LimitedInputStreamEngine.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;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * LimitedInputStream
 *
 *
 * @author Poli Andrea (apoli@link.it)
 * @author $Author$
 * @version $Rev$, $Date$
 */
public class LimitedInputStreamEngine extends FilterInputStream {

    private long limitBytes;
    private long count;
    
    private InputStream isWrapped = null;
    private String prefixError = "";
    private Map<Object> ctx;
    private boolean checkDisabled = false;

    private ILimitExceededNotifier notifier;
    
    protected LimitedInputStreamEngine(InputStream inputStream, long limitBytes, String prefixError, Map<Object> ctx, ILimitExceededNotifier notifier) throws IOException {
        super(inputStream);
        this.limitBytes = limitBytes;
        
        this.isWrapped = inputStream;
        if(prefixError!=null) {
            this.prefixError = prefixError;
        }
        this.ctx = ctx;
        if(this.limitBytes<=0) {
            throw new IOException("Invalid limit");
        }
        
        this.notifier = notifier;
    }
    
    public InputStream getIsWrapped() {
        return this.isWrapped;
    }

    protected void disableCheck() {
        this.checkDisabled = true;
    }
    protected void updateThreshold(long limitBytes) throws IOException {
        if(this.limitBytes<=0) {
            throw new IOException("Invalid limit");
        }
        this.limitBytes = limitBytes;
    }
    protected void updateContext(Map<Object> ctx) {
        this.ctx = ctx;
    }
    protected void updateNotifier(ILimitExceededNotifier notifier) {
        this.notifier = notifier;
    }

    private void checkLimit() throws IOException {
        if(this.checkDisabled) {
            return; // e' stato disabilitato dopo averlo creato
        }
        if (this.count > this.limitBytes) {
            
            /**System.out.println("Raggiunto limite dopo aver letto: "+this.count);*/
            
            payloadTooLarge(this.prefixError, this.ctx, this.notifier, this.count);
            
        }
    }
    public static void payloadTooLarge(String prefixError, Map<Object> ctx, ILimitExceededNotifier notifier, long count) throws LimitExceededIOException {
        limitExceeded(prefixError, LimitedInputStream.ERROR_PAYLOAD_TOO_LARGE_MSG, false, ctx, notifier, count);
    }
    public static void contentLenghtLimitExceeded(String prefixError, Map<Object> ctx, ILimitExceededNotifier notifier, long count) throws LimitExceededIOException {
        limitExceeded(prefixError, LimitedInputStream.ERROR_CONTENT_LENGTH_EXCEEDED_MSG, true, ctx, notifier, count);
    }
    private static void limitExceeded(String prefixError, String error, boolean contentLengthExceeded, Map<Object> ctx, ILimitExceededNotifier notifier, long count) throws LimitExceededIOException {
        String errorMsg = prefixError+error;
        if(ctx!=null) {
            ctx.put(LimitedInputStream.ERROR_MSG_KEY, errorMsg);
        }
        LimitExceededIOException exc = new LimitExceededIOException(errorMsg);
        if(ctx!=null) {
            ctx.put(LimitedInputStream.EXCEPTION_KEY, exc);
        }
        
        if(notifier!=null) {
            notifier.notify(count, contentLengthExceeded);
        }
        
        throw exc;
    }

    @Override
    public int read() throws IOException {
        int res = super.read();
        if (res != -1) {
            this.count++;
            checkLimit();
        }
        return res;
    }

    @Override
    public int read(byte[] b, int off, int len) throws IOException {
        int res = super.read(b, off, len);
        if (res > 0) {
            this.count += res;
            checkLimit();
        }
        return res;
    }

}