JsonApiClient 
This gem is meant to help you build an API client for interacting with REST APIs as laid out by http://jsonapi.org. It attempts to give you a query building framework that is easy to understand (it is similar to ActiveRecord scopes).
Note: master is currently tracking the 1.0.0 specification. If you’re looking for the older code, see 0.x branch
Usage
You will want to create your own resource classes that inherit from JsonApiClient::Resource similar to how you would create an ActiveRecord class. You may also want to create your own abstract base class to share common behavior. Additionally, you will probably want to namespace your models. Namespacing your model will not affect the url routing to that resource.
```ruby module MyApi # this is an “abstract” base class that class Base < JsonApiClient::Resource # set the api base url in an abstract base class self.site = “http://example.com/” end
class Article < Base end
class Comment < Base end
class Person < Base end end ```
By convention, we guess the resource route from the class name. In the above example, Article’s path is “http://example.com/articles” and Person’s path would be “http://example.com/people”.
Some basic example usage:
```ruby MyApi::Article.all MyApi::Article.where(author_id: 1).find(2) MyApi::Article.where(author_id: 1).all
MyApi::Person.where(name: “foo”).order(created_at: :desc).includes(:preferences, :cars).all
u = MyApi::Person.new(first_name: “bar”, last_name: “foo”) u.save
u = MyApi::Person.find(1).first u.update_attributes( a: “b”, c: “d” )
u = MyApi::Person.create( a: “b”, c: “d” ) ```
All class level finders/creators should return a JsonApiClient::ResultSet which behaves like an Array and contains extra data about the api response.
Handling Validation Errors
Out of the box, json_api_client handles server side validation only.
```ruby User.create(name: “Bob”, email_address: “invalid email”) # => false
user = User.new(name: “Bob”, email_address: “invalid email”) user.save # => false
returns an error collector which is array-like
user.errors # => [“Email address is invalid”]
get all error titles
user.errors.full_messages # => [“Email address is invalid”]
get errors for a specific parameter
user.errors[:email_address] # => [“Email address is invalid”]
user = User.find(1) user.update_attributes(email_address: “invalid email”) # => false
user.errors # => [“Email address is invalid”]
user.email_address # => “invalid email” ```
For now we are assuming that error sources are all parameters.
If you want to add client side validation, I suggest creating a form model class that uses ActiveModel’s validations.
Meta information
If the response has a top level meta data section, we can access it via the meta accessor on ResultSet.
```ruby # Example response: { “meta”: { “copyright”: “Copyright 2015 Example Corp.”, “authors”: [ “Yehuda Katz”, “Steve Klabnik”, “Dan Gebhardt” ] }, “data”: { // … } } articles = Articles.all
articles.meta.copyright # => “Copyright 2015 Example Corp.”
articles.meta.authors # => [“Yehuda Katz”, “Steve Klabnik”, “Dan Gebhardt”] ```
Top-level Links
If the resource returns top level links, we can access them via the links accessor on ResultSet.
ruby
articles = Articles.find(1)
articles.links.related
Nested Resources
You can force nested resource paths for your models by using a belongs_to association.
Note: Using belongs_to is only necessary for setting a nested path.
```ruby module MyApi class Account < JsonApiClient::Resource belongs_to :user end end
try to find without the nested parameter
MyApi::Account.find(1) # => raises ArgumentError
makes request to /users/2/accounts/1
MyApi::Account.where(user_id: 2).find(1) # => returns ResultSet ```
Custom Methods
You can create custom methods on both collections (class method) and members (instance methods).
```ruby module MyApi class User < JsonApiClient::Resource # GET /users/search custom_endpoint :search, on: :collection, request_method: :get
# PUT /users/:id/verify
custom_endpoint :verify, on: :member, request_method: :put end end
makes GET request to /users/search?name=Jeff
MyApi::User.search(name: ‘Jeff’) # => <ResultSet of MyApi::User instances>
user = MyApi::User.find(1) # makes PUT request to /users/1/verify?foo=bar user.verify(foo: ‘bar’) ```
Fetching Includes
If the response returns a compound document, then we should be able to get the related resources.
```ruby # makes request to /articles/1?include=author,comments.author results = Article.includes(:author, :comments => :author).find(1)
should not have to make additional requests to the server
authors = results.map(&:author) ```
Sparse Fieldsets
```ruby # makes request to /articles?fields[articles]=title,body article = Article.select(“title”, “body”).first
should have fetched the requested fields
article.title # => “Rails is Omakase”
should not have returned the created_at
article.created_at # => raise NoMethodError ```
Sorting
```ruby # makes request to /people?sort=age youngest = Person.order(:age).all
also makes request to /people?sort=age
youngest = Person.order(age: :asc).all
makes request to /people?sort=-age
oldest = Person.order(age: :desc).all ```
Paginating
Requesting
```ruby # makes request to /articles?page=2&per_page=30 articles = Article.page(2).per(30).to_a
also makes request to /articles?page=2&per_page=30
articles = Article.paginate(page: 2, per_page: 30).to_a ```
Note: The mapping of pagination parameters is done by the query_builder which is customizable.
Browsing
If the response contains additional pagination links, you can also get at those:
ruby
articles = Article.paginate(page: 2, per_page: 30).to_a
articles.pages.next
articles.pages.last
Library compatibility
A JsonApiClient::ResultSet object should be paginatable with both kaminari and will_paginate.
Filtering
ruby
# makes request to /people?filter[name]=Jeff
Person.where(name: 'Jeff').all
Schema
You can define schema within your client model. You can define basic types and set default values if you wish. If you declare a basic type, we will try to cast any input to be that type.
The added benefit of declaring your schema is that you can access fields before data is set (otherwise, you’ll get a NoMethodError).
Note: This is completely optional. This will set default values and handle typecasting.
Example
```ruby class User < JsonApiClient::Resource property :name, type: :string property :is_admin, type: :boolean, default: false property :points_accrued, type: :int, default: 0 property :averge_points_per_day, type: :float end
default values
u = User.new
u.name # => nil
u.is_admin # => false
u.points_accrued # => 0
casting
u.average_points_per_day = “0.3” u.average_points_per_day # => 0.3 ```
Types
The basic types that we allow are:
:intor:integer:float:string:time- *Note: Include the time zone in the string if it’s different than local time.:boolean- Note: we will cast the string version of “true” and “false” to their respective values
Also, we consider nil to be an acceptable value and will not cast the value.
Note : Do not map the primary key as int.
Customizing
Paths
You can customize this path by changing your resource’s table_name:
```ruby module MyApi class SomeResource < Base def self.table_name “foobar” end end end
requests http://example.com/foobar
MyApi::SomeResource.all ```
Custom headers
You can inject custom headers on resource request by wrapping your code into block:
ruby
MyApi::SomeResource.with_headers(x_access_token: 'secure_token_here') do
MyApi::SomeResource.find(1)
end
Connections
You can configure your API client to use a custom connection that implementes the run instance method. It should return data that your parser can handle. The default connection class wraps Faraday and lets you add middleware.
```ruby class NullConnection def initialize(*args) end
def run(request_method, path, params = {}, headers = {}) end
def use(*args); end end
class CustomConnectionResource < TestResource self.connection_class = NullConnection end ```
Connection Options
You can configure your connection using Faraday middleware. In general, you’ll want to do this in a base model that all your resources inherit from:
```ruby MyApi::Base.connection do |connection| # set OAuth2 headers connection.use FaradayMiddleware::OAuth2, ‘MYTOKEN’
# log responses connection.use Faraday::Response::Logger
connection.use MyCustomMiddleware end
module MyApi class User < Base # will use the customized connection end end ```
Specifying an HTTP Proxy
All resources have a class method connection_options used to pass options to the JsonApiClient::Connection initializer.
```ruby MyApi::Base.connection_options[:proxy] = ‘http://proxy.example.com’ MyApi::Base.connection do |connection| # … end
module MyApi class User < Base # will use the customized connection with proxy end end ```
Custom Parser
You can configure your API client to use a custom parser that implements the parse class method. It should return a JsonApiClient::ResultSet instance. You can use it by setting the parser attribute on your model:
```ruby class MyCustomParser def self.parse(klass, response) # … # returns some ResultSet object end end
class MyApi::Base < JsonApiClient::Resource self.parser = MyCustomParser end ```
Custom Query Builder
You can customize how the scope builder methods map to request parameters.
```ruby class MyQueryBuilder def initialize(klass); end
def where(conditions = {}) end
# … add order, includes, paginate, page, first, build end
class MyApi::Base < JsonApiClient::Resource self.query_builder = MyQueryBuilder end ```
Custom Paginator
You can customize how your resources find pagination information from the response.
```ruby class MyPaginator def initialize(result_set, data); end # implement current_page, total_entries, etc end
class MyApi::Base < JsonApiClient::Resource self.paginator = MyPaginator end ```
Changelog
See changelog