/**
* Initialization of new http connection.
* \param host - Host name without protocols.
* \param port - Server's port.
* \param uri - The URI of resource.
* \param CAcert - The Base64 encode root certificate string
* \return True as default.
* If no certificate string provided, use (const char*)NULL to CAcert param 
*/
bool http_begin(const char* host, uint16_t port, const char* uri, const char* CAcert);

/**
* Check the http connection status.
* \return True if connected.
*/
bool http_connected();

/**
* Establish http connection if header provided and send it, send payload if provided.
* \param header - The header string (constant chars array).
* \param payload - The payload string (constant chars array), optional.
* \return http status code, Return zero if new http connection and header and/or payload sent 
* with no error or no header and payload provided. If obly payload provided, no new http connection was established.
*/
int http_sendRequest(const char* header, const char* payload);

/**
* Send extra header without making new http connection (if http_sendRequest has been called)
* \param header - The header string (constant chars array).
* \return True if header sending success.
* Need to call http_sendRequest with header first. 
*/
bool http_sendHeader(const char* header);

/**
* Get the WiFi client pointer.
* \return WiFi client pointer.
*/
WiFiClient* http_getStreamPtr(void);


/**
* Set debug print to serial.
* 
* \param cb - callback function that accept constant char array (const char*).
*/
void setDebugCallback(DebugMsgCallback cb);

    
/**
* Start connect to host.
* 
* \return bool status of connection.
*/
bool http_connect(void);

/**
* Start connect to host with STARTTLS command.
* 
* \return bool status of connection.
*/
bool http_connect(bool starttls);