conf.yaml

imap:
    server: imap.gmail.com
    port: 993
    user: YOUR GMAIL ADDRESS
    password: YOUR PASSWORD
    mailbox: INBOX

gmail_to_rss.rb

#!/usr/bin/env ruby
#
#  Created by  on 2009-04-25.
#  Copyright (c) 2009. All rights reserved.
require 'net/imap'
require 'yaml'
require 'rss/maker'

conf=YAML::load(File.open('conf.yaml'))

version = "2.0" # ["0.9", "1.0", "2.0"]
destination = "test_maker.xml" # local file to write

imap = Net::IMAP.new(conf['imap']['server'],conf['imap']['port'],true)
imap.login(conf['imap']['user'], conf['imap']['password'])
imap.select(conf['imap']['mailbox'])
content = RSS::Maker.make(version) do |m|
  m.channel.title = "Gmail Feed"
  m.channel.link = "http://www.interfacelab.com"
  m.channel.description = "Gmail inbox as RSS"
  m.items.do_sort = true # sort items by date

  imap.search(["NOT", "DELETED"]).each do |message_id|
    envelope=imap.fetch(message_id, "ENVELOPE")[0].attr["ENVELOPE"]
    body=imap.fetch(message_id, "BODY[TEXT]")[0].attr["BODY[TEXT]"]

    puts "#{envelope.from[0].name}: \t#{envelope.subject}\n"

    i = m.items.new_item
    i.title = envelope.subject
    i.description = body
    i.date = Time.parse(envelope.date)
#    break
  end
end
File.open(destination,"w") do |f|
  f.write(content)#  break
end  
imap.logout()
imap.disconnect()

rubyrss.rb

#
# RubyRSS
# Copyright (c) 2006 Sergey Tikhonov <st@dairon.net>
# Distributed under MIT License
#

require "simple-rss"
require "open-uri"
load "templates.rb"

class RubyRSS
  attr_accessor :title, :link, :desc, :date, :items
  attr_reader :filename
 
  class Item < self
    attr_accessor :title, :link, :desc, :date
    def initialize( title, link, desc, date )
      @title = title
      @link = link
      @desc = desc
      @date = date
    end
  end

  def initialize( filename )
    @filename = filename
    @title = ""
    @link = ""
    @date = Time.new
    @items = []
  end

  def parse( template_name = "default" )
    rss = SimpleRSS.parse open(@filename)

    @title = rss.channel.title
    @link = rss.channel.link
    @date = rss.channel.pubDate || rss.channel.lastBuildDate || rss.channel.modified || Time.now.gmtime
    rss.items.each { |item|
      d = item.pubDate || item.lastBuildDate || item.modified || Time.now.gmtime
      @items << Item.new( item.title, item.link, item.description, d )
    }

    html = $html_templates[ template_name ].strip
    item_html = ($1).strip if html =~ /#items-start(?::\d+)?(.+)#items-end/m

    num_items, desc_size = 10, 0
    num_items = ($1).to_i if html =~ /#items-start:(\d+)/
    desc_size = ($1).to_i if html =~ /#item-desc:(\d+)/

    html.gsub!( /#title/, title )
    html.gsub!( /#link/, link )
    html.gsub!( /#desc/, desc ) if desc
    html.gsub!( /#date/, date.to_s )
    items_html = ""
    items[0..num_items].each { |item|
      temp_html = item_html.dup
      temp_html.gsub!( /#item-title/, item.title )
      temp_html.gsub!( /#item-link/, item.link )
      d = item.desc
      if desc_size != 0
        d = CGI.unescapeHTML(d).gsub( /<([^>]+)>/, "" )
        d = d[ 0, desc_size ]
        d.gsub!( /(\s[^\s]*)$/, "&hellip;" )
      end
      temp_html.gsub!( /#item-desc(:\d+)?/, d )
      temp_html.gsub!( /#item-date/, item.date.strftime("%b %d %H:%M") )
      items_html << temp_html
    }
    html.gsub!( /#items-start(:\d+)?(.*)#items-end/m, items_html )
    html
  end

  def generate( template_name = "rss2.0" )
    rss = $rss_templates[ template_name ].strip
    item_rss = ($1).strip if rss =~ /#items-start(.+)#items-end/m
    
    rss.gsub!( /#title/, title )
    rss.gsub!( /#link/, link )
    rss.gsub!( /#desc/, desc )
    rss.gsub!( /#date/, date.to_s )
    items_rss = ""
    items.each { |item|
      temp_rss = item_rss.dup
      temp_rss.gsub!( /#item-title/, item.title )
      temp_rss.gsub!( /#item-link/, item.link )
      temp_rss.gsub!( /#item-desc/, CGI.escapeHTML(item.desc) )
      temp_rss.gsub!( /#item-date/, item.date.to_s )
      items_rss << temp_rss + "\n"
    }
    rss.gsub!( /#items-start\n(.*)#items-end\n/m, items_rss )
    rss
  end
end

simple-rss.rb

require 'cgi'
require 'time'

class SimpleRSS
  VERSION = "1.2"
  
	attr_reader :items, :source
	alias :entries :items

	@@feed_tags = [
		:id,
		:title, :subtitle, :link,
		:description, 
		:author, :webMaster, :managingEditor, :contributor,
		:pubDate, :lastBuildDate, :updated, :'dc:date',
		:generator, :language, :docs, :cloud,
		:ttl, :skipHours, :skipDays,
		:image, :logo, :icon, :rating,
		:rights, :copyright,
		:textInput, :'feedburner:browserFriendly',
		:'itunes:author', :'itunes:category'
	]

	@@item_tags = [
		:id,
		:title, :link, :'link+alternate', :'link+self', :'link+edit', :'link+replies',
		:author, :contributor,
		:description, :summary, :content, :'content:encoded', :comments,
		:pubDate, :published, :updated, :expirationDate, :modified, :'dc:date',
		:category, :guid,
		:'trackback:ping', :'trackback:about',
		:'dc:creator', :'dc:title', :'dc:subject', :'dc:rights', :'dc:publisher',
		:'feedburner:origLink'
	]

	def initialize(source)
		@source = source.respond_to?(:read) ? source.read : source.to_s
		@items = Array.new

		parse
	end

	def channel() self end
	alias :feed :channel

	class << self
		def feed_tags
			@@feed_tags
		end
		def feed_tags=(ft)
			@@feed_tags = ft
		end

		def item_tags
			@@item_tags
		end
		def item_tags=(it)
			@@item_tags = it
		end

		# The strict attribute is for compatibility with Ruby's standard RSS parser
		def parse(source, do_validate=true, ignore_unknown_element=true, parser_class=false)
			new source
		end
	end

	private

	def parse
	  raise SimpleRSSError, "Poorly formatted feed" unless @source =~ %r{<(channel|feed).*?>.*?</(channel|feed)>}mi
	  
		# Feed's title and link
		feed_content = $1 if @source =~ %r{(.*?)<(rss:|atom:)?(item|entry).*?>.*?</(rss:|atom:)?(item|entry)>}mi
		
		@@feed_tags.each do |tag|
			if feed_content && feed_content =~ %r{<(rss:|atom:)?#{tag}(.*?)>(.*?)</(rss:|atom:)?#{tag}>}mi
				nil
			elsif feed_content && feed_content =~ %r{<(rss:|atom:)?#{tag}(.*?)\/\s*>}mi
				nil
			elsif @source =~ %r{<(rss:|atom:)?#{tag}(.*?)>(.*?)</(rss:|atom:)?#{tag}>}mi
				nil
			elsif @source =~ %r{<(rss:|atom:)?#{tag}(.*?)\/\s*>}mi
				nil
			end
			
			if $2 || $3
        tag_cleaned = clean_tag(tag)
        eval %{ @#{ tag_cleaned } = clean_content(tag, $2, $3) }
        self.class.class_eval %{ attr_reader :#{ tag_cleaned } }
			end
		end

		# RSS items' title, link, and description
		@source.scan( %r{<(rss:|atom:)?(item|entry)([\s][^>]*)?>(.*?)</(rss:|atom:)?(item|entry)>}mi ) do |match|
			item = Hash.new
			@@item_tags.each do |tag|
			  if tag.to_s.include?("+")
			    tag_data = tag.to_s.split("+")
			    tag = tag_data[0]
			    rel = tag_data[1]
			    
  				if match[3] =~ %r{<(rss:|atom:)?#{tag}(.*?)rel=['"]#{rel}['"](.*?)>(.*?)</(rss:|atom:)?#{tag}>}mi
            nil
  				elsif match[3] =~ %r{<(rss:|atom:)?#{tag}(.*?)rel=['"]#{rel}['"](.*?)/\s*>}mi
  				  nil
  				end
  				item[clean_tag("#{tag}+#{rel}")] = clean_content(tag, $3, $4) if $3 || $4
		    else
  				if match[3] =~ %r{<(rss:|atom:)?#{tag}(.*?)>(.*?)</(rss:|atom:)?#{tag}>}mi
  					nil
  				elsif match[3] =~ %r{<(rss:|atom:)?#{tag}(.*?)/\s*>}mi
  					nil
  				end
  				item[clean_tag(tag)] = clean_content(tag, $2, $3) if $2 || $3
				end
			end
			def item.method_missing(name, *args) self[name] end
			@items << item
		end

	end

	def clean_content(tag, attrs, content)
		content = content.to_s
		case tag
			when :pubDate, :lastBuildDate, :published, :updated, :expirationDate, :modified, :'dc:date'
				Time.parse(content) rescue unescape(content)
			when :author, :contributor, :skipHours, :skipDays
				unescape(content.gsub(/<.*?>/,''))
			else
				content.empty? && "#{attrs} " =~ /href=['"]?([^'"]*)['" ]/mi ? $1.strip : unescape(content)
		end
	end

	def clean_tag(tag)
		tag.to_s.gsub(':','_').intern
	end
	
  def unescape(content)
  	if content =~ /([^-_.!~*'()a-zA-Z\d;\/?:@&=+$,\[\]]%)/n then
  		CGI.unescape(content).gsub(/(<!\[CDATA\[|\]\]>)/,'').strip
  	else
  		content.gsub(/(<!\[CDATA\[|\]\]>)/,'').strip
  	end
  end
end

class SimpleRSSError < StandardError
end

templates.rb

#
# RubyRSS
# Copyright (c) 2006 Sergey Tikhonov <st@dairon.net>
# Distributed under MIT License
#

$html_templates = { "default" => '
<h3><a href="#link">#title</a></h3>
<ul>

#items-start:5
<li><a href="#item-link">#item-title</a> (#item-date)<br/>
    #item-desc:100</li>
#items-end

</ul>
'
}

$rss_templates = { "rss2.0" => '
<?xml version="1.0" encoding="iso-8859-1"?>
<rss version="2.0">
<channel>
<title>#title</title>
<link>#link</link>
<description>#desc</description>
<pubDate>#date</pubDate>
<language>en-us</language>
<ttl>60</ttl>

#items-start
<item>
<title>#item-title</title>
<link>#item-link</link>
<description>#item-desc</description>
<pubDate>#item-date</pubDate>
<guid isPermaLink="true">#item-link</guid>
</item>
#items-end

</channel>
</rss>
'
}