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# coding: utf-8
require 'htmlentities'
# Support functions for Premailer
module HtmlToPlainText
# Returns the text in UTF-8 format with all HTML tags removed
#
# HTML content can be omitted from the output by surrounding it in the following comments:
#
# <!-- start text/html -->
# <!-- end text/html -->
#
# TODO: add support for DL, OL
# TODO: this is not safe and needs a real html parser to work
def convert_to_text(html, line_length = 65, from_charset = 'UTF-8')
txt = html
# strip text ignored html. Useful for removing
# headers and footers that aren't needed in the
# text version
txt.gsub!(/<!-- start text\/html -->.*?<!-- end text\/html -->/m, '')
# replace images with their alt attributes
# for img tags with "" for attribute quotes
# with or without closing tag
# eg. the following formats:
# <img alt="" />
# <img alt="">
txt.gsub!(/<img[^>]+?alt="([^"]*)"[^>]*>/i, '\1')
# for img tags with '' for attribute quotes
# with or without closing tag
# eg. the following formats:
# <img alt='' />
# <img alt=''>
txt.gsub!(/<img[^>]+?alt='([^']*)'[^>]*>/i, '\1')
# remove script tags and content
txt.gsub!(/<script.*?\/script>/m, '')
# links with double quotes
txt.gsub!(/<a\s[^\n]*?href=["'](mailto:)?([^"]*)["][^>]*>(.*?)<\/a>/im) do |s|
if $3.empty?
''
elsif $3.strip.downcase == $2.strip.downcase
$3.strip
else
$3.strip + ' ( ' + $2.strip + ' )'
end
end
# links with single quotes
txt.gsub!(/<a\s[^\n]*?href=["'](mailto:)?([^']*)['][^>]*>(.*?)<\/a>/im) do |s|
if $3.empty?
''
elsif $3.strip.downcase == $2.strip.downcase
$3.strip
else
$3.strip + ' ( ' + $2.strip + ' )'
end
end
# handle headings (H1-H6)
txt.gsub!(/(<\/h[1-6]>)/i, "\n\\1") # move closing tags to new lines
txt.gsub!(/[\s]*<h([1-6]+)[^>]*>[\s]*(.*)[\s]*<\/h[1-6]+>/i) do |s|
hlevel = $1.to_i
htext = $2
htext.gsub!(/<br[\s]*\/?>/i, "\n") # handle <br>s
htext.gsub!(/<\/?[^>]*>/i, '') # strip tags
# determine maximum line length
hlength = 0
htext.each_line { |l| llength = l.strip.length; hlength = llength if llength > hlength }
hlength = line_length if hlength > line_length
case hlevel
when 1 # H1, asterisks above and below
htext = ('*' * hlength) + "\n" + htext + "\n" + ('*' * hlength)
when 2 # H1, dashes above and below
htext = ('-' * hlength) + "\n" + htext + "\n" + ('-' * hlength)
else # H3-H6, dashes below
htext = htext + "\n" + ('-' * hlength)
end
"\n\n" + htext + "\n\n"
end
# wrap spans
txt.gsub!(/(<\/span>)[\s]+(<span)/mi, '\1 \2')
# lists -- TODO: should handle ordered lists
txt.gsub!(/[\s]*(<li[^>]*>)[\s]*/i, '* ')
# list not followed by a newline
txt.gsub!(/<\/li>[\s]*(?![\n])/i, "\n")
# paragraphs and line breaks
txt.gsub!(/<\/p>/i, "\n\n")
txt.gsub!(/<br[\/ ]*>/i, "\n")
# strip remaining tags
txt.gsub!(/<\/?[^>]*>/, '')
# decode HTML entities
he = HTMLEntities.new
txt = he.decode(txt)
# word wrap
txt = word_wrap(txt, line_length)
# remove linefeeds (\r\n and \r -> \n)
txt.gsub!(/\r\n?/, "\n")
# strip extra spaces
txt.gsub!(/[ \t]*\302\240+[ \t]*/, " ") # non-breaking spaces -> spaces
txt.gsub!(/\n[ \t]+/, "\n") # space at start of lines
txt.gsub!(/[ \t]+\n/, "\n") # space at end of lines
# no more than two consecutive newlines
txt.gsub!(/[\n]{3,}/, "\n\n")
# the word messes up the parens
txt.gsub!(/\(([ \n])(http[^)]+)([\n ])\)/) do |s|
($1 == "\n" ? $1 : '' ) + '( ' + $2 + ' )' + ($3 == "\n" ? $1 : '' )
end
txt.strip
end
# Taken from Rails' word_wrap helper (http://api.rubyonrails.org/classes/ActionView/Helpers/TextHelper.html#method-i-word_wrap)
def word_wrap(txt, line_length)
txt.split("\n").collect do |line|
line.length > line_length ? line.gsub(/(.{1,#{line_length}})(\s+|$)/, "\\1\n").strip : line
end * "\n"
end
end
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