obs-websocket-tally/src/main.cpp

#include <ESP8266WiFi.h>
#include <WebSocketsClient.h>
#include <ArduinoJson.h>
#include <FastLED.h>
#include <Hash.h>
#include <SHA256.h>
#include <Base64.h>

// BEGIN CONFIGURATION

#define LED_COUNT 19
#define LED_BRIGHTNESS 100
#define LED_PIN D4

#define WIFI_SSID ""
#define WIFI_PASS ""

#define OBS_HOST ""
#define OBS_PORT 4444
#define OBS_PASS ""

#define OBS_SOURCE ""

// END CONFIGURATION

#define HASH_SIZE 32

CRGB leds[LED_COUNT];
WebSocketsClient webSocket;
SHA256 sha256;

bool is_currently_live = false;
bool is_currently_preview = false;

void set_program() {
    fill_solid(leds, LED_COUNT, CRGB::Red);
    FastLED.show();
}

void set_preview() {
    fill_solid(leds, LED_COUNT, CRGB::Green);
    FastLED.show();
}

void set_idle() {
    fill_solid(leds, LED_COUNT, CRGB::Black);
    FastLED.show();
}

void set_error() {
    fill_solid(leds, LED_COUNT, CRGB::Purple);
    FastLED.show();
}

void handleWebSocketEvent(WStype_t type, uint8_t * payload, size_t length) {
    switch(type) {
        case WStype_DISCONNECTED:
            Serial.println("[WS] disconnected");
            /*
                We do NOT set the LEDs to off in here on purpose. Maybe
                just the wifi connection was interrupted or something
                like that. It is important we don't disable the LEDs, in
                case the OBS instance is still running.

                We do, however, set the LEDs to the "error" state, to
                indicate we don't currently know what OBS is showing.
            */
            set_error();
            break;

        case WStype_CONNECTED:
            Serial.printf("[WS] connected to %s\n", payload);
            // Find out if we need authentication
            webSocket.sendTXT("{\"request-type\":\"GetAuthRequired\",\"message-id\":\"1\"}");
            break;

        case WStype_TEXT: {
            Serial.printf("[WS] %s", payload);

            StaticJsonDocument<5000> doc;
            DeserializationError error = deserializeJson(doc, payload);

            if (error) {
                Serial.print("deserializeJson() failed: ");
                Serial.println(error.c_str());
                break;
            }

            if (doc.containsKey("authRequired")) {
                Serial.println("[OBS] auth requested");

                sha256.reset();
                sha256.update(OBS_PASS, strlen(OBS_PASS));
                const char* salt = doc["salt"];
                sha256.update(salt, strlen(salt));
                char value[HASH_SIZE];
                sha256.finalize(value, HASH_SIZE);

                Serial.print("[OBS] sha256 authentication hash is: ");
                for (size_t i = 0; i < HASH_SIZE; i++) {
                    Serial.print(static_cast<unsigned int>(value[i]), HEX);
                }
                Serial.println();

                int encodedLength = Base64.encodedLength(HASH_SIZE);
                char encodedPassSaltHash[encodedLength];
                Base64.encode(encodedPassSaltHash, value, HASH_SIZE);

                const char* challenge = doc["challenge"];
                sha256.reset();
                sha256.update(encodedPassSaltHash, encodedLength);
                sha256.update(challenge, strlen(challenge));
                sha256.finalize(value, HASH_SIZE);

                Serial.print("[OBS] sha256 challenge hash is: ");
                for (size_t i = 0; i < HASH_SIZE; i++) {
                    Serial.print(static_cast<unsigned int>(value[i]), HEX);
                }
                Serial.println();

                char encodedAuthString[encodedLength];
                Base64.encode(encodedAuthString, value, HASH_SIZE);

                String authRequest = String("{\"request-type\":\"Authenticate\",\"message-id\":\"2\",\"auth\":\"") + encodedAuthString + "\"}";
                webSocket.sendTXT(authRequest);
                break;

            } else if (doc.containsKey("message-id") && (doc["message-id"]) == "2") {
                if (strcmp(doc["status"], "ok") == 0) {
                    Serial.println("[OBS] authentication successful");
                    webSocket.sendTXT("{\"request-type\":\"GetCurrentScene\",\"message-id\":\"3\"}");
                    webSocket.sendTXT("{\"request-type\":\"GetPreviewScene\",\"message-id\":\"4\"}");
                } else {
                    Serial.println("Authenticated FAILED");
                    set_error();
                }
                break;
            } else if (doc.containsKey("update-type")) {
                bool my_source_in_current_event = false;

                for (uint8_t i = 0; i < doc["sources"].size(); i++) {
                    if (strcmp(doc["sources"][i]["name"], OBS_SOURCE) == 0) {
                        my_source_in_current_event = true;
                    }
                }

                if (strcmp(doc["update-type"], "SwitchScenes") == 0 || strcmp(doc["update-type"], "GetCurrentScene") == 0) {
                    if (my_source_in_current_event) {
                        is_currently_live = true;
                    } else {
                        is_currently_live = false;
                    }
                } else if (strcmp(doc["update-type"], "PreviewSceneChanged") == 0 || strcmp(doc["update-type"], "GetPreviewScene") == 0) {
                    if (my_source_in_current_event) {
                        is_currently_preview = true;
                    } else {
                        is_currently_preview = false;
                    }
                } else if (strcmp(doc["update-type"], "Exiting") == 0) {
                    is_currently_preview = false;
                    is_currently_live = false;
                } else if (strcmp(doc["update-type"], "StudioModeSwitched") == 0 && doc["new-state"] == false) {
                    is_currently_preview = false;
                }
            }

            if (is_currently_live) {
                set_program();
            } else if (is_currently_preview) {
                set_preview();
            } else {
                set_idle();
            }
        }

        case WStype_BIN:
        case WStype_ERROR:
        case WStype_FRAGMENT_TEXT_START:
        case WStype_FRAGMENT_BIN_START:
        case WStype_FRAGMENT:
        case WStype_FRAGMENT_FIN:
        case WStype_PING:
        case WStype_PONG:
            break;
    }
}

void setup() {
    Serial.begin(115200);

    Serial.println("[Tally] starting up");

    FastLED.addLeds<WS2812B, LED_PIN, GRB>(leds, LED_COUNT);
    FastLED.setBrightness(LED_BRIGHTNESS);

    set_error();
    delay(500);
    set_idle();
    delay(500);
    set_error();
    delay(500);
    set_idle();
    delay(200);

    Serial.printf("[Tally] connecting to wifi ssid: %s\n", WIFI_SSID);

    WiFi.mode(WIFI_STA);
    WiFi.begin(WIFI_SSID, WIFI_PASS);

    while(WiFi.status() != WL_CONNECTED) {
        delay(250);
        Serial.print(".");
    }
    Serial.println();
    Serial.print("[Tally] connected to wifi, ip address");
    Serial.println(WiFi.localIP());

    Serial.println("[Tally] connecting to OBS");
    webSocket.begin(OBS_HOST, OBS_PORT, "/");
    webSocket.onEvent(handleWebSocketEvent);
    webSocket.setReconnectInterval(2000);

    Serial.println("[Tally] startup complete");
}

void loop() {
    webSocket.loop();
}