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Arduino platform

The library defines three interfaces to abstract the platform:

  • IWifiManager — WiFi management.
  • ICredentialStore — device identity storage.
  • IHttpClient — HTTP requests.

Arduino implementations of these interfaces are in platform/arduino/. They are compiled only for ESP32/Arduino.

ArduinoWifiManager

Implements IWifiManager on top of Arduino WiFi.

class ArduinoWifiManager : public IWifiManager {
    void begin(const char* ssid, const char* password) override;
    bool connect() override;
    bool isConnected() override;
    void disconnect() override;
    void getLocalIP(char* buffer, size_t bufferSize) override;
    void getSSID(char* buffer, size_t bufferSize) override;
    int  getRSSI() override;
    void getMacAddress(char* buffer, size_t bufferSize) override;
    void loop() override;
};

begin() stores credentials and initiates connection. Safe to call multiple times (e.g., after Improv provisioning).

loop() is called inside CloudStateMachine::loop(). The product does not need to call it.

ArduinoCredentialStore

Implements ICredentialStore via ESP32 NVS (Preferences), namespace "idryer".

Stores three fields:

NVS key Content
serial device serial number (MQTT username)
token device token (MQTT password)
deviceId backend UUID (after claiming) 
bool load(DeviceIdentity& identity);  // true if token is not empty
bool save(const DeviceIdentity& identity);
void clear();

Additional method:

void seedSerialFromMac();

If NVS has no serial number — generates one from the WiFi MAC address in the format DEVICE_AABBCCDDEEFF and saves it. Call in setup() before runtime.begin().

ArduinoHttpClient

Implements IHttpClient via WiFiClientSecure.

bool postJson(const char* url, const char* body, JsonDocument& response) override;
bool getJson(const char* url, JsonDocument& response) override;
void setTimeout(uint32_t timeoutMs) override; // default 10000 ms

Uses the Let's Encrypt ISRG Root X1 root CA (from root_ca.h). Used by CloudStateMachine for provisioning and claim polling. The product does not call it directly.

ArduinoWifiStore

Separate class (does not implement an interface) for storing WiFi credentials in NVS, namespace "wifi". Used together with Improv WiFi.

bool load(char* ssid, size_t ssidLen, char* password, size_t passLen);
void save(const char* ssid, const char* password);

Typical usage in setup():

ArduinoWifiStore wifiStore;

// Restore saved credentials
char ssid[64], pass[64];
if (wifiStore.load(ssid, sizeof(ssid), pass, sizeof(pass))) {
    wifi.begin(ssid, pass);
}

// Save after Improv
improv.onImprovConnected([&](const char* s, const char* p) {
    wifiStore.save(s, p);
    wifi.begin(s, p);
});

HAL: ArduinoTime and ArduinoLogger

hal/hal_arduino.h contains Arduino implementations of HAL interfaces:

  • ArduinoTime — delegates millis(), micros(), delay(), delayMicroseconds().
  • ArduinoLogger — formatted output to Stream with levels and ANSI colors.
  • ArduinoSerial — wraps HardwareSerial for UartBridge.

Initialization:

// In setup() — logs disabled while Improv owns Serial
idryer::hal::initArduinoHal(nullptr);

// After WiFi connects
idryer::hal::initArduinoHal(&Serial);

initArduinoHal(nullptr) is safe to call: all HAL_LOG_* macros become no-ops.

Why this abstraction is needed

CloudStateMachine accepts IWifiManager* and ICredentialStore*. This allows:

  • Running tests on a host without real WiFi (replace with mocks).
  • Supporting another platform (non-Arduino) without changing the library core.
  • Testing provisioning logic independently of hardware.

In practice, only Arduino implementations are used in iDryer products.