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https://github.com/alexfernandez/simplecached

Simplified version of memcached, useful for didactic purposes
https://github.com/alexfernandez/simplecached

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Simplified version of memcached, useful for didactic purposes

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# simplecached



Simplified version of memcached, useful for didactic purposes.



## Installation



Just run:



    npm install simplecached



or add it to your dependencies in package.json:



    "dependencies": {

        "simplecached": "*",

        ...

    },



## Server



To start a server, just require simplecached and create a server:



    var simplecached = require('simplecached');

    var server = new simplecached.Server();



To start the server on a port different than the default (11311),

add it to the Server constructor:



    var server = simplecached.Server(port);



Also a callback can be added to be notified when the server has started:



    var server = simplecached.Server(port, function(error, result) {

        console.log('Server started');

    });



To stop the server, call close() on it:



    server.close();



## Client



To create a client for a simplecached server, just create it.



    var simplecached = require('simplecached');

    var client = new simplecached.Client();



### new Client(options, callback);



The client constructor accepts an options object with port and host.

Also, an optional callback can be added to be notified when the client is connected.



    var options = {

        port: 11312,

        host: '192.168.1.15'

    };

    var client = new simplecached.Client(options, function(error) {

        console.log('Connected');

    });



The following functions can be called on the client.



### client.get(key, callback);



Get a key from the remote simplecached.

The callback is a `function(error, result)` that will be called either with an error or the result,

or null if the value was not found.



### client.set(key, value, callback);



Set a value into the remote simplecached.

The callback is a `function(error, result)` that will be called with an error or a result.

The `result` can be true if the value was stored, false otherwise.



### client.delete(key, callback);



Delete a value from the remote simplecached.

The callback is a `function(error, result)` that will be called with an error or a result.

The `result` can be true if the value was deleted, false if not found.



### client.close(callback);



Close the connection. The optional callback will be called after the connection is actually closed.



### Example



The following code opens a connection to a remote simplecached server.

Then it sets a key, retrieves it and checks that the value is correct.

Then it closes the connection.



    var simplecached = require('simplecached');

    var options = {

        port: 11312,

        host: '192.168.1.15'

    };

    var client = new client.Client(options, function(error) {

        console.assert(!error, 'Could not open connection');

        var key = 'testing';

        var value = 'real value';

        client.set(key, value, function(error, result) {

            console.assert(!error, 'Error setting key');

            console.assert(result, 'Could not set key');

            client.get(key, function(error, result) {

                console.assert(!error, 'Error getting key');

                console.assert(result == value, 'Invalid get key');

                client.delete(key, function(error, result) {

                    console.assert(!error, 'Error deleting key');

                    console.assert(result, 'Could not delete key');

                    client.close(function(error) {

                        console.assert(!error, 'Error closing client');

                    });

                });

            });

        });

    });



The pyramid of callbacks can be avoided with a few named functions.



## Protocol



The line protocol for simplecached is a simplified version of memcached's.



### `get \r\n`



Gets a key from the cache. The response can be either:



    VALUE \r\n



when a value is found, or



    END\r\n



if the value was not found.



### `set  \r\n`



Sets a value in the cache, always a string (without line feeds).

The response can be either:



    STORED\r\n



if the value was stored, or



    NOT_STORED\r\n



otherwise.



### `delete \r\n`



Deletes a value from the cache.

The response can be either:



    DELETED\r\n



if the value was stored, or



    NOT_FOUND\r\n



otherwise.



### `quit\r\n`



Close the connection.



## License



Simplecached is licensed under the MIT license.

Please consult the LICENSE file for details.