package org.alleypress.servlet.filter;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
/**
* Collect info on which browsers are accessing your application and record it to a
* database. You will need to initialze the following parameters:
*
<init-param>
<param-name>driver</param-name>
<param-value>org.gjt.mm.mysql.Driver</param-value>
</init-param>
<init-param>
<param-name>url</param-name>
<param-value>jdbc:mysql://localhost:3306/stats</param-value>
</init-param>
<init-param>
<param-name>username</param-name>
<param-value>user</param-value>
</init-param>
<init-param>
<param-name>password</param-name>
<param-value>pass</param-value>
</init-param>
*
* Right now this is really oriented towards a MySql database, but it could
* enhanced to be confiurable for any database by adding some parameters.
* It doesn't use a connection pool becuase the writes should be fairly infrequent
* Here's the table that needs to be setup:
*
CREATE TABLE browser (
agent varchar(255) NOT NULL default '',
total int(10) unsigned NOT NULL default '0',
last_update timestamp(14) NOT NULL,
app_id int(10) unsigned NOT NULL default '0',
PRIMARY KEY (`agent`)
) TYPE=InnoDB'
*
* @author Tom Crofton
* @version 1.3
* @email croftontom@yahoo.com
* @created Jan 27, 2006
* @last Feb 3, 2006
*
*/
public class BrowserInfo implements Filter {
private class MyInt {
private int val=1;
public void incr() {val++;}
public Integer getInt() {return new Integer(val);}
public int getVal() {return val;};
}
private static final int UPDATE_TIME=1000*60*15; //15 minutes
private static final int UPDATE_COUNT=100; //100 requests
private Map agents = new HashMap();
private String driverClass = null;
private String connectUrl = null;
private String username = null;
private String password = null;
private int appId = 0;
private long updateTime = 0;
private int updateCount = 0;
/*
* Initialize the driver,url,username, and password params. Also try connecting to
* the database to make sure the settings are good.
*
* @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
*
*/
public void init(FilterConfig config) throws ServletException {
//grab the parameters
driverClass=config.getInitParameter("driver");
connectUrl=config.getInitParameter("url");
username=config.getInitParameter("username");
password=config.getInitParameter("password");
if (connectUrl==null) throw new ServletException("parameter 'url' not specified");
if (username==null) throw new ServletException("parameter 'username' not specified");
if (password==null) throw new ServletException("parameter 'password' not specified");
try {
appId=Integer.parseInt(config.getInitParameter("appId"));
} catch (Exception e) {
throw new ServletException("parameter 'appId' is missing or invalid");
}
if (driverClass==null) throw new ServletException("parameter 'driver' not specified");
try {
Class.forName(driverClass);
} catch (ClassNotFoundException e) {
throw new ServletException("could not load db driver "+driverClass);
}
//establish a database connection or throw exception
try {
Connection conn = DriverManager.getConnection(connectUrl, username, password);
ResultSet rs = conn.createStatement().executeQuery("select count(*) from browser");
rs.next();
conn.close();
} catch (SQLException e) {
throw new ServletException(e);
}
}
/*
* Takes the User-Agent header from the request and maintiains a Map of agents and
* counts. After the buffer is full or enough time has passed, on the next request
* the data is written out to the database.
*
* @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
*/
public void doFilter(ServletRequest req, ServletResponse resp,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest request=(HttpServletRequest)req;
String ag=request.getHeader("User-Agent");
if (ag!=null) {
if (agents.containsKey(ag)) {
((MyInt)agents.get(ag)).incr();
} else {
agents.put(ag,new MyInt());
}
updateCount++;
if (timeToUpdate()) {
try {
writeCounts();
resetCounts();
} catch (SQLException e) {
throw new ServletException(e);
}
}
}
chain.doFilter(request,resp);
}
private void resetCounts() {
updateCount=0;
updateTime=System.currentTimeMillis();
agents.clear();
}
private boolean timeToUpdate() {
return (updateCount>UPDATE_COUNT || System.currentTimeMillis()>(updateTime+UPDATE_TIME) );
}
/* (non-Javadoc)
* @see javax.servlet.Filter#destroy()
*/
public void destroy() {
try {
writeCounts();
} catch (SQLException e) {
//kinda forced to abandon this
e.printStackTrace();
}
}
private synchronized void writeCounts() throws SQLException {
if (agents.isEmpty()) return; //nothing to do
Connection conn = DriverManager.getConnection(connectUrl, username, password);
PreparedStatement psSelect= conn.prepareStatement("select total from browser where agent=? and app_id=?");
PreparedStatement psIns = conn.prepareStatement("insert into browser (agent,total,last_update,app_id) values (?,?,current_timestamp(),?)");
PreparedStatement psUpdate = conn.prepareStatement("update browser set total=?,last_update=current_timestamp() where agent=? and app_id=?");
psSelect.setInt(2,appId);
psIns.setInt(3,appId);
psUpdate.setInt(3,appId);
Iterator it=agents.keySet().iterator();
while (it.hasNext()) {
String agentName=(String)it.next();
psSelect.setString(1,agentName);
ResultSet rs=psSelect.executeQuery();
if (rs.next()) {
int ttl=rs.getInt("total");
ttl=ttl+ ((MyInt)agents.get(agentName)).getVal();
psUpdate.setInt(1,ttl);
psUpdate.setString(2,agentName);
psUpdate.executeUpdate();
} else {
psIns.setString(1,agentName);
psIns.setInt(2,((MyInt)agents.get(agentName)).getVal());
psIns.executeUpdate();
}
}
conn.close();
}
}