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Methods documented for Client in Arduino
Methods and properties described further down are specific to ESP8266. They are not covered in Arduino WiFi library documentation. Before they are fully documented please refer to information below.
flush(timeoutMs)
and stop(timeoutMs)
both have now an optional argument: timeout
in millisecond, and both return a boolean.
Default input value 0 means that effective value is left at the discretion of the implementer.
flush()
returning true
indicates that output data have effectively been sent, and false
that a timeout has occurred.
stop()
returns false
in case of an issue when closing the client (for instance a timed-out flush
). Depending on implementation, its parameter can be passed to flush()
.
void abort();
Originally proposed in #8738
Unlike stop()
, immediately shuts down internal connection object.
Under usual circumstances, we either enter CLOSE_WAIT
or TIME_WAIT
state. But, the connection object is not freed right away, and requires us to either
* wait until malloc()
returns NULL
when our TCP stack tries to allocate memory for a new connection
* manually call tcp_kill_timewait()
to forcibly stop the 'oldest' connection
This API frees up resources used by the connection. Consider using it instead of stop()
if your application handles a lot of clients and frequently runs out of available heap memory.
Example:
# define MIN_HEAP_FREE 20000 // or whatever min available heap memory convienent for your application
auto client = server.accept();
// ... do something with the client object ...
if (ESP.getFreeHeap() >= MIN_HEAP_FREE) {
client.stop();
} else {
client.abort();
}
setNoDelay(nodelay)
With nodelay
set to true
, this function will to disable Nagle algorithm.
This algorithm is intended to reduce TCP/IP traffic of small packets sent over the network by combining a number of small outgoing messages, and sending them all at once. The downside of such approach is effectively delaying individual messages until a big enough packet is assembled.
Example:
client.setNoDelay(true);
Returns whether NoDelay is enabled or not for the current connection.
This is an experimental API that will set the client in synchronized mode.
In this mode, every write()
is flushed. It means that after a call to
write()
, data are ensured to be received where they went sent to (that is
flush
semantic).
When set to true
in WiFiClient
implementation,
- It slows down transfers, and implicitly disable the Nagle algorithm.
- It also allows to avoid a temporary copy of data that otherwise consumes
at most
TCP_SND_BUF
= (2 *MSS
) bytes per connection,
Returns whether Sync is enabled or not for the current connection.
These set the default value for both setSync
and setNoDelay
for
every future instance of WiFiClient
(including those coming from
WiFiServer.available()
by default).
Default values are false for both NoDelay
and Sync
.
This means that Nagle is enabled by default for all new connections.
Return the values to be used as default for NoDelay and Sync for all future connections.
uint8_t status ()
virtual size_t write (const uint8_t *buf, size_t size)
size_t write_P (PGM_P buf, size_t size)
size_t write (Stream &stream)
size_t write (Stream &stream, size_t unitSize) __attribute__((deprecated))
virtual int read (uint8_t *buf, size_t size)
virtual int peek ()
virtual size_t peekBytes (uint8_t *buffer, size_t length)
size_t peekBytes (char *buffer, size_t length)
virtual operator bool ()
IPAddress remoteIP ()
uint16_t remotePort ()
IPAddress localIP ()
uint16_t localPort ()
Documentation for the above functions is not yet available.