klapi/modules/Filters/FilterService.js

const express = require('express');
const Module = require('../../base/Module');
const RepositorySystem = require('../../systems/RepositorySystem');
const RoutingSystem = require('../../systems/RoutingSystem');
const FilterTypes = {}

class FilterService  {
	constructor(){
    	this.FilterTypes = FilterTypes;
	}
}

FilterService.buildQuery = function(query,filter) {
		switch(filter['type']){
			case 'onetoone':
				return query.where((builder) => 
					(filter['options'] || []).reduce((res, opt) => {
						return res.orWhere(filter['field'], opt);
					}, builder)
				);
			case 'manytomany':
				return query.where((builder) => 
					(filter['options'] || []).reduce((res, opt) => {
						return res.where(filter['field'], 'like', '%' + opt + '%');
					}, builder)
				);
			case 'includes':
				return query.whereIn(filter['field'],filter['options'])
			case 'equals':
				return query.where(filter['field'],filter['options'])
			case 'search':
				return query.where((builder) => 
					(filter['field'].split(',')).reduce((res, field) => {
						// return res.orWhere(field, 'like', '%' + filter['options'][0] + '%');
						return res.orWhere((sbuilder) =>
							(filter['options'][0].split(' ')).reduce((res, opt) => {
								return res.where(field, 'like', '%' + opt + '%');
							}, sbuilder));
					}, builder)
				);
				return query.where(filter['field'], 'like', '%' + filter['options'] + '%');
			case 'less':
				return query.where(filter['field'], '<', filter['options']);
			case 'more':
				return query.where(filter['field'], '>', filter['options']);
			case 'ascending':
				return query.orderBy(filter['field'],'asc')
			case 'descending':
				return query.orderBy(filter['field'],'desc')
			case 'value_range':
				return query.whereBetween(filter['field'],filter['options'])
			case 'raw':
				break; // RAW SQL - Injection
				// return query.whereRaw(filter['options'])
			default: return query;
		}
	}
  	
//array of filters that coming from front-end (can be one also)
FilterService.parseFilters = (query, filters = []) => {
		filters.forEach((filter, index) => {
			query = FilterService.buildQuery(query, filter);
		});
		// console.log(query.toString()); // debug query
		return query;
	}

FilterService.Middleware = (req, res, next) => {
	if(req.query.filters){
		let filters = JSON.parse(req.query.filters)
		req.filters = filters.map((filter) => {
			switch(filter.type){
				case 'select':
				case 'exact':
					filter.type = 'includes';
					return filter;
				case 'range':
 					filter.type = 'value_range';
					return filter;
				default:
					return filter;
			}
		})
		req.filters.push({
			type: 'equals',
			field: 'deleted',
			options: false
		});
	}
	next();
}

module.exports = FilterService;