如何通过背后的代码从第三方获取用户的客户端IP

Question

I am using this script to get User's Client IP:

<script type="text/javascript" src="http://geoiplookup.wikimedia.org/"></script>

I can get the IP using JavaScript as Geo.IP , but I need to get it in code behind on button click.

Something like:

protected void Button1_Click(object sender, EventArgs e)
{
    string IP = string.Empty;

    // IP = ???

    // Validation code

}

Any ideas?

Thanks in advance...

Answer 1

Why the client-side script? Request.UserHostAddress sounds like what you're looking for. :)

protected void Button1_Click(object sender, EventArgs e)
{
    string IP = Request.UserHostAddress;

    // Validation code

}

Answer 2

If you really can't use server variables, or if you need the geo information as well as the IP, you'll need something like the following:

<!-- Get geo information -->
<script type="text/javascript"
    src="http://geoiplookup.wikimedia.org/">
</script>
<!-- JavaScript object-to-JSON -->
<!-- Don't actually hotlink this; host it yourself -->
<script type="text/javascript" 
    src="https://github.com/douglascrockford/JSON-js/blob/master/json2.js">
</script>
<!-- Hidden field to hold result -->
<asp:HiddenField id="hdnGeo" runat="server"></asp:HiddenField>
<!-- Script to populate field -->
<script type="text/javascript">
    document.getElementById('<%= hdnGeo.ClientID %>').value =
        JSON.stringify(Geo);
</script>

This puts the JSON equivalent of the Geo object in your geoiplookup reference

{"city":"London","country":"GB","lat":"51.514198","lon":"-0.093100",
 "IP":"193.129.26.250","netmask":"24"}

into an ASP.NET hidden field.

Then, on the server, you can access it like:

protected void Button1_Click(object sender, EventArgs e)
{
    string json = hdnGeo.Value;
    var dictionary = new JavaScriptSerializer()
        .Deserialize<Dictionary<string, string>>(json);
    string city = dictionary["city"];
    string lat = dictionary["lat"];
    string lon = dictionary["lon"];
    string IP = dictionary["IP"];
    string netmask = dictionary["netmask"];
}