把any-db的查询用Q封装为promise风格

promisedQuery.js

var _ = require('underscore');
var Q = require('q');

var pool = require('any-db').createPool('postgres://dev:[email protected]/lysine', {name: 'test', min: 3, max: 10, log: true});

function query(sql, params) {
    return _query(sql, params, false);
}

function stream_query(sql, params) {
    return _query(sql, params, true);
}

function _query(sql, params, stream) {
    var query;
    var defered = Q.defer();
    var args = [sql, params || []];

    stream = _.isUndefined(stream) ? false : !!stream;

    pool.query.apply(pool, args)
        .on('row', function(row, res) {
            if (!stream) res.addRow(row);
            defered.notify(row);
        })
        .on('error', function(err) { defered.reject('error'); })
        .on('end', function(res) { defered.resolve(res); });

    return defered.promise;
}

stream_query('select now()', [])
    .progress(function(row) {
        console.log('progress');
        console.log(row);
    })
    .then(function(res) {
        console.log('resolve');
        console.log(res);
    })
    .catch(function(err) {
        console.log('reject');
        console.log(err);
    })
    .finally(_.bind(pool.close, pool));

function _exit() {
    pool.close();
    console.log('pool closed');
}

process.on('SIGINT', _exit);
process.on('SIGHUP', _exit);
process.on('SIGQUIT', _exit);