[feature:lib] Add serialization support

lib/arx.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'cgi'
+require 'json'
 require 'nokogiri'
 require 'open-uri'
 require 'happymapper'

lib/arx/entities/author.rb

@@ -5,6 +5,9 @@ class Author
     include HappyMapper
     include Inspector
 
+    # The attributes of an arXiv paper's author.
+    ATTRIBUTES = %i[name affiliated? affiliations]
+
     tag 'author'
 
     # @!method name
@@ -23,6 +26,27 @@ def affiliated?
       !affiliations.empty?
     end
 
-    inspector :name, :affiliated?, :affiliations
+    # Serializes the {Author} object into a +Hash+.
+    #
+    # @return [Hash]
+    def to_h
+      Hash[*ATTRIBUTES.map {|_| [_, send(_)]}.flatten(1)]
+    end
+
+    # Serializes the {Author} object into a valid JSON hash.
+    #
+    # @return [Hash] The resulting JSON hash.
+    def as_json
+      JSON.parse to_json
+    end
+
+    # Serializes the {Author} object into a valid JSON string.
+    #
+    # @return [String] The resulting JSON string.
+    def to_json
+      to_h.to_json
+    end
+
+    inspector *ATTRIBUTES
   end
 end

lib/arx/entities/category.rb

@@ -5,6 +5,9 @@ class Category
     include HappyMapper
     include Inspector
 
+    # The attributes of an arXiv paper's category.
+    ATTRIBUTES = %i[name full_name]
+
     tag 'category'
 
     # @!method name
@@ -19,6 +22,27 @@ def full_name
       CATEGORIES[name]
     end
 
-    inspector :name, :full_name
+    # Serializes the {Category} object into a +Hash+.
+    #
+    # @return [Hash]
+    def to_h
+      Hash[*ATTRIBUTES.map {|_| [_, send(_)]}.flatten(1)]
+    end
+
+    # Serializes the {Category} object into a valid JSON hash.
+    #
+    # @return [Hash] The resulting JSON hash.
+    def as_json
+      JSON.parse to_json
+    end
+
+    # Serializes the {Category} object into a valid JSON string.
+    #
+    # @return [String] The resulting JSON string.
+    def to_json
+      to_h.to_json
+    end
+
+    inspector *ATTRIBUTES
   end
 end

lib/arx/entities/paper.rb

@@ -5,6 +5,19 @@ class Paper
     include HappyMapper
     include Inspector
 
+    # The attributes of an arXiv paper.
+    # @note {comment}, {journal}, {pdf_url} and {doi_url} may raise errors when called.
+    ATTRIBUTES = %i[
+      id url version revision?
+      title summary authors
+      primary_category categories
+      published_at updated_at
+      comment? comment
+      journal? journal
+      pdf? pdf_url
+      doi? doi_url
+    ]
+
     tag 'entry'
 
     element :id, Cleaner, parser: :clean, tag: 'id'
@@ -159,15 +172,36 @@ def revision?
       end
     end
 
-    inspector *%i[
-      id url version revision?
-      title summary authors
-      primary_category categories
-      published_at updated_at
-      comment? comment
-      journal? journal
-      pdf? pdf_url
-      doi? doi_url
-    ]
+    # Serializes the {Paper} object into a +Hash+.
+    #
+    # @param deep [Boolean] Whether to deep-serialize {Author} and {Category} objects.
+    # @return [Hash]
+    def to_h(deep = false)
+      Hash[*ATTRIBUTES.map {|_| [_, send(_)] rescue nil}.compact.flatten(1)].tap do |hash|
+        if deep
+          hash[:authors].map! &:to_h
+          hash[:categories].map! &:to_h
+          hash[:primary_category] = hash[:primary_category].to_h
+        end
+      end
+    end
+
+    # Serializes the {Paper} object into a valid JSON hash.
+    #
+    # @note Deep-serializes {Author} and {Category} objects.
+    # @return [Hash] The resulting JSON hash.
+    def as_json
+      JSON.parse to_json
+    end
+
+    # Serializes the {Paper} object into a valid JSON string.
+    #
+    # @note Deep-serializes {Author} and {Category} objects.
+    # @return [String] The resulting JSON string.
+    def to_json
+      to_h(true).to_json
+    end
+
+    inspector *ATTRIBUTES
   end
 end

spec/arx/entities/author_spec.rb

@@ -31,4 +31,53 @@
       it { expect(authors[1].affiliations).to be_empty }
     end
   end
+  context '#to_h' do
+    context 'cond-mat/9609089' do
+      subject { authors[0].to_h }
+
+      it { is_expected.to be_a Hash }
+      it { expect(subject.keys).to all be_a Symbol }
+      it { is_expected.to eq({affiliated?: true, affiliations: ["Philipps University Marburg, Germany"], name: "K. Bott"}) }
+    end
+    context '1105.5379' do
+      subject { authors[1].to_h }
+
+      it { is_expected.to eq({name: "Aapo Kyrola", affiliated?: false, affiliations: []}) }
+    end
+    context '1710.02185' do
+      subject { Arx.get('1710.02185').authors.first.to_h }
+
+      it { is_expected.to eq({name: "The LIGO Scientific Collaboration", affiliated?: false, affiliations: []}) }
+    end
+  end
+  context '#as_json' do
+    context 'cond-mat/9609089' do
+      subject { authors[0].as_json }
+
+      it { is_expected.to be_a Hash }
+      it { expect(subject.keys).to all be_a String }
+      it { is_expected.to eq({'affiliated?'=>true, 'affiliations'=>["Philipps University Marburg, Germany"], 'name'=>"K. Bott"}) }
+    end
+    context '1105.5379' do
+      subject { authors[1].as_json }
+
+      it { is_expected.to be_a Hash }
+      it { expect(subject.keys).to all be_a String }
+      it { is_expected.to eq({'name'=>"Aapo Kyrola", 'affiliated?'=>false, 'affiliations'=>[]}) }
+    end
+  end
+  context '#to_json' do
+    context 'cond-mat/9609089' do
+      subject { authors[0].to_json }
+
+      it { is_expected.to be_a String }
+      it { is_expected.to eq "{\"name\":\"K. Bott\",\"affiliated?\":true,\"affiliations\":[\"Philipps University Marburg, Germany\"]}" }
+    end
+    context '1105.5379' do
+      subject { authors[1].to_json }
+
+      it { is_expected.to be_a String }
+      it { is_expected.to eq "{\"name\":\"Aapo Kyrola\",\"affiliated?\":false,\"affiliations\":[]}" }
+    end
+  end
 end

spec/arx/entities/category_spec.rb

@@ -35,4 +35,87 @@
       it { expect(subject[2].full_name).to be_nil } # ACM classes
     end
   end
+  context '#to_h' do
+    context 'cond-mat/9609089' do
+      subject { categories[0].to_h }
+
+      it { is_expected.to be_a Hash }
+      it { expect(subject.keys).to all be_a Symbol }
+      it { is_expected.to eq({full_name: "Condensed Matter", name: "cond-mat"}) }
+    end
+    context '1105.5379' do
+      subject { categories[1].to_h }
+
+      it { is_expected.to be_a Hash }
+      it { expect(subject.keys).to all be_a Symbol }
+      it { is_expected.to eq({full_name: "Learning", name: "cs.LG"}) }
+    end
+    context '1710.02185' do
+      subject { Arx.get('1710.02185').primary_category.to_h }
+
+      it { is_expected.to be_a Hash }
+      it { expect(subject.keys).to all be_a Symbol }
+      it { is_expected.to eq({full_name: "General Relativity and Quantum Cosmology", name: "gr-qc"}) }
+    end
+  end
+  context '#as_json' do
+    context 'cond-mat/9609089' do
+      subject { categories[0].as_json }
+
+      it { is_expected.to be_a Hash }
+      it { expect(subject.keys).to all be_a String }
+      it { is_expected.to eq({"full_name"=>"Condensed Matter", "name"=>"cond-mat"}) }
+    end
+    context '1105.5379' do
+      subject { categories[1].as_json }
+
+      it { is_expected.to be_a Hash }
+      it { expect(subject.keys).to all be_a String }
+      it { is_expected.to eq({"full_name"=>"Learning", "name"=>"cs.LG"}) }
+    end
+    context '1703.04834' do
+      context 'MSC' do
+        subject { Arx.get('1703.04834').categories[1].as_json }
+
+        it { is_expected.to be_a Hash }
+        it { expect(subject.keys).to all be_a String }
+        it { is_expected.to eq({"full_name"=>nil, "name"=>"03D05"}) }
+      end
+      context 'ACM' do
+        subject { Arx.get('1703.04834').categories[2].as_json }
+
+        it { is_expected.to be_a Hash }
+        it { expect(subject.keys).to all be_a String }
+        it { is_expected.to eq({"full_name"=>nil, "name"=>"F.1.1; F.4.1"}) }
+      end
+    end
+  end
+  context '#to_json' do
+    context 'cond-mat/9609089' do
+      subject { categories[0].to_json }
+
+      it { is_expected.to be_a String }
+      it { is_expected.to eq("{\"name\":\"cond-mat\",\"full_name\":\"Condensed Matter\"}") }
+    end
+    context '1105.5379' do
+      subject { categories[1].to_json }
+
+      it { is_expected.to be_a String }
+      it { is_expected.to eq("{\"name\":\"cs.LG\",\"full_name\":\"Learning\"}") }
+    end
+    context '1703.04834' do
+      context 'MSC' do
+        subject { Arx.get('1703.04834').categories[1].to_json }
+
+        it { is_expected.to be_a String }
+        it { is_expected.to eq("{\"name\":\"03D05\",\"full_name\":null}") }
+      end
+      context 'ACM' do
+        subject { Arx.get('1703.04834').categories[2].to_json }
+
+        it { is_expected.to be_a String }
+        it { is_expected.to eq("{\"name\":\"F.1.1; F.4.1\",\"full_name\":null}") }
+      end
+    end
+  end
 end