Esp32 Tutorial: Wi-Fi Web Server with SD Card Storage

bool tWeb::handleFile(AsyncWebServerRequest* req, String path, int code)
{
    // can't begin sd card?
    if (!m_sd->begin())
        return false;

    // open file
    File f = m_sd->openRead(path);
    if (!f) // can't open file?
    {
        m_sd->end(); // end sd access
        return false;
    }
    // is f a directory ?
    if (f.isDirectory())
    {
        f.close(); // close directory
        path = path + ("/" WEB_INDEX); // update path
        f = m_sd->openRead(path); // open index.html inside folder
        if (!f) // file does not exist?
        {
            m_sd->end(); // end sd access
            return false;
        }
    }
    // buffer for mime type string
    char mime[32];
    if (!getMime(path, mime)) // invalid mime type?
    {
        //Serial.println("handleFile: invalid mime: " + String(mime));
        f.close(); // close file
        m_sd->end(); // end sd access
        return false;
    }
    // end card usage
    m_sd->end();

    // Create response (the function inside will run once per chunk until the whole file is sent)
    AsyncWebServerResponse* resp = req->beginChunkedResponse(mime, [&f, this, path](uint8_t* buf, size_t maxlen, size_t index) -> size_t
    {
        if (!m_sd->begin()) // Can't start card?
        {
            Serial.println("beginChunkedResponse: No SD");
            return 0;
        }
        File f = m_sd->openRead(path); // open file
        if (!f) // cant open file?
        {
            Serial.println("beginChunkedResponse: Failed to open file");
            m_sd->end(); // end sd card
            return 0;
        }
        if (!f.available()) // file unavailable?
        {
            Serial.println("beginChunkedResponse: File not available?");
            f.close(); // close file
            m_sd->end(); // end sd card
            return 0;
        }
        f.seek(index); // set read position to index
        size_t len = f.read(buf, maxlen); // read chunk
        f.close(); // close file
        m_sd->end(); // end sd access
        return len;
    });
    resp->setCode(code); // set response code

    req->send(resp); // send response
    return true;
}