node-query/lib/QueryParser.js

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'use strict';
let helpers = require('./helpers');
// --------------------------------------------------------------------------
module.exports = class QueryParser {
/**
* @constructor
*
* @param {Driver} driver - The driver object for the database in use
* @return {void}
*/
constructor(driver) {
this.driver = driver;
let matchPatterns = {
'function': /([a-z0-9_]+\((.*)\))/i,
operator: /\!=?|\=|\+|&&?|~|\|\|?|\^|\/|<>|>=?|<=?|\-|%|OR|AND|NOT|XOR/ig,
literal: /([0-9]+)|'(.*?)'|true|false/ig
};
// Full pattern for identifiers
// Making sure that literals and functions aren't matched
matchPatterns.identifier = new RegExp(
'('
+ '(?!'
+ matchPatterns['function'].source + '|'
+ matchPatterns.literal.source
+ ')'
+ '([a-z_\-]+[0-9]*\\.?)'
+ ')+'
, 'ig');
// Full pattern for determining ordering of the pieces
matchPatterns.joinCombined = new RegExp(
matchPatterns['function'].source + "+|"
+ matchPatterns.literal.source + '+|'
+ matchPatterns.identifier.source
+ '|(' + matchPatterns.operator.source + ')+'
, 'ig');
this.matchPatterns = matchPatterns;
this.identifierBlacklist = ['true','false','null'];
}
/**
* Filter matched patterns
*
* @param {Array} array - Set of possible matches
* @return {Array|null} - Filtered set of possible matches
*/
filterMatches(array) {
let output = [];
// Return non-array matches
if (helpers.isNull(array)) return null;
if (helpers.isScalar(array) || helpers.isUndefined(array)) return output;
array.forEach(item => {
output.push(item);
});
return output;
}
/**
* Check if the string contains an operator, and if so, return the operator(s).
* If there are no matches, return null
*
* @param {String} string - the string to check
* @return {Array|null} - List of operators
*/
hasOperator(string) {
return this.filterMatches(string.match(this.matchPatterns.operator));
}
/**
* Tokenize the sql into parts for additional processing
*
* @param {String} sql - Join sql to parse
* @return {Object} - Join condition components
*/
parseJoin(sql) {
let matches = {};
let output = {
functions: [],
identifiers: [],
operators: [],
literals: []
};
// Get clause components
matches.functions = sql.match(new RegExp(this.matchPatterns['function'].source, 'ig'));
matches.identifiers = sql.match(this.matchPatterns.identifier);
matches.operators = sql.match(this.matchPatterns.operator);
matches.literals = sql.match(this.matchPatterns.literal);
// Get everything at once for ordering
matches.combined = sql.match(this.matchPatterns.joinCombined);
// Flatten the matches to increase relevance
Object.keys(matches).forEach(key => {
output[key] = this.filterMatches(matches[key]);
});
return output;
}
/**
* Return the output of the parsing of the join condition
*
* @param {String} condition - The join condition to evalate
* @return {String} - The parsed/escaped join condition
*/
compileJoin(condition) {
let parts = this.parseJoin(condition);
// Quote the identifiers
parts.combined.forEach((part, i) => {
if (parts.identifiers.indexOf(part) !== -1 && ! helpers.isNumber(part))
{
parts.combined[i] = this.driver.quoteIdentifiers(part);
}
});
return parts.combined.join(' ');
}
/**
* Parse a where clause to separate functions from values
*
* @param {Driver} driver - The current db driver
* @param {State} state - Query Builder state object
* @return {String} - The parsed/escaped where condition
*/
parseWhere(driver, state) {
let whereMap = state.whereMap;
let whereValues = state.rawWhereValues;
let outputMap = [];
let outputValues = [];
Object.keys(whereMap).forEach(key => {
// Combine fields, operators, functions and values into a full clause
// to have a common starting flow
let fullClause = '';
// Add an explicit = sign where one is inferred
if ( ! this.hasOperator(key))
{
fullClause = key + ' = ' + whereMap[key];
}
else if (whereMap[key] === key)
{
fullClause = key;
}
else
{
fullClause = key + ' ' + whereMap[key];
}
// Separate the clause into separate pieces
let parts = this.parseJoin(fullClause);
// Filter explicit literals from lists of matches
if (whereValues.indexOf(whereMap[key]) !== -1)
{
let value = whereMap[key];
let identIndex = (helpers.isArray(parts.identifiers)) ? parts.identifiers.indexOf(value) : -1;
let litIndex = (helpers.isArray(parts.literals)) ? parts.literals.indexOf(value) : -1;
let combIndex = (helpers.isArray(parts.combined)) ? parts.combined.indexOf(value) : -1;
let funcIndex = (helpers.isArray(parts.functions)) ? parts.functions.indexOf(value) : -1;
let inOutputArray = outputValues.indexOf(value) !== -1;
// Remove the identifier in question,
// and add to the output values array
if (identIndex !== -1)
{
parts.identifiers.splice(identIndex, 1);
if ( ! inOutputArray)
{
outputValues.push(value);
inOutputArray = true;
}
}
// Remove the value from the literals list
// so it is not added twice
if (litIndex !== -1)
{
parts.literals.splice(litIndex, 1);
if ( ! inOutputArray)
{
outputValues.push(value);
inOutputArray = true;
}
}
// Remove the value from the combined list
// and replace it with a placeholder
if (combIndex !== -1 && funcIndex === -1)
{
// Make sure to skip functions when replacing values
parts.combined[combIndex] = '?';
if ( ! inOutputArray)
{
outputValues.push(value);
inOutputArray = true;
}
}
}
// Filter false positive identifiers
parts.identifiers = parts.identifiers || [];
parts.identifiers = parts.identifiers.filter(item => {
let isInCombinedMatches = parts.combined.indexOf(item) !== -1;
let isNotInBlackList = this.identifierBlacklist.indexOf(item.toLowerCase()) === -1;
return isInCombinedMatches && isNotInBlackList;
}, this);
// Quote identifiers
if (helpers.isArray(parts.identifiers))
{
parts.identifiers.forEach(ident => {
let index = parts.combined.indexOf(ident);
if (index !== -1)
{
parts.combined[index] = driver.quoteIdentifiers(ident);
}
});
}
// Replace each literal with a placeholder in the map
// and add the literal to the values,
// This should only apply to literal values that are not
// explicitly mapped to values, but have to be parsed from
// a where condition,
if (helpers.isArray(parts.literals))
{
parts.literals.forEach(lit => {
let litIndex = parts.combined.indexOf(lit);
if (litIndex !== -1)
{
parts.combined[litIndex] = (helpers.isArray(parts.operators)) ? '?' : '= ?';
outputValues.push(lit);
}
});
}
outputMap.push(parts.combined.join(' '));
});
state.rawWhereValues = [];
state.whereValues = state.whereValues.concat(outputValues);
state.whereMap = outputMap;
return state;
}
}