144 lines
3.8 KiB
JavaScript
144 lines
3.8 KiB
JavaScript
'use strict';
|
|
|
|
var assert = require('assert');
|
|
var Connector = require('loopback-connector').Connector;
|
|
var debug = require('debug')('loopback:connector:kv-memory');
|
|
var util = require('util');
|
|
|
|
exports.initialize = function initializeDataSource(dataSource, cb) {
|
|
var settings = dataSource.settings;
|
|
dataSource.connector = new KeyValueMemoryConnector(settings, dataSource);
|
|
if (cb) process.nextTick(cb);
|
|
};
|
|
|
|
function KeyValueMemoryConnector(settings, dataSource) {
|
|
Connector.call(this, 'kv-memory', settings);
|
|
|
|
debug('Connector settings', settings);
|
|
|
|
this.dataSource = dataSource;
|
|
this.DataAccessObject = dataSource.juggler.KeyValueAccessObject;
|
|
|
|
this._store = Object.create(null);
|
|
|
|
this._setupRegularCleanup();
|
|
};
|
|
util.inherits(KeyValueMemoryConnector, Connector);
|
|
|
|
KeyValueMemoryConnector.prototype._setupRegularCleanup = function() {
|
|
// Scan the database for expired keys at a regular interval
|
|
// in order to release memory. Note that GET operation checks
|
|
// key expiration too, the scheduled cleanup is merely a performance
|
|
// optimization.
|
|
var self = this;
|
|
this._cleanupTimer = setInterval(
|
|
function() { self._removeExpiredItems(); },
|
|
1000);
|
|
this._cleanupTimer.unref();
|
|
};
|
|
|
|
KeyValueMemoryConnector._removeExpiredItems = function() {
|
|
debug('Running scheduled cleanup of expired items.');
|
|
for (var modelName in this._store) {
|
|
var modelStore = this._store[modelName];
|
|
for (var key in modelStore) {
|
|
if (modelStore[key].isExpired()) {
|
|
debug('Removing expired key', key);
|
|
delete modelStore[key];
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
KeyValueMemoryConnector.prototype._getStoreForModel = function(modelName) {
|
|
if (!(modelName in this._store)) {
|
|
this._store[modelName] = Object.create(null);
|
|
}
|
|
return this._store[modelName];
|
|
};
|
|
|
|
KeyValueMemoryConnector.prototype.get =
|
|
function(modelName, key, options, callback) {
|
|
var store = this._getStoreForModel(modelName);
|
|
var item = store[key];
|
|
|
|
if (item && item.isExpired()) {
|
|
debug('Removing expired key', key);
|
|
delete store[key];
|
|
item = undefined;
|
|
}
|
|
|
|
var value = item ? item.value : null;
|
|
|
|
debug('GET %j %j -> %s', modelName, key, value);
|
|
|
|
if (/^buffer:/.test(value)) {
|
|
value = new Buffer(value.slice(7), 'base64');
|
|
} else if (/^date:/.test(value)) {
|
|
value = new Date(value.slice(5));
|
|
} else if (value != null) {
|
|
value = JSON.parse(value);
|
|
}
|
|
|
|
process.nextTick(function() {
|
|
callback(null, value);
|
|
});
|
|
};
|
|
|
|
KeyValueMemoryConnector.prototype.set =
|
|
function(modelName, key, value, options, callback) {
|
|
var store = this._getStoreForModel(modelName);
|
|
var value;
|
|
if (Buffer.isBuffer(value)) {
|
|
value = 'buffer:' + value.toString('base64');
|
|
} else if (value instanceof Date) {
|
|
value = 'date:' + value.toISOString();
|
|
} else {
|
|
value = JSON.stringify(value);
|
|
}
|
|
|
|
debug('SET %j %j %s %j', modelName, key, value, options);
|
|
store[key] = new StoreItem(value, options && options.ttl);
|
|
|
|
process.nextTick(callback);
|
|
};
|
|
|
|
KeyValueMemoryConnector.prototype.expire =
|
|
function(modelName, key, ttl, options, callback) {
|
|
var store = this._getStoreForModel(modelName);
|
|
|
|
if (!(key in store)) {
|
|
return process.nextTick(function() {
|
|
callback(new Error('Cannot expire unknown key ' + key));
|
|
});
|
|
}
|
|
|
|
debug('EXPIRE %j %j %s', modelName, key, ttl || '(never)');
|
|
store[key].setTtl(ttl);
|
|
process.nextTick(callback);
|
|
};
|
|
|
|
KeyValueMemoryConnector.prototype.disconnect = function(callback) {
|
|
if (this._cleanupTimer)
|
|
clearInterval(this._cleanupTimer);
|
|
this._cleanupTimer = null;
|
|
process.nextTick(callback);
|
|
};
|
|
|
|
function StoreItem(value, ttl) {
|
|
this.value = value;
|
|
this.setTtl(ttl);
|
|
}
|
|
|
|
StoreItem.prototype.isExpired = function() {
|
|
return this.expires && this.expires <= Date.now();
|
|
};
|
|
|
|
StoreItem.prototype.setTtl = function(ttl) {
|
|
if (ttl) {
|
|
this.expires = Date.now() + ttl;
|
|
} else {
|
|
this.expires = undefined;
|
|
}
|
|
};
|