ClientBlocker 1.5

Musings of a Ph.D. student in Computer Science

Published on January 9, 2007

Today I made some changes in my ClientBlocker. This may be the last version of this HTTPModule and I won't update it anymore (because it doesn't need any features though).

Using this HTTPModule you can block or trust on single IPs or a range of IPs and also use a free webservice to block site visitors based on their country.

In addition to making some minor changes I simplified the source code and solved a major bug. Now it works brilliantly. Main changes in code logic have been applied here:

#region Public methods
 
public void Init(HttpApplication context)
{
    context.BeginRequest += new EventHandler(context_BeginRequest);
}
 
public void Dispose()
{
}
 
#endregion
 
#region Handlers
 
void context_BeginRequest(object sender, EventArgs e)
{
    HttpApplication application = sender as HttpApplication;
 
    bool block = false;
 
    // Configurations
    this.filePath = application.Server.MapPath
        (ConfigurationManager.AppSettings["CB_BlockedIPsFile"].ToString());
 
    this.checkService = Convert.ToBoolean
        (ConfigurationManager.AppSettings["CB_CheckService"]);
 
    if (this.checkService == true)
    {
        string[] CountriesTemp = ConfigurationManager.AppSettings
            ["CB_BlockedCountries"].ToString().Split(' ');
        this.blockedCountries = GetArrayList(CountriesTemp);
    }
 
 
    try
    {
        string clientIP = application.Request.UserHostAddress;
 
        CheckIPs objChecker = new CheckIPs(this.filePath);
 
        if (objChecker.CheckIP(clientIP) == false)
        {
            if (this.checkService == true)
            {
                // User wants to check with webservice
                XmlDocument doc = new XmlDocument();
                string serviceURL = "http://api.hostip.info/?ip=" + clientIP;
 
                doc.Load(serviceURL);
 
                XmlNamespaceManager NSManager = new XmlNamespaceManager(doc.NameTable);
                NSManager.AddNamespace("hostip", "http://www.hostip.info/api");
                string query = "//hostip:countryAbbrev";
                XmlNode node = doc.SelectSingleNode(query, NSManager);
 
                string country = null;
                if (node != null)
                {
                    country = node.InnerText;
                }
 
 
                if (this.blockedCountries.Contains(country) == true)
                {
                    block = true;
                }
                else
                {
                    block = false;
                }
            }
            else
            {
                block = true;
            }
        }
    }
    catch
    {
        // On any unexpected error we let visitor to visit website
    }
 
    if (block)
    {
        // Blocking process
        application.Response.StatusCode = 200;
        application.Response.SuppressContent = true;
        application.Response.End();
    }
}
 
#endregion

Like the past you can use an XML file to set trusted and blocked IPs. Below is a sample file:

<?xml version="1.0" encoding="utf-8" ?>
<ips>
  <trusted>
    <ip value="127.0.0.1"/>
    <range lower="128.0.0.0" upper="128.255.255.255" />
  </trusted>
  <blocked>
    <range lower="127.0.0.0" upper="127.255.255.255" />
  </blocked>
</ips>

Configurations in Web.Config file look like this:

<?xml version="1.0" encoding="utf-8"?>
 
<configuration>
 
  <appSettings>
    <add key="CB_BlockedIPsFile" value="~/IPs.xml"/>
    <add key="CB_CheckService" value="false"/>
    <add key="CB_BlockedCountries" value="IR RU"/>
  </appSettings>
 
  <system.web>
    <httpModules>
      <add type="ClientBlocker.Blocker, ClientBlocker" name="ClientBlocker" />
    </httpModules>
  </system.web>
 
</configuration>

New version is available on my file gallery with source code and installation instructions and you can download it.

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Jan 09, 2007 8:04 AM
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