index.js

// cheapo gulp-load-plugins
var $ = {
  map: require('gulp-map'),
  markdown: require('gulp-markdown'),
  util: require('gulp-util'),
  filetree: require('gulp-filetree'),
  size: require('gulp-size'),
  frontMatter: require('gulp-front-matter')
}

var path = require('path')
var lazypipe = require('lazypipe')

// for async for template loading
var Q = require('kew')
var fs = require('fs')
var jade = require('jade')
var File = require('vinyl')

// showing off
var archy = require('archy')
var chalk = require('chalk')

/**
 * Render the template, injecting the file into `page.file`.
 *
 * Switch templates by settings `meta.layout` on the file.
 *
 * Template variables:
 *
 * - page: Vinyl object <File ..>
 * - page.meta: Front-matter properties
 * - page.tree: Site tree
 * - page.subtree: Subtree rooted at this file
 * - page.content: Main content of the current page
 *
 * The nodes in the tree's (Treenode) have the following properties:
 *
 * - node.leaf: value at current node (Vinyl object) (may be undefined)
 * - node.parent: parent node (Treenode) (undefined for root)
 * - node.label: string label (~ path.basename(file.path))
 * - node.nodes: (empty) array of Treenodes that are children of this node
 *
 * There are also some methods on Treenodes.
 *
 * - node.is_leaf(): true if no children
 * - node.is_singleton(): true if has only one child
 * - node.is_last_child(): true if it is the last child of the parent
 *
 */

function render_tmpl () {
  // store compiled templates for great good
  var cache = {}

  var compile_template = function (filename) {
    return Q
      .fcall(function () {
        // return cached immediately
        if (cache[filename]) {
          return cache[filename]
        }

        // (asynchronously) load and compile template
        $.util.log('loading template: ' + filename)
        return Q
          .nfcall(fs.readFile, filename)
          .then(function (tmpl_content) {
            // turn template in promise returning function and cache it
            var compiled = jade.compile(tmpl_content, {pretty: true, filename: filename})
            $.util.log('compiled template: ' + chalk.yellow(filename))
            return (cache[filename] = compiled)
          })
      })
      .fail(function (err) {
        $.util.log('failed compiling jade template', chalk.red(err))
      })
  }

  return $.map(function (file) {
    // select template
    var t = (file.frontMatter && file.frontMatter.layout) || 'default'

    // pull from cache, compile if needed
    return compile_template('templates/' + t + '.jade')
      .then(function (compiled_template) {
        $.util.log('rendering [' + chalk.yellow(t) + '] "' +
          chalk.magenta(path.basename(file.path)) + '"')

        try {
          // render it with template variable 'page'
          var html = compiled_template({page: file})
        } catch (err) {
          console.log('[' + chalk.red('ERR') +
            '] Failed rendering jade template\n\t' +
            chalk.red(err.message))
        }

        return new File({
          cwd: file.cwd,
          base: file.base,
          path: file.path.replace(/\.md$/, '.html'),
          contents: new Buffer(html)
        })
      })
      .fail(function (err) {
        $.util.log('Failed rendering jade template', chalk.red(err))
      })
  })
}

// replace [[My Page]] with <a href='My-Page.html'>My Page</a>
/*
var resolve_wiki_links = function () {
  return $.replace(/\[\[(.*?)\]\]/g,
    function wikiLink (match, text) {
      var href = text.trim().replace(/ /g, '-') + '.html'
      return '<a href="' + href + '">' + text + '</a>'
    })
}
*/

var extended_attributes = function (file) {
  file.path = file.path && file.path.replace(/\.md$/, '.html')
  file.basename = path.basename(file.path)
  file.shortName = file.basename && file.basename.replace(/\.html$/, '')
  file.href = file.relative
  return file
}

var show_tree_once = function () {
  var once = false
  return $.map(function (file) {
    if (!once && file.tree) {
      $.util.log('File tree\n' + archy(file.tree))
      once = true
    }
    return file
  })
}

module.exports = lazypipe()
  .pipe($.map, extended_attributes)
  .pipe($.frontMatter)
  .pipe($.markdown)
  // //	.pipe(resolve_wiki_links)
  .pipe($.filetree)
  .pipe(show_tree_once)
  .pipe(render_tmpl)
  .pipe($.size)