CKSource

CKFinder functionality can be extended with server-side plugins. Although the full source code of the CKFinder server connector is available and can be modified in any way desired, a much better way of enhancing the CKFinder connector is to create a plugin.

The main advantages of plugins are:

• Upgrades are much easier.
• The plugin code is stored in a single place.
• Plugins can be easily disabled when they are not needed anymore.

Common use cases:

• Adding a new server-side command (i.e. fileditor and imageresize plugin).
• Working with uploaded files (i.e. watermark plugin).
• Extending information returned by the Init command (i.e. imageresize plugin).

Creating a plugin

Step1: Create plugin folder

Create a directory for your plugin inside of the "plugins" directory (by default CKFinder comes with three plugins: dummy, fileeditor, imagreresize). Let's use "myplugin" as the plugin name and use the same name for our new folder.

Step2: Create plugin file

Inside of your plugin's folder ("myplugin") create an empty file named plugin.asp.

Step3: Add plugin definition

// Let's create an empty ASP file for now

Step4: Enable plugin

Add an INCLUDE statement in the ASP configuration file (config.asp):

<!-- #INCLUDE file="plugins/myplugin/plugin.asp" -->

ASP plugin system

Hooks

CKFinder provides several hooks that can be used to extend the functionality of the CKFinder application. Assigning a function (also known as an event handler) to a hook will cause that function to be called at the appropriate point in the main CKFinder code, to perform whatever additional task(s) the developer thinks would be useful at that point. Each hook can have multiple handlers assigned to it, in which case it will call the functions in the order that they are assigned.

Hooks should be assigned in a plugin file. To assign a event listener to a hook call:

CKFinder_AddHook "EventName", CommandHandler

where EventName is the name of a hook and CommandHandler is an object that contains a method named OnEventName.

Available hooks

Hook	Since	Description
AfterFileUpload	2.0	Executed after successful file upload.
BeforeExecuteCommand	2.0	Executed before a server side command is executed.
InitCommand	2.0	Executed straight before sending the result of the Init command.

Enabling JavaScript plugin

Sometimes a server side plugin might come with a client side (JavaScript) plugin, that should be automatically enabled when the server side plugin is enabled. To enable a JavaScript plugin inside your ASP plugin, use CKFinder_AddPlugin function.

To enable a plugin, simply call CKFinder_AddPlugin.

CKFinder_AddPlugin "myplugin"

This code is virtually equal to specyfying in config.js:

config.extraPlugins = 'myplugin';

but the advantage of defining it in plugin.asp is that it will be enabled only when the server side plugin is also enabled.

Sample plugin: FileSize (adding new server side command - complete example)

Introduction

Probably the best way to learn new things is to write a code, so let's write a plugin that adds a new server side command to the connector. We'll create a command that returns a size of a given file.

If you're unfamiliar with CKFinder architecture, please take a look at Server Side Integration documentation. Alternatively, just bear in mind that CKFinder is an AJAX application and that the connection between the user interface running in a browser and the server connector is simply made of AJAX calls to the connector. Check AJAX calls in Firebug to better understand CKFinder.

The FileSize plugin should provide a new command named "FileSize", in other words, calling:

/ckfinder/core/connector/asp/connector.asp?command=FileSize&type=Files&currentFolder=%2F&fileName=foobar.jpg

(assuming that foobar.jpg exists) should return a valid XML response:

<Connector resourceType="Files">
<Error number="0"/>
<CurrentFolder path="/" url="/ckfinder/userfiles/files/" acl="255"/>
<FileSize size="5647"/>
</Connector>

For the sake of simplicity, we'll first create a simple plugin.asp that just does exactly what we need:

<script runat="server" language="VBScript">

' (2)
class CKFinder_Connector_CommandHandler_FileSize
    ' Pseudo inheritance
    private base
 
    ' (2) Since we want to send a XML response, we'll extend the XmlCommandHandlerBase class
    Private Sub Class_Initialize()
        Set base = new CKFinder_Connector_CommandHandler_XmlCommandHandlerBase
        Set base.child = me
    End Sub
 
    ' Pseudo inheritance
    Public Property Get currentFolder()
        Set currentFolder = base.currentFolder
    End Property
 
    Public Sub sendResponse(response)
        base.sendResponse(response)
    End sub
 
    Public Property Get ErrorHandler()
        Set ErrorHandler = base.ErrorHandler
    End Property
 
    ' (4) The buildXml method is used to construct an XML response
    function buildXml( oXML )
        Dim fileName
        fileName = request("fileName")
 
        Dim oUFS
        Set oUFS = oCKFinder_Factory.UtilsFileSystem
 
        Dim filePath
        filePath = oUFS.combinePaths(currentFolder.getServerPath(), fileName)
 
        ' (5) Adding a <FileSize> element to the XML response.
        Dim size, oNode
        size = oUFS.GetFileSize(filePath)
        Set oNode = oXML.connectorNode.addChild("FileSize")
        oNode.addAttribute "size", size
 
    End function
 
    ' Our event listener:
    ' (3) Register the "FileSize" command
    public function onBeforeExecuteCommand( command )
        if ( command = "FileSize" ) then
            ' The sendResponse method is defined in XmlCommandHandlerBase, it creates 
            ' a basic XML response and calls the buildXml()method 
            sendResponse( response )
            ' false = stop further execution.
            onBeforeExecuteCommand = False
            Exit function
        End if
 
        onBeforeExecuteCommand = True
    End Function
 
End Class
 
Dim CommandHandler_FileSize
Set CommandHandler_FileSize = new CKFinder_Connector_CommandHandler_FileSize
 
' (1) Object assigned to a hook must contain event listener named "onEventName"
' (the event name is BeforeExecuteCommand, so we must define an onBeforeExecuteCommand method).
CKFinder_AddHook "BeforeExecuteCommand", CommandHandler_FileSize
CKFinder_AddPlugin "myplugin"
 
</script>

Step1: Register an event handler

CKFinder_AddHook "BeforeExecuteCommand", CommandHandler_FileSize

Step2: Create a class

If your plugin returns an XML response, you'll usually just extend the XmlCommandHandlerBase class to reduce the amount of code to write, however it is not a requirement.

class CKFinder_Connector_CommandHandler_FileSize
	' Pseudo inheritance
	private base
 
	' Since we want to send a XML response, we'll extend the XmlCommandHandlerBase class
	Private Sub Class_Initialize()
		Set base = new CKFinder_Connector_CommandHandler_XmlCommandHandlerBase
		Set base.child = me
	End Sub

	' ...

End Class

Step3: Create an event handler

Our event handler defined in (1) should be called "OnBeforeExecuteCommand", so let's define such function.

public function onBeforeExecuteCommand( command )
' ...

Step4: Create the buildXml method

In the onBeforeExecuteCommand method we have called sendResponse. The sendResponse method is defined in XmlCommandHandlerBase class, it creates a basic XML response and calls the buildXml method, which we need to define.

function buildXml( oXML )
' ...

Step5: Construct the XML response

The main task of the buildXml method is to construct an XML response, so we're doing it below:

Dim size, oNode
size = oUFS.GetFileSize(filePath)
Set oNode = oXML.connectorNode.addChild("FileSize")
oNode.addAttribute "size", size

Full source code

plugin.asp

The full source code of a plugin with all necessary security checks: (save the code as plugin.asp in "plugins/myplugin" folder)

<script runat="server" language="VBScript">

' (2)
class CKFinder_Connector_CommandHandler_FileSize
    ' Pseudo inheritance
    private base

    ' (2) Since we want to send a XML response, we'll extend the XmlCommandHandlerBase class
    Private Sub Class_Initialize()
        Set base = new CKFinder_Connector_CommandHandler_XmlCommandHandlerBase
        Set base.child = me
    End Sub

    Private Sub Class_Terminate()
        Set base.child = Nothing
        Set base = Nothing
    End Sub

    ' Pseudo inheritance
    Public Property Get currentFolder()
        Set currentFolder = base.currentFolder
    End Property

    Public Sub sendResponse(response)
        base.sendResponse(response)
    End sub

    Public Property Get ErrorHandler()
        Set ErrorHandler = base.ErrorHandler
    End Property

    ' (4) The buildXml method is used to construct an XML response
    function buildXml( oXML )

        if not(currentFolder.checkAcl(CKFINDER_CONNECTOR_ACL_FILE_VIEW)) then
            errorHandler.throwError CKFINDER_CONNECTOR_ERROR_UNAUTHORIZED, "", "ACL check failed"
        End if

        Dim resourceTypeInfo
        Set resourceTypeInfo = currentFolder.getResourceTypeConfig()

        Dim fileName
        fileName = request("fileName")
        If (fileName="") then
            errorHandler.throwError CKFINDER_CONNECTOR_ERROR_INVALID_NAME, "", "Missing filename"
        End if

        Dim oUFS
        Set oUFS = oCKFinder_Factory.UtilsFileSystem

        if (Not oUFS.checkFileName(fileName) or resourceTypeInfo.checkIsHiddenFile(fileName)) then
            errorHandler.throwError CKFINDER_CONNECTOR_ERROR_INVALID_REQUEST, "", "Invalid filename"
        End if

        if (Not resourceTypeInfo.checkExtension(fileName)) then
             errorHandler.throwError CKFINDER_CONNECTOR_ERROR_INVALID_REQUEST, "", "Invalid extension"
        End if

        Dim filePath
        filePath = oUFS.combinePaths(currentFolder.getServerPath(), fileName)

        If Not(oUFS.fileExists(filePath)) then
             errorHandler.throwError CKFINDER_CONNECTOR_ERROR_FILE_NOT_FOUND, "", "File doesn't exists: " & filePath
        End if

        ' (5) Adding a <FileSize> element to the XML response.
        Dim size, oNode
        size = oUFS.GetFileSize(filePath)
        Set oNode = oXML.connectorNode.addChild("FileSize")
        oNode.addAttribute "size", size

    End function

    ' Our event listener:
    ' (3) Register the "FileSize" command
    public function onBeforeExecuteCommand( command )
        if ( command = "FileSize" ) then
			' The sendResponse method is defined in XmlCommandHandlerBase, it creates 
			' a basic XML response and calls the buildXml()method 
			sendResponse( response )
				' false = stop further execution.
			onBeforeExecuteCommand = False
			Exit function
        End if

        onBeforeExecuteCommand = True
    End Function

End Class

Dim CommandHandler_FileSize
If (TypeName(oCKFinder_Factory) <> "Empty") then
    Set CommandHandler_FileSize = new CKFinder_Connector_CommandHandler_FileSize

    ' (1) Object assigned to a hook must contain event listener named "onEventName"
    ' (the event name is BeforeExecuteCommand, so we must define an onBeforeExecuteCommand method).
    CKFinder_AddHook "BeforeExecuteCommand", CommandHandler_FileSize
    CKFinder_AddPlugin "myplugin"
End if

</script>

plugin.js

.. and the client side (JavaScript) plugin that will call the FileSize command: (save the code as plugin.js in "plugins/myplugin" folder)

CKFinder.addPlugin( 'myplugin', function( api ) {
	api.addFileContextMenuOption( { label : 'File Size', command : "FileSize" } , function( api, file )
	{
		api.connector.sendCommand( 'FileSize', { fileName : api.getSelectedFile().name }, function( xml )
		{
			if ( xml.checkError() )
				return;

			var size = xml.selectSingleNode( 'Connector/FileSize/@size' );
			api.openMsgDialog( "", "The exact size of a file is: " + size.value + " bytes");
		} );
	});
});