Networking (TCP/TLS)¶

(kaappi net) — shared TCP client/server and TLS client. Used internally by kaappi-redis, kaappi-http, and kaappi-web.

thottam install kaappi-net

You typically don't use this library directly — the higher-level libraries handle it. But it's available for custom protocols.

TCP Client¶

(import (kaappi net))

(let ((fd (tcp-connect "example.com" 80)))
  (let ((req (string->utf8 "GET / HTTP/1.0\r\nHost: example.com\r\n\r\n")))
    (tcp-send fd req (bytevector-length req)))
  (let ((buf (make-bytevector 4096 0)))
    (let ((n (tcp-recv fd buf 4096)))
      (display (utf8->string (bytevector-copy buf 0 n)))))
  (tcp-close fd))

TCP Server¶

(let ((listen-fd (tcp-listen "0.0.0.0" 8080)))
  (let loop ()
    (let ((client-fd (tcp-accept listen-fd)))
      ;; handle client...
      (tcp-close client-fd)
      (loop))))

TLS Client¶

(let ((ssl (tls-connect "api.github.com" 443)))
  (tls-send ssl request-bv (bytevector-length request-bv))
  (tls-recv ssl buf len)
  (tls-close ssl))

TLS includes SNI (Server Name Indication) and certificate verification via OpenSSL.

API¶

TCP¶

Procedure	Description
`(tcp-connect host port [timeout])`	Connect to host:port, returns fd
`(tcp-listen host port [backlog])`	Bind + listen, returns listen fd
`(tcp-accept listen-fd)`	Accept connection, returns client fd
`(tcp-send fd buf len)`	Send bytes
`(tcp-recv fd buf len)`	Receive bytes (0 = EOF)
`(tcp-close fd)`	Close socket
`(tcp-last-error)`	Last errno

TLS¶

Procedure	Description
`(tls-connect host port [timeout])`	TLS handshake, returns handle
`(tls-send ssl buf len)`	Send over TLS
`(tls-recv ssl buf len)`	Receive over TLS
`(tls-close ssl)`	Shutdown TLS + close socket

Non-blocking¶

Procedure	Description
`(set-nonblocking fd)`	Set O_NONBLOCK on socket
`(poll-read fd timeout-ms)`	1 = ready, 0 = timeout, -1 = error
`(nb-accept listen-fd)`	Non-blocking accept (-2 = EAGAIN)