LdapFilter.java

/*
 * GovWay - A customizable API Gateway 
 * https://govway.org
 * 
 * Copyright (c) 2005-2025 Link.it srl (https://link.it). 
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3, as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

package org.openspcoop2.utils.transport.ldap;

import java.text.ParseException;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.naming.NamingException;
import javax.naming.directory.Attributes;

/**
 * classe che implementa i filtri di ricerca
 * 
 * @author Tommaso Burlon (tommaso.burlon@link.it)
 * @author $Author$ 
 * @version $Rev$, $Date$
 *
 */
public class LdapFilter {

    private String key = null;
    private String value = null;
    private List<LdapFilter> subFilters = null;
    private FilterType type = null;
    
    private enum FilterType {
        AND("&"), OR("|"), NOT("!"), EQUALS("="), PRESENCE("=*"), GTE(">="), LTE("<="), TRUE(null), FALSE(null);
        
        private String operator;
        private FilterType(String op) {
            this.operator = op;
        }
        
        @Override
        public String toString() {
            return this.operator;
        }
        
        public static FilterType fromString(String str) {
            FilterType[] types = FilterType.values();
            for (FilterType type : types)
                if (type.toString().equals(str))
                    return type;
            return null;
        }
    }

    private LdapFilter() {}
    
    private LdapFilter(FilterType type) {
        this.type = type;
    }
    
    private LdapFilter(FilterType type, String key, String value) {
        this.key = key;
        this.value = value;
        this.type = type;
    }
    
    private LdapFilter(FilterType type, List<LdapFilter> subFilters) {
        this.subFilters = subFilters;
        this.type = type;
    }
    
    private String getOperator() {
        return this.type.toString();
    }
    
    private StringBuilder buildString(StringBuilder ret) {
        switch (this.type) {
        case AND:
        case OR:
        case NOT:
            ret.append("(").append(this.getOperator());
            for (LdapFilter subFilter : this.subFilters) {
                subFilter.buildString(ret);
            }
            ret.append(")");
            break;
        case EQUALS:
        case PRESENCE:
        case GTE:
        case LTE:
            ret.append("(").append(this.key).append(this.getOperator()).append(this.value).append(")");
            break;
        case TRUE:
            ret.append("(&)");
            break;
        case FALSE:
            ret.append("(|)");
            break;
        }
        return ret;
    }
    
    @Override
    public String toString() {
        StringBuilder ret = new StringBuilder();
        return this.buildString(ret).toString();
    }
    
    // operatori
    public static LdapFilter and(LdapFilter ...filters) {
        return new LdapFilter(FilterType.AND, List.of(filters));
    }
    
    public boolean isAndFilter() {
        return this.type.equals(FilterType.AND);
    }
    
    public static LdapFilter or(LdapFilter ...filters) {
        return new LdapFilter(FilterType.OR, List.of(filters));
    }
    
    public boolean isOrFilter() {
        return this.type.equals(FilterType.OR);
    }
    
    public static LdapFilter not(LdapFilter filter) {
        return new LdapFilter(FilterType.NOT, List.of(filter));
    }
    
    public boolean isNotFilter() {
        return this.type.equals(FilterType.NOT);
    }
    
    public static LdapFilter absoluteTrue() {
        return new LdapFilter(FilterType.TRUE);
    }
    
    public boolean isAbsoluteTrueFilter() {
        return this.type.equals(FilterType.TRUE);
    }
    
    public static LdapFilter absoluteFalse() {
        return new LdapFilter(FilterType.FALSE);
    }
    
    public boolean isAbsoluteFalseFilter() {
        return this.type.equals(FilterType.FALSE);
    }
    
    // condizioni di base
    public static LdapFilter isPresent(String attribute) {
        return new LdapFilter(FilterType.PRESENCE, attribute, "");
    }

    public static LdapFilter isEqual(String attribute, String value) {
        return new LdapFilter(FilterType.EQUALS, attribute, value);
    }
    
    public static LdapFilter isAbsent(String attribute) {
        return LdapFilter.not(LdapFilter.isPresent(attribute));
    }
    
    public static LdapFilter isGreaterEqual(String attribute, String value) {
        return new LdapFilter(FilterType.GTE, attribute, value);
    }
    
    public static LdapFilter isLessEqual(String attribute, String value) {
        return new LdapFilter(FilterType.LTE, attribute, value);
    }
    
    // parse del filtro da una stringa
    private static final Pattern operatorsPatern = Pattern.compile("(=|<=|>=|\\&|\\|)");
    private static LdapFilter parseCondition(String raw, int start, int end) throws ParseException {
        
        if (raw.charAt(start) != '(')
            throw new ParseException("la condizione non inizia con una parentesi", start);
        if (raw.charAt(end - 1) != ')')
            throw new ParseException("la condizione non finisce con una parentesi", end - 1);
        
        Matcher matcher = operatorsPatern.matcher(raw).region(start, end);
        if (!matcher.find())
            throw new ParseException("operatore non presente o non riconusciuto operatori possibili: =,<=,>=,&,|", start + 1);
        if (matcher.groupCount() != 1)
            throw new ParseException("inseriti piu operatori in una signola condizione", matcher.end());
        
        String key = raw.substring(start + 1, matcher.start(0));
        FilterType op = FilterType.fromString(raw.substring(matcher.start(0), matcher.end(0)));
        String value = raw.substring(matcher.end(0), end - 1);
                
        if (op == null)
            throw new ParseException("operatore non riconusciuto operatori possibili: =,<=,>=,&,|,=*", start + 1);
        
        if (op.equals(FilterType.OR) || op.equals(FilterType.AND)) {
            if (key.isEmpty() && value.isEmpty())
                return op.equals(FilterType.OR) ? LdapFilter.absoluteFalse() : LdapFilter.absoluteTrue();
            throw new ParseException("condizione non valida, atteso absolute true/false ma chiave valore presenti", start + 1);
        }
        
        if (op.equals(FilterType.EQUALS) && value.equals("*"))
            return LdapFilter.isPresent(key);
        return new LdapFilter(op, key, value);
    }
    
    private static LdapFilter parseOperator(String raw, int start, int end, List<LdapFilter> subFilters) throws ParseException {
        if (raw.length() <= start + 1 || raw.length() < end)
            throw new ParseException("lunghezza stringa operatore tropo breve", start + 1);
        
        char op = raw.charAt(start + 1);
        FilterType type = null;
        if (op == '|') type = FilterType.OR;
        if (op == '&') type = FilterType.AND;
        if (op == '!') type = FilterType.NOT;
        if (type == null) throw new ParseException("tipo operatore di aggregazione ldap non riconosciuto: " + op, start + 1);
        
        return new LdapFilter(type, subFilters);
    }
        
    public static LdapFilter parse(String raw) throws ParseException {
        boolean isCondition = true;
        String in = raw.replace(" ", "");
        
        Deque<List<LdapFilter>> filters = new ArrayDeque<>();
        Deque<Integer> brackets = new ArrayDeque<>();
        
        filters.push(new ArrayList<>());
        for (int i = 0; i < in.length(); i++) {
            if(in.charAt(i) == '(') {
                brackets.push(i);
                filters.push(new ArrayList<>());
                isCondition = true;
            }
            if (in.charAt(i) == ')') {
                if (brackets.isEmpty())
                    throw new ParseException("parentesi chiusa non accoppiata con una aperta", i);
                int prev = brackets.pop();
                
                if (isCondition) {
                    filters.pop();
                    filters.peek().add(parseCondition(in, prev, i + 1));
                    isCondition = false;
                } else {
                    List<LdapFilter> subFilters = filters.pop();
                    filters.peek().add(parseOperator(in, prev, i + 1, subFilters));
                }
            }
        }
        
        return filters.peek().get(0);
    }
    
    // controlla se un attributo rispetta il filtro
    public boolean check(Attributes attrs) {
        
        try {
            switch (this.type) {
            case TRUE: return false;
            case FALSE: return true;
            case AND:
                for (LdapFilter filter : this.subFilters)
                    if (!filter.check(attrs))
                        return false;
                return true;
            case OR:
                for (LdapFilter filter : this.subFilters)
                    if (filter.check(attrs))
                        return true;
                return false;
            case NOT:
                return !this.subFilters.get(0).check(attrs);
            case EQUALS:
                if (attrs.get(this.key) == null) return false;
                Pattern pattern = Pattern.compile(this.value.replace("*", ".*"), Pattern.CASE_INSENSITIVE);
                Matcher matcher = pattern.matcher((String)attrs.get(this.key).get(0));
                return matcher.find();
            case PRESENCE:
                return attrs.get(this.key) != null;
            case GTE: return this.value.compareTo((String)attrs.get(this.key).get(0)) <= 0;
            case LTE: return this.value.compareTo((String)attrs.get(this.key).get(0)) >= 0;
            default: return false;
            }
        } catch(NamingException e) {
            return false;
        }
    }
}