: ");Serial.println(sizeof(sensor_data));
    Serial.print("_salt: ");Serial.println(sensor_data._salt);
    Serial.print("volt: ");Serial.println(sensor_data.volt);
    Serial.print("temp: ");Serial.println(sensor_data.temp);
    Serial.print("humidity: ");Serial.println(sensor_data.humidity);
    Serial.print("clientId: ");Serial.println(sensor_data.clientId);
    Serial.print("location: ");Serial.println(sensor_data.location);
    Serial.print("room: ");Serial.println(sensor_data.room);
    Serial.print("sensorId: ");Serial.println(sensor_data.sensorId);
    Serial.println("-----------");    
    Serial.flush();
    delay(3000);

    // Use WiFiClient class to create TCP connections
    WiFiClient client;
    const int httpPort = 80;
    if (!client.connect(host, httpPort)) {
      Serial.println("connection failed");

      return;
    }

    // We now create a URI for the request
    char url[6] = "/data";
    char tempQueryString[500];
    sprintf(tempQueryString, "?message=%i/%s/%s/%i/temp_%i,%i/%s/%s/%i/humidity_%i,%i/%s/%s/%i/voltage_%i", sensor_data.clientId,
                                                                                                         sensor_data.location,
                                                                                                         sensor_data.room,
                                                                                                         sensor_data.sensorId,
                                                                                                         sensor_data.temp,
                                                                                                         sensor_data.clientId,
                                                                                                         sensor_data.location,
                                                                                                         sensor_data.room,
                                                                                                         sensor_data.sensorId,
                                                                                                         sensor_data.humidity,
                                                                                                         sensor_data.clientId,
                                                                                                         sensor_data.location,
                                                                                                         sensor_data.room,
                                                                                                         sensor_data.sensorId,
                                                                                                         sensor_data.volt);
    
    Serial.print("Requesting URL: ");
    Serial.print(url);
    Serial.println(tempQueryString);
    
    // This will send the request to the server
    client.print(String("GET ") + url + tempQueryString + " HTTP/1.1\r\n" +
                 "Host: " + host + "\r\n" + 
                 "Connection: close\r\n\r\n");

    // delay until we are likely to have received a response from the server.
    // if there's been no response after this delay, the following while
    // loop will be skipped.
    delay(500);
    
    // Read all the lines of the reply from server and print them to Serial
    while(client.available()){
      String line = client.readStringUntil('\r');
      Serial.print(line);
    }
    Serial.println("===========");
    Serial.println("");
  }
}

void connectToWifi() {
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");  
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());  
}

void restartRadio(){
  yield(); // give wifi functionality some time to do its operations

  radio.begin(); // Start up the radio
  network.begin(/*channel*/ 90, /*node address*/ this_node);

  //  radio.setPALevel(RF24_PA_HIGH);
  //  radio.setDataRate(RF24_250KBPS);
  //  radio.openReadingPipe(1, pipes[1]);
  //  radio.openWritingPipe(pipes[0]);
  //  radio.openReadingPipe(1,pipes[0]);
  //  radio.openWritingPipe(pipes[1]);
  //  radio.stopListening();
  network.update(); // always be pumping the network
}

the code shows error #include<avr/pgmspace.h> not available even after downloading the file and putting it up in library

the code shows #include <avr/pgmspace.h> error. please help