Abusing HTTParty for a Tender client

We all know how great Tender is and had a chance to play with their great API while writing a tool to send out an email every morning with any pending issues.

They’ve done some really great stuff with it, especially with their use of URI Templates.

If you haven’t played with URI Templates before, an example of their JSON with a template in it looks like:

{"site_href": "http://api.tenderapp.com/{site_permalink}"}

which, with the Addressable gem would allow us to say:

>> require 'addressable/template'
>> tmpl = Addressable::Template.new('http://api.tenderapp.com/{site_permalink}')
>> tmpl.expand('site_permalink' => 'help').to_s
=> http://api.tenderapp.com/help

To make things nice and strait forward, Tender follows the convention of using _href as the suffix for any key that contains a template. I was able to use this along with a little magic I snuck into Hash to make my code that much prettier.

All that was required to expand the templates was a little module:

module JsonHelpers
  def href(key, opts = {})

which I was able to mix in to any Hash that was returned:

# Make the JSON a litte bit more fun to work with
def self.add_json_helpers(data)
  case data
  when Hash
    data.send(:extend, TenderSummary::JsonHelpers)
    data.each { |_, value| add_json_helpers(value) }
  when Array
    data.each { |elem| add_json_helpers(elem) }

and then tell HTTParty to use it by specifying a custom parser:

module TenderSummary
  class TenderApi
    include HTTParty
    headers  'Accept' => 'application/vnd.tender-v1+json'
    format   :json
    parser   Proc.new { |b| add_json_helpers(Crack::JSON.parse(b)) }

    # ...

With all this done, it made it very simple to generate the URLs to the resources I wanted access to.

# assuming `site` holds the JSON returned from
# 'http://api.tenderapp.com/{site_permalink}'
discussion_url = site.href(:discussions, :state => :pending)

You can see the entire class of TenderApi on GitHub.

Posted Wednesday, January 6 2010 (∞).

written by Eric Lindvall

I also appear on the internet on GitHub and Twitter as @lindvall and work hard to make Papertrail awesome.

themed by Adam Lloyd.