PHP is a powerful open source server-sided scripting language that can be used on a wide variety of operating systems and webservers, including Apache on UNIX and IIS on Windows.
PHP contains numerous extensions which enable you to dynamically create images and flash files, parse xml, connect to remote servers using pop, imap, ftp, http and raw sockets, natively access many database servers including PostgreSql, MySQL and Microsoft SQL Server, compress and decompress files, lookup domain names and and much more.
PHP has an excellent manual and online documentation which covers every function for every extension available.
A month ago I posted a PHP email message class for extracting attachments and have been asked by a couple of people how to extract inline images and make it so they can appear in the HTML content of the email. This post shows how to do this, using my email class to get the email.
I have a number of batch processes that run using PHP as the command interpreter, and discovered after making a change to one of them the other day that the variables available to PHP in the $_SERVER superglobal are different depending on whether it’s run via an SSH session or cron. This post shows the difference on Debian 6. The values available are probably the same on other distros.
The PHP IMAP functions imap_fetchstructure and imap_fetchbody are used to work out the structure of an email and get the message body and attachments, but they can be fiddly to use because the message parts can be nested. This post has a function which effectively flattens the message parts into a new array, indexed by the part number which can be directly passed to imap_fetchbody.
There may be times when a static variable is needed in a PHP function; static variables maintain their value between function calls and are tidier than using a global variable because they cannot be modified outside of the function.
It’s funny when you’ve been programming in a language for a long time and fall into odd assumptions about particular functions. For some reason I appear to have assumed there was no way to escape characters in PHP’s date function. Then yesterday I saw some sample code where a character was escaped and double checked in the manual. Sure enough, you can escape characters and it’s obvious. I just thought I’d share it here in case you’re making the same mistake I was.
The Simple HTML DOM Parser is a useful tool for extracting content from web pages using jQuery like syntax. If multiple pages are loaded into the parser the available memory will eventually be exhausted and a fatal error will occur.