Recently I’ve been building, where you can convert your instagram page into a blog.

An interesting challenge was receiving a raw text from Instagram Basic Display API, and scanning it for mentions and hashtags, and converting hashtags into URLs:


Highlight mentions

The below regex searches for words starting with @ and replaces these words with themselves wrapped into some html:

# app/helpers/application_helper.rb
def with_mentions(text)
  return nil if text.blank?

  text.gsub!(/\S*@(\[[^\]]+\]|\S+)/, '<span style="color: blue;">\1</span>')

text = '@yaro is the coolest #ruby programmer in #europe'
# => "<span style=\"color: blue;\">yaro</span> is the coolest #ruby programmer in #europe"

You could try doing it in a simple way as above, but the below approach will give you much more control over the result.

So I will pass the Post record, scan the the Post.body for #, replace each hashtagged word with a link.

If you use the below method in a Rails helper, you won’t need ActionController::Base.helpers, Rails.application.routes.url_helpers, onlypath: true. I’ve added them so that you can use it in the console.

# app/helpers/application_helper.rb

# delegate :link_to, to: 'ActionController::Base.helpers'
# delegate :posts_path, to: 'Rails.application.routes.url_helpers'

include Rails.application.routes.url_helpers
def with_hashtags(text)
  return nil if text.blank?

  hashtags = text.scan(/#\w+/)
  hashtags.flatten.each do |hashtag|
    hashtag_link =
      ActionController::Base.helpers.link_to hashtag, posts_path(caption: hashtag, onlypath: true), class: 'hashtag'
    text.gsub!(hashtag, hashtag_link)

text = "Втікаю в вихідні 💙 #cannes #cotedazur #frenchriviera #france #friday"
# => "Втікаю в вихідні 💙 <a class=\"hashtag\" href=\"/?caption=%23cannes&amp;onlypath=true\">#cannes</a> <a class=\"hashtag\" href=\"/?caption=%23cotedazur&amp;onlypath=true\">#cotedazur</a> <a class=\"hashtag\" href=\"/?caption=%23frenchriviera&amp;onlypath=true\">#frenchriviera</a> <a class=\"hashtag\" href=\"/?caption=%23france&amp;onlypath=true\">#france</a> <a class=\"hashtag\" href=\"/?caption=%23friday&amp;onlypath=true\">#friday</a>"

Here’s the final result in my case: click hashtag -> refresh page with this hashtag in the search bar (search by hashtag):


P.S. here is the pull request where I added this functionality to the app.