Web Development London UK » php

Remove all linebreaks in PHP

Admin — Mon, 30 Jan 2012 09:22:57 +0000

If you are having problems with a string that keeps adding a line break when output from PHP to HTML then the following code will work wonders for you!

$string_with_line_break = "blabla\nbla\r";

$string_without_line_break = trim(preg_replace( "/\s+/","",$string_with_line_break));

Replace all spaces in HTML with except in HTML tags using PHP

Admin — Sun, 29 May 2011 16:56:13 +0000

If you would like to replace all the spaces in an HTML string with so that you can render it out to the browser but you also want to retain current spaces in HTML tags you can use the below method:

$inputString=‘1 2        3′;
$outputString=preg_replace_callback("#>[^<]+<#","relSpaces",$inputString);
function relSpaces($match){return str_replace(" "," ",$match[0]);}

This will replace:
“1 2 3″

..to look like this:
“1 2 3″

Using PHP to validate an IP address

Admin — Wed, 18 May 2011 08:47:13 +0000

You can use the PHP code below to check if an IP address is valid or not.

$ip = ""; //enter a valid or invalid ip address here

if(filter_var($ip, FILTER_VALIDATE_IP)) {

// The IP Address is valid

} else {

// The IP Address is not valid

}

Wasn’t that easy!?!

Hide all error messages PHP

Admin — Thu, 28 Apr 2011 09:03:20 +0000

PHP Error messages showing up in your web applications are a dangerous thing. Not only does it look unprofessional, but it is also a serious security concern!

Once you have completed debugging your website or web application you can place the following one liner at the beginning of your code, this will turn off error reporting and therefore make sure that no application details are spilled to your users.

error_reporting(0);

If a single line of code is causing the problems it is safer to use the at symbol (@) to suppress any errors it may cause.
You can also use “or die()” to stop the execution of your code after the suppressed error incase the remainder of your code relies on that function to return a value.
In the example below we will use the “@” and “or die” to handle everything:

@mysql_query("SELECT * FROM `anInvalidTableName`") or die("There was an error! ".mysql_error());

It is also good practise to make sure that all variables are set and are not empty before trying to access them.

For example:

if (isset($myVar) && !empty($myVar)) {

// $myVar is now safe to use!

}

What is xmlrpc.php?

Admin — Tue, 22 Feb 2011 11:02:59 +0000

It is a script which allows clients to make procedural calls over the net.
As it says in the name, the encoding is XML and because it is used on websites we can make the fair assessment that it uses the HTTP protocol.

If we break the name down we get: XML transmition via Remote Procedure Calls.

So you are still not sure what this is all about? Read on..

xmlrpc.com has a very simple yet rather effective diagram which illustrates what’s going on with it all:

As we can see above, xmlrpc is basically a simple way of transporting data using a common protocol used on the web.

This file is usually added to the root of a domain when using packages such as WordPress, Drupal or similar.

XMLRPC.php only accepts POST requests so using the CURL library or similar would be the best option when interacting with it. The PHP source file is quite long so I will not include it here, as it is 3375lines long. But you can easily find it online using your favorite search engine!

Stop That Referrer in PHP!

Admin — Mon, 01 Nov 2010 12:34:50 +0000

Today I will show you a method to stop the traffic that a referrer site is sending your way, you may wonder why you would want to ignore traffic, after all, isn’t inbound traffic to your site fantastic no matter what?

The simple answer is “NO!”

Let me explain it in a real life situation so that you can better understand where to use this.

Understanding where to use it

You have a site that is using a web service or API of yours and it is sending loads of unwanted traffic your way, you actually want the service to be equally distributed but this one particular site is just overdoing it. So you want to stop all their traffic to you and only allow proper direct API requests or whatever the case.

Now for some code

At the very top of the php page that is being called – in our example we will call it “http://andrewodendaal.com/api/” – you will add in the following PHP code:

if (strstr($_SERVER[‘HTTP_REFERER’],"theotherdomain.com")) {

   header("Location: http://theotherdomain.com");

}

Make sure to add this code before any other code or rendering objects, otherwise you will receive a PHP error!

Explaining the code

What this code will do: it will check to see if the visitor came from that site or was somehow referred from it and it will just send them back to that site’s homepage.

And bandwidth?

This technique does not get rid of the bandwidth used up entirely as the visitor still connects to your site, but it does not show the user anything as the php redirection header kicks in prior to any browser rendering. So as they click on the link at the original site, it immediately takes them to that site’s homepage. Very minimal bandwidth usage occurs during this period.

Error 500 php_value .htaccess

Admin — Tue, 14 Sep 2010 12:00:23 +0000

I noticed on some server setups I could not do the following inside a .htacess file:

php_value upload_max_filesize 250M
php_value post_max_size 250M

I was getting an error 500 Internal Server Error with the above code in the .htaccess file.

What to do to correct this is create a file called php.ini and save it in the same location as your .htaccess file and enter the following code instead:

upload_max_filesize = “250M”
post_max_size = “250M”

CSS background image data: base64?

Admin — Thu, 09 Sep 2010 15:22:53 +0000

What the heck is all that Gobbledygook in the CSS?

So you have noticed that bit of css that says something like this in the CSS source-code and you have no idea what it could be?
url(“data:image/gif;base64,R0lGODlfMAMEAIABAKysrObm5iH5BAEAAAEALAAAAAAwAwQAAAJOhI+py30Bo5y02ouz3rz7D4biSJbmiabqyrbuC8fyTKPOjedHzff+DwwKh8Si8YhMKku6pvOxjEqn1Kr1is1qt7ynV8cNi8fksvmMTiMLAD4=”) no-repeat scroll 50% 0 transparent

It is a technique called Data URLs and using PHP – or your favourite server-side script – you can generate these nifty little things.

An example of how to generate it in PHP:

.myClassName {
background: url(data:image/gif;base64,) top left no-repeat;
}

What you need to know over and above:
You will need to have your CSS file(s) saved as in the PHP extension ( e.g. myCSSFile.php ).
This allows the server to process the PHP code contained in the CSS, so in a way you have a dynamic CSS file creator.

What’s so good about Data URLs?
They aren’t all that weird after all, they actually help conserve bandwidth due to less HTTP requests. This brings us to the next step you need to know!

Caching problems!
The problem with this approach is that you will need to recalculate the string everytime you change the image, otherwise browsers tend to cache what they remember seeing and use that instead!

PHP's typeof – gettype()

Admin — Mon, 06 Sep 2010 07:47:30 +0000

Quite often you may need the ability to check what type of data type a variable is.

In most programming languages this is possible to do and is usually called typeof().
PHP too has a way to check this, it is called gettype() and it’s so simple to use.

All you have to do is echo out a call to gettype() with your variable as the first argument.

Like so:

function foo($bar) {

echo gettype($bar);

}

foo("stringVar);

//echo’s "stringVar";

foo($arrayVar);

//echo’s "array";

In the above script we create a function called foo which has 1 argument, it can take any data type so we call it twice, one with a string argument and secondly with an array argument.

Read the official documentation on gettype here.

Actionscript 2 & PHP Data Transfer

Admin — Mon, 17 May 2010 11:09:32 +0000

In the below example we will use Actionscript 2 to call a remote PHP file that will return data to it.
It is a simple way of transferring data between the server and client.

Actionscript 2 Code:

callRemoteFile = function(ourVariable:String) {

        var result_lv:LoadVars = new LoadVars();

    result_lv.onLoad = function(success:Boolean) {

                if (success) {

                        if (result_lv.message=="success")

                                trace("done! "+result_lv.returnValue);

                        else

                                trace(result_lv.message);

                } else {

                        trace("Error connecting to server");

                        return false;

                }

    };

    var send_lv:LoadVars = new LoadVars();

    send_lv.ourVariable = ourVariable;

    send_lv.sendAndLoad("http://www.andrewodendaal.com/example/file.php", result_lv, "POST");

}

callRemoteFile("some text here");

PHP Code:

        if (isset($_POST)) echo "a=1&message=success&returnValue=".$_POST["ourVariable"]."&b=2";

        else echo "a=0&message=failed&returnValue=nothing&b=1";

?>