example.js

function example(){

    var plv8 = require('./plv8')

    var options = {
        user: 'postgres',
        password: 'password',
        database: 'data',
        host: '127.0.0.1',
        port: 9999
    };

    plv8.connect(options, function(err, plv8){

        plv8.configure(function(err, result){
            plv8.set("first", {a:2}, function(){
                plv8.get("first", function(err, result){
                    console.log("get result:", result);
                })
            });

            var queryFunction1 = function (input){
                return {happy:"day", text:input.a};
            };

            var queryFunction2 = function (input){
                plv8.setSync("second", {hello:"world"});
                return plv8.getSync("second");
            };

            var displayResult = function(err, result){
                if(err) console.dir(err)
                console.log("call result:", JSON.stringify(result));
            };

            plv8.define(queryFunction1, function(){
                plv8.call(queryFunction1, {a:12345}, displayResult);
            });

            plv8.define(queryFunction2, function(){
                plv8.call(queryFunction2, null, displayResult);
            });
        });


    })

}

example();

plv8.js

var plv8 = module.exports = {
    connect : function (options, connectionCallback){
       var pg = require('pg');
        pg.connect(new pg.Client(options), function(err, client, done) {
            var plv8Connection = {
                client:client,
                prefix:options.prefix || "plv8_",
                dataName:options.dataName || "jsonData",
                generatedNames:[[],[]],
                configure: function(callback){
                    //todo: consider enabling coffeescript support with CREATE EXTENSION plcoffee;?
                    var queryString = "CREATE EXTENSION plv8; CREATE TABLE IF NOT EXISTS " + plv8Connection.dataName + " ( id text UNIQUE, data json );"
                    var result = plv8Connection.client.query(queryString, [], function (err, result){
                        done();
                        callback(err, result);
                    })
                },
                get: function(key, callback){
                    var queryString = "select * from " +  plv8Connection.dataName + " where id = '" + key.toString() + "'";
                    var result = plv8Connection.client.query(queryString, [], function (err, result){
                        done();
                        var deepResult = err ? undefined : result.rows.length > 0 && result.rows[0].data;
                        callback(err, deepResult);
                    })
                },
                set: function(key, value, callback){
                    var valueJson = JSON.stringify(value)
                    var queryString = "UPDATE " +  plv8Connection.dataName + " SET data='" + valueJson + "' WHERE id='" + key + "'; \n"
                                    + "insert into " +  plv8Connection.dataName + " (id, data) select '" + key + "', '" + valueJson + "'\n"
                                    + "WHERE NOT EXISTS (SELECT 1 FROM " +  plv8Connection.dataName + " WHERE id='" + key + "');"
                    var result = plv8Connection.client.query(queryString, [], function (err, result){
                        done();
                        callback(err, result);
                    })
                },
                define: function(queryFn, callback){
                    var fnString = queryFn.toString();
                    var fnBody = fnString.substring(fnString.indexOf("{") + 1, fnString.lastIndexOf("}"));
                    var fnName = plv8Connection.prefix;
                    if(queryFn.name.length > 0) fnName += queryFn.name;
                    else {
                        plv8Connection.generatedNames[0].push(queryFn);
                        plv8Connection.generatedNames[1].push(fnName += "Generated_" + Math.random().toString().replace(/\./,""));
                    }
                    var isv = "STABLE"; //todo: calculate based on function contents or have it passed via args
                    var helperFn = function(){
                        var plv8Connection = {dataName: "jsonData"};
                        var console = {log: function(message){plv8.elog(INFO, '', JSON.stringify(arguments))}};
                        plv8.getSync = function(key){return plv8.execute("select * from " + plv8Connection.dataName + " where id='" + key + "'")};
                        plv8.setSync = function(key, value){
                            var valueJson = JSON.stringify(value)
                            var queryString = "UPDATE " +  plv8Connection.dataName + " SET data='" + valueJson + "' WHERE id='" + key + "'; \n"
                                + "insert into " +  plv8Connection.dataName + " (id, data) select '" + key + "', '" + valueJson + "'\n"
                                + "WHERE NOT EXISTS (SELECT 1 FROM " +  plv8Connection.dataName + " WHERE id='" + key + "');"
                            return plv8.execute(queryString);
                        }
                        plv8.get = function(key, callback){var result = plv8.getSync(key); callback && callback(undefined, result); return result;}
                        plv8.set = function(key, value, callback){var result = plv8.setSync(key, value); callback && callback(undefined, result); return result;}
                        plv8.query = function(query, args, callback){var result = plv8.execute(query, args); callback && callback(undefined, result); return result;}
                    }
                    var helperFnString = helperFn.toString();
                    var helperFnBody = helperFnString.substring(helperFnString.indexOf("{") + 1, helperFnString.lastIndexOf("}"));
                    var queryString = " create or replace function " + fnName + " (input json )"
                        + " RETURNS json LANGUAGE plv8 " + isv
                        + " AS $javascript$\n" + helperFnBody + ";\n" + fnBody + "\n$javascript$";
                    var result = plv8Connection.client.query(queryString, [], function (err, result){
                        done();
                        callback(err, result);
                    })
                },
                call: function(queryFn, input, callback){
                    if(!input) input = null;
                    var fnName = "";
                    if(queryFn.name.length > 0) fnName = plv8Connection.prefix + queryFn.name;
                    else {
                        var index = plv8Connection.generatedNames[0].indexOf(queryFn);
                        fnName += plv8Connection.generatedNames[1][index];
                    }
                    var queryString = "select " + fnName + "('" + JSON.stringify(input) + "')";
                    var result = plv8Connection.client.query(queryString, [], function (err, result){
                        done();
                        var deepResult = err ? undefined : result.rows.length > 0 && result.rows[0][Object.keys(result.rows[0])[0]];
                        callback(err, deepResult);
                    })
                },
                query: function(query, args, callback){
                    return plv8Connection.client.query(query, args, callback)
                }
            }
            connectionCallback(err, plv8Connection)
        });
        //todo: provide a sql injection attack protection layer and improved error handling for when the module is used by novices
    }
}