[Outreachy Round 27] Create ReferenceCounterApi class to hit new Reference Counter API

lib/reference_counter_api.rb

@@ -0,0 +1,100 @@
+# frozen_string_literal: true
+
+require_dependency "#{Rails.root}/lib/errors/api_error_handling"
+
+# Gets data from reference-counter Toolforge tool
+# https://toolsadmin.wikimedia.org/tools/id/reference-counter
+class ReferenceCounterApi
+  include ApiErrorHandling
+
+  TOOLFORGE_SERVER_URL = 'https://reference-counter.toolforge.org'
+
+  # This class is not designed for use with wikidata, as that wiki works pretty
+  # different from other wikis and it has its own method of calculating references.
+  # The reference-counter Toolforge API doesn't work for wikidata either for the
+  # same reason.
+  def self.valid_wiki?(wiki)
+    return wiki.project != 'wikidata'
+  end
+
+  def initialize(wiki, update_service = nil)
+    raise InvalidProjectError unless ReferenceCounterApi.valid_wiki?(wiki)
+    @project_code = wiki.project
+    @language_code = wiki.language
+    @update_service = update_service
+    @errors = []
+  end
+
+  # This is the main entry point.
+  # Given an array of revision ids, it returns a hash with the number of references
+  # for those revision ids.
+  # Format result example:
+  # { 'rev_id0' => { 'num_ref' => 10 }
+  #   ...
+  #   'rev_idn' => { "num_ref" => 0 }
+  # }
+  def get_number_of_references_from_revision_ids(rev_ids)
+    # Restart errors array
+    @errors = []
+    results = {}
+    rev_ids.each do |rev_id|
+      results.deep_merge!({ rev_id.to_s => get_number_of_references_from_revision_id(rev_id) })
+    end
+
+    log_error_batch(rev_ids)
+
+    return results
+  end
+
+  private
+
+  # Given a revision ID, it retrieves a hash containing the reference count from the
+  # reference-counter Toolforge API.
+  # If the API response is not 200 or an error occurs, it returns nil.
+  # Any encountered errors are logged in Sentry at the batch level.
+  def get_number_of_references_from_revision_id(rev_id)
+    response = toolforge_server.get(references_query_url(rev_id))
+    parsed_response = Oj.load(response.body)
+    if response.status == 200
+      return { 'num_ref' => parsed_response['num_ref'] }
+    else
+      # Log the error and return empty hash
+      Sentry.capture_message 'Non-200 response hitting references counter API',
+                             level: 'warning', extra: { project_code: @project_code,
+                             language_code: @language_code, rev_id:,
+                             status_code: response.status, content: parsed_response }
+      return {}
+    end
+  rescue StandardError => e
+    @errors << e
+    return {}
+  end
+
+  class InvalidProjectError < StandardError
+  end
+
+  def references_query_url(rev_id)
+    "/api/v1/references/#{@project_code}/#{@language_code}/#{rev_id}"
+  end
+
+  def toolforge_server
+    connection = Faraday.new(
+      url: TOOLFORGE_SERVER_URL,
+      headers: {
+        'Content-Type': 'application/json'
+      }
+    )
+    connection
+  end
+
+  TYPICAL_ERRORS = [Faraday::TimeoutError,
+                    Faraday::ConnectionFailed].freeze
+
+  def log_error_batch(rev_ids)
+    return if @errors.empty?
+
+    log_error(@errors.first, update_service: @update_service,
+    sentry_extra: { rev_ids:, project_code: @project_code,
+    language_code: @language_code, error_count: @errors.count })
+  end
+end

spec/lib/reference_counter_api_spec.rb

@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+require "#{Rails.root}/lib/reference_counter_api"
+
+describe ReferenceCounterApi do
+  before { stub_wiki_validation }
+
+  let(:en_wikipedia) { Wiki.get_or_create(language: 'en', project: 'wikipedia') }
+  let(:es_wiktionary) { Wiki.get_or_create(language: 'es', project: 'wiktionary') }
+  let(:wikidata) { Wiki.get_or_create(language: nil, project: 'wikidata') }
+  let(:deleted_rev_ids) { [708326238] }
+  let(:rev_ids) { [5006940, 5006942, 5006946] }
+
+  it 'raises InvalidProjectError if using wikidata project' do
+    expect do
+      described_class.new(wikidata)
+    end.to raise_error(described_class::InvalidProjectError)
+  end
+
+  it 'returns the number of references if response is 200 OK', vcr: true do
+    ref_counter_api = described_class.new(es_wiktionary)
+    response = ref_counter_api.get_number_of_references_from_revision_ids rev_ids
+    expect(response.dig('5006940', 'num_ref')).to eq(10)
+    expect(response.dig('5006942', 'num_ref')).to eq(4)
+    expect(response.dig('5006946', 'num_ref')).to eq(2)
+  end
+
+  it 'returns empty hash and logs the message if response is not 200 OK', vcr: true do
+    ref_counter_api = described_class.new(en_wikipedia)
+    expect(Sentry).to receive(:capture_message).with(
+      'Non-200 response hitting references counter API',
+      level: 'warning',
+      extra: {
+        project_code: 'wikipedia',
+        language_code: 'en',
+        rev_id: 708326238,
+        status_code: 404,
+        content: {
+            'description' =>
+            "You don't have permission to view deleted text or changes between deleted revisions."
+        }
+      }
+    )
+    response = ref_counter_api.get_number_of_references_from_revision_ids deleted_rev_ids
+    expect(response.dig('708326238')).to eq({})
+  end
+
+  it 'returns empty hash and logs the error if an unexpected error raises', vcr: true do
+    reference_counter_api = described_class.new(es_wiktionary)
+
+    allow_any_instance_of(Faraday::Connection).to receive(:get)
+      .and_raise(Faraday::TimeoutError)
+
+    expect_any_instance_of(described_class).to receive(:log_error).with(
+      Faraday::TimeoutError,
+      update_service: nil,
+      sentry_extra: {
+         project_code: 'wiktionary',
+         language_code: 'es',
+         rev_ids: [5006940, 5006942, 5006946],
+         error_count: 3
+     }
+    )
+    response = reference_counter_api.get_number_of_references_from_revision_ids rev_ids
+    expect(response.dig('5006940')).to eq({})
+    expect(response.dig('5006942')).to eq({})
+    expect(response.dig('5006946')).to eq({})
+  end
+end