rails: get a teaser/excerpt for an article
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22-08-2019 - |
Question
I have a page that will list news articles. To cut down on the page's length, I only want to display a teaser (the first 200 words / 600 letters of the article) and then display a "more..." link, that, when clicked, will expand the rest of the article in a jQuery/Javascript way. Now, I've all that figured out and even found the following helper method on some paste page, which will make sure, that the news article (string) is not chopped up right in the middle of a word:
def shorten (string, count = 30)
if string.length >= count
shortened = string[0, count]
splitted = shortened.split(/\s/)
words = splitted.length
splitted[0, words-1].join(" ") + ' ...'
else
string
end
end
The problem that I have is that the news article bodies that I get from the DB are formatted HTML. So if I'm unlucky, the above helper will chop up my article string right in the middle of an html tag and insert the "more..." string there (e.g. between ""), which will corrupt my html on the page.
Is there any way around this or is there a plugin out there that I can use to generate excerpts/teasers from an HTML string?
Solution 3
Thanks a lot for your answers! However, in the meantime I stumbled upon the jQuery HTML Truncator plugin, which perfectly fits my purposes and shifts the truncation to the client-side. It doesn't get any easier :-)
OTHER TIPS
You can use a combination of Sanitize and Truncate.
truncate("And they found that many people were sleeping better.",
:omission => "... (continued)", :length => 15)
# => And they found... (continued)
I'm doing a similar task where I have blog posts and I just want to show a quick excerpt. So in my view I simply do:
sanitize(truncate(blog_post.body, length: 150))
That strips out the HTML tags, gives me the first 150 characters and is handled in the view so it's MVC friendly.
Good luck!
My answer here should do work. The original question (err, asked by me) was about truncating markdown, but I ended up converting the markdown to HTML then truncating that, so it should work.
Of course if your site gets much traffic, you should cache the excerpt (perhaps when the post is created/updated, you could store the excerpt in the database?), this would also mean you could allow the user to modify or enter their own excerpt
Usage:
>> puts "<p><b><a href=\"hi\">Something</a></p>".truncate_html(5, at_end = "...")
=> <p><b><a href="hi">Someth...</a></b></p>
..and the code (copied from the other answer):
require 'rexml/parsers/pullparser'
class String
def truncate_html(len = 30, at_end = nil)
p = REXML::Parsers::PullParser.new(self)
tags = []
new_len = len
results = ''
while p.has_next? && new_len > 0
p_e = p.pull
case p_e.event_type
when :start_element
tags.push p_e[0]
results << "<#{tags.last}#{attrs_to_s(p_e[1])}>"
when :end_element
results << "</#{tags.pop}>"
when :text
results << p_e[0][0..new_len]
new_len -= p_e[0].length
else
results << "<!-- #{p_e.inspect} -->"
end
end
if at_end
results << "..."
end
tags.reverse.each do |tag|
results << "</#{tag}>"
end
results
end
private
def attrs_to_s(attrs)
if attrs.empty?
''
else
' ' + attrs.to_a.map { |attr| %{#{attr[0]}="#{attr[1]}"} }.join(' ')
end
end
end
you would have to write a more complex parsers if you dont want to split in the middle of html elements. it would have to remember if it is in the middle of a <> block and if its between two tags.
even if you did that, you would still have problems. if some put the whole article into an html element, since the parser couldnt split it anywhere, because of the missing closing tag.
if it is possible at all i would try not to put any tags into the articles or keep it to tags that dont contain anything (no <div>
and so on). that way you would only have to check if you are in the middle of a tag which is pretty simple:
def shorten (string, count = 30)
if string.length >= count
shortened = string[0, count]
splitted = shortened.split(/\s/)
words = splitted.length
if(splitted[words-1].include? "<")
splitted[0,words-2].join(" ") + ' ...'
else
splitted[0, words-1].join(" ") + ' ...'
else
string
end
end
I would have sanitized the HTML and extracted the first sentence. Assuming you have an article model, with a 'body' attribute that contains the HTML:
# lib/core_ext/string.rb
class String
def first_sentence
self[/(\A[^.|!|?]+)/, 1]
end
end
# app/models/article.rb
def teaser
HTML::FullSanitizer.new.sanitize(body).first_sentence
end
This would convert "<b>This</b> is an <em>important</em> article! And here is the rest of the article." into "This is an important article".
I solved this using following solution
Install gem 'sanitize'
gem install sanitize
and used following code, here body is text containing html tags.
<%= content_tag :div, Sanitize.clean(truncate(body, length: 200, separator: ' ', omission: "... #{ link_to '(continue)', '#' }"), Sanitize::Config::BASIC).html_safe %>
Gives excerpt with valid html. I hope it helps somebody.
There is now a gem named HTMLTruncator that takes care of this for you. I've used it to display post excerpts and the like, and it's very robust.