PHP

PHP is a powerful tool, but if you create any piece of software there are one or two things that you should never rely on.

A good example is using PHP short tags. This is a short hand way of stating that this block are to be parsed as PHP. This is an example of a normal tag.

<?php echo 'Hello World'; >

Here is the same code using short tags.

<? echo 'Hello World'; >

Another alternative, if you just want to print the output of a variable, is to use the following.

<?='Hello World'; >

The short tags setting can be turned on or off in the php.ini file. If you create an application that relies on these short tags then you will find that on some systems the short tags setting is turned off, which means that your software will simply not work.

One nice feature for any blog or site (especially news sites) is to have a little list of forthcoming events that would interest your readers. One way of collating this information is to scour the web and update the list manually. However, this is time consuming and tedious, especially as there is an easier way to do it.

Have a look at the Yahoo site called Upcoming. On this site you can search for events on lots of different subjects in lots of different locations all over the world. Also, if you have an event you can put it up on the site.

The PHPNW conference was this weekend, and 8 members of staff from my company showed up to support the PHP community and learn a couple of things along the way. The conference consisted of 174 attendees, with 12 sessions hosted by 16 speakers.

The talks ranged from simple usability and design to getting started in Drupal and they were all well researched, planned and executed. I was especially impressed with the 3D timeline used in the Twittex talk.

The two talks that stood out for me where the Introduction to the Zend Framework and HTML to Drupal in 30 minutes. I will definitely be looking into these two products, and perhaps even buying a book on the Zend Framework.

This common problem has stumped many programmers in the past, so I thought I would add in my little part. Whilst doing research for this I managed to find a site called www.streetmap.co.uk which has a nice little PostCode to geographical reference tool. Using a simple URL parameter I was able to give the site a PostCode and strip the longitude and latitude from the resulting HTML. Here is the function I came up with.

I was sent an email the other day that contained some text were the start and end letter of each word were left alone, but the middle of each word was randomized. The weird part was that the text was still readable, which is due to the way in which the brain processes words.

I wondered if I could replicate this using a PHP script. All I would need to do is split apart the sentence into the component words and loop through those words, randomizing the middle of them. Clearly, it is not possible to mix up the order of letters in a word less than four characters long so a check would be needed for this. This is what I cam up with:

I have talked about generating random passwords before. Although that function generated some nice passwords, they perhaps aren't as unique as they ought to be.

This function, take from Webtoolkit creates passwords of different length with varying levels of complexity.

Creating image thumbnails is a pretty common practice, and there are a few scripts available that allow you to do this in PHP using the GD2 library. However, they are normally overkill for what should be a simple task, so after a bit of searching and testing I found the following ImageResize class, which is taken from http://shiege.com/scripts/thumbnail/. I have modified the code to be PHP5, but if you want the PHP4 version then you can get it from the site.

I have talked previously about getting an IP address of a visitor with PHP. The failing in using the value of $_SERVER["REMOTE_ADDR"] is that if the visitor is using a proxy then you will get the proxy IP address and not the visitors real IP address.

This function works by going through any variables in the $_SERVER array that might exist that would contain information to do with IP addresses. If they are all empty then the function finally looks at $_SERVER["REMOTE_ADDR"] value and returns this as a default.

I have been asked a couple of times recently if PHP has a function that will move a file, so I thought I would put the solution here.

PHP has a function called rename() which can be used to rename a file, but because of the way it works it can be used to move files. Let's say that you wanted to rename a file called test.txt to test_back.txt, this can be accomplished by doing the following.

rename("test.txt", "test_back.txt");

However, if you want to move the file from one directory to another you can do the following.

rename("test.txt", "backups/test_back.txt");

The return value of rename() is boolean that tells you if the rename was successful or not, this can be used to error check like this.

File permissions are important, especially if you want to let a user agent view a file. If the file doesn't have the correct permissions then it will not be accessed and could cause your script to fail. To get around this you might want to use the following function. It uses the PHP function chmod(), which sets permissions, but it does this recursively from wherever you set it off from.