webapi-eca/js/db_interface.js

264 lines
8.4 KiB
JavaScript

// # DB Interface
// Handles the connection to the database and provides functionalities for
// event/action modules, rules and the encrypted storing of authentication tokens.
// ## General
// General functionality as a wrapper for the module holds initialization,
// encryption/decryption, the retrieval of modules and shut down.
// Modules of the same group, e.g. action modules are registered in an unordered
// set in the database, from where they can be retrieved again. For example a new
// action module has its ID (e.g 'probinder') first registered in the set
// 'action_modules' and then stored in the db with the key 'action\_module\_' + ID
// (e.g. action\_module\_probinder).
'use strict';
var redis = require('redis'),
crypto = require('crypto'),
log = require('./logging'),
crypto_key, db;
// @function init()
/*
* Initializes the DB connection. Requires a port where the DB listens to requests
* and a key that is used for encryptions.
* @param {int} db_port
*/
exports.init = function(db_port, key, cbDone){
if(!db_port || !key) {
log.error('DB', 'No DB port or cipher key defined!');
return null;
}
crypto_key = key;
db = redis.createClient(db_port);
db.on("error", function (err) {
log.error('DB', ' Message from DB: ' + err);
});
if(cbDone) cbDone();
};
/**
* ### encrypt
*/
function encrypt(plainText) {
if(!plainText) return null;
try {
var enciph = crypto.createCipher('aes-256-cbc', crypto_key);
var et = enciph.update(plainText, 'utf8', 'base64') + enciph.final('base64');
log.print('DB', 'Encrypted credentials into: ' + et);
return et;
} catch (err) {
log.error('DB', 'in encrypting: ' + err);
return null;
}
}
/**
* ### decrypt
*/
function decrypt(crypticText) {
if(!crypticText) return null;
try {
var deciph = crypto.createDecipher('aes-256-cbc', crypto_key);
return deciph.update(crypticText, 'base64', 'utf8') + deciph.final('utf8');
} catch (err) {
log.error('DB', 'in decrypting: ' + err);
return null;
}
}
/**
* ### replyHandler
* Abstraction answer handling for simple information replies from the DB.
* @param {String} action the action to be displayed in the output string.
*/
function replyHandler(action) {
return function(err, reply) {
if(err) log.error('DB', ' during "' + action + '": ' + err);
else log.print('DB', action + ': ' + reply);
};
}
/**
* ### getSetRecords
* The general structure for modules is that the key is stored in a set.
* By fetching all set entries we can then fetch all modules, which is
* automated in this function.
*
* @param {String} set the set name how it is stored in the DB
* @param {function} funcSingle the function that fetches single entries from the DB
* @param {function} callback the function to be called on success or error, receives
* arguments (err, obj)
*/
function getSetRecords(set, funcSingle, callback) {
db.smembers(set, function(err, reply) {
if(err) log.error('DB', 'fetching ' + set + ': ' + err);
else {
if(reply.length === 0) {
callback(null, null);
} else {
var semaphore = reply.length, objReplies = {};
setTimeout(function() {
if(semaphore > 0) {
callback('Timeout fetching ' + set, null);
}
}, 1000);
for(var i = 0; i < reply.length; i++){
funcSingle(reply[i], function(prop) {
return function(err, reply) {
if(err) log.error('DB', ' fetching single element: ' + prop);
else {
objReplies[prop] = reply;
if(--semaphore === 0) callback(null, objReplies);
}
};
}(reply[i]));
}
}
}
});
}
// @method shutDown()
// Shuts down the db link.
exports.shutDown = function() { db.quit(); };
// ## Action Modules
/**
* ### storeActionModule
* Store a string representation of an action module in the DB.
* @param {String} id the unique identifier of the module
* @param {String} data the string representation
*/
exports.storeActionModule = function(id, data) {
db.sadd('action_modules', id, replyHandler('storing action module key ' + id));
db.set('action_module_' + id, data, replyHandler('storing action module ' + id));
};
/**
* ### getActionModule(id, callback)
* Query the DB for an action module.
* @param {String} id the module id
* @param {function} callback the callback to receive the answer (err, obj)
*/
exports.getActionModule = function(id, callback) {
if(callback) db.get('action_module_' + id, callback);
};
/**
* ### getActionModules(callback)
* Fetch all action modules.
* @param {function} callback the callback to receive the answer (err, obj)
*/
exports.getActionModules = function(callback) {
getSetRecords('action_modules', exports.getActionModule, callback);
};
/**
* storeActionModuleAuth(id, data)
* Store a string representation of the authentication parameters for an action module.
* @param {String} id the unique identifier of the module
* @param {String} data the string representation
*/
exports.storeActionModuleAuth = function(id, data) {
if(data) {
db.sadd('action_modules_auth', id, replyHandler('storing action module auth key ' + id));
db.set('action_module_' + id +'_auth', encrypt(data), replyHandler('storing action module auth ' + id));
}
};
/**
* ### getActionModuleAuth(id, callback)
* Query the DB for an action module authentication token.
* @param {String} id the module id
* @param {function} callback the callback to receive the answer (err, obj)
*/
exports.getActionModuleAuth = function(id, callback) {
if(callback) db.get('action_module_' + id + '_auth', function(err, txt) { callback(err, decrypt(txt)); });
};
// ## Event Modules
/**
* ### storeEventModule(id, data)
* Store a string representation of an event module in the DB.
* @param {String} id the unique identifier of the module
* @param {String} data the string representation
*/
exports.storeEventModule = function(id, data) {
db.sadd('event_modules', id, replyHandler('storing event module key ' + id));
db.set('event_module_' + id, data, replyHandler('storing event module ' + id));
};
/**
* ### getEventModule(id, callback)
* Query the DB for an event module.
* @param {String} id the module id
* @param {function} callback the callback to receive the answer (err, obj)
*/
exports.getEventModule = function(id, callback) {
if(callback) db.get('event_module_' + id, callback);
};
/**
* ### getEventModules(callback)
* Fetch all event modules.
* @param {function} callback the callback that receives the arguments (err, obj)
*/
exports.getEventModules = function(callback) {
getSetRecords('event_modules', exports.getEventModule, callback);
};
/**
* ### storeEventModuleAuth(id, data)
* Store a string representation of he authentication parameters for an event module.
* @param {String} id the unique identifier of the module
* @param {String} data the string representation
*/
exports.storeEventModuleAuth = function(id, data) {
if(data) {
db.sadd('event_modules_auth', id, replyHandler('storing event module auth key ' + id));
db.set('event_module_' + id +'_auth', encrypt(data), replyHandler('storing event module auth ' + id));
}
};
// @method getEventModuleAuth(id, callback)
// Query the DB for an event module authentication token.
// @param {String} id the module id
// @param {function} callback the callback to receive the answer (err, obj)
exports.getEventModuleAuth = function(id, callback) {
if(callback) db.get('event_module_' + id +'_auth', function(err, txt) { callback(err, decrypt(txt)); });
};
// ## Rules
// @method storeRule(id, data)
// Store a string representation of a rule in the DB.
// @param {String} id the unique identifier of the rule
// @param {String} data the string representation
exports.storeRule = function(id, data) {
db.sadd('rules', id, replyHandler('storing rule key ' + id));
db.set('rule_' + id, data, replyHandler('storing rule ' + id));
};
// @method getRule(id, callback)
// Query the DB for a rule.
// @param {String} id the rule id
// @param {function} callback the callback to receive the answer (err, obj)
exports.getRule = function(id, callback) {
db.get('rule_' + id, callback);
};
// @method getRules(callback)
// Fetch all rules from the database.
// @param {function} callback the callback to receive the answer (err, obj)
exports.getRules = function(callback) {
getSetRecords('rules', exports.getRule, callback);
};