onebox
======
[](https://rubygems.org/gems/onebox)
[](https://codeclimate.com/github/dysania/onebox)
[](https://travis-ci.org/discourse/onebox)
Onebox is a library for turning media URLs into simple HTML previews of the resource.
Onebox currently has support for page, image, and video URLs for many popular sites.
It's great if you want users to input URLs and have your application convert them into
rich previews for display. For example, a link to a YouTube video would be automatically
converted into a video player.
It was originally created for [Discourse](http://discourse.org) but has since been
extracted into this convenient gem for all to use!
Usage
-----
Using onebox is fairly simple!
First, make sure the library is required:
``` ruby
require "onebox"
```
Then pass a link to the library's interface:
``` ruby
require "onebox"
url = "http://www.amazon.com/gp/product/B005T3GRNW/ref=s9_simh_gw_p147_d0_i2"
preview = Onebox.preview(url)
```
This will contain a simple Onebox::Preview object that handles all the transformation.
From here you either call `Onebox::Preview#to_s` or just pass the object to a string:
``` ruby
require "onebox"
url = "http://www.amazon.com/gp/product/B005T3GRNW/ref=s9_simh_gw_p147_d0_i2"
preview = Onebox.preview(url)
"#{preview}" == preview.to_s #=> true
```
Onebox has its own caching system but you can also provide (or turn off) your own system:
``` ruby
require "onebox"
url = "http://www.amazon.com/gp/product/B005T3GRNW/ref=s9_simh_gw_p147_d0_i2"
preview = Onebox.preview(url, cache: Rails.cache)
"#{preview}" == preview.to_s #=> true
```
In addition you can set your own options with this handy interface:
``` ruby
require "onebox"
Onebox.options = {
cache: Rails.cache
}
url = "http://www.amazon.com/gp/product/B005T3GRNW/ref=s9_simh_gw_p147_d0_i2"
preview = Onebox.preview(url)
"#{preview}" == preview.to_s #=> true
```
Ruby Support
------------
The onebox library is supported on all "officially" supported versions of Ruby.
This means you must be on Ruby 2.3 or above for it to work.
Development Preview Interface
-----------------------------
The onebox gem comes with a development server for previewing the results
of your changes. You can run it by running `bundle exec rake server` after checking
out the project. You can then try out URLs.
The server doesn't reload code changes automatically (PRs accepted!) so
make sure to hit CTRL-C and restart the server to try a code change out.
Adding Support for a new URL
----------------------------
1. Check if the site supports [oEmbed](http://oembed.com/) or [Open Graph](https://developers.facebook.com/docs/opengraph/).
If it does, you can probably get away with just whitelisting the URL in `Onebox::Engine::WhitelistedGenericOnebox` (see: [Whitelisted Generic Onebox caveats](#user-content-whitelisted-generic-onebox-caveats)).
If the site does not support open standards, you can create a new engine.
2. Create new onebox engine
``` ruby
# in lib/onebox/engine/name_onebox.rb
module Onebox
module Engine
class NameOnebox
include LayoutSupport
include HTML
private
def data
{
url: @url,
name: raw.css("h1").inner_text,
image: raw.css("#main-image").first["src"],
description: raw.css("#postBodyPS").inner_text
}
end
end
end
end
```
3. Create new onebox spec using [FakeWeb](https://github.com/chrisk/fakeweb)
``` ruby
# in spec/lib/onebox/engine/name_spec.rb
require "spec_helper"
describe Onebox::Engine::NameOnebox do
let(:link) { "http://example.com" }
let(:html) { described_class.new(link).to_html }
before do
fake(link, response("name.response"))
end
it "has the video's title" do
expect(html).to include("title")
end
it "has the video's still shot" do
expect(html).to include("photo.jpg")
end
it "has the video's description" do
expect(html).to include("description")
end
it "has the URL to the resource" do
expect(html).to include(link)
end
end
```
4. Create new mustache template
``` html
# in templates/name.mustache
```
5. Create new fixture from HTML response for your FakeWeb request(s)
``` bash
curl --output spec/fixtures/oneboxname.response -L -X -GET http://example.com
```
6. Require in Engine module
``` ruby
# in lib/onebox/engine.rb
require_relative "engine/name_onebox"
```
Whitelisted Generic Onebox caveats
----------------------------------
The Whitedlisted Generic Onebox has some caveats for it's use, beyond simply whitelisting the domain.
1. The domain must be whitelisted
2. The URL you're oneboxing cannot be a root url (e.g. `http://example.com` won't work, but `http://example.com/page` will)
3. If the oneboxed URL responds with oEmbed and has a `rich` type: the `html` content must contain an `