How do I...Write a Deki extension for PHP?

Getting Started

In order to make the DekiWiki Extension for PHP work, first make sure you have a PHP server running. In order for your PHP server to communicate with Deki Wiki via XML-RPC you need to download a XML-RPC library from Incutio. It's called IXR_Library.inc.php.txt.  Right click on the link and Save As: IXR_Library.inc.php

Once you've added that library into the directory you would like to work out of, you also need to copy DekiExt.php.

Now that you have the necessary files needed for your PHP server, you can now write the PHP that will be used for your extension.

Writing your PHP extension - Simple Case

First, make sure you include the DekiExt.php file in your own .php file.

include('DekiExt.php');

Next, call the function DekiExt, which will help you create your extension. This part is required in order for your php extension to work. The DekiExt function takes in 3 parameters: title, extension metadata (optional), and an array mapping your extension functions to your functions in PHP. And the list of extension functions follows this format.

DekiExt(
    
    // Title of your Deki Wiki Extension
    "Acme HelloWorld Service",                           

    // (Optional) Metadata about the Deki Wiki Extension
    null,

    // List of Extension Functions
    array(
        "sayHello():str" => "HelloWorld"
    )
);

The above DekiExt function is written with the most minimal amount of information possible to get DekiWiki to run your PHP extension. Once you have that done, you can write your HelloWorld function:

function HelloWorld()
{
    return "Hello World";
}

  To view the whole file: test.php

With just those few lines of code put together, all you need to do next is register your newly created PHP file as a Deki Wiki Extension. You do this by first going into your Control Panel page. On the Control Panel page, select the Service Management.

When you're in the Service Management page, create a new Remote service and fill in the input boxes with their appropriate information:

• Type: In our case, we want to choose Extension.
• Description: your extension name
• URI: location of your extension
• Status: enabled (default)

Once this is done, you can now call your php HelloWorld function from any page in Deki Wiki.  

Once you save your changes, the outcome of the HelloWorld function will show up on your Deki Wiki page:

Writing your PHP extension - with Extension MetaData

Next, we include some extension metadata to our DekiExt: description, copyright, uri.help, and namespace. For a full compilation of extension info types you can use.

DekiExt(
    
    //Title of your Deki Wiki Extension
    "Mindtouch Deki Extension Php Service",                           

    //(Optional) Metadata about the Deki Wiki Extension
    array(
        "description" => "Extension to embed friendly Acme greetings.",               
        "copyright"   => "Copyright Acme Inc. 2008", 
        "uri.help"    => "http://acme.corp/HelloWorldHelp.html",
        "namespace"   => "test"
    ), 

    //List of Extension Functions
    array(
        "Greeting(first:str, last:str):str" => "myGreeting",          
    )
);

As you see, you can fill the extension with preset keys and values that will be added into the generated xml page when you register your PHP file as an extension. Once this is done, create the matching function derived from your last parameter in DekiExt:

function myGreeting($args) 
{
	list($first, $last) = $args; 
	return 'Hello World, my name is '.$first.' '.$last;
}

NOTE: when writing your functions, you can only put in one parameter. Because the IXR_Library treats the incoming XML-RPC params as an array isntead of parameters that are supposed to be mapped accordingly. As you will notice in the sample function, we tell the extension that the user will be passing in 2 parameters from Deki Wiki. However, on the Php side, we will only take 1 parameter of type array. You can either handle the incoming array by calling it's incidies or remap it using list(p1, p2, p3, etc...) like in the function above.

Like before in your simple sample, register your PHP file as a Remote extension in the Service Managment page and then call it in your DekiWiki editor.

When we have a namespace in our extension metadata, we call our function from Deki Wiki like this:

{{namespace.functionName()}}

Writing your PHP extension - Advanced Sample

In this sample, we will show you different ways you can use PHP to create a page with more functionality.

Like before, add the include the DekiExt.php file and then create your own DekiExt function with the parameters you want. 

DekiExt(

    //Title of your Deki Wiki Extension
    "Acme Php Service",

    //Title of your Deki Wiki Extension
    array( 
        "description" => "date offset, random links, Phil's BBQ open hours, and email functions", 
        "copyright" => "Acme Random Functions 2000", 
        "uri.help" => "http://acme.org/AcmeHelp.html",
        "namespace" => "test"
    ), 
	
    //List of Extension Functions
    array( 
        "time(days:num):str"                           => "daysLater",
        "randLink(random:bool, link:str):str"          => "randomTinyUrl",
        "philsOpen(day:str, open:str, closed:str):str" => "philsOpen",
        "send(to:str, subject:str, body:str):str"      => "sendEmail"
    )
);

Now that you have the DekiExt function setup, you can write your functions that match the function array you listed as a parameter in DekiExt.

function daysLater($arg)
{
	$offset = time() + ($arg * 24 * 60 * 60);
	return  date('Y-m-d',$offset) ."\n";
}

function randomTinyUrl($args)
{
	list($isRandom, $uri) = $args;
	if($isRandom)
		$seed = rand(0, 5000);
	else
		$seed = $uri;
	return "http://tinyurl.com/".$seed;
}

function philsOpen($arg)
{
	list($day, $opening, $closing) = $arg;
	
	$timestamp = time() -7*3600;
	$now = gmdate('h a', $timestamp);
	$today = gmdate('D', $timestamp);
	$givenDay = gmdate('D', strtotime($day));
	$open = gmdate('h a',strtotime($opening));
	$close  = gmdate('h a',strtotime($closing));
	if($open == $close)
	{
		return 'closed';
	}
	else if((strtotime($today) == strtotime($givenDay)))
	{
		if(strtotime($close)-strtotime($now) < 0)
			return 'closed';
		else
			return 'open today, will close in: ' . gmdate('H',strtotime($close)-strtotime($now)). ' hours';
	}
	else
	{
		return $open . ' to ' . $close;
	}
}

function sendEmail($arg)
{
	list($to, $subject, $body) = $arg;

	// Additional Headers
	$headers = 'From: youremail@example.com'."\r\n".
		'Cc: yourContact@example.com'."\r\n";

	if(mail($to, $subject, $body, $headers))
	{
		return "Mail sent successfully.";
	}
	else
	{
		return "Was unable to send mail.";
	}
}

Returning XML From Your PHP Extension

While XML-RPC does not support XML, DekiScript does, so you can actually return something in xml format. However, since the PHP server only handles the XML-RPC standard, we still cannot call a function using a parameter of type XML. 

Like before, setup the DekiExt. Notice how the return is of type xml:

DekiExt(
		//title
		"Mindtouch Deki Extension Php Return XML Service", 

		//extension options
		array("namespace" => "xmlRetSample"), 

		//function information to php function Name mapping 
		array(
			"formatReturn(first : str, last : str):xml" => "xmlReturn"
		)
);

Next, we write out our xmlReturn function:

function xmlReturn($args) 
 {
	    list($first, $last) = $args;

	
	    $str ='<html><head>'.
			'<script type="text/javascript" src="http://this_is_a_test/"></script>'.
			'</head><body>'.
			'<table border="1"><tr><td>'.$first.'<br/></td><td>'.
			$last.'</td></tr></table></body></html>';

	    return $str;
 }

 After that, Register your php extension, and call it like all the other extension samples.

Extension Function to Function Name Mapping Format

function_name(parameter1:type, parameter2:type, parameter3:type ...etc....):return_type => your_php_function_name

The types that are allowed for parameters and the return are: any, nil, num, str, bool, list,and map.

There is also a special case with xml, while you can return something of xml type, you cannot give a parameter a xml type.

NOTE: Even though the types uri exists in DekiScript, it cannot be used in PHP extensions since they are not supported by XML-RPC.

Additional Extension Information

The different kinds of extension metadata that can be set

For more information, please refer to HERE.

Conclusion

Now that DekiWiki is compatible with standards compliant XML-RPC, we can now call Php functions located on our own server from DekiWiki. In order to do this, we only need to add 2 php files, to act as a server that will communicated with DekiWiki via XML-RPC and turn our DekiExt function parameter information into a deki extension xml page. From this, we can easily add our PHP file (with the required DekiExt information filled in) as a remote service and begin to use our own php functions within seconds.