Add Fb::Page#posts

CHANGELOG.md

@@ -10,3 +10,4 @@ For more information about changelogs, check
 
 * [FEATURE] Added `Fb::User`
 * [FEATURE] Added `Fb::Page`
+* [FEATURE] Added `Fb::Page#posts`

README.md

@@ -33,14 +33,25 @@ user.email # => 'john.smith@example.com'
 Fb::User#pages
 --------------
 
-Given an user access token with the `manage_pages` scope, you can get the list of Facebook pages managed by the user by calling:
+Given an user access token with the `pages_show_list` scope, you can get the list of Facebook pages managed by the user by calling:
 
 ```ruby
 user = Fb::User.new access_token: '--valid-access-token--'
 user.pages
 # => [#<Fb::Page: id="1234", name="sample1">, #<Fb::Page: id="5678", name="sample2">]
 ```
 
+Fb::Page#posts
+--------------
+
+Given a page with posts, you can get the posts on the page since creation by calling:
+
+```ruby
+page = Fb::Page.new access_token: '--valid-access-token--'
+page.posts
+# => [#<Fb::Post: id="1234", type="video">, #<Fb::Post: id="5678", type="video">]
+```
+
 ## Development
 
 To run tests, obtain a long-term access token for a Facebook user who manages

lib/fb/core.rb

@@ -1,6 +1,9 @@
 require 'fb/support'
+require 'fb/paginated_request'
+require 'fb/resource'
 require 'fb/page'
 require 'fb/user'
+require 'fb/post'
 
 # An object-oriented Ruby client for the Facebook Graph API.
 # @see http://www.rubydoc.info/gems/fb-core/

lib/fb/core/version.rb

@@ -3,6 +3,6 @@ module Fb
   class Core
     # @return [String] the SemVer-compatible gem version.
     # @see http://semver.org
-    VERSION = '1.0.0.alpha2'
+    VERSION = '1.0.0.alpha3'
   end
 end

lib/fb/page.rb

@@ -1,7 +1,7 @@
 module Fb
   # Provides methods to interact with Facebook pages through the Graph API.
   # @see https://developers.facebook.com/docs/graph-api/reference/page/
-  class Page
+  class Page < Resource
     # @option [String] the page’s unique ID.
     attr_reader :id
 
@@ -15,10 +15,24 @@ class Page
     # @option [String] :id The page’s unique ID.
     # @option [String] :name The page’s name.
     # @option [String] :category The page’s category.
+    # @option [String] :access_token an access token for the page.
     def initialize(options = {})
       @id = options[:id]
       @name = options[:name]
       @category = options[:category]
+      @access_token = options[:access_token]
+    end
+
+    # @return [Array<Fb::Post>] the posts published on the page.
+    def posts
+      @posts ||= begin
+        fields = %i(type created_time).join ','
+        params = {access_token: @access_token, limit: 100, fields: fields}
+        request = PaginatedRequest.new path: "/v2.9/#{@id}/posts", params: params
+        request.run.body['data'].map do |post_data|
+          Post.new symbolize_keys post_data
+        end
+      end
     end
 
     # @return [String] the representation of the page.

lib/fb/paginated_request.rb

@@ -0,0 +1,22 @@
+module Fb
+  # Provides a wrapper for HTTPRequest when the result has pagination links.
+  # @api private
+  class PaginatedRequest < HTTPRequest
+    # Sends the request and returns the response with the body parsed from JSON.
+    # If the response body contains a link to the next page, fetches that page
+    # as well and combines the data with the previous page.
+    # @return [Net::HTTPResponse] if the request succeeds.
+    # @raise [Fb::HTTPError] if the request fails.
+    def run
+      response = super
+      while after = response.body.dig('paging', 'cursors', 'after')
+        next_params = @params.merge after: after, limit: 100
+        next_request = HTTPRequest.new path: @path, params: next_params
+        next_body = next_request.run.body
+        response.body['paging'] = next_body['paging']
+        response.body['data'].concat next_body['data']
+      end
+      response
+    end
+  end
+end

lib/fb/post.rb

@@ -0,0 +1,31 @@
+# Ruby client to authenticate a Facebook user.
+# @see http://www.rubydoc.info/gems/Fb/
+module Fb
+  # Fb::Post reprensents a Facebook post. Post provides getters for:
+  #   :id, :title, :url, :created_time, and :type.
+  class Post
+    # @option [String] the post’s unique ID.
+    attr_reader :id
+
+    # @option [String] the post’s type.
+    attr_reader :type
+
+    # @option [Time] the post’s creation time.
+    attr_reader :created_at
+
+    # @param [Hash] options the options to initialize an instance of Fb::Post.
+    # @option [String] :id the post id.
+    # @option [String] :type the post’s type.
+    # @option [String] :created_time the post’s creation time in iso8601 format.
+    def initialize(options = {})
+      @id = options[:id]
+      @type = options[:type]
+      @created_at = Time.parse(options[:created_time]) if options[:created_time]
+    end
+
+    # @return [String] the representation of the post.
+    def to_s
+      %Q(#<#{self.class.name} #{@id} "#{@type}">)
+    end
+  end
+end

lib/fb/resource.rb

@@ -0,0 +1,11 @@
+module Fb
+  # Provides a base class for Facebook resources (users, pages, ...)
+  class Resource
+  private
+    def symbolize_keys(hash)
+      {}.tap do |new_hash|
+        hash.each_key{|key| new_hash[key.to_sym] = hash[key]}
+      end
+    end
+  end
+end

lib/fb/user.rb

@@ -1,7 +1,7 @@
 module Fb
   # Provides methods to interact with Facebook users through the Graph API.
   # @see https://developers.facebook.com/docs/graph-api/reference/user/
-  class User
+  class User < Resource
     # @param [Hash] options to initialize a User object.
     # @option [String] :access_token an access token for the user.
     def initialize(options = {})
@@ -23,17 +23,9 @@ def pages
         params = {access_token: @access_token}
         request = HTTPRequest.new path: '/me/accounts', params: params
         request.run.body['data'].map do |page_data|
-          Page.new symbolize_keys(page_data)
+          Page.new symbolize_keys(page_data.merge access_token: @access_token)
         end
       end
     end
-
-  private
-
-    def symbolize_keys(hash)
-      {}.tap do |new_hash|
-        hash.each_key{|key| new_hash[key.to_sym] = hash[key]}
-      end
-    end
   end
 end

spec/page/posts_spec.rb

@@ -0,0 +1,24 @@
+require 'spec_helper'
+
+RSpec.describe 'Fb::Page#posts' do
+  context 'given an invalid access token' do
+    let(:page) { Fb::Page.new access_token: 'invalid_token' }
+
+    it 'raises Fb::HTTPError' do
+      expect{page.posts}.to raise_error Fb::HTTPError
+    end
+  end
+
+  context 'given a valid access_token' do
+    let(:user) { Fb::User.new access_token: ENV['FB_TEST_ACCESS_TOKEN'] }
+    let(:page) { user.pages.first }
+
+    it 'returns array of Post for any given page' do
+      expect(page.posts).to be_a(Array)
+      expect(page.posts).to all (be_a Fb::Post)
+      expect(page.posts.map &:id).to all(be_a String)
+      expect(page.posts.map &:type).to all(be_a String)
+      expect(page.posts.map &:created_at).to all(be_a Time)
+    end
+  end
+end

spec/paginated_request_spec.rb

@@ -0,0 +1,16 @@
+require 'spec_helper'
+
+RSpec.describe 'Fb::PaginatedRequest#run' do
+  let(:params) { {access_token: ENV['FB_TEST_ACCESS_TOKEN']} }
+  let(:request) { Fb::PaginatedRequest.new path: path, params: params }
+
+  context 'given a request which more than one page of results' do
+    let(:path) { '/v2.9/20531316728/posts' } # Posts by Facebook
+
+    it 'returns all the results, not just the first page' do
+      response = request.run
+      expect(response).to be_a Net::HTTPOK
+      expect(response.body['data'].size).to be > 100
+    end
+  end
+end

spec/post/to_s_spec.rb

@@ -0,0 +1,9 @@
+require 'spec_helper'
+
+RSpec.describe 'Fb::Post#to_s' do
+  let(:post) { Fb::Post.new id: 123, type: 'video' }
+
+  it 'returns a pretty string representation' do
+    expect(post.to_s).to eq '#<Fb::Post 123 "video">'
+  end
+end