src/PDOX.js
var Q = require("q");
var mysql = require("mysql");
/**
* Routines to handle connection chores.
* https://www.npmjs.com/package/mysql
*/
class PDOX {
/**
* Create the database conection pools.
* @param {Config} Configuration object
*/
constructor(CFG) {
/**
* A reference to the configuration object
*
* @private
*/
this._CFG = CFG; // Retain for leter
/**
* The database pool (private)
* https://www.npmjs.com/package/mysql#pooling-connections
*
* @private
*/
this._pool = null;
// Create a MySql pool
var pool = mysql.createPool({
host : CFG.dbhost,
port : CFG.dbport,
database : CFG.dbname,
// TODO: Pool parameters
user : CFG.dbuser,
password : CFG.dbpass
});
// Test the pool (async - will fail later)
/*
this._testPool(pool).then(function (message) {
console.log(message);
});
*/
this._pool = pool;
}
/**
* Replace {p} with the configured database table prefix.
*/
setPrefix(sql) {
return sql.replace(/{p}/g, this._CFG.dbprefix);
}
/**
* Dp field Substitution
*/
static substituteFields(conn, sql, data) {
let retval = sql.replace(/\:(\w+)/g, function (txt, key) {
if (data.hasOwnProperty(key)) {
if ( typeof data[key] == 'undefined' || data[key] === null ) {
console.log("NULL at",key);
return 'NULL';
}
return conn.escape(data[key]);
}
console.log("Warning: substitution key not found:",key);
return txt;
});
return retval;
}
/**
* Make the PDO-style format substitutions work
*
* https://www.npmjs.com/package/mysql#preparing-queries
*
* connection.query("UPDATE posts SET title = :title",
* { title: "Hello MySQL" });
*
* @private
*/
_setupFormat(connection) {
connection.config.queryFormat = function (query, values) {
if (!values) return query;
return query.replace(/\:(\w+)/g, function (txt, key) {
if (values.hasOwnProperty(key)) {
if ( typeof values[key] == 'undefined' || values[key] === null ) {
// console.log("NULL at",key);
return 'NULL';
}
return this.escape(values[key]);
}
console.log("Warning: substitution key not found:",key);
return txt;
}.bind(this));
};
}
/**
* Test the pool
*
* @private
*/
_testPool(pool) {
var deferred = Q.defer();
pool.getConnection(function(err, conn){
conn.query("SELECT 1 + 1 AS solution", function(err, rows) {
if (err) {
console.log("Unable to make database pool");
console.log("This could be incorrect configuration or missing database");
console.log("Here are the rough instructions to make the database tables:");
console.log(" CREATE DATABASE tsugi DEFAULT CHARACTER SET utf8;");
console.log(" GRANT ALL ON tsugi.* TO 'ltiuser'@'localhost' IDENTIFIED BY 'ltipassword';");
console.log(" GRANT ALL ON tsugi.* TO 'ltiuser'@'127.0.0.1' IDENTIFIED BY 'ltipassword';");
conn.release();
deferred.reject(err);
}
conn.release();
deferred.resolve('Pool test success');
})
});
return deferred.promise;
}
/**
* Get a connection promise from the pool
* Make sure to do a cop.release()
*
* var thekey = '12345';
* pdox.cop.then( function(connection) {
* let sql = 'SELECT * FROM lti_key WHERE key_key = :key';
* connection.query(sql, { key: thekey }, function(err, rows, fields) {
* if (err) {
* console.log('Could not load data query');
* } else {
* console.log("Rows:",rows.length);
* }
* connection.release();
* });
* });
*/
cop() {
var deferred = Q.defer();
var setupFormat = this._setupFormat;
this._pool.getConnection(function(err, connection) {
if(err) {
deferred.reject(err);
} else {
setupFormat(connection);
deferred.resolve(connection);
}
});
return deferred.promise;
}
/**
* Run a query and return all the rows from the query and throw any error.
*
* let sql = 'SELECT * FROM {p}lti_key WHERE key_key = :key_key';
* pdox.allRowsDie(sql,{ key_key: thekey }).then(
* function(rows) {
* console.log("Rows:",rows.length);
* },
* function(reason) {
* console.log("Bummer",reason);
* }
* );
*
* @param {string} sql The SQL to use - it is ok to use {p} for
* the database prefix.
* @param {object} data The key-value pairs for substitution
*/
allRowsDie(sql, data=null) {
return this.allRows(sql,data,true);
}
/**
* Run a query and return all the rows or an error from the query.
*
* let sql = 'SELECT * FROM lti_key WHERE key_key = :key_key';
* pdox.allRows(sql,{ key_key: thekey }, false).then(
* function(rows) {
* console.log("Rows:",rows.length);
* },
* function(reason) {
* console.log("Bummer",reason);
* }
* );
*
* @param {string} sql The SQL to use - it is ok to use {p} for
* the database prefix - must be SELECT
* @param {object} data The key-value pairs for substitution
* @param {boolean} dothrow Whether to throw or return the error
*/
allRows(sql, data=null, dothrow=false) {
// console.log("allRowsDie",sql); console.log(" ",data);
var deferred = Q.defer();
sql = this.setPrefix(sql);
this.cop().then( function(connection) {
sql = PDOX.substituteFields(connection, sql, data);
connection.query(sql, data, function(err, rows, fields) {
if (err) {
console.log('Could not load data query');
console.log(sql);
console.log(data);
connection.release();
let myerror = 'Could not load data query '+sql;
if ( dothrow ) {
deferred.reject(myerror);
} else {
deferred.resolve(myerror);
}
} else {
// console.log('query die returning rows:', rows.length);
connection.release();
deferred.resolve(rows);
}
});
}).catch (function (connectionError) {
deferred.reject (connectionError);
});
return deferred.promise;
}
/**
* Run a query and return the number of affected rows, throw on error
*
* sql = "DELETE FROM {p}lti_unit_test WHERE name='tsugi'";
* pdox.query(sql).then( function(retval) {
* console.log("DELETE retval:",retval);
* });
*
* @param {string} sql The SQL to use - it is ok to use {p} for
* the database prefix - must not be a SELECT
* @param {object} data The key-value pairs for substitution (optional)
*/
query(sql, data=null) {
return this.queryFull(sql, data, 0, true);
}
/**
* Run a query and return the number of changed rows, throw on error
*
* sql = "UPDATE {p}lti_unit_test SET email=:new WHERE name='tsugi'";
* pdox.queryChanged(sql, {new:'tsugi@fred.com'}).then(
* function(retval) {
* console.log("UPDATE retval:",retval);
* }
* );
*
* @param {string} sql The SQL to use - it is ok to use {p} for
* the database prefix - must not be a SELECT
* @param {object} data The key-value pairs for substitution (optional)
*/
queryChanged(sql, data=null) {
return this.queryFull(sql, data, 1, true);
}
/**
* Run an INSERT and return the generated key, throw on error
*
* sql = "INSERT INTO {p}lti_unit_test (name,email)
* VALUES ('tsugi', 'tsugi@zap.com')";
* pdox.insertKey(sql).then( function(retval) {
* console.log("INSERT retval:",retval);
* });
*
* @param {string} sql The SQL to use - it is ok to use {p} for
* the database prefix - must be an INSERT to a table with
* an auto-increment field.
* @param {object} data The key-value pairs for substitution (optional)
*/
insertKey(sql, data=null) {
return this.queryFull(sql, data, 2, true);
}
/**
* Run a query and return the appropriate result for the query
*
* This has more parameters and is typically used by methods with
* simpler signatures.
*
* @param {string} sql The SQL to use - it is ok to use {p} for
* the database prefix - must not be SELECT.
* @param {object} data The key-value pairs for substitution
* @param {number} returnval What to return from the function.
* 0=rows affected, 1=rows changed, 2=last insert id
* @param {boolean} dothrow Whether to throw or return the error
*/
queryFull(sql, data=null, returnval=0, dothrow=false) {
// console.log("queryFull",sql); console.log(" ",data);
var deferred = Q.defer();
sql = this.setPrefix(sql);
this.cop().then( function(connection) {
sql = PDOX.substituteFields(connection, sql, data);
connection.query(sql, data, function(err, result) {
if (err) {
console.log('Could not execute query');
console.log(sql);
console.log(data);
connection.release();
let myerror = 'Could not execute query '+sql;
if ( dothrow ) {
deferred.reject(myerror);
} else {
deferred.resolve(myerror);
}
} else {
// console.log('query die returning rows:', rows.length);
connection.release();
if ( returnval == 2 ) {
deferred.resolve(result.insertId);
} else if ( returnval == 1 ) {
deferred.resolve(result.changedRows);
} else {
deferred.resolve(result.affectedRows);
}
}
});
}).catch (function (connectionError) {
deferred.reject (connectionError);
});
return deferred.promise;
}
}
module.exports = PDOX;
