Filters: search links query

Gemfile

@@ -19,12 +19,22 @@ gem 'jbuilder', '~> 2.7'
 # Reduces boot times through caching; required in config/boot.rb
 gem 'bootsnap', '>= 1.4.2', require: false
 
+# START: ADDED GEMS
+
 # Graphql rails
 gem 'graphql', '1.9.17'
 
 # Ensure secure passwords
 gem 'bcrypt', '~> 3.1.13'
 
+# Graphiql GUI
+gem 'graphiql-rails', '1.7.0', group: :development
+
+# Filter mutations (for search)
+gem 'search_object_graphql', '0.3.1'
+
+# END: ADDED GEMS
+
 group :development, :test do
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console
   gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
@@ -41,6 +51,3 @@ end
 
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
 gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
-
-# Graphiql GUI
-gem 'graphiql-rails', '1.7.0', group: :development

Gemfile.lock

@@ -140,6 +140,10 @@ GEM
       sprockets (> 3.0)
       sprockets-rails
       tilt
+    search_object (1.2.4)
+    search_object_graphql (0.3.1)
+      graphql (~> 1.8)
+      search_object (~> 1.2.2)
     spring (2.1.1)
     spring-watcher-listen (2.0.1)
       listen (>= 2.7, < 4.0)
@@ -181,6 +185,7 @@ DEPENDENCIES
   puma (~> 4.1)
   rails (~> 6.0.3, >= 6.0.3.4)
   sass-rails (>= 6)
+  search_object_graphql (= 0.3.1)
   spring
   spring-watcher-listen (~> 2.0.0)
   sqlite3 (~> 1.4)

app/graphql/resolvers/search_links.rb

@@ -0,0 +1,40 @@
+require 'search_object'
+require 'search_object/plugin/graphql'
+
+class Resolvers::SearchLinks
+  # include SearchObject for GraphQL
+  include SearchObject.module(:graphql)
+
+  # scope is starting point for search
+  scope { Link.all }
+
+  type [Types::LinkType]
+
+  # inline input type definition for the advanced filter
+  class LinkFilter < ::Types::BaseInputObject
+    argument :OR, [self], required: false
+    argument :description_contains, String, required: false
+    argument :url_contains, String, required: false
+  end
+
+  # when "filter" is passed "apply_filter" would be called to narrow the scope
+  option :filter, type: LinkFilter, with: :apply_filter
+
+  # apply_filter recursively loops through "OR" branches
+  def apply_filter(scope, value)
+    branches = normalize_filters(value).reduce { |a, b| a.or(b) }
+    scope.merge branches
+  end
+
+  def normalize_filters(value, branches = [])
+    scope = Link.all
+    scope = scope.where('description LIKE ?', "%#{value[:description_contains]}%") if value[:description_contains]
+    scope = scope.where('url LIKE ?', "%#{value[:url_contains]}%") if value[:url_contains]
+
+    branches << scope
+
+    value[:OR].reduce(branches) { |s, v| normalize_filters(v, s) } if value[:OR].present?
+
+    branches
+  end
+end

app/graphql/types/query_type.rb

@@ -3,6 +3,7 @@ class QueryType < BaseObject
     # queries are just represented as fields
     # `all_links` is automatically camelcased to `allLinks`
     field :all_links, [LinkType], null: false
+    field :search_links, resolver: Resolvers::SearchLinks
 
     # this method is invoked, when `all_link` fields is being resolved
     def all_links