PHP Tutorial: Raw Encoding

Today's tip is quick and dirty. I spent my time mulling over the Observer pattern and a story about a royal wedding, but it just wouldn't come together before bedtime.

So today's tip is about rawurlencode().

Encoding is useful when you need to compose a GET URL that has parameters in it containing characters that are technically illegal to use in a URL (like spaces) or that might mess up your query string (like ampersands and question marks). This is where urlencode() always seemed to come in handy.

$customername = "Ted Fischer";
$customeraddress = "124 Main St.";
$closestXstreets = "Main & Vincent";

$displayclientlocationURL = 
   "http://spgulhankmeder.com/mapit?name=" . urlencode($customername).
   "&address=" . urlencode($customeraddress) .
   "&xstreets=" . urlencode($closestXstreets);

echo "<a href=\"$displayclientlocationURL\">Map it</a>";

This returns:

<a href="http://spgulhankmeder.com/mapit?name=Ted+Fischer&address=124+Main+St.&xstreets=Main+%26+Vincent">Map it</a>

All the spaces are converted to plusses and the ampersand that's part of content instead of control has been converted to %26.

That might be okay, but I've found out the hard way that not every receiving server is going to convert those pluses back to spaces. Some don't back-convert them, particularly if they're not running PHP. See the spec in RFC 3986 says that spaces should be rendered as %20, not as +. If you're in a mixed environment and can't be sure the receiving server will treat pluses as spaces, using rawurlencode will get you the following:

<a href="http://spgulhankmeder.com/mapit?name=Ted%20Fischer&address=124%20Main%20St.&xstreets=Main%20%26%20Vincent">Map it</a>

And that will be understood and decoded properly in more places in my experience. I've known about urlencode() for a while now, but it's raw version is new to me and now I'm sharing it.