node-query/lib/query-parser.js

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'use strict';
var helpers = require('./helpers');
var matchPatterns = {
'function': /([a-z0-9_]+\((.*)\))/i,
operator: /\!=?|\=|\+|&&?|~|\|\|?|\^|\/|<>|>=?|<=?|\-|%|OR|AND|NOT|XOR/ig,
literal: /([0-9]+)|'(.*?)'|true|false/ig
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};
// 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');
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// Full pattern for determining ordering of the pieces
matchPatterns.joinCombined = new RegExp(
matchPatterns['function'].source + "+|"
+ matchPatterns.literal.source + '+|'
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+ matchPatterns.identifier.source
+ '|(' + matchPatterns.operator.source + ')+'
, 'ig');
var identifierBlacklist = ['true','false','null'];
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var filterMatches = function(array) {
var output = [];
// Return non-array matches
if (helpers.isNull(array)) return null;
if (helpers.isScalar(array) || helpers.isUndefined(array)) return output;
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array.forEach(function(item) {
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output.push(item);
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});
return output;
};
// --------------------------------------------------------------------------
/**
* @constructor
* @param {Driver} - The driver object for the database in use
* @module query-parser
*/
var QueryParser = function(driver) {
// That 'new' keyword is annoying
if ( ! (this instanceof QueryParser)) return new QueryParser(driver);
/**
* 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}
*/
this.hasOperator = function(string) {
return filterMatches(string.match(matchPatterns.operator));
}
/**
* Tokenize the sql into parts for additional processing
*
* @param {String} sql
* @return {Object}
*/
this.parseJoin = function(sql) {
var matches = {};
var output = {};
// Get clause components
matches.functions = sql.match(new RegExp(matchPatterns['function'].source, 'ig'));
matches.identifiers = sql.match(matchPatterns.identifier);
matches.operators = sql.match(matchPatterns.operator);
matches.literals = sql.match(matchPatterns.literal);
// Get everything at once for ordering
matches.combined = sql.match(matchPatterns.joinCombined);
// Flatten the matches to increase relevance
Object.keys(matches).forEach(function(key) {
output[key] = filterMatches(matches[key]);
});
return output;
};
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/**
* 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
*/
this.compileJoin = function(condition) {
var parts = this.parseJoin(condition);
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var count = parts.identifiers.length;
var i;
// Quote the identifiers
parts.combined.forEach(function(part, i) {
if (parts.identifiers.indexOf(part) !== -1 && ! helpers.isNumber(part))
{
parts.combined[i] = driver.quoteIdentifiers(part);
}
});
return parts.combined.join(' ');
};
/**
* Parse a where clause to separate functions from values
*
* @param {Object} driver
* @param {State} state
* @return {String} - The parsed/escaped where condition
*/
this.parseWhere = function(driver, state) {
var whereMap = state.whereMap,
whereValues = state.rawWhereValues;
var outputMap = [];
var outputValues = [];
Object.keys(whereMap).forEach(function(key) {
// Combine fields, operators, functions and values into a full clause
// to have a common starting flow
var fullClause = '';
// Add an explicit = sign where one is inferred
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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
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var parts = this.parseJoin(fullClause);
// Filter explicit literals from lists of matches
if (whereValues.indexOf(whereMap[key]) !== -1)
{
var value = whereMap[key];
var identIndex = (helpers.isArray(parts.identifiers)) ? parts.identifiers.indexOf(value) : -1;
var litIndex = (helpers.isArray(parts.literals)) ? parts.literals.indexOf(value) : -1;
var combIndex = (helpers.isArray(parts.combined)) ? parts.combined.indexOf(value) : -1;
var funcIndex = (helpers.isArray(parts.functions)) ? parts.functions.indexOf(value) : -1;
var 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)
{
// Make sure to skip functions when replacing values
if (funcIndex === -1)
{
parts.combined[combIndex] = '?';
if ( ! inOutputArray)
{
outputValues.push(value);
inOutputArray = true;
}
}
}
}
// Filter false positive identifiers
parts.identifiers = parts.identifiers.filter(function(item) {
var isInCombinedMatches = parts.combined.indexOf(item) !== -1;
var isNotInBlackList = identifierBlacklist.indexOf(item.toLowerCase()) === -1;
return isInCombinedMatches && isNotInBlackList;
});
// Quote identifiers
if (helpers.isArray(parts.identifiers))
{
parts.identifiers.forEach(function(ident) {
var 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(function(lit) {
var litIndex = parts.combined.indexOf(lit);
if (litIndex !== -1)
{
parts.combined[litIndex] = (helpers.isArray(parts.operators)) ? '?' : '= ?';
outputValues.push(lit);
}
});
}
outputMap.push(parts.combined.join(' '));
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}, this);
state.rawWhereValues = [];
state.whereValues = state.whereValues.concat(outputValues);
state.whereMap = outputMap;
return state;
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};
};
module.exports = QueryParser;