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Article contents:== chicken-nanomsg [[toc:]] [[http://call-cc.org/|Chicken Scheme]] bindings for the lightweight ZMQ-alternative, [[http://nanomsg.org/|nanomsg]]. There [[http://api.call-cc.org/doc/zmq|exists Chicken ZMQ bindings]], but this turned out to be a little troublesome with zmq_poll blocking other srfi-18 threads. === Why nanomsg Nanomsg is smaller, written in C, has a simplified API (sockets are simple ints), no multipart messages, and has explicit support for poll on a socket's recv file-descriptor, which integrates well with [[http://call-cc.org/|Chicken Scheme]]. === Requirements This egg requires [[https://github.com/nanomsg/nanomsg/releases/tag/1.0.0|nanomsg-1.0.0]] or higher. === Repository [[https://github.com/Adellica/chicken-nanomsg]] === API <procedure>(nn-socket protocol [domain])</procedure> [[http://nanomsg.org/v1.0.0/nn_socket.3.html|Create]] a nanomsg socket. Protocol can be any of the symbols {{pair}}, {{pub}}, {{sub}}, {{pull}}, {{push}}, {{req}}, {{rep}}, {{surveyor}}, {{respondent}} or {{bus}}. Domain can be the symbol {{sp}} or {{sp-raw}}, and defaults to {{sp}}. The returned socket is automatically closed with {{nn-close}} when it is garbage-collected. <procedure>(nn-socket* protocol [domain])</procedure> Just like {{nn-socket}}, but does '''not''' attach a finalizer on the returned socket object. You must manually call {{nn-close}} on the socket after use. <procedure>(nn-bind socket address)</procedure> [[http://nanomsg.org/v1.0.0/nn_bind.3.html|Binds]] nanomsg socket to address, where address is a string of the form {{"ipc:///var/ipc/music.nn.pair"}} or {{"tcp://0.0.0.0:10080"}}. If the nn-library can't parse the address string, it throws an "Illegal argument" error. <procedure>(nn-connect socket address)</procedure> [[http://nanomsg.org/v1.0.0/nn_connect.3.html|Connects]] nanomsg socket {{socket}} to {{address}}. <procedure>(nn-subscribe socket prefix)</procedure> Set the [[http://nanomsg.org/v1.0.0/nn_pubsub.7.html|NN_SUB_SUBSCRIBE]] option on {{socket}} which will make the socket receive to all messages that start with {{prefix}}. Note that if this is never called, {{(nn-sock 'sub)}} sockets will never receive anything. <procedure>(nn-send socket msg)</procedure> Send a message on {{socket}}, using the socket's semantics. {{msg}} must be a string. This will not block other srfi-18 threads. Returns the number of bytes sent. <procedure>(nn-send* socket msg flags)</procedure> Like {{nn-send}}, but may block other srfi-18 threads when {{flags}} is {{0}}. {{flags}} may be {{nn/dontwait}} in which case {{nn-send*}} always returns immediately, and returns {{#f}} is the operation would block (number of bytes otherwise). <procedure>(nn-recv socket)</procedure> Receive a message from socket. This blocks until a message is received from nanomsg, but it does not block other srfi-18 threads. It always returns a string. An error is thrown if the socket is in an illegal state. Note that memory is copied from the nanomsg buffer into a new scheme string. <procedure>(nn-recv* socket flags)</procedure> Receive a message from socket. This will block other srfi-18 threads, unless the {{nn/dontwait}} flag is specified, in which case {{nn-recv*}} will exit immediately with either a message as a string or #f (for {{EAGAIN}}). An error is thrown if {{socket}} is in an illegal state. Note that this can be combined with {{(nn-socket-rcvfd socket)}} for custom polling. <procedure>(nn-close socket)</procedure> Explicitly close {{socket}}. This is normally not needed as this is done in the socket's finalizer. <procedure>(nn-shutdown socket endpoint)</procedure> Removed {{endpoint}} from {{socket}}. See [[http://nanomsg.org/v1.0.0/nn_shutdown.3.html|nn_shutdown]]. <procedure>(nn-get-statistic socket statistic)</procedure> Retrieve a statistic from {{socket}}. {{statistic}} may be any one of these symbols: {{established-connections}} {{accepted-connections}} {{dropped-connections}} {{broken-connections}} {{connect-errors}} {{bind-errors}} {{accept-errors}} {{current-connections}} {{inprogress-connections}} {{current-ep-errors}} {{messages-sent}} {{messages-received}} {{bytes-sent}} {{bytes-received}} {{current-snd-priority}}. See [[http://nanomsg.org/v1.0.0/nn_get_statistic.3.html|nn_get_statistic]]. <procedure>(nn-socket-name socket)</procedure> <procedure>(nn-socket-linger socket)</procedure> <procedure>(nn-socket-rcvtimeo socket)</procedure> <procedure>(nn-socket-sndtimeo socket)</procedure> <procedure>(nn-socket-rcvbuf socket)</procedure> <procedure>(nn-socket-sndbuf socket)</procedure> <procedure>(nn-socket-sndfd socket)</procedure> <procedure>(nn-socket-rcvfd socket)</procedure> <procedure>(nn-socket-protocol socket)</procedure> <procedure>(nn-socket-domain socket)</procedure> <procedure>(nn-socket-maxttl socket)</procedure> <procedure>(nn-socket-rcvmaxsize socket)</procedure> <procedure>(nn-socket-rcvprio socket)</procedure> <procedure>(nn-socket-sndprio socket)</procedure> <procedure>(nn-socket-reconnect-ivl-max socket)</procedure> <procedure>(nn-socket-reconnect-ivl socket)</procedure> <procedure>(nn-socket-ipv4only socket)</procedure> <procedure>(nn-req-socket-resend-ivl socket)</procedure> Retrieve the socket option associated with {{socket}}. Most of these also provide setters so that you can, for example, can do {{(set! (nn-socket-name s) "foo")}}. For other socket options, try {{nn-getsockopt/string}}, {{nn-getsockopt/int}}, {{nn-setsockopt/string}} and {{nn-setsockopt/int}}. === Development Status These bindings to nanomsg 1.0.0 should be fairly complete, the only missing functionality is the control messages ({{nn_recvmsg}}, {{nn_sendmsg}} and {{nn_cmsg}}). Also, note that the egg hasn't undergode rigerous testing in the field yet. === Sample <enscript highlight="scheme"> ;; test.scm (import nanomsg) (define s (nn-socket 'rep)) (nn-bind s "tcp://127.0.0.1:22022") (let loop ((n 0)) (nn-send s (conc (nn-recv s) " " n)) (loop (add1 n))) (nn-close s) </enscript> then test with the brilliant {{nanocat}} util that comes with [nanomsg]: <enscript highlight="bash"> $ csi -s test.scm & $ nanocat --req -l22022 -D"bottles of beer:" -A --interval 1 </enscript>Description of your changes:

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