haste-server/lib/document_stores/postgres.js

// /*global require,module,process*/

const postgres = require('pg');
const winston = require('winston');

// create table entries (id serial primary key, key varchar(255) not null, value text not null, expiration int, unique(key));

// A postgres document store
const PostgresDocumentStore = function (options){
	this.expireJS = options.expire;
	this.connectionUrl = process.env.DATABASE_URL || options.connectionUrl;
};

PostgresDocumentStore.prototype = {

	// Set a given key
	set: function (key, data, callback, skipExpire){
		const now = Math.floor(Date.now() / 1000);
		const that = this;
		this.safeConnect(function (err, client, done){
			if (err){ return callback(false); }
			client.query('INSERT INTO entries (key, value, expiration) VALUES ($1, $2, $3)', [
				key,
				data,
				that.expireJS && !skipExpire ? that.expireJS + now : null
			], function (err){
				if (err){
					winston.error('error persisting value to postgres', { error: err });
					return callback(false);
				}
				callback(true);
				done();
			});
		});
	},

	// Get a given key's data
	get: function (key, callback, skipExpire){
		const now = Math.floor(Date.now() / 1000);
		const that = this;
		this.safeConnect(function (err, client, done){
			if (err){ return callback(false); }
			client.query('SELECT id,value,expiration from entries where KEY = $1 and (expiration IS NULL or expiration > $2)', [key, now],
				function (err, result){
					if (err){
						winston.error('error retrieving value from postgres', { error: err });
						return callback(false);
					}
					callback(result.rows.length ? result.rows[0].value : false);
					if (result.rows.length && that.expireJS && !skipExpire){
						client.query('UPDATE entries SET expiration = $1 WHERE ID = $2', [
							that.expireJS + now,
							result.rows[0].id
						], function (err){
							if (!err){
								done();
							}
						});
					} else {
						done();
					}
				});
		});
	},

	// A connection wrapper
	safeConnect: function (callback){
		postgres.connect(this.connectionUrl, function (err, client, done){
			if (err){
				winston.error('error connecting to postgres', { error: err });
				callback(err);
			} else {
				callback(undefined, client, done);
			}
		});
	}

};

module.exports = PostgresDocumentStore;