api_handler.cpp

#include "api_handler.h"
#include <string>
#include <vector>

int64_t lastApiUpdatedAt = 1 * 1000;
int apiPeriod = 5 * 1000;
HTTPClient http;

int errorCounter = 0;

void parseServerResponse(String payload) {
  DynamicJsonBuffer jsonBuffer;
  JsonObject& parsed = jsonBuffer.parseObject(payload);

  if (!parsed.success()) {
    Serial.println("Parsing failed");
    return;
  }

  Serial.println(payload);
}

void scrapeApi() {
  if (WiFi.status() != WL_CONNECTED) { return; }
  Serial.println("======= Scraping API");
  String url = "http://headers.jsontest.com/";
  http.begin(url);
  int httpCode = http.GET();

  if (httpCode > 0) {
    if (httpCode == HTTP_CODE_OK) {
      errorCounter = 0;
      String payload = http.getString();
      parseServerResponse(payload);
    }
  } else {
    Serial.print("[HTTP] GET... failed, error: ");
    Serial.println(http.errorToString(httpCode).c_str());
    printWiFiDebug();
    errorCounter++;
    Serial.print("Error count: ");
    Serial.println(errorCounter);
    if (errorCounter > 3) { initWifi(); errorCounter = 0; }
  }

  http.end();
  yield();
}

void scrapeApiHandler() {
  int64_t currentMillis = millis();
  if (currentMillis > lastApiUpdatedAt + apiPeriod) {
    scrapeApi();
    lastApiUpdatedAt = currentMillis;
  }
}

api_handler.h

#ifndef SRC_API_HANDLER_H_
#define SRC_API_HANDLER_H_

#ifdef ESP8266

#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>

#elif defined(ESP32)

#include <esp_wifi.h>
#include <WiFi.h>
#include <HTTPClient.h>

#endif

#include <ArduinoJson.h>
#include "wifi_handler.h"

extern HTTPClient http;

void scrapeApiHandler();
#endif  // SRC_API_HANDLER_H_

main.cpp

#include "main.h"

void setup() {
  Serial.begin(9600);
  initWifi();
}

void loop() {
  scrapeApiHandler();
  yield();
}

main.h

#ifndef SRC_MAIN_H_
#define SRC_MAIN_H_

#include <Arduino.h>
#include <ArduinoJson.h>

#include "api_handler.h"
#include "wifi_handler.h"

#endif  // SRC_MAIN_H_

platformio.ini

; PlatformIO Project Configuration File
;
;   Build options: build flags, source filter
;   Upload options: custom upload port, speed and extra flags
;   Library options: dependencies, extra library storages
;   Advanced options: extra scripting
;
; Please visit documentation for the other options and examples
; https://docs.platformio.org/page/projectconf.html

[platformio]
env_default = esp12e
; env_default = esp32dev
[env:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino
upload_speed = 921600
lib_deps =
  ArduinoJson@5.13.2
[env:esp12e]
platform = espressif8266
board = esp12e
framework = arduino
upload_speed = 921600
lib_archive = false
lib_deps =
  ArduinoJson@5.13.2

wifi_handler.cpp

#include "wifi_handler.h"

void printWiFiDebug() {
  Serial.print("Wifi status: ");
  Serial.print(WiFi.status());
  Serial.print(" (Connected = ");
  Serial.print(WL_CONNECTED);
  Serial.print(")");
  long rssi = WiFi.RSSI();
  Serial.print("Wifi signal: ");
  Serial.println(rssi);
}

bool isWifiConnected() {
  if (WiFi.status() == WL_CONNECTED) { return true; }
  return false;
}

void initWifi() {
  Serial.println("Initializing WiFi");
  WiFi.disconnect(true);
  WiFi.softAPdisconnect(true);
  WiFi.mode(WIFI_STA);
  wifi_set_sleep_type(NONE_SLEEP_T);

  delay(100);
  
  WiFi.begin("xxx", "xxx");

  int seconds = 0;

  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print(".");
    seconds++;
    if (seconds > 15) { Serial.println("Failed connecting to WiFi"); return; }
  }

  Serial.print("\nConnected to WiFI with local IP: ");
  Serial.println(WiFi.localIP());
}

wifi_handler.h

#ifndef SRC_WIFI_HANDLER_H_
#define SRC_WIFI_HANDLER_H_

#include <Arduino.h>

#ifdef ESP8266
#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>

#elif defined(ESP32)
#include <esp_wifi.h>
#include <WiFi.h>
#include <WebServer.h>

#endif

bool isWifiConnected();
void initWifi();
void printWiFiDebug();
#endif  // SRC_WIFI_HANDLER_H_