wxpython While executing a wxpython script if a error occurs then a white window popups with some message, and it disappears fast enough before it can be read. So here is a fix to pause it and read it what and where the error in the code is : app = wx.App(redirect=False) MyFrame(None).Show() app.MainLoop() The… Read More »
Database applications written in php often need to export data for reporting purpose. A popular export format is excel. Excel is a spreadsheet that lays out data in a grid format. Excel itself is a microsoft proprietory format. There are many libraries available for php like Spreadsheet_Excel_Writer pear package etc that can do the job…. Read More »
The SQL Script should have comments starting with – or — only on new lines and each command should end with a ; . Reading a sql file and putting all of it in a string variable and feeding to the execute command would result in an exception. All instructions must be executed individually. A… Read More »
Configuration files are used in applications to store settings, user preferences and other configuration parameters of an application so that. When configurations are changed from within the application these need to be saved so that next time the application starts with these new settings. In Java reading and writing to a configuration is pretty simple… Read More »
Raw sockets with winpcap A previous post explains how to send on windows xp. However the winsock api has limited raw socket support in windows versions greater than windows xp+sp1. Therefore winpcap has to be used to send raw packets on higher windows versions. Winpcap is a packet driver useful for packet capturing and sending… Read More »
Port Scanning searches for open ports on a remote system. The basic logic for a portscanner would be to connect to the port we want to check. If the socket gives a valid connection without any error then the port is open , closed otherwise (or inaccessible, or filtered). This basic technique is called TCP… Read More »
DNS Query When we type a web url or domain in our browser a dns request is immediately send by our browser to a DNS server to get the IP address of that web address. In winsock applications we achieve this by gethostbyname() and things are pretty simple. In this article we shall do this… Read More »
Winsock packet sniffer A packet sniffer is a program that can sniff the packets moving on the network. All applications communicate over the network with data packets where each packet contains part of the whole data being exchanged. A sniffer is able to pickup these individual packets and read them. In this post we are… Read More »
Raw sockets using winsock Raw sockets or “Raw Packets”, enable a program to access the entire contents of a packet or datagram, both for reading and writing purpose. In other words, you can fabricate a whole packet according to your likes and dislikes. For example, a TCP packet would contain an IP header, a TCP… Read More »
Permutations Permutations is the set of all different unique arrangements of the letters of the string. So for the string “ABC” there are 6 permutations – ABC, ACB, BAC, BCA, CAB, CBA. The permutations can also be taken on a smaller length. For example if we want to get permutations of ABC over only 2… Read More »