memcached protocol server framework

This is a memcached protocol server framework.

You can implement a server, supports memcached protocol.

So, it means you can write a KVS supports memcached protocol, very easy.

SYNOPSIS

/**
 * This is an example server to implement memcached like on-memory KVS
 * with MemcachedProtocolServer.
 */

var Server = require('../index.js').Server;

var port = process.argv[2] || 22422;

var server = new Server();
server.on('error', function (e) {
    console.log("# Socket error!!: " + e);
});
server.on('end', function () {
    console.log("# END!!");
});
server.setHandlers({
    GET: function (sock, keys) {
        var self = this;
        keys.forEach(function (key) {
            if (self.storage[key]) {
                var entry = self.storage[key];
                sock.sendValue(key, entry[0], entry[1]);
            }
        });
        sock.sendEnd();
    },
    SET: function (sock, key, flags, exptime, data, noreply) {
        var self = this;
        self.storage[key] = [flags, data];
        if (!noreply) {
            sock.sendStored();
        }
    },
    DELETE: function (sock, key, noreply) {
    if (this.storage[key]) {
        delete this.storage[key];
        if (!noreply) {
            sock.sendDeleted();
        }
    } else {
        if (!noreply) {
            sock.sendNotFound();
        }
    }
    },
    DECR: function (sock, key, value, noreply) {
        if (this.storage[key]) {
            var v = parseInt(this.storage[key][1], 10);
            this.storage[key][1] = '' + (v - value);
            if (!noreply) {
                sock.write(''+(v-value)+"\r\n");
            }
        } else {
            if (!noreply) {
                sock.sendNotFound();
            }
        }
    },
    INCR: function (sock, key, value, noreply) {
        if (this.storage[key]) {
            var v = parseInt(this.storage[key][1], 10);
            this.storage[key][1] = '' + (v + value);
            if (!noreply) {
                sock.write(''+(v+value)+"\r\n");
            }
        } else {
            if (!noreply) {
                sock.sendNotFound();
            }
        }
    },
    VERSION: function (sock) {
        sock.sendVersion("4649");
    },
    FLUSH_ALL: function (sock, delay, noreply) {
        this.storage = {};
        if (!noreply) {
            sock.sendOK();
        }
    }
});
server.storage = {};
server.listen(port);

Classes

require('memcached-protocol-server').Server

var new Server();

Create a new instance of server.

server.listen(port[, host])

Listen the port.

server.setHandlers(handlermap)

Set a command handler in Object. For more details, please see a eg/memd.js and library source code itself.

require('memcached-protocol-server').Socket

This is a client connection socket object. You don't need create this object. MemcachedProtocolServer passes this type of object to your handler.

This object provides a lot of methods to say memcached protocol. But you need to study only two methods simply, It's 'close' and 'write'. Another methods are wrapper of 'write'.

sock.close()

Close a client socket.

sock.write()

Write a data to socket.

sock.sendStat(name, value)

Send a stat line.

sock.sendTouch()

Synonym of

    sock.write("TOUCHED\r\n");

sock.sendError:()

    sock.write("ERROR\r\n");

sock.sendEnd()

    sock.write("END\r\n");

sock.sendStored()

    sock.write("STORED\r\n");

sock.sendDeleted()

    sock.write("DELETED\r\n");

sock.sendNotStored()

    sock.write("NOT_STORED\r\n");

sock.sendExists()

    sock.write("EXISTS\r\n");

sock.sendOK()

    sock.write("OK\r\n");

sock.sendNotFound()

    sock.write("NOT_FOUND\r\n");

sock.sendServerError(error)

    sock.write("SERVER_ERROR " + error + "\r\n");

sock.sendClientError(error)

    sock.write("CLIENT_ERROR " + error + "\r\n");

sock.sendValue(key, flags, data_block[, cas_unique])

It sends following command for 'get' command.

// VALUE <key> <flags> <bytes> [<cas unique>]\r\n
// <data block>\r\n

sock.sendVersion(version)

    sock.write("VERSION " + version + "\r\n");

SEE ALSO

https://github.com/memcached/memcached/blob/master/doc/protocol.txt