UNIT 04 - Webskins I

Objectives

In this unit we learn about webskins: the "view" for FarCry Framework. Webskins form the presentation tier of any FarCry application. By the end of this unit you should have a basic understanding of how webskins are managed, their relationship to content types and how to create your own.

The Webskin

The webskin is a templating layer that effectively translates your data into a view. Typically this is an HTML page or fragment of HTML representing a content teaser or some other element used in assembling a page. But a webskin could just as easily be outputting a form, RSS, XML or other format.

In its basic form we can run a webskin on an object by using the following URL Syntax:

http://superheroes.local?objectid=E689D66F-96FD-E9F6-B1AF64B8DAE78A69&view=displayPageStandard

The url above is running the webskin "displayPageStandard" on the object with the objectid of "E689D66F-96FD-E9F6-B1AF64B8DAE78A69"

Where to Find Webskins

Webskins are all located in a single folder under your project root called "webskin" funnily enough. Inside that directory branch you should find a single folder for each content type you want a webskin for.

c:\farcry
    \projects
      \myproject
        \webskin
          \dmHTML
          \dmNews
          \dmEvent
          \myContentType

Walkthrough: Call a Webskin on a HTML Object

In this walkthrough we're going to call the standard dmHTML webskins on the Home Page HTML object.

1. Login to the Webtop and click on the Home Page dmHTML object in the site tree (the white page icon... not the blue dmNavigation object)
2. Copy the objectid of this object to the ClipBoard (located at the bottom of the summary for the object)
3. Now, locate the ./webskin/dmHTML folder in your project
4. Take note of the current webskins in that folder.
5. Now enter a url to call the various webskins in that folder using the following format

   http://superheroes.local/index.cfm?objectid=E689D66F-96FD-E9F6-B1AF64B8DAE78A69&view=displayPageStandard
   http://superheroes.local/index.cfm?objectid=E689D66F-96FD-E9F6-B1AF64B8DAE78A69&view=displayPage3Col
   http://superheroes.local/index.cfm?objectid=E689D66F-96FD-E9F6-B1AF64B8DAE78A69&view=displayTeaserStandard
   

6. Discuss how this forms the basis of almost ALL web applications

Creating Webskins

Webskins are literally just ColdFusion templates. Any file with a .cfm extension in a directory under ./myproject/webskin will be registered as a webskin by the FarCry Framework. Consequently only files that you intend to be webskins should ever be stored here. To create a webskin simply create the template in the correct directory and RELOAD the application.

Although you can give your webskin template any file name, in practise it makes sense to follow the naming standards used by the rest of the community. The following table outlines common naming prefixes for templates and explains their uses within the FarCry framework. An asterisk denotes a wildcard, where you would use your own unique name to differentiate templates of similar purpose.

These are just a few of the regularly used webskin names within the FarCry framework.

Hooking Up The Webskin To Data

Every time a webskin is invoked it is done so in the context of a specific content object. For example, viewing a particular news article in with a displayPageStandard, or a product item with displayPageProduct.cfm, or whatever. FarCry always provides the entire content object record to the webskin (or view) as a structure called stobj. stobj contains the typename, and all the property keys and values for the object in question, including array properties.

The data contained in the stobj structure can be referenced in the normal way, and then combined with mark-up to produce the desired output. The similarity between this and any normal procedural ColdFusion template is deliberate - the framework authors have tried hard to make the creation of webskins or views very similar to building a simple ColdFusion template.

<!--- Example Webskin Template -- Dead Simple --->
<cfoutput>
<h1>#stobj.title#</h1>
#stobj.body#
</cfoutput>

Webskin Metadata

Every template can be supplemented with metadata. You should make a habit of this as it makes the whole system read much better, helping to provide human readable template names, inline documentation and so on. Metadata is incorporated by including a series of specific comments at the top of each template.

Template metadata is always stored in a ColdFusion comment. On initialisation, FarCry scans the registered webskins for their additional metadata and stores it in memory. If you make a change to the metadata you may need to re-start the application in order to see the change come into effect.

<!--- @@displayname: Core Home Page --->
<!--- @@description: Home page for the FarCry Core developer portal. --->
<!--- @@author: Matthew Bryant (mbryant@daemon.com.au)--->

Walkthrough: Create displayPageSuper.cfm

In this walkthrough we're going to create a simple dmHTML webskin template to play with some of the ideas we've just considered.

1. Locate the ./webskin/dmHTML folder in your project
2. Create a file called displayPageSuper.cfm
3. Write up some basic HTML in a <cfoutput>

   <!--- @@displayname: Demo Template --->
   <cfoutput>
   <h1>Hello Cruel World</h1>
   </cfoutput>
   

4. Reload the application to pick up the template change. Use the [Reload Application] tool in the webtop.
5. Select the Site Overview Tab. Edit the FarCry Support HTML page and change its template to the one you just created.
6. Save and Preview the page. Check the HTML source and discuss with your instructor.
7. Edit your template and add a cfdump to the page for stobj

   <cfdump var="#stobj#" label="Content Object" />
   

8. Save and preview the page.

Static Media Assets

In a FarCry project we normally make a distinction between media assets (such as files, images, video, etc) that are managed by the application (ie. Content Managed) and assets which are hard-coded and fixed in the code base (ie. Application Chrome).

When you are dealing with the application's chrome, the fixed static images and so on that make up the graphic theme of the site, in most instances you do not want to have these mixed with assets that are content managed by users. The standard for managing media assets of this nature is to store them under the webroot (for obvious reasons) in a directory called ./wsimages/ or under the ./css/images directory if they are relative to the style sheet.

c:\farcry
    \projects
      \myproject
        \webskin
        \www (standard project webroot)
          \wsimages
          \css\images

Webskin Tag Libraries

Remember a webskin is just like a ColdFusion template - you can do all sorts of things. The webskin is strictly speaking a VIEW and following good programming practise you should refrain from doing business logic in this area. However, you can reference ColdFusion tags, FarCry service components and custom tag libraries as needed.

FarCry has a special custom tag library dedicated to making life easier when building webskins. In includes all sorts of goodies from building navigation, to breadcrumbs, to rendering other views and more. You can find this library in the core framework at: ./core/tags/webskin To make use of these tags you will need to import them first.

<!--- @@displayname: Home Page --->
<!--- @@author: Matthew Bryant (mbryant@daemon.com.au)--->

<!--- import tag libraries --->
<cfimport taglib="/farcry/core/tags/webskin" prefix="skin" />

<skin:breadcrumb />

Walkthrough: Putting It All Together

Get comfortable with how webskins are assembled in the real world. You should be able to dissect the sample application webskins and understand how they have been put together.

1. Review the other templates in the ./webskin/dmHTML directory with your instructor
2. Consider the use of custom tags, headers, footers and other layout mechanisms