Ohanakapa

A ruby wrapper for the Ohana API

Quick start

Install via Rubygems

gem install ohanakapa

... or add to your Gemfile

gem "ohanakapa", "~> 1.0"

Example app

Prefer to learn from live implementations? We built a website that consumes the Ohana API via this wrapper. The code is open source in this repo.

Making requests

API methods are available as module methods (consuming module-level configuration) or as client instance methods.

# Provide an API Token
Ohanakapa.configure do |c|
  c.api_token = 'your_token'
end

# Fetch all locations
Ohanakapa.locations

or

# Provide an API Token
client = Ohanakapa::Client.new :api_token => 'your_token'
# Fetch all locations
client.locations

A token will automatically be generated for you when you register an Ohana API app.

Consuming resources

Most methods return a Resource object which provides dot notation and [] access for fields returned in the API response.

# Fetch a location
location = Ohanakapa.location '1'
puts location.name
# => "Center on Homelessness"
puts location.fields
# => <Set: {:id, :accessibility, :address, :ask_for, :contacts, :coordinates, :description, :emails, :faxes, :languages, :mail_address, :name, :phones, :short_desc, :transportation, :updated_at, :urls, :url, :services, :organization, :other_locations}>
puts location[:address]
# => {
street: "472 Harbor Blvd.",
city: "Belmont",
state: "CA",
zip: "94002"
}

Searching

# Search for food in ZIP code 94403
Ohanakapa.search("search", :keyword => "food", :location => "94403")

# Find all parks in the database
Ohanakapa.search("search", :kind => "Parks")

# Find all farmers' markets that participate in Market Match
Ohanakapa.search("search", :kind => "Farmers' Markets", :market_match => "1")

See the API search docs for all the possible parameters.

Note: URL fields are culled into a separate .rels collection for easier Hypermedia support.

# Fetch an organization
org = Ohanakapa.organization '2'
org.rels[:locations].href
# => "http://ohana-api-demo.herokuapp.com/api/organizations/2/locations"

Accessing HTTP responses

While most methods return a Resource object or a Boolean, sometimes you may need access to the raw HTTP response headers. You can access the last HTTP response with Client#last_response:

location    = Ohanakapa.location '2'
response    = Ohanakapa.last_response
etag        = response.headers[:etag]
total_count = response.headers["X-Total-Count"]

See the API docs for a full list of custom response headers.

Authentication

Ohanakapa supports the API Token method supported by the Ohana API:

Application authentication

Ohanakapa supports application-only authentication using API Token application client credentials. Using application credentials will result in making API calls on behalf of an application in order to take advantage of the higher rate limit.

client = Ohanakapa::Client.new(:api_token => "<your 32 char token>")

location = client.locations '2'

Configuration and defaults

While Ohanakapa::Client accepts a range of options when creating a new client instance, Ohanakapa's configuration API allows you to set your configuration options at the module level. This is particularly handy if you're creating a number of client instances based on some shared defaults.

Hypermedia agent

Ohanakapa is hypermedia-enabled. Under the hood, {Ohanakapa::Client} uses Sawyer, a hypermedia client built on Faraday.

Hypermedia in Ohanakapa

Resources returned by Ohanakapa methods contain not only data but hypermedia link relations:

org = Ohanakapa.organization '2'

# Get the locations rel, returned from the API
# as locations_url in the resource
org.rels[:locations].href
# => "http://ohana-api-demo.herokuapp.com/api/organizations/2/locations"

locations = org.rels[:locations].get.data
locations.last.name
# => "Vocational Rehabilitation Services (VRS) Workcenter"

When processing API responses, all *_url attributes are culled in to the link relations collection. Any url attribute becomes .rels[:self].

Advanced usage

Since Ohanakapa employs Faraday under the hood, some behavior can be extended via middleware.

Debugging

Often, it helps to know what Ohanakapa is doing under the hood. Faraday makes it easy to peek into the underlying HTTP traffic:

stack = Faraday::RackBuilder.new do |builder|
  builder.response :logger
  builder.use Ohanakapa::Response::RaiseError
  builder.adapter Faraday.default_adapter
end
Ohanakapa.middleware = stack
Ohanakapa.location '2'

I, [2013-08-29T23:37:58.314434 #26983]  INFO -- : get http://ohana-api-demo.herokuapp.com/api/locations/2
D, [2013-08-29T23:37:58.314535 #26983] DEBUG -- request: Accept: "application/vnd.ohanapi-v1+json"
User-Agent: "Ohanakapa Ruby Gem 1.0.0"
I, [2013-08-29T23:37:58.706479 #26983]  INFO -- Status: 200
D, [2013-08-29T23:37:58.706565 #26983] DEBUG -- response: cache-control: "max-age=0, private, must-revalidate"
content-type: "application/json"
date: "Fri, 30 Aug 2013 06:37:58 GMT"
etag: "\"bce45b81bf5b2e01cabf2c24308ac140\""
status: "200 OK"
x-rack-cache: "miss"
x-ratelimit-limit: "60"
x-ratelimit-remaining: "59"
x-request-id: "2ad07e30d8e53c25e9e364254d69b34b"
x-runtime: "0.037184"
x-ua-compatible: "IE=Edge,chrome=1"
content-length: "3961"
connection: "Close"
...

See the Faraday README for more middleware magic.

Caching

If you want to boost performance, stretch your API rate limit, or avoid paying the hypermedia tax, you can use Faraday Http Cache.

Add the gem to your Gemfile

gem 'faraday-http-cache'

Next, construct your own Faraday middleware. The example below assumes you are using Memcache via :dalli_store:

# config/initializers/ohanakapa.rb
cache_store = ActiveSupport::Cache.lookup_store(:dalli_store)

stack = Faraday::RackBuilder.new do |builder|
  builder.use Faraday::HttpCache, store: cache_store
  builder.use Ohanakapa::Response::RaiseError
  builder.adapter Faraday.default_adapter
end
Ohanakapa.middleware = stack

Once configured, the middleware will store responses in cache based on ETag fingerprint and serve those back up for future 304 responses for the same resource. See the project README for advanced usage.

Hacking on Ohanakapa

If you want to hack on Ohanakapa locally, we try to make bootstrapping the project as painless as possible. Just clone and run:

script/bootstrap

This will install project dependencies and get you up and running. If you want to run a Ruby console to poke on Ohanakapa, you can crank one up with:

script/console

Using the scripts in ./scripts instead of bundle exec rspec, bundle console, etc. ensures your dependencies are up-to-date.

Running and writing new tests

Ohanakapa uses VCR for recording and playing back API fixtures during test runs. These fixtures are part of the Git project in the spec/cassettes folder. For the most part, tests use an authenticated client, using a token stored in ENV['OHANAKAPA_TEST_API_TOKEN'] (use the token from your registered app, or create a new app.) If you're not recording new cassettes, you don't need to have this set. If you do need to record new cassettes, this token can be any Ohana API token because the test suite strips the actual token from the cassette output before storing to disk.

Since we periodically refresh our cassettes, please keep some points in mind when writing new specs.

• Specs should be idempotent. The HTTP calls made during a spec should be able to be run over and over. This means deleting a known resource prior to creating it if the name has to be unique.
• Specs should be able to be run in random order. If a spec depends on another resource as a fixture, make sure that's created in the scope of the spec and not depend on a previous spec to create the data needed.
• Do not depend on authenticated user info. Instead of asserting actual values in resources, try to assert the existence of a key or that a response is an Array. We're testing the client, not the API.

Submitting a Pull Request

0. Check out Hacking on Ohanakapa in the README guide for bootstrapping the project for local development.
1. Fork the repository.
2. Create a topic branch.
3. Add specs for your unimplemented feature or bug fix.
4. Run bundle exec rspec-queue spec. If your specs pass, return to step 3.
5. Implement your feature or bug fix.
6. Run bundle exec rspec-queue spec. If your specs fail, return to step 5.
7. Run open coverage/index.html. If your changes are not completely covered by your tests, return to step 3.
8. Add documentation for your feature or bug fix.
9. Run bundle exec rake doc:yard. If your changes are not 100% documented, go back to step 8.
10. Add, commit, and push your changes.
11. Submit a pull request.

Supported Ruby Versions

This library aims to support and is tested against the following Ruby implementations:

• Ruby 1.9.2
• Ruby 1.9.3
• Ruby 2.0.0

If something doesn't work on one of these Ruby versions, it's a bug.

This library may inadvertently work (or seem to work) on other Ruby implementations, however support will only be provided for the versions listed above.

If you would like this library to support another Ruby version, you may volunteer to be a maintainer. Being a maintainer entails making sure all tests run and pass on that implementation. When something breaks on your implementation, you will be responsible for providing patches in a timely fashion. If critical issues for a particular implementation exist at the time of a major release, support for that Ruby version may be dropped.

Versioning

This library aims to adhere to Semantic Versioning 2.0.0. Violations of this scheme should be reported as bugs. Specifically, if a minor or patch version is released that breaks backward compatibility, that version should be immediately yanked and/or a new version should be immediately released that restores compatibility. Breaking changes to the public API will only be introduced with new major versions. As a result of this policy, you can (and should) specify a dependency on this gem using the Pessimistic Version Constraint with two digits of precision. For example:

spec.add_dependency 'ohanakapa', '~> 1.0'

Copyright

Copyright (c) 2013 Code for America. See LICENSE for details. This wrapper is based on the excellent GitHub Ruby API wrapper, which is Copyright (c) 2009-2013 Wynn Netherland, Adam Stacoviak, Erik Michaels-Ober.