CODEWITHSUNDEEP
ruby-on-railsrubytexttruncate
oldhomemovie
oldhomemovie

Reputation: 15129

Rails: Smart text truncation

I wonder if there's a plugin to enable a sort of smart truncation. I need to truncate my text with a precision of a word or of a sentence.

For example:

Post.my_message.smart_truncate(
    "Once upon a time in a world far far away. And they found that many people
     were sleeping better.", :sentences => 1)
# => Once upon a time in a world far far away.

or

Post.my_message.smart_truncate(
    "Once upon a time in a world far far away. And they found that many people
     were sleeping better.", :words => 12)
# => Once upon a time in a world far far away. And they ...

Upvotes: 10

Views: 4749

Answers (5)

soulofpeace
soulofpeace

Reputation: 81

This will truncate at the word boundary based on the char_limit length specified. So it will not truncate the sentence at weird places 

def smart_truncate(text, char_limit)
    size = 0
    text.split().reject do |token|
      size += token.size() + 1
      size > char_limit
    end.join(' ') + ( text.size() > char_limit ? ' ' + '...' : '' )
end

Upvotes: 8

Arne L.
Arne L.

Reputation: 2320

The gem truncate_html does this job. It also can skip over pieces of HTML – which can be quiet useful – and offers the possibility to customize the word boundary regex. Furthermore the defaults for all parameters can be configured eg in your config/environment.rb.

Example:

some_html = '<ul><li><a href="http://whatever">This is a link</a></li></ul>'

truncate_html(some_html, :length => 15, :omission => '...(continued)')
=> <ul><li><a href="http://whatever">This...(continued)</a></li></ul>

Upvotes: 1

Yavor Ivanov
Yavor Ivanov

Reputation: 449

Working for quite a while now on some updates with different projects and I came up with these refinements of the code that seem much more usable in real life scenarios.

def smart_truncate_characters(text, char_limit)
  text = text.to_s
  text = text.squish
  size = 0
  new_text = text.mb_chars.split().reject do |token|
    size+=token.size()
    size>char_limit
  end.join(" ")
  if size > char_limit
    return new_text += '…'
  else
    return new_text
  end
end

def smart_truncate_sentences(text, sentence_limit)
  text = text.to_s
  text = text.squish
  size = 0
  arr = text.mb_chars.split(/(?:\.|\?|\!)(?= [^a-z]|$)/)
  arr = arr[0...sentence_limit]
  new_text = arr.join(".")
  new_text += '.'
end

def smart_truncate(text, sentence_limit, char_limit)
  text =  smart_truncate_sentences(text, sentence_limit)
  text =  smart_truncate_characters(text, char_limit)
end

Upvotes: 0

Yavor Ivanov
Yavor Ivanov

Reputation: 449

Nice helper. Since I had a different experience I did change it so that it stops on the last word and work with character limit. I think this is much more real world scenario in most apps.

Update: Took the code above and updated it a bit. Seemed much nicer approach for old ruby and works with utf8.

def smart_truncate(text, char_limit)
  text = text.squish
  size = 0
  text.mb_chars.split().reject do |token|
    size+=token.size()
    size>char_limit
  end.join(" ")
end

Upvotes: 0

Mike Woodhouse
Mike Woodhouse

Reputation: 52316

I haven't seen such a plugin, but there was a similar question that could serve as the basis for a lib or helper function.

The way you show the function seems to put it as an extension to String: unless you really want to be able to do this outside of a view, I'd be inclined to go for a function in application_helper.rb. Something like this, perhaps?

module ApplicationHelper

  def smart_truncate(s, opts = {})
    opts = {:words => 12}.merge(opts)
    if opts[:sentences]
      return s.split(/\.(\s|$)+/)[0, opts[:sentences]].map{|s| s.strip}.join('. ') + '.'
    end
    a = s.split(/\s/) # or /[ ]+/ to only split on spaces
    n = opts[:words]
    a[0...n].join(' ') + (a.size > n ? '...' : '')
  end
end

smart_truncate("a b c. d e f. g h i.", :sentences => 2) #=> "a b c. d e f."
smart_truncate("apple blueberry cherry plum", :words => 3) #=> "apple blueberry cherry..."

Upvotes: 20

Related Questions