July 24, 2008

Three little characters  designed to make your life hell

On more than one occasion these characters  have turned up just when everything else seems fine.  Known as a “BOM” or Byte Order Mark they can be extremely annoying.

What is  ???

 is often seen at the top left corner of a web page.  When you open the source file and compare that to the output source you will not find , so what causes  to appear in your file?

The reason is your editor has saved the file as UTF-8.  With the ever increasing complexity of character encoding some editors ignore your settings and update your configuration to use UTF-8. Even if you have been using ASCII without any trouble since 1982!

The Fix

Change the character encoding of your page.  With most editors all you need to do is select properties and then choose ASCII then save the file.

Changing the meta tag alone is not enough, with extended attributes on files now no one can be sure where a browser or whatever reader your using will use to determine how to display it.

July 7, 2008

Limiting text input to characters and digits

To remove stuff such as punction and spaces (or anything you want) from a text box before sending to the server for validation you can use code like this, first the HTML:-

<input 
name="name" 
onblur="this.value = entrycheck(this.value);" 
type="text" 
size="20">

And then the following Javascript will remove invalid characters when the user moves to another field:-

<script type="text/javascript">
function namecheck(theInput) {
  var valid = 'abcdefghijklmnopqrstuvwxyz1234567890';
  var test ='';
  var ret ='';
  for(i=0;i<theInput.length;i++) {
    test = theInput.substr(i,1);
    if(valid.indexOf(test.toLowerCase()) != -1) {
      ret = ret + test;
    }
  }
  return ret;
}
</script>

In this example I just want digits and characters. If you want to add certain punctuation such as stops and commas just add them to the valid variable.

April 24, 2008

ASP code to block multiple ranges of IP’s from your site

It wasn’t long before I needed to expand upon banning a few IP’s. I needed to be able to ban whole networks so here’s the Q&D solution:-

First create a text file called ipsec.txt and enter some IP’s you wish to ban, to ban a network just leave off the end of the IP class number, for example:-

10.20.30.40
10.50

In the above example the first is a specific IP that you wish to ban, the second will ban all IP addresses that start 10.50 (for example 10.50.20.1 and 10.50.100.1 will both be banned). Enter as many as you like, one per line.

Now create or edit your global.asa file and add the following code to the session_onstart sub procedure:

sub session_onstart
  remote_ip = request.servervariables("Remote_Addr")
  ipsec     = server.mappath("/ipsec.txt")
  ips       = getFileContents(ipsec)
  ips       = split(ips,vbcrlf)
 
  for each ip in ips
    if len(trim(ip)) > 0 then
      ip_parts        = split(ip,".")
      remote_ip_parts = split(remote_ip,".")
      found = true
      for x = 0 to ubound(ip_parts)
        if ip_parts(x) <> remote_ip_parts(x) then
          found = false
          exit for
        end if
      next
      If found then
        response.redirect "/redir.html?ip=" & remote_ip
      end if
    end if
  Next
end sub

Replace /redir.html with a file or location you want to redirect banned ip’s too.

As this code runs in the session_onstart section of the global.asa it will be run only once for each visitor, this means that during the session they could return and this code would be bypased. If that is a concern modify the code to be a common function and place it strategically, perhaps in a common file called throughout the website.

April 22, 2008

Write ASP and need a way to block IP’s from your site?

This demonstrates how to ban a single IP address, later, I’ll show how to ban whole networks but chances are you will be able to work that out for yourself anyway after reading this anyway.

If global.asa does not exist then create it and add the following:

sub session_onstart
 
  ip = request.servervariables("Remote_Addr")
 
  select case ip
    case "111.111.111.111", "111.111.111.112", "111.111.111.123"
      response.redirect "http://www.example.com"
  end select
 
end sub

Replace 111.111.111.11x with the IP addresses you wish to ban, note they are comma separated and the last one is not followed with a comma.

You can change the redirection to a page on your site that informs them they are no longer allowed (a bit vindictive), to a blank page is probably best or you could even forward them on to a competitor :D

November 29, 2007

Mass Category Adder Plugin for Wordpress

If you create a lot of Wordpress blogs you probably like to prepare a list of categories for inclusion.  This plugin simplifies the process by allowing you to add them all at once.

Mass Category Adder Plugin for Wordpress

Add one category per line then click the “Add Categories” button.  All categories will be created for you turning a 30 minute job into a 5 second one :)

Installation

Upload the masscats folder to your plugin folder.  Activate the plugin and then locate the “Mass Category Adder” menu in the Wordpress “Manage” menu.

Download Mass Category Adder Plugin