Can't get a transcription from ESP32

API
1

Hi! I’m trying to make an Speech-To-Text using an ESP32 board.
I’m currently modifying a non-finished library that integrates OpenAI API with Arduino code (in github me-no-dev/OpenAI-ESP32).
I modified the code to only use a function to send the audio (in chunks) to the server:

String OpenAI_AudioTranscription::file(File& audio_file, OpenAI_Audio_Input_Format f) {
    if (!audio_file) {
        Serial.println("Invalid file handle");
        return "";
    }

    if (oai.getWiFiClient() == nullptr) {
        Serial.println("WiFi client not set");
        return "";
    }

    String endpoint = "audio/transcriptions";
    String boundary = "----WebKitFormBoundary9HKFexBRLrf9dcpY";
    String itemPrefix = "--" + boundary + "\r\nContent-Disposition: form-data; name=";

    // Calcular el tamaño total del cuerpo de la petición
    String reqBody = itemPrefix + "\"model\"\r\n\r\nwhisper-1\r\n";
    if (prompt != NULL) {
        reqBody += itemPrefix + "\"prompt\"\r\n\r\n" + String(prompt) + "\r\n";
    }
    if (response_format != OPENAI_AUDIO_RESPONSE_FORMAT_JSON) {
        reqBody += itemPrefix + "\"response_format\"\r\n\r\n" + String(audio_response_formats[response_format]) + "\r\n";
    }
    if (temperature != 0) {
        reqBody += itemPrefix + "\"temperature\"\r\n\r\n" + String(temperature) + "\r\n";
    }
    if (language != NULL) {
        reqBody += itemPrefix + "\"language\"\r\n\r\n" + String(language) + "\r\n";
    }
    reqBody += itemPrefix + "\"file\"; filename=\"audio." + String(audio_input_formats[f]) + "\"\r\nContent-Type: " + String(audio_input_mime[f]) + "\r\n\r\n";

    String reqEndBody = "\r\n--" + boundary + "--\r\n";

    size_t totalLength = reqBody.length() + audio_file.size() + reqEndBody.length();

    // Iniciar la conexión HTTP
    HttpClient http(*oai.getWiFiClient(), "api.openai.com", 80);
    http.beginRequest();
    http.post("/v1/" + endpoint);
    http.sendHeader("Content-Type", "multipart/form-data; boundary=" + boundary);
    http.sendHeader("Authorization", "Bearer " + oai.getApiKey());
    http.sendHeader("Content-Length", totalLength);
    http.beginBody();

    // Enviar la primera parte del cuerpo (headers del form-data)
    http.write((const uint8_t*)reqBody.c_str(), reqBody.length());

    // Enviar el archivo en chunks
    const size_t CHUNK_SIZE = 1024; // Ajusta según la memoria disponible
    uint8_t buffer[CHUNK_SIZE];

    while (audio_file.available()) {
        size_t bytesRead = audio_file.read(buffer, CHUNK_SIZE);
        if (bytesRead > 0) {
            http.write(buffer, bytesRead);
        }
    }

    // Enviar la parte final del cuerpo
    http.write((const uint8_t*)reqEndBody.c_str(), reqEndBody.length());
    http.endRequest();

    // Procesar la respuesta
    int statusCode = http.responseStatusCode();
    String result = "";

    if (statusCode == 200) {
        // Leer la respuesta en chunks también
        const size_t READ_CHUNK_SIZE = 64; // Tamaño del buffer de lectura
        char responseBuffer[READ_CHUNK_SIZE + 1];

        while (http.available()) {
            int bytesRead = http.read((uint8_t*)responseBuffer, READ_CHUNK_SIZE);
            if (bytesRead > 0) {
                responseBuffer[bytesRead] = 0; // Null terminator
                result += responseBuffer;
            }
        }
    }
    else {
        Serial.println("HTTP Error: " + String(statusCode));
    }

    http.stop();

    // Procesar el JSON de respuesta
    if (!result.length()) {
        Serial.println("Empty result!");
        return result;
    }

    cJSON* json = cJSON_Parse(result.c_str());
    String error = getJsonError(json);
    result = "";

    if (error.length()) {
        Serial.println(error);
    }
    else if (cJSON_HasObjectItem(json, "text")) {
        cJSON* text = cJSON_GetObjectItem(json, "text");
        result = String(cJSON_GetStringValue(text));
    }

    cJSON_Delete(json);
    return result;
}

But I’m getting HTTP Error: -3 (??) in console.
I guess I’m making the http request not in the correct way.
Can someone help me? Thanks!!