sqlitecache - A super basic layer on top of sqlite for caching certain types of requests. Works well as a replacement (especially in dev) for memcached when working w/ limited/throttled services (like Embed.ly or LinkedIn's API).

index.js

var Sqlite = require('sqlite3').verbose();
 
function SqliteCache( config ) {
  config = config || {};
  this.db = new Sqlite.Database( config.db || void(0)); // will create an in-memory store if path is undefined.
  this.bucket = config.bucket || '';
  this.duration = config.duration || 1000 * 60 * 5;//defaults to 5 minutes

  //initialize table
  this.db.run("CREATE TABLE IF NOT EXISTS cache (key TEXT PRIMARY KEY ASC, expires INTEGER, result TEXT)");
  //clean out old keys on startup
  this.db.run('DELETE FROM cache WHERE expires <= ?', [ Date.now() ], function() {});
}
SqliteCache.prototype = {
  get: function(key, callback) {
    var self = this;
    key = this.bucket + key;
  
    //this.db.get('SELECT * FROM cache WHERE key = "?" AND expires >= ? LIMIT 1',[ key, Date.now()], function(err, row) {
    this.db.get('SELECT * FROM cache WHERE key = "' + key + '" AND expires >= ' + Date.now() + ' LIMIT 1', function(err, row) {
      var result = row && JSON.parse(row.result);
      callback.call(self, err, result);
    });
  },
  set: function(key, value, callback) {
    var self = this,
        expires = Date.now() + this.duration,
        resultVal = JSON.stringify(value).replace(/'/g, '\'\'');
    key = this.bucket + key;
    //this.db.run('INSERT OR REPLACE INTO cache (key, expires, result) VALUES ("?", ?, "?")', [key, expires, resultVal], function(err) {
    this.db.run("INSERT OR REPLACE INTO cache (key, expires, result) VALUES ('" + key + "', " + expires + ", '" + resultVal + "')", function(err) {
      callback.call(self, err, value);
    });
  },
  contains: function(key, callback) {
    var self = this;
    this.get(key, function(err, result) {
      callback.call(self, err, !!result);
    });
  },
  remove: function(key, callback) {
    var self = this;
    this.db.run('DELETE FROM cache WHERE key <= ?', [ key ], function(err, result) {
      //TODO: not sure what result says. Could we pass that to the callback function?
      callback.call(self, err, !err);
    });
  }
};
module.exports = SqliteCache;

package.json

{
  "name": "sqlitecache",
  "author": "Matt Powell",
  "description": "tbd",
  "main": "./index.js",
  "version": "0.0.1"
}

Now, you can run this: npm install https://gist.github.com/mattpowell/4976057/download