Php is used to write web applications which are online and publicly accessible. Therefore security is a fundamental necessity of these applications to keep the data safe and free from unauthorized access. Below are a bunch of simple tips/hacks/ideas to design your php applications to have better security. The Code 1. Avoid short tags If… Read More »
In this series we are going to look into some useful tips and techniques that can be used to improve and optimise your php code. Note that these php tips are meant for beginners and not those who are already using mvc frameworks etc. The Techniques 1. Do not use relative paths , instead define… Read More »
Like any other language php applications often need to execute system commands like they are run from the terminal/console/commandline. Php has multiple functions to do this task. Lets take a look at each of these 1. system “system() is just like the C version of the function in that it executes the given command and… Read More »
On linux , the list of locales installed on the system can be fetched through the terminal command locale -a : $ locale -a C C.UTF-8 en_AG en_AG.utf8 en_AU.utf8 en_BW.utf8 en_CA.utf8 en_DK.utf8 en_GB.utf8 en_HK.utf8 en_IE.utf8 en_IN en_IN.utf8 en_NG en_NG.utf8 en_NZ.utf8 en_PH.utf8 en_SG.utf8 en_US.utf8 en_ZA.utf8 en_ZM en_ZM.utf8 en_ZW.utf8 es_AR.utf8 es_BO.utf8 es_CL.utf8 es_CO.utf8 es_CR.utf8 es_DO.utf8 es_EC.utf8 es_ES.utf8… Read More »
This is a small script written in php that can fetch the whois information of an ip address from regional internet registries (RIR). Useful in finding information about ip address.
The simplexml extension of php is quite simple and easy to use when it comes to parsing “well-formatted” xml files. Well formatted means , xml that is not broken or does not have too many errors. One of the most handy functions of this extension is simplexml_load_string. Here is an example : <?php $xml =… Read More »
MPDF Many php applications need to create pdf of documents like invoice , receipt and even id card etc. In this article we shall create a pdf invoice using the mpdf pdf creation library. Mpdf is made in php without any other external library. Mpdf parses css much better than any other free pdf libraries… Read More »
Packet Sniffer Example of a packet sniffer is Wireshark. Packet sniffers pick up the packets going in and out of a system and analyse them and present them to user for further analysis. In this post we are going to code a simple packet sniffer in php. The basic theory this packet sniffer is that… Read More »
Php functions like zip_open return an error number if they fail. To get the corresponding error message from the error number , use the following function. function zip_error_message($errno) { // using constant name as a string to make this function PHP4 compatible $zipFileFunctionsErrors = array( 'ZIPARCHIVE::ER_MULTIDISK' => 'Multi-disk zip archives not supported.', 'ZIPARCHIVE::ER_RENAME' => 'Renaming… Read More »
When a browser makes a request to a php script, the browser sends some http headers which can look like this : Host: localhost Connection: keep-alive User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/535.2 (KHTML, like Gecko) Chrome/15.0.874.121 Safari/535.2 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: UTF-8,*;q=0.5 Cookie: username=admin; password=21232ffc3; PHPSESSID=o5m4e2td1m66c4pkjdag9vs0u2 The php script under request ,… Read More »
In this article we are going to login into Google Adsense and retrieve earnings. Google Adsense now has a new interface and so needs a different kind of coding. In this example we shall fetch “yesterday’s” earnings sitewise. Create a Report to be fetched : First open the sitewise report in the Performance Tab in… Read More »
PHP has a useful function called dns_get_record that can be used to get different types of records for a give domain , very easily. These include the nameserver records, A records, CNAME records, MX records, SOA records etc. The following examples are using the interactive shell, but you would use the function the same way… Read More »
PHP Handlers PHP handlers are a link between a webserver(say Apache) and the PHP libraries. PHP handlers enable a webserver to load the PHP library in a certain manner and execute the PHP code and return the output to the webserver. There are many different kind of PHP handler setups available. Each has its own… Read More »
In this tutorial, I am going to show you a simple way to write a Hit Counter script in PHP to save and display the number of visits to your website. We will basically store and increment the hits in a file, that can be used to display the total hit count as well. The… Read More »
A port scanner is a program designed to probe a server or host for open ports. Looking at open ports, one can tell what services might be running on the remote server. We earlier made a TCP Connect port scanner in C here – https://www.binarytides.com/tcp-connect-port-scanner-code-c-winsock/ and here – https://www.binarytides.com/tcp-connect-port-scanner-c-code-linux-sockets/ Now we shall try making the… 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 function is_image($path) { $a = getimagesize($path); $image_type =… Read More »
In many php applications there are multiple tasks that need to be run via cron at different times. In a typical application you may be doing the following tasks via cronjobs : 1. Backup database. 2. Send out email to subscribers. 3. Clear temporary files. 4. Fetch xml feeds from some source and store them… Read More »
desktop:~$ php -a Interactive shell php > echo time(); 1319362432 php > 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… 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 desktop:~$ php -a Interactive shell php > echo strtotime("0000-00-00 00:00:00"); -62170005200 php > echo… Read More »
The autoincrement feature in mysql allows us to create numeric fields that automatically increment by 1 for every row inserted. It does it atomically so we don’t have to worry about any duplicates or collision. However, there are situations when we need an autoincrement field to reset at regular intervals like every month or so…. Read More »