Streaming human readable command protocol
npm install hprotocol
hprotocol allows you to easily generate a command protocol that its easy to parse both for programs and human beings.
As an example lets generate a protocol that echoes a value
var hprotocol = require('hprotocol');
var net = require('net');
var protocol = hprotocol()
.use('echo value > value');
net.createServer(function(socket) {
var client = protocol();
// listen for the echo command
client.on('echo', function(value, callback) {
callback(null, 'echo: '+value);
});
// setup the pipe chain
socket.pipe(client.stream).pipe(socket);
// print the protocol specification for easier usage
socket.write(client.specification);
}).listen(9999);The echo value > value syntax denotes an echo command that accepts a value and returns a value.
Open a new termainal and try interfacing with the server.
$ nc localhost 9999 # create a socket to the server
$ echo test # send a echo command
$ > test # this is the reply from the server
Similary you can interface with the server using node:
var client = protocol(); // using the same protocol as above
var socket = net.connect(9999, 'localhost');
socket.pipe(client.stream).pipe(socket);
client.echo('test', function(err, value) {
console.log(value); // prints echo: test
});Optionally you can use pass the stream to protocol to setup the pipe chain for you
var socket = net.connect(9999, 'localhost');
var client = protocol(socket);
client.echo(...);Similary to the above example the command syntax is always
command argument1 argument2 ... > response
If the command does not have a response just do
command argument1 arguments2
If a series of arguments should the passed as an array add ... to the syntax
command test args... > response
Similary if your response is an array
command test args... > response...
Some examples of this could be
var protocol = hprotocol()
.use('hello')
.use('add numbers... > number')
.use('reverse values... > values...')
var client = protocol();
client.on('hello', function() {
// no response for this since no > in the spec
console.log('hello world');
});
client.on('add', function(numbers, callback) {
numbers = numbers.map(Number); // convert to numbers
var sum = numbers.reduce(function(a, b) {
return a+b;
}, 0);
callback(null, sum); // return a single value
});
client.on('reverse', function(values, callback) {
callback(null, values.reverse());
});
// setup a pipe chain
socket.pipe(client.stream).pipe(socket);If the above socket was listening on port 9999 we could do
echo 'add 1 2 3 4' | nc localhost 9999
# prints > 10
MIT