Pcapy In the previous articles we coded packet sniffers in python using raw sockets. Now lets use the libpcap library for the same. Libpcap is the packet capture library for linux and has wrappers for most languages. In python there are multiple libpcap wrappers like pcapy, pypcap etc. In this article we shall use the… Read More »
Wrapper class for socket functions The standard socket library in C comes with a lot of functions for every task like connecting, sending data and receiving data etc. However knowing the syntax of all the functions and calling them again and again and in the right sequence could be a bit intimidating. Using a class… Read More »
Socket function – recv() If you are writing a network application using sockets in C that communicates with a remote server and fetches data, then you must be aware of the recv function that is used to receive data. The recv function can only receive a specified number of bytes in the response. If the… Read More »
UDP Sockets in Php In a previous article we learnt about writing simple server and clients using TCP sockets in php. In this article we are going to use udp sockets for the same. UDP sockets are much simpler to work with since they are connection-less. A udp server just has an socket that waits… Read More »
UDP sockets UDP stands for User Datagram Protocol and is an alternative protocol to TCP the most common protocol used for data transfer over the internet. UDP is different from TCP in a number of ways. Most importantly UDP is a connectionless protocol. TCP vs UDP In the TCP protocol first a connection is established… Read More »
UDP sockets This article describes how to write a simple echo server and client using udp sockets in C on Linux/Unix platform. UDP sockets or Datagram sockets are different from the TCP sockets in a number of ways. The most important difference is that UDP sockets are not connection oriented. More technically speaking, a UDP… Read More »
Socket function – recv() If you are writing a socket program in python that communicates with some remote machine or server to receive data, then you shall be using the recv() function to receive data on a socket. The recv() can receive only a specified number of bytes into a string buffer. If the incoming… Read More »
The DomDocument class in php can be used to parse html/xml content and build objects that can be queried using standard functions to extract values. The following functions are quite useful: getElementsByTagName – Get all elements under a node that match a tagname getNamedItem – Get element with a particular “name=” attribute. Useful to find… Read More »
Scraper scripts often need to extract all links on a given page. This can be done in a number of ways like regex, domdocument etc. Here is simple code snippet to do this using domdocument. /* Function to get all links on a certain url using the DomDocument */ function get_links($link) { //return array $ret… Read More »
Often numbers are to be written with a proper suffix, like 1st, 2nd, 3rd, 15th, 21st and so on. So here is a quick function to do the same for a number. Technique 1 /* This function will add st, nd, rd, th to the end of numbers */ function ordinal($i) { $l = substr($i,-1);… Read More »
In a previous example we learnt about the . In this example we shall build a basic ECHO client and server. The server/client shown here use TCP sockets or SOCK_STREAM. Tcp sockets are connection oriented, means that they have a concept of independent connection on a certain port which one application can use at a… Read More »
Socket programming in Java This is a quick guide/tutorial to learning socket programming in Java. The Socket class is documented at http://docs.oracle.com/javase/1.4.2/docs/api/java/net/Socket.html To summarise the basics, sockets are the fundamental “things” behind any kind of network communications done by your computer. For example when you type www.google.com in your web browser, it opens a socket… Read More »
Tutorial on how to code simple network servers and clients using low level Socket api in python.
Php and tcp/ip sockets This is a quick guide to learning socket programming in php. Socket programming php is very similar to C. Most functions are similar in names, parameters and output. However unlike C, socket programs written in php would run the same way on any os that has php installed. So the code… Read More »
What are callbacks Callback is a piece of code that is passed to some other functions as a parameter, such that it can be executed before or after a certain event or change of state. A common example of callbacks can be seen in javascript when using the jquery ajax function. $.ajax({ url: 'ajax/test.html', success:… Read More »
The idea behind serializing a variable is to create a storable string format of it, such that the same variable can be recreated later when required using the string. 1. serialize and unserialize These are the traditional functions to serialize and unserialize data in PHP. $a = array('a' => 'Apple' ,'b' => 'banana' , 'c'… Read More »
Github Login Github has become a very popular social login on websites related to programming and development. Github itself is a big storehouse of opensource projects and community of developers. Github oAuth documentation can be found at http://developer.github.com/v3/oauth/. Register website with Github oAuth The first thing to do would be to register your website with… Read More »
Yahoo OpenId In the previous article, we learned how to integrate . Its good to know that Yahoo is also an openid provider and “Login with Yahoo” can be added to a website in a very similar manner. Yahoo’s openid discovery url is http://me.yahoo.com/. The rest of the code is very simple. Code <?php /*… Read More »
OpenId A very popular login method now a days is to allow users to login through their google, openid etc accounts. One popular protocol being used is the OpenId. According to wikipedia : OpenID is an open standard that describes how users can be authenticated in a decentralized manner, eliminating the need for services to… Read More »
Clientside certificates are often used in soap webservices. For example the wsdl file link might require a clientside certificate. The server throws an error like this : HTTP Error 403.7 – Forbidden: SSL client certificate is required. Curl Command To use clientside certificate with curl , test the following command curl –cert certificate_file.pem https://www.example.com/some_protected_page or… Read More »