Monday, 9 January 2017

Procedural Website? - Part 1

Web Site Needed

Apparance is at the stage now where it needs a proper web-site to bring together all the information accumulating around the project and provide a hub for people to find out all about it.  It's going to need all the usual stuff; summary pages, a gallery, detailed project information, feature lists, technical information, contact information, blog, documentation, and contact information.  Something like this:
A prototype Apparance homepage.
There are many ways to approach creating a web site.  It could be out-sourced, built using an online web-site maker, using offline tools, crafting from the many kits and examples available, or writing it all by hand in notepad.
Not having huge resources available and having hand crafted a few pages in my time I figured it would be best, at least in the short term to code it up myself.  So, given that I'm 'living and breathing procedural' right now, is there any reason not to try and do this procedurally, with Apparance?
I can't see anyone else making websites procedurally!  Am I crazy?


I'm not familiar with all that is trendy in web development and I'd like to keep things simple so I'm thinking static HTML pages with CSS styling.  I'd like to be able to author page content in some sort of simple format and not have to be editing html or using any web design tools to make changes.  Any image manipulation should preferably be handled automatically or with little interaction. Given this, some process will be needed to effectively compile the content, images, structure, and styling together into each page.


Content Processing

Simple format text files with basic formatting information you say?  Sounds like mark-down to me.  A bit of digging found a rather impressive command line utility called Pandoc which actually will convert a plethora of document formats.  By default though passing in simple markdown text it will spit out an HTML fragment.
Pandoc, by default converts markdown into HTML
Perfect for injecting into the structure needed around it to form a complete page.

Image Processing

The most common need for image preparation on a web page has to be scaling to generate thumbnail previews, something we're going to need to show off all the visual goodness of Apparance.  A well know tool that handles this adequately is Image Magick.  Again a command line tools with a huge number of features and functions, it comes with an command specifically designed for generating thumbnails.
Image Magick, great for quickly handling thumbnail generation
Perfect to add to the arsenal of tools for building my pages.


Now to the question of automation; how best to take all this and build pages out of it?  Let's look at the requirements.
  1. Generate the common page HTML and CSS according to the page design.
  2. Launch Pandoc to turn the page content into HTML.
  3. Launch Image Magick to generate thumbnails for the images.
  4. Combine the HTML into pages.
  5. Assemble it all in a suitable file/folder structure for serving as a web-site.

Doing it wrong

There are existing static web page compilers available (e.g. Hugo) I could use.  I could write a program to do it, or come up with something in python or similar scripting languages.  But thinking about Apparance and some of the philosophies behind it I realised that these approaches went against it on several levels.
First, there was the baking process, the page needed to be compiled before it could be viewed.  Now, whilst any process of assembling a page requires time to complete, with scripts and command line tools there are still several steps involved in getting from making a change to seeing the results.  You lose the immediacy of a truly interactive editing experience.
Second, committing anything to script or code goes against the data-driven approach, and again, you lose the direct connection between your design and the results.

We've seen this before

Having already worked on interactive editing and text based processing with the material and shader system in Apparance it seemed like a similar approach could be applied here.  Why not use procedures in Apparance to handle the HTML composition, the control of command line utilities, and the manipulation of files and the directory structure?  It would mean any part of the web-site could be editing and you would get to see the results in real-time!  This was clearly the path to follow.

And So; To Procedural

A few things would be needed to be added to Apparance's capabilities for us to be able to support this though:
  1. Extra string handling functions - we are going to be doing more fancy things than we did with shader building.
  2. File handling operations - we are actually going outside the application, to work with files.
  3. An operator for spawning processes and collecting their output - to allow us to use other tools to do our bidding.
With all this in place, we are in a position to start building the site by creating procedures and letting Apparance do the work.  Next time we'll have a look at how this went and what it's like to work with.  Here's a sneak peek at the editor with the procedure for writing out the HTML pages.
Procedure to write out an HTML page

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