Network Programming in .NET

A pastebin is designed to be an easy way to quickly post some text online, so that others can see it. It also has applications in cross-firewall data traversal, where one peer can upload data to a pastebin, and the other peer can poll the pastebin for the message to arrive.  This was the kind of pastebin I was after.

I looked at pastebin.com and paste.kde.org, to see if they were suitable. Paste.kde.org seemed promising,  where you could paste easily, using a URL like this:

http://paste.kde.org/?paste_data=Hello+World&paste_lang=c&api_submit=true&mode=xml&paste_project=fiachspastebin

Which would return an ID, which you could retrieve using http://paste.kde.org/api/xml/117613, for example. The problem came, when I wanted to list all pastes by a particular user, or project, and I spotted that it wasn’t working as expected, like http://paste.kde.org/~fiachspastebin/api/xml/all/ seemed to return numerous pastes by other users.

So, I decided to write my own pastebin, which would store the messages in-memory. This meant that they would be deleted as the IIS worker process recycled, but, I didn’t need longevity.

Using two simple actions “action=update” which either created or updated a paste, and assigned it to a “user“, containing the text contained in the “text” querystring parameter. Then when “action=get” then the text associated with that “user” would be returned.

So, to store text with a user, you simply call:

http://url/pastebin.aspx?action=update&user=dananos&text=Hello+World

Then to retrieve that text you call

http://url/pastebin.aspx?action=get&user=dananos

And that’s it. The code I used is below:

  public static Hashtable data = new Hashtable();
    protected void Page_Load(object sender, EventArgs e)
    {
        string action = Request.QueryString["Action"];
        string user = Request.QueryString["User"];
        string text = Request.QueryString["Text"];
        if (string.IsNullOrEmpty(action) || string.IsNullOrEmpty(user))
        {
            Response.Write("Action and User is required");
            return;
        }
        if (action == "update")
        {
            PasteBin.data[user] = text;
            Response.Write("OK");
        }
        if (action == "get")
        {
            if (PasteBin.data.ContainsKey(user))
            {
                Response.Write(PasteBin.data[user]);
            }
            else
            {
                Response.Write("NO DATA");
            }
        }
    }

I’ve ported the same code to PHP, for Linux users. This code requires the $_APP library, which is posted at http://www.leosingleton.com/projects/code/phpapp/

This is hosted at http://pastebin.omadataobjects.com/bin.php

<?php
include("app.php");
application_start();
$action = $_REQUEST["action"];
$user = $_REQUEST["user"];
$text = $_REQUEST["text"];
if ($action == "" || $user == "")
{
   echo("action and user is required");
}
else
{
   if ($action=="update")
   {
	$_APP[$user] = $text;
	echo "OK";
   }
   if ($action=="get")
   {
	echo stripslashes($_APP[$user]);
   }
}
application_end();
?>