API pagination for all collections using Link header

6 files changed, 85 insertions, 19 deletions

diff --git a/app/controllers/api/v1/accounts_controller.rb b/app/controllers/api/v1/accounts_controller.rb
index 4140439a8..f2049cd55 100644
--- a/app/controllers/api/v1/accounts_controller.rb
+++ b/app/controllers/api/v1/accounts_controller.rb
@@ -4,7 +4,7 @@ class Api::V1::AccountsController < ApiController
   before_action :require_user!, except: [:show, :following, :followers, :statuses]
   before_action :set_account, except: [:verify_credentials, :suggestions]
 
-  respond_to    :json
+  respond_to :json
 
   def show
   end
@@ -15,12 +15,26 @@ class Api::V1::AccountsController < ApiController
   end
 
   def following
-    @accounts = @account.following.with_counters.limit(40)
+    results   = Follow.where(account: @account).paginate_by_max_id(DEFAULT_ACCOUNTS_LIMIT, params[:max_id], params[:since_id])
+    @accounts = Account.where(id: results.map(&:account_id)).with_counters.to_a
+
+    next_path = following_api_v1_account_url(max_id: results.last.id)    if results.size == DEFAULT_ACCOUNTS_LIMIT
+    prev_path = following_api_v1_account_url(since_id: results.first.id) if results.size > 0
+
+    set_pagination_headers(next_path, prev_path)
+
     render action: :index
   end
 
   def followers
-    @accounts = @account.followers.with_counters.limit(40)
+    results   = Follow.where(target_account: @account).paginate_by_max_id(DEFAULT_ACCOUNTS_LIMIT, params[:max_id], params[:since_id])
+    @accounts = Account.where(id: results.map(&:account_id)).with_counters.to_a
+
+    next_path = following_api_v1_account_url(max_id: results.last.id)    if results.size == DEFAULT_ACCOUNTS_LIMIT
+    prev_path = following_api_v1_account_url(since_id: results.first.id) if results.size > 0
+
+    set_pagination_headers(next_path, prev_path)
+
     render action: :index
   end
 
@@ -35,8 +49,14 @@ class Api::V1::AccountsController < ApiController
   end
 
   def statuses
-    @statuses = @account.statuses.with_includes.with_counters.paginate_by_max_id(20, params[:max_id], params[:since_id]).to_a
+    @statuses = @account.statuses.with_includes.with_counters.paginate_by_max_id(DEFAULT_STATUSES_LIMIT, params[:max_id], params[:since_id]).to_a
+
     set_maps(@statuses)
+
+    next_path = statuses_api_v1_account_url(max_id: @statuses.last.id)    if @statuses.size == DEFAULT_STATUSES_LIMIT
+    prev_path = statuses_api_v1_account_url(since_id: @statuses.first.id) if @statuses.size > 0
+
+    set_pagination_headers(next_path, prev_path)
   end
 
   def follow
diff --git a/app/controllers/api/v1/follows_controller.rb b/app/controllers/api/v1/follows_controller.rb
index 80a5aedf2..6a77c4d66 100644
--- a/app/controllers/api/v1/follows_controller.rb
+++ b/app/controllers/api/v1/follows_controller.rb
@@ -2,7 +2,7 @@ class Api::V1::FollowsController < ApiController
   before_action -> { doorkeeper_authorize! :follow }
   before_action :require_user!
 
-  respond_to    :json
+  respond_to :json
 
   def create
     raise ActiveRecord::RecordNotFound if params[:uri].blank?
diff --git a/app/controllers/api/v1/media_controller.rb b/app/controllers/api/v1/media_controller.rb
index ab216f9c9..6b93e47b4 100644
--- a/app/controllers/api/v1/media_controller.rb
+++ b/app/controllers/api/v1/media_controller.rb
@@ -2,7 +2,7 @@ class Api::V1::MediaController < ApiController
   before_action -> { doorkeeper_authorize! :write }
   before_action :require_user!
 
-  respond_to    :json
+  respond_to :json
 
   def create
     @media = MediaAttachment.create!(account: current_user.account, file: params[:file])
diff --git a/app/controllers/api/v1/statuses_controller.rb b/app/controllers/api/v1/statuses_controller.rb
index 51a044a6c..3c86cae00 100644
--- a/app/controllers/api/v1/statuses_controller.rb
+++ b/app/controllers/api/v1/statuses_controller.rb
@@ -15,12 +15,26 @@ class Api::V1::StatusesController < ApiController
   end
 
   def reblogged_by
-    @accounts = @status.reblogged_by(40)
+    results   = @status.reblogs.paginate_by_max_id(DEFAULT_ACCOUNTS_LIMIT, params[:max_id], params[:since_id])
+    @accounts = Account.where(id: results.map(&:account_id)).with_counters.to_a
+
+    next_path = reblogged_by_api_v1_status_url(max_id: results.last.id)    if results.size == DEFAULT_ACCOUNTS_LIMIT
+    prev_path = reblogged_by_api_v1_status_url(since_id: results.first.id) if results.size > 0
+
+    set_pagination_headers(next_path, prev_path)
+
     render action: :accounts
   end
 
   def favourited_by
-    @accounts = @status.favourited_by(40)
+    results   = @status.favourites.paginate_by_max_id(DEFAULT_ACCOUNTS_LIMIT, params[:max_id], params[:since_id])
+    @accounts = Account.where(id: results.map(&:account_id)).with_counters.to_a
+
+    next_path = favourited_by_api_v1_status_url(max_id: results.last.id)    if results.size == DEFAULT_ACCOUNTS_LIMIT
+    prev_path = favourited_by_api_v1_status_url(since_id: results.first.id) if results.size > 0
+
+    set_pagination_headers(next_path, prev_path)
+
     render action: :accounts
   end
 
diff --git a/app/controllers/api/v1/timelines_controller.rb b/app/controllers/api/v1/timelines_controller.rb
index e5176dd4b..6d7858c76 100644
--- a/app/controllers/api/v1/timelines_controller.rb
+++ b/app/controllers/api/v1/timelines_controller.rb
@@ -5,32 +5,54 @@ class Api::V1::TimelinesController < ApiController
   respond_to :json
 
   def home
-    @statuses = Feed.new(:home, current_account).get(20, params[:max_id], params[:since_id]).to_a
+    @statuses = Feed.new(:home, current_account).get(DEFAULT_STATUSES_LIMIT, params[:max_id], params[:since_id]).to_a
+
     set_maps(@statuses)
+
+    next_path = api_v1_home_timeline_url(max_id: @statuses.last.id)    if @statuses.size == DEFAULT_STATUSES_LIMIT
+    prev_path = api_v1_home_timeline_url(since_id: @statuses.first.id) if @statuses.size > 0
+
+    set_pagination_headers(next_path, prev_path)
+
     render action: :index
   end
 
   def mentions
-    @statuses = Feed.new(:mentions, current_account).get(20, params[:max_id], params[:since_id]).to_a
+    @statuses = Feed.new(:mentions, current_account).get(DEFAULT_STATUSES_LIMIT, params[:max_id], params[:since_id]).to_a
+
     set_maps(@statuses)
+
+    next_path = api_v1_mentions_timeline_url(max_id: @statuses.last.id)    if @statuses.size == DEFAULT_STATUSES_LIMIT
+    prev_path = api_v1_mentions_timeline_url(since_id: @statuses.first.id) if @statuses.size > 0
+
+    set_pagination_headers(next_path, prev_path)
+
     render action: :index
   end
 
   def public
-    @statuses = Status.as_public_timeline(current_account).paginate_by_max_id(20, params[:max_id], params[:since_id]).to_a
+    @statuses = Status.as_public_timeline(current_account).paginate_by_max_id(DEFAULT_STATUSES_LIMIT, params[:max_id], params[:since_id]).to_a
+
     set_maps(@statuses)
+
+    next_path = api_v1_public_timeline_url(max_id: @statuses.last.id)    if @statuses.size == DEFAULT_STATUSES_LIMIT
+    prev_path = api_v1_public_timeline_url(since_id: @statuses.first.id) if @statuses.size > 0
+
+    set_pagination_headers(next_path, prev_path)
+
     render action: :index
   end
 
   def tag
-    @tag = Tag.find_by(name: params[:id].downcase)
-
-    if @tag.nil?
-      @statuses = []
-    else
-      @statuses = Status.as_tag_timeline(@tag, current_account).paginate_by_max_id(20, params[:max_id], params[:since_id]).to_a
-      set_maps(@statuses)
-    end
+    @tag      = Tag.find_by(name: params[:id].downcase)
+    @statuses = @tag.nil? ? [] : Status.as_tag_timeline(@tag, current_account).paginate_by_max_id(DEFAULT_STATUSES_LIMIT, params[:max_id], params[:since_id]).to_a
+
+    set_maps(@statuses)
+
+    next_path = api_v1_hashtag_timeline_url(params[:id], max_id: @statuses.last.id)    if @statuses.size == DEFAULT_STATUSES_LIMIT
+    prev_path = api_v1_hashtag_timeline_url(params[:id], since_id: @statuses.first.id) if @statuses.size > 0
+
+    set_pagination_headers(next_path, prev_path)
 
     render action: :index
   end
diff --git a/app/controllers/api_controller.rb b/app/controllers/api_controller.rb
index db4035a96..5243f7d7b 100644
--- a/app/controllers/api_controller.rb
+++ b/app/controllers/api_controller.rb
@@ -1,4 +1,7 @@
 class ApiController < ApplicationController
+  DEFAULT_STATUSES_LIMIT = 20
+  DEFAULT_ACCOUNTS_LIMIT = 40
+
   protect_from_forgery with: :null_session
 
   skip_before_action :verify_authenticity_token
@@ -54,6 +57,13 @@ class ApiController < ApplicationController
     response.headers['Access-Control-Allow-Headers']  = 'Origin, X-Requested-With, Content-Type, Accept, Authorization'
   end
 
+  def set_pagination_headers(next_path = nil, prev_path = nil)
+    links = []
+    links << [next_path, [['rel', 'next']]] if next_path
+    links << [prev_path, [['rel', 'prev']]] if prev_path
+    response.headers['Link'] = LinkHeader.new(links)
+  end
+
   def current_resource_owner
     User.find(doorkeeper_token.resource_owner_id) if doorkeeper_token
   end