A port scanner is a software application designed to probe a server or host for open ports. We earlier made a TCP Connect port scanner in C here – https://www.binarytides.com/blog/tcp-connect-port-scanner-code-in-c-with-winsock/ and here – https://www.binarytides.com/blog/tcp-connect-port-scanner-with-linux-sockets-bsd/ Now we shall try making the same in PHP. The code is very simple : Using fsockopen Output : The above… Read More »
The getimagesize function of php provides lot of information about an image file , including its type. The type can be used to check if the file is a valid image file or not. To check if a file is an image or not, use the function $a[0] and $a[1] are the width and height… Read More »
In many php applications there are multiple tasks that need to be run via cron at different times. In a typical application you may be doing the following tasks via cronjobs : 1. Backup database. 2. Send out email to subscribers. 3. Clear temporary files. 4. Fetch xml feeds from some source and store them… Read More »
Above is an example of a given timestamp. And a cron schedule can look like this 0 5 * * * – which means run everyday at 5 hours and 0 minutes. Now in a php application you may need to test if a given timestamp , say 1319362432 matches a given cron schedule like… Read More »
The strtotime function is used to convert a date in various formats to a timestamp. However its behaviour is different based on architecture it is running on, whether 32bit or 64bit. Lets take a few examples : In 64 bit environment Over here we can see that strtotime is producing timestamps for far dates like… Read More »
There are situations when we need an autoincrement field to reset every month or so. Example : Invoice Numbers : Month of october Month of november and so on. Groupwise autoincrement P1 , P2 , Q1 , Q2 , Q3 , Q4 , P3 , R1 , P4 … Myisam table has a feature where… Read More »
If a file is to be saved in at path /var/www/a/b/c/d/abc.zip where the directory c and d dont exist then the directories have to created. Here is a function that uses recursion to check for directories in a path and create them if they do not exist : The above will create the directories a… Read More »
Box2d Box2d is a 2d physics simulation library written for C++ and ported to many languages including Javascript. From Box2d’s Website Box2D is a feature rich 2D rigid body physics engine, written in C++ by Erin Catto. It has been used in many games, including Crayon Physics Deluxe, winner of the 2008 Independant Game Festival… Read More »
This article is an extension of the article : https://www.binarytides.com/blog/dns-query-code-in-c-with-winsock/ The Linux version has some changes. On Linux the dns server ips are stored in a file called /etc/resolv.conf. So the get_dns_servers function will open this file and pickup the dns server ip addresses. A typical /etc/resolv.conf file can look like this : # Generated… Read More »
PHP’s session_start method stores the session data in files by default. These files are stored in the tmp directory of the OS and are cleared at intervals by the garbage collector. Alternatively the session data can be stored in database as well. Storing session data in database has certain advantages : 1. Limit the number… Read More »