If you are developing PHP code for a website, you might sometimes want to check which version of Apache or PHP will be running the website. This is particularly true if you use some functionality that was included in a particular revision of the software or if you want to avoid security holes that were…
If your website has a lot of images it is often convenient to create and show a dynamic thumbnail image. This will save on processor and download time for your visitors, who only have to download the images they want to see. One great way to do this is with the GD library. Before you…
When you are working on your website, you will sometimes want to change the level of error reporting that your code returns. This is a great way to get full diagnostic information to fix a problem in your latest piece of code, but be careful only to show error reporting on your test site and…
When you are developing or supporting a website, it does not always work perfectly. Sometimes a visitor will abort a script that is running, and when that happens, you want to try and avoid that causing a client disconnect. The ignore_user_abort() function determines whether the remote client can abort the running of the script. This…
A simple but valuable feature of dynamic websites is displaying the current date and time. With PHP, this is easy to do with the date() and time() functions and is a great way for beginners to get their feet wet: Sometimes it is not sufficient to display the time in just your local time zone….
One of the most valuable additions to MySQL 5 is the subquery, which lets you execute SQL like this: Unfortunately, MySQL 4 lacks this feature and is still prevalent in many web hosts. If you need to use a subquery, try the following workaround in PHP; Step by step: Get an array of user_ids from…
No, this isn’t about getting frustrated with PHP and nuking your server… this is a couple of very useful (although hard to remember) array functions. explode() will take a string and give you an array, splitting that string on the delimiter you give. For example, if you have a list of comma-separated values, you will…
To find out the full details of any given variable in PHP, use the handy var_dump() function as follows: This will show you the PHP variable type, its value, and if it is an object or array. The structure and all information will be output recursively. The only slight disadvantage to using var_dump() is that…
To get a random row from your table, you can use the following trick: This will return a single random row from myTable. Remember that you can also use a WHERE clause to narrow down the records before choosing a random one. This is a more efficient way of finding a random result than it…
If you have a problem debugging any PHP code, a good first step is ensuring all errors are showing. Simply use the following code at the beginning of your script: You may find that the server you are using or the code written by somebody else is hiding too many errors for you to work…
