chasm

Module to asynchronously determine port availability.

npm install chasm

Usage

• Single Port - provide a single numerical value to have Chasm return the its availability.
• Smallest - will return the smallest available port.
• Largest - will return the largest available port.
• Port Array - provide an array of numerical values to have Chasm return each of the availabilities in the order provided.
• Port Range - provide a minimum or maximum, or both, to have Chasm return the available port(s) within the specified range. You can additionally specify if you'd want the last port in the range or all the ports (without specification, Chasm will assume the first.) Specifying last will return the largest available port within the range. Specifying all will return all the ports with the range and their availabilities. While all port lookups are non-blocking, large ranges with all resulting ports will take additional time.
• Allow Reserved - will set the floor of the port range from 1025 to 1, expect the unexpected.

While asynchronous, depending on the amount of ports to process, some statements may take longer to finish than others (even if they were called a way ahead of time.)

Programmatically

var Chasm = require('chasm')

Chasm(ports,function(err,result){
    
    if(err) console.error('Uh-oh!',err)
    else console.log('Done!',result)
  }
);

Call Chasm with ports and a callback. Valid ports arguments are just below. The callback will include two variables, the first will be an error (defined if anything messed up with Node.js' net module) and the second will be the results.

var Chasm = require('chasm')

/* We'll simulate a used port. After this,
// port '10100' will be in use and Chasm
// will report its availability as 'false'.
*/
require('net').createServer().listen(10100);

Chasm('smallest',console.log); // null 1025
Chasm('largest',console.log); // null 65535

Chasm(10100,console.log); // null false
Chasm(10101,console.log); // null 10101

Chasm([10099,10100,10001],console.log); // null [10099,false,10001]

Chasm({'min':10100,'max':10102},console.log); // null 10101
Chasm({'get':'first','min':10100,'max':10102},console.log); // null 10101
Chasm({'get':'last','min':10100,'max':10102},console.log);  // null 10102
Chasm({'get':'all','min':10100,'max':10102},console.log);   // null [false,10101,10102]

var Chasm = require('chasm');

Chasm('smallest',console.log); // null 1025
Chasm.allowReserved();
Chasm('smallest',console.log); // null 1

To-dos

• Have a reservation system that will hold a provided port and release it on command?.. provide the user the ability to reserve a port and switch it when the application is ready.
• Have a service identifier, similar to Wireshark?.. without creating any new standards, it'd be useful to determine what service is behind the port (assuming it wants to be identified.)