Metalsmith Gist Embed Plugin

gistfile1.js

/**
 * Module dependencies.
 */

var request = require('request');
var Q       = require('q');

/**
* GistEmbed prototype.
*/
var app = GistEmbed.prototype;

/**
* Expose `plugin`.
*/
exports = module.exports = function() {

  return function ( files, metalsmith, done ) {
    new GistEmbed( files )
      .init(function() {
        done();
      });
  };

};

/**
* Initialize a new `GistEmbed`.
*
* @api public
*/

function GistEmbed( files ) {

  this.files = files;
  this.posts = [];

  Object.keys( files ).forEach( function( file ) {
    if ( files[file].gist ) {
      this.posts.push( file ) ;
    }
  }.bind(this));

}

app.init = function( callback ) {

  if ( !this.posts.length ) {
    return callback();
  }

  var that = this;
  var total = this.posts.length;
  var isDone = function() {
    total -= 1;
    if ( total === 0 ) {
      callback();
    }
  }

  this.posts.forEach( function( file ) {
    that.postWithGist( file, function() {
      isDone();
    });
  });

};

app.postWithGist = function( file, callback ) {

  if ( typeof this.files[file].gist === 'string' ) {
    this.files[file].gist = this.helpers.toArray( this.files[file].gist );
  }

  var that = this;
  var total = this.files[file].gist.length;
  var isDone = function() {
    total -= 1;
    if ( total === 0 ) {
      callback();
    }
  }

  this.files[file].gist.forEach( function( gist ) {
    that.requestGithubGists( gist )
      .then( function( ghGist ) {
        that.replacePost( file, gist, ghGist, function( res ) {
          isDone();
        });
      }, function( err ) {
         console.log('err', err);
         isDone();
      });

  });


};

app.requestGithubGists = function( gist ) {

  var deferred = Q.defer();
  var url = 'https://gist.github.com/'+gist+'.json';
  request( url , function ( error, response, body ) {

    if ( !error && response.statusCode === 200 ) {
      var res = JSON.parse(body);
      deferred.resolve( res );
    } else {
      deferred.reject( true );
    }

  });

  return deferred.promise;

};


app.replacePost = function ( file, gist, ghGist, callback ) {

  var style = '<link rel="stylesheet" href="' + ghGist.stylesheet + '">',
      value = style + ' ' + ghGist.div,
      contents = this.helpers.replaceGist( this.files[file].contents, gist, value );

  this.files[file].contents = new Buffer( contents );
  callback('replaced ' + gist );

};

/**
* Helpers
*/

app.helpers = {

  replaceGist: function( contents, gist, value ) {
    return contents.toString().replace("gist:" + gist, value);
  },

  toArray: function( gist ) {
    return gist.trim()
      .replace(/([\s-,])/g,'|')
      .split('|')
      .filter(function( a ){ return a; } );
  }

};

// page.md 
---
title: "Another Foo Bar"
date: 2014-03-01
template: article.hbt
tags: ruby on rails
gist: expalmer/cfbaf085256d5902ce2d, expalmer/5f1693761a94c215cb23
---

# here I put the same gist:id that I put above in array
gist:expalmer/cfbaf085256d5902ce2d

# here too
gist:expalmer/5f1693761a94c215cb23


// index.js
var gistEmbed   = require('./gist-embed');

Metalsmith(__dirname)
    .use(collections({
        articles: {
            pattern: 'content/articles/*.md',
            sortBy: 'date',
            reverse: true
        }
    }))
    .use(markdown())
    .use(gistEmbed()) 
    
    .. continue ...