Class: EmailReplyTrimmer

Inherits:
Object
  • Object
show all
Defined in:
lib/email_reply_trimmer.rb

Constant Summary collapse

VERSION = 
"0.2.0"
DELIMITER = 
"d"
EMBEDDED = 
"b"
EMPTY = 
"e"
EMAIL_HEADER = 
"h"
QUOTE = 
"q"
SIGNATURE = 
"s"
TEXT = 
"t"

Class Method Summary collapse

Class Method Details

.extract_embedded_email(text) ⇒ Object 



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# File 'lib/email_reply_trimmer.rb', line 141

def self.extract_embedded_email(text)
  return if text.nil? || text =~ /\A[[:space:]]*\z/m

  # do some cleanup
  preprocess!(text)

  # from now on, we'll work on a line-by-line basis
  lines = text.split("\n")

  # identify content of each lines
  pattern = lines.map { |l| identify_line_content(l) }.join

  if index = pattern =~ /(?:h[eqd]*?){3,}[tq]/
    embedded = lines[index..-1].join("\n").strip
  elsif index = pattern =~ /b(?:[eqd]*){3,}[tq]/
    # Exception for email clients (macOS / iOS) which embed fwd emails in quotes.
    embedded = lines[index + 1..-1].map { |l| l.gsub(/^>\s*/, '') }.join("\n").strip
  end

  if index
    before = lines[0...(pattern[0...index] =~ /e*(b[eqd]*|b*[ed]*)$/)].join("\n").strip
    [embedded, before]
  end
end

.identify_line_content(line) ⇒ Object 



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# File 'lib/email_reply_trimmer.rb', line 21

def self.identify_line_content(line)
  return EMPTY        if EmptyLineMatcher.match? line
  return DELIMITER    if DelimiterMatcher.match? line
  return SIGNATURE    if SignatureMatcher.match? line
  return EMBEDDED     if EmbeddedEmailMatcher.match? line
  return EMAIL_HEADER if EmailHeaderMatcher.match? line
  return QUOTE        if QuoteMatcher.match? line
  TEXT
end

.trim(text, split = false) ⇒ Object 



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# File 'lib/email_reply_trimmer.rb', line 31

def self.trim(text, split = false)
  return if text.nil? || text =~ /\A[[:space:]]*\z/m

  # do some cleanup
  preprocess!(text)

  # stash the code blocks - replace them with hashes
  text, blocks = hoist_code_blocks(text)

  # from now on, we'll work on a line-by-line basis
  lines = text.split("\n")
  lines_dup = lines.dup

  # create a string of characters, one per line, according to the line content
  pattern = lines.map { |l| identify_line_content(l) }.join

  # remove everything after the first delimiter
  if pattern =~ /d/
    index = pattern =~ /d/
    pattern = pattern[0...index]
    lines = lines[0...index]
  end

  # remove all mobile signatures
  while pattern =~ /s/
    index = pattern =~ /s/
    pattern.slice!(index)
    lines.slice!(index)
  end

  # when the reply is at the end of the email
  if is_reply_at_end?(pattern)
    index = pattern =~ /t[et]*$/
    pattern = ""
    lines = lines[index..-1]
  end

  # if there is an embedded email marker, not followed by a quote
  # then take everything up to that marker
  if pattern =~ /te*b[^q]*$/
    index = pattern =~ /te*b[^q]*$/
    pattern = pattern[0..index]
    lines = lines[0..index]
  end

  # if there is an embedded email marker, followed by a huge quote
  # then take everything up to that marker
  if pattern =~ /te*b[eqbh]*([te]*)$/ && $1.count("t") < 7
    index = pattern =~ /te*b[eqbh]*[te]*$/
    pattern = pattern[0..index]
    lines = lines[0..index]
  end

  # if there is some text before a huge quote ending the email,
  # then remove the quote
  if pattern =~ /t?e*[qbe]+$/
    index = pattern =~ /t?e*[qbe]+$/
    pattern = pattern[0..index]
    lines = lines[0..index]
  end

  # if there still are some embedded email markers, just remove them
  while pattern =~ /b/
    index = pattern =~ /b/
    pattern.slice!(index)
    lines.slice!(index)
  end

  # fix email headers when they span over multiple lines
  if pattern =~ /h+[hte]+h+e/
    index = pattern =~ /h+[hte]+h+e/
    size = pattern[/h+[hte]+h+e/].size
    size.times.each { |s| pattern[index + s] = EMAIL_HEADER }
  end

  # if there are at least 3 consecutive email headers,
  # take everything up to these headers
  if pattern =~ /t[eq]*h{3,}/
    index = pattern =~ /t[eq]*h{3,}/
    pattern = pattern[0..index]
    lines = lines[0..index]
  end

  # if there still are some email headers, just remove them
  while pattern =~ /h/
    index = pattern =~ /h/
    pattern.slice!(index)
    lines.slice!(index)
  end

  # remove trailing quotes when there's at least one line of text
  if pattern =~ /t/ && pattern =~ /[eq]+$/
    index = pattern =~ /[eq]+$/
    pattern = pattern[0...index]
    lines = lines[0...index]
  end

  # results
  trimmed = lines.join("\n").strip

  # re-inject code blocks
  blocks.each { |token, block| trimmed.gsub!(token, block) }

  if split
    [trimmed, compute_elided(lines_dup, lines)]
  else
    trimmed
  end
end