nn_ws - WebSocket transport mechanism
The WebSocket transport uses the framing protocol specified in RFC 6455 to
transport messages. The initial handshake is done using HTTP headers, with the
Sec-Websocket-Protocol header set to the SP protocol used by the server. For
example, a REQ client will send rep.sp.nanomsg.org.
Each SP message is transported in a single WebSocket frame, with no additional
data or headers applied. By default this library sends and expects to receive
When calling either nn_bind() or nn_connect(), omitting the port defaults to the
RFC 6455 default port 80 for HTTP. For example, ws://127.0.0.1 is equivalent
WebSocket over TLS is not supported by this library, at this time.
When calling nn_connect(), the URI may also optionally include the path to a
resource and/or query parameters.
Example 1. Path and query parameters
s1 = nn_socket (AF_SP, NN_PAIR);
nn_connect (s1, "ws://example.com/path?query=value");
This implementation includes the full path and any query parameters in the HTTP
handshake when establishing connections with nn_connect(). This information is
not available via the nanomsg API afterwards, however.
Likewise, this implementation does not examine or use either any path or query
parameters that may be supplied to nn_bind(), as it only binds to the TCP
port. This implementation acts as a limited HTTP server that offers SP over
WebSocket at all URIs for the given TCP address.
Applications, however, should not depend on this behavior; intervening
infrastructure may proxy, filter or route based on URI, and other
implementations of the SP over WebSocket protocol may offer other HTTP
services at the same TCP port, utilizing the path, query parameters, or both
to determine the service to be used.
This option may be set to NN_WS_MSG_TYPE_TEXT or
NN_WS_MSG_TYPE_BINARY. The value of this determines whether data messages are
sent as WebSocket text frames, or binary frames, per RFC 6455. Text frames
should contain only valid UTF-8 text in their payload, or they will be
rejected. Binary frames may contain any data. Not all WebSocket
implementations support binary frames. The default is to send binary frames.
This option may also be specified as control data when when sending a message
This option, when set to 1, disables Nagle’s
algorithm. It also disables delaying of TCP acknowledgments. Using this option
improves latency at the expense of throughput. Type of this option is int.
Default value is 0.
nn_bind (s1, "ws://*:5555");
nn_connect (s2, "ws://myserver:5555");
nn_tcp(7) nn_inproc(7) nn_ipc(7) nn_bind(3) nn_connect(3) nanomsg(7)