node stream tests : It's a simple protocol parser. I created it for test the NODE Stream module. #devsample

.jshintrc

{
  "curly": true,
  "eqeqeq": true,
  "immed": true,
  "latedef": true,
  "newcap": true,
  "noarg": true,
  "sub": true,
  "undef": true,
  "unused": "vars",
  "boss": true,
  "eqnull": true,
  "node": true,
  "trailing": true
}

nclient.js

/*
 * node stream tests - Client
 */

'use strict';

var logger = require('winston'),
    _ = require('underscore');

exports = module.exports = function (opts) {
    var net = require('net'),
        proto = require('./nsrv-protocol'),
        Incoming = proto.Incoming,
        Outgoing = proto.Outgoing,
        client,
        defaultTagetAddr = { host : 'localhost', port : 8095 },
        clientOpts = {
            targetSrv : defaultTagetAddr
        };

    /* update client options */
    logger.debug('starting client, input opts %s', JSON.stringify(opts));
    _.each(_.keys(clientOpts), function (opt) {
        if (opts[opt]) {
            clientOpts[opt] = opts[opt];
        }
    });
    logger.info('starting client, opts %s', JSON.stringify(clientOpts));

    /* connect to server */
    client = net.connect({
        host : clientOpts.targetSrv.host,
        port : clientOpts.targetSrv.port
    },
    function() {
        var req = new Outgoing(),
            res = new Incoming();

        logger.info('connected to %s', JSON.stringify(clientOpts.targetSrv));

        client.on('close', function (hasErr) {
            logger.info('socket closed. hasErr %s', hasErr);
        });

        /* startup the request & response streams */
        res.on('error', function (err) {
            /* close the socket when error occued */
            logger.error('Remote %s: An error occued on the response stream');
            client.end(null);
            client.destroy();
        });

        req.on('error', function (err) {
            /* close the socket when error occued */
            logger.error('Remote %s: An error occued on the request stream.');
            client.end(null);
            client.destroy();
        });

        res.on('eval', function (cmd) {
            if (!cmd.command) {
                logger.error('Serv got an empty command');
                return;
            }
            else if (cmd.command === 'echo') {
                /* echo command */
                if (cmd.msg) {
                    logger.info('Serv echo rep = [%s]', cmd.msg);
                }
                else {
                    logger.debug('Client got an error echo rep');
                }
            }
        });
        req.pipe(client).pipe(res);

        /* send requests to server */
        req.send({ command : 'echo', msg : 'request 1'}, function () {
            logger.info('sent request 1');
        });
        req.send({ command : 'echo', msg : 'request 2'}, function () {
            logger.info('sent request 2');
        });
        req.send({ command : 'bye'}, function () {
            logger.info('sent bye');
        });
    });

};

function main() {
    var argv = require('optimist').argv;

    /* startup the logger and set it to console */
    logger.cli();
    logger.default.transports.console.timestamp = true;
    if (argv.logLevel) {
        logger.default.transports.console.level = argv.logLevel;
        logger.info('Set logLevel to %s', argv.logLevel);
    }
    /* run the serv with the argv options */
    exports(argv);
}

if (require.main === module) {
    /* current module is the node main module */
    main();
}

nsrv-protocol.js

/*
 * node stream tests - Protocol stream
 *
 * It's a simple protocol. I created it for test the NODE Stream module.
 *
 * Protocol: (All the protocol Buffer are UTF8 Strings')
 *
 * ---------------------------------------
 *    '{JSON String 1}'\n
 *    '{JSON String 2}'\n
 *    .....
 *    '{JSON String n}'\n
 *    \n
 * ---------------------------------------
 *
 * Sample Client: nclient.js
 * Sample Server: nsrv.js
 *
 * TODO: 
 * 1. need a Handshake command for check the Protocol versions.
 * 2. add unit test
 */
'use strict';

var logger = require('winston'),
    util = require('util'),
    _ = require('underscore'),
    Transform = require('stream').Transform;

/* the construct of IncomingStream */
function IncomingStream(opts) {
    var self = this,
        streamOpts = {},
        incomingOpts;

    if (!(self instanceof IncomingStream)) {
        logger.warn('the caller directly using IncomingStream');
        return new IncomingStream(opts);
    }
    logger.debug('creating IncomingStream');
    Transform.call(self, streamOpts);

    /* startup options */
    incomingOpts = {
        Eval : function (command) {
            logger.info('New incoming command %s',
                JSON.stringify(command));
            self.emit('eval', command);
        }
    };
    if (opts) {
        /* update customer's options */
        _.each(_.keys(incomingOpts), function (opt) {
            if (opts[opt]) {
                logger.debug('Update incoming stream opt %s', opt);
                incomingOpts[opt] = opts[opt];
            }
        });
    }
    self._eval = incomingOpts.Eval;
    self._lastChunk = null;
}

/* the construct of OutgoingStream */
function OutgoingStream() {
    var self = this,
        streamOpts = {};

    if (!(self instanceof OutgoingStream)) {
        logger.warn('the caller directly using OutgoingStream');
        return new OutgoingStream();
    }
    logger.debug('creating OutgoingStream');
    Transform.call(self, streamOpts);
}

/* set the base class and export the streams  */
util.inherits(IncomingStream, Transform);
util.inherits(OutgoingStream, Transform);
exports.Incoming = IncomingStream;
exports.Outgoing = OutgoingStream;

/* transform function for IncomingStream */
IncomingStream.prototype._transform = function (chunk, encoding, callback) {
    if (!chunk) {
        logger.debug('incoming, get an empty chunk');
        callback();
        return;
    }
    logger.debug('incoming chunk size %d', chunk.length);
    this._incomingProcess(chunk);
    callback();
};

IncomingStream.prototype._incomingProcess = function (chunk) {
    var TERMINATE = 10, /* TERMINATE flag is 10 ('\n') */
        self = this,
        curChunk, i, findFirstTerminate, idxTerminate, cmdBuf, remain, cmdsStr;

    /* parse the chunks */
    curChunk = this._lastChunk ? Buffer.concat([this._lastChunk, chunk]) : chunk;
    findFirstTerminate = false;
    idxTerminate = -1;
    for (i = 0; i < curChunk.length; ++i) {
        if (curChunk[i] === TERMINATE) {
            if (!findFirstTerminate) {
                findFirstTerminate = true;
            }
            else {
                idxTerminate = i;
            }
        }
        else {
            findFirstTerminate = false;
        }
    }

    if (idxTerminate === -1) {
        /* still waitting \n\n */
        logger.debug('cannot find terminate flag & waitting next chunk');
        this._lastChunk = curChunk;
    }
    else if (idxTerminate === curChunk.length) {
        logger.debug('Terminate flag is the end of chunk');
        cmdBuf = curChunk;
        this._lastChunk = null;
    }
    else if (idxTerminate < curChunk.length) {
        logger.debug('idxTerminate < curChunk.length');
        cmdBuf = curChunk.slice(0, idxTerminate);
        remain = curChunk.slice(idxTerminate + 1);
        this.push(remain);
    }
    else {
        /* this can't be happening */
        logger.error('bad protocol format. idxTerminate > curChunk.length');
        this.emit('error', { code : 'Bad Chunk' });
    }

    if (cmdBuf) {
        cmdsStr = cmdBuf.toString('utf8');
        _.each(cmdsStr.split('\n'), function (cmdStr) {
            var cmdObj;
            if (cmdStr.length === 0) {
                return;
            }
            try {
                cmdObj = JSON.parse(cmdStr);
                logger.debug('receive a new command %s', JSON.stringify(cmdObj));
                self._eval(cmdObj);
            }
            catch (exception) {
                logger.error('receive a bad command string, %s', cmdStr);
            }
        });
    }
};

/* transform function for OutgoingStream */
OutgoingStream.prototype._transform = function (chunk, encoding, callback) {
    if (!chunk) {
        logger.debug('outgoing, get an empty chunk');
        callback();
        return;
    }
    logger.debug('outgoing chunk size %d', chunk.length);
    this.push(chunk);
    callback();
};

OutgoingStream.prototype.flush = function (callback) {
    var cmdBuf = new Buffer('\n', 'utf8');
    this.write(cmdBuf, 'utf8', callback);
};

OutgoingStream.prototype.send = function (command, opts, callback) {
    var cmdBuf,
        sendOpts = {
            flush : true
        };

    /* update send options */
    if (opts) {
        _.each(_.keys(sendOpts), function (opt) {
            if (opts[opt]) {
                sendOpts[opt] = opts[opt];
            }
        });
    }
    if (sendOpts.flush) {
        cmdBuf = new Buffer(util.format('%j\n\n', command), 'utf8');
    }
    else {
        cmdBuf = new Buffer(util.format('%j\n', command), 'utf8');
    }
    this.write(cmdBuf, 'utf8', callback);
};

nsrv.js

/*
 * node stream tests - Server
 */

'use strict';

var logger = require('winston'),
    util = require('util'),
    _ = require('underscore');

exports = module.exports = function (opts) {
    var net = require('net'),
        proto = require('./nsrv-protocol'),
        Incoming = proto.Incoming,
        Outgoing = proto.Outgoing,
        serv,
        startListening = false,
        defaultSrvAddr = { host : 'localhost', port : 8095 },
        srvOpts = {
            address : defaultSrvAddr
        };

    /* update server options */
    logger.debug('starting serv, input opts %s', JSON.stringify(opts));
    _.each(_.keys(srvOpts), function (opt) {
        if (opts[opt]) {
            srvOpts[opt] = opts[opt];
        }
    });
    logger.info('starting serv, opts %s', JSON.stringify(srvOpts));

    /* create server */
    serv = net.createServer({ allowHalfOpen: true }, function (sock) {
        var remote = util.format('%s:%d', sock.remoteAddress, sock.remotePort),
            req = new Incoming(),
            res = new Outgoing();

        logger.info('new connection from %s', remote);
        sock.on('close', function (hadErr) {
            logger.info('socket closed (%s). hadErr %s', remote, hadErr);
        });

        sock.on('error', function (err) {
            logger.error('error occued on socket (%s), error %s', remote, err.code);
        });

        /* startup the request & response streams */
        res.on('error', function (err) {
            /* close the socket when error occued */
            logger.error('Remote %s: An error occued on the response stream (%s).',
                remote, err);
            sock.end(null);
        });

        req.on('error', function (err) {
            /* close the socket when error occued */
            logger.error('Remote %s: An error occued on the request stream (%s).',
                remote, err);
            sock.end(null);
        });

        req.on('eval', function (cmd) {
            if (!cmd.command) {
                logger.error('Serv got an empty command');
                return;
            }
            if (cmd.command === 'bye') {
                /* disconnect command */
                sock.end();
            }
            else if (cmd.command === 'echo') {
                /* echo command */
                if (cmd.msg) {
                    res.send({
                        command : 'echo',
                        msg : util.format('Serv response message (%s)', cmd.msg)
                    });
                }
                else {
                    logger.error('serv got an error "echo" command. Cannot parse "msg" filed');
                }
            }
        });

        res.pipe(sock).pipe(req);
    });

    serv.on('error', function (err) {
        logger.error('An error occured, server error code %s', err.code);
        if (startListening) {
            serv.close();
            startListening = false;
        }
    });

    serv.on('listening', function () {
        logger.info('server started');
        startListening = true;
    });

    /* start the server */
    logger.info('start listen on %s', JSON.stringify(srvOpts.address));
    serv.listen(srvOpts.address.port, srvOpts.address.host);
};

function main() {
    var argv = require('optimist').argv;

    /* startup the logger and set it to console */
    logger.cli();
    logger.default.transports.console.timestamp = true;
    if (argv.logLevel) {
        logger.default.transports.console.level = argv.logLevel;
        logger.info('Set logLevel to %s', argv.logLevel);
    }
    /* run the serv with the argv options */
    exports(argv);
}

if (require.main === module) {
    /* current module is the node main module */
    main();
}

package.json

{
  "name": "nstream-tests",
  "version": "0.0.0",
  "description": "Node Stream Tests",
  "author": {
    "name": "LeXiongJia",
    "email": "lexiongjia@gmail.com"
  },
  "licenses": [
    {
      "type": "MIT"
    }
  ],
  "dependencies": {
    "underscore": "~1.5.2",
    "winston": "~0.7.2",
    "optimist": "~0.6.0"
  }
}