const Adapter = require('../../Adapter');
const Result = require('../../Result');
const Helpers = require('../../Helpers');
const pg = require('pg');
const url = require('url');
class Pg extends Adapter {
constructor (config) {
let instance = null;
let connectionString = Pg.formatConnectionString(config);
Eif (connectionString !== '') {
const conn = new pg.Client(connectionString);
conn.connect(err => {
Iif (err) {
throw new Error(err);
}
});
instance = Promise.resolve(conn);
}
super(instance);
}
/**
* Convert the connection object to a connection string
*
* @param {Object} config - the configuration object
* @return {String} - the connection string
*/
static formatConnectionString (config) {
let connectionString = '';
if (Helpers.isObject(config)) {
const host = config.host || 'localhost';
const user = config.user || 'postgres';
const password = `:${config.password}` || '';
const port = config.port || 5432;
const conn = {
protocol: 'postgres',
slashes: true,
host: `${host}:${port}`,
auth: `${user}${password}`,
pathname: config.database
};
connectionString = url.format(conn);
} else Eif (Helpers.isString(config)) {
connectionString = config;
}
return connectionString;
}
/**
* Transform the adapter's result into a standard format
*
* @param {*} result - original driver result object
* @return {Result} - standard result object
*/
transformResult (result) {
Iif (result == null) {
return new Result();
}
const cols = [];
result.fields.forEach(field => {
cols.push(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
* @return {void|Promise} - Returns a promise if no callback is provided
*/
execute (sql, params) {
// Replace question marks with numbered placeholders, because this adapter is different...
let count = 0;
sql = sql.replace(/\?/g, () => {
count++;
return `$${count}`;
});
return this.instance.then(conn => {
return new Promise((resolve, reject) => {
conn.query(sql, params, (err, result) =>
(err)
? reject(err)
: resolve(this.transformResult(result))
);
});
});
}
}
module.exports = Pg;
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