PageVariabilityCheck.java

/*******************************************************************************
 * Copyright (c) 2011 Subgraph.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     Subgraph - initial API and implementation
 ******************************************************************************/
package com.subgraph.vega.impl.scanner.handlers;

import org.apache.http.client.methods.HttpUriRequest;

import com.subgraph.vega.api.http.requests.IHttpResponse;
import com.subgraph.vega.api.http.requests.IPageFingerprint;
import com.subgraph.vega.api.scanner.IInjectionModuleContext;
import com.subgraph.vega.api.scanner.IPathState;

public class PageVariabilityCheck extends CrawlerModule {
	private final static int BH_CHECKS = 15;

	private final InjectionChecks injectionChecks;

	public PageVariabilityCheck(InjectionChecks injectionChecks) {
		this.injectionChecks = injectionChecks;
	}

	@Override
	public void initialize(IPathState ps) {
		final IInjectionModuleContext ctx = ps.createModuleContext();

		for(int i = 0; i < BH_CHECKS; i++) {
			ctx.submitRequest(ps.createRequest(), this, i);
		}
	}


	@Override
	public void runModule(HttpUriRequest request, IHttpResponse response, IInjectionModuleContext ctx) {
		final IPathState ps = ctx.getPathState();

		if(response.isFetchFail())
			ctx.error(request, response, "Failed to fetch response during page variability check");
		else
			testResponse(request, response, ctx);

		ctx.incrementResponseCount();
		if(!ctx.allResponsesReceived())
			return;

		if(ps.getResponseVaries())
			return;

		injectionChecks.launchInjectionModules(ps);

	}

	private void testResponse(HttpUriRequest request, IHttpResponse response, IInjectionModuleContext ctx) {
		final IPageFingerprint fp = response.getPageFingerprint();
		final IPathState ps = ctx.getPathState();
		if(!ps.matchesPathFingerprint(fp)) {
			ps.setResponseVaries();
			ctx.debug("Response varies");
		}
	}
}