pg-redis

A pg query wrapper with implicit redis query caching.

Installation

npm i --save pg-redis pg redis

Usage

var pgRedis = require('pg-redis');
pgRedis.init({
    // a node-postgres config object, documented at
    // https://github.com/brianc/node-postgres/wiki/Client#parameters
});

// normal usage, caches the result for two minutes
pgRedis.query('select * from entity', {
  duration: 120
}).then(function (results) {
  console.log(results);
}, function (error) {
  console.error(error);
}).done();

// bypassing the cache in favor of the prepare/execute api
pgRedis.prepare('select * from entity where date between ? and ?').then(function (stmt) {
  stmt.execute([startDate, endDate]).then(function (results) {
    console.log(results);
  }).done();
}).done();

// efficient batching operations can be done this way
// pass batch:true in prepare options to initiate a new batch operation
pgRedis.prepare('begin; create temporary table temp_table like (table)', {batch:true}).then(function (stmt) {
    // we must call release() when done with the transaction
    // stmt.release is only defined for the first prepared statement in a chain with {batch:true}
    var release = stmt.release;
    stmt.execute().then(function () {
        pgRedis.prepare('insert into temp_table values ($1, $2, $3)', {client:stmt.client}, function(stmt) {
            var data = [[1,2,3], [4,5,6], [7,8,9]],
                inserts = [];

            // build an array of promises to insert individual rows
            for (var i = 0; i < data.length; i++) {
                inserts.push(stmt.execute(data[i]));
            }

            // perform inserts in parallel using the same connection
            p.all(inserts).then(function () {
                // make sure that release() is called regardless of success or failure
                pgRedis.prepare('select merge_data(); commit;').then(function (stmt) {
                    // release the connection regardless of commit result
                    stmt.execute().then(null, function (err) {
                        console.error('an error occurred executing the merge statement', err);
                    }).fin(function () { release(); }).done();
                }, function (err) {
                    console.error('an error occurred preparing the merge statement', err);
                }).done();
            }, function (err) {
                console.error('an error occurred during the insertion of data', err);
            }).done();
        }, function (err) {
            console.error('an error occurred preparing the insert statement', err);
        }).done();
    }, function (err) {
        console.error('an error occurred preparing the temporary table creation statement', err);
    }).done();
}).done();

Testing

npm test