node-query/lib/adapters/Pg.js

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'use strict';
const Adapter = require('../Adapter');
const Result = require('../Result');
const getArgs = require('getargs');
const helpers = require('../helpers');
const pg = require('pg');
const url = require('url');
class Pg extends Adapter {
constructor (config) {
let instance = null;
let connectionString = '';
if (helpers.isObject(config)) {
let host = config.host || 'localhost';
let user = config.user || 'postgres';
let password = `:${config.password}` || '';
let port = config.port || 5432;
let conn = {
protocol: 'postgres',
slashes: true,
host: `${host}:${port}`,
auth: `${user}${password}`,
pathname: config.database
};
connectionString = url.format(conn);
} else if (helpers.isString(config)) {
connectionString = config;
}
if (connectionString !== '') {
instance = new pg.Client(connectionString);
instance.connect(err => {
if (err) {
throw new Error(err);
}
});
}
super(instance);
}
/**
* Transform the adapter's result into a standard format
*
* @param {*} result - original driver result object
* @return {Result} - standard result object
*/
transformResult (result) {
if (result == null) {
return new Result();
}
let cols = [];
result.fields.forEach(field => {
cols = field.name;
});
return new Result(result.rows, cols);
}
/**
* Run the sql query as a prepared statement
*
* @param {String} sql - The sql with placeholders
* @param {Array} params - The values to insert into the query
* @param {Function} [callback] - Callback to run when a response is recieved
* @return {void|Promise} - Returns a promise if no callback is provided
*/
execute (/* sql, params, callback */) {
let args = getArgs('sql:string, [params]:array, [callback]:function', arguments);
// Replace question marks with numbered placeholders, because this adapter is different...
let count = 0;
args.sql = args.sql.replace(/\?/g, () => {
count++;
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return `$${count}`;
});
if (!args.callback) {
return new Promise((resolve, reject) => {
this.instance.query(args.sql, args.params, (err, result) =>
(err)
? reject(err)
: resolve(this.transformResult(result))
);
});
}
return this.instance.query(args.sql, args.params, (err, origResult) => {
let result = this.transformResult(origResult);
return args.callback(err, result);
});
}
}
module.exports = Pg;