A node.js binding for using POSIX message queues
A node.js addon for using POSIX message queues.
node.js -- v0.6.0 or newer
Linux 2.6.6+ or FreeBSD kernel with POSIX message queue support compiled in (CONFIG_POSIX_MQUEUE, which is enabled by default)
man mq_overviewfor how/where to modify global POSIX message queue resource limits
npm install pmq
var PosixMQ = require'pmq';var readbuf mq;mq = ;mqon'messages'var n;while n = thisshiftreadbuf !== falseconsole.log'Received message (' + n + ' bytes): ' + readbuftoString'utf8' 0 n;console.log'Messages left: ' + thiscurmsgs;thisunlink;thisclose;;mqopen name: '/pmqtest' ;readbuf = mqmsgsize;
var PosixMQ = require'pmq';var mq writebuf r;mq = ;mqopenname: '/pmqtest'create: truemode: '0777';writebuf = 1;dowritebuf0 = MathfloorMathrandom * 93 + 33;while r = mqpushwritebuf !== false;mqclose;
messages() - Emitted every time the queue goes from empty to having at least one message.
drain() - Emitted when there is room for at least one message in the queue.
(constructor)() - Creates and returns a new PosixMQ instance.
open(<object>config) - (void) - Connects to a queue. Valid properties in config are:
<string>name - The name of the queue to open, it MUST start with a '/'.
<boolean>create - Set to true to create the queue if it doesn't already exist. The queue will be owned by the user and group of the current process.
<boolean>exclusive - If creating a queue, set to
true if you want to ensure a queue with the given name does not already exist.
<mixed>mode - If creating a queue, this is the permissions to use. This can be an octal string (e.g. '0777') or an integer.
<integer>maxmsgs - If creating a queue, this is the maximum number of messages the queue can hold. This value is subject to the system limits in place and defaults to
<integer>msgsize - If creating a queue, this is the maximum size of each message (in bytes) in the queue. This value is subject to the system limits in place and defaults to
close() - (void) - Disconnects from the queue.
unlink() - (void) - Removes the queue from the system.
push(<Buffer>data[, <integer>priority]) - <boolean> - Pushes a message with the contents of data onto the queue with the optional priority (defaults to 0). The priority is an integer between 0 and 31 inclusive.
shift(<Buffer>readbuf[, <boolean>returnTuple]) - (mixed) - Shifts the next message off the queue and stores it in readbuf. If returnTuple is set to true, an Array containing the number of bytes in the shifted message and the message's priority are returned, otherwise just the number of bytes is returned (default). If there was nothing on the queue, false is returned.
isFull - <boolean> - Convenience property that returns true if curmsgs === maxmsgs.
maxmsgs - <integer> - The maximum number of messages in the queue.
msgsize - <integer> - The maximum size of messages in the queue.
curmsgs - <integer> - The number of messages currently in the queue.