FEATURE: search entire knowledge base body as well as title

Previously search was only searching through the title of topics

This introduces full text search.

It also means we get automatic stemming which gives far better results.

lib/knowledge_explorer/query.rb

@@ -36,7 +36,8 @@ module KnowledgeExplorer
 
         if tags_count == tag_filters.length
           tag_filters.each_with_index do |tag, index|
-            sql_alias = ['t', index].join
+            # to_i to make it clear this is not an injection
+            sql_alias = "t#{index.to_i}"
             results = results.joins("INNER JOIN topic_tags #{sql_alias} ON #{sql_alias}.topic_id = topics.id AND #{sql_alias}.tag_id = #{tag}")
           end
         else
@@ -46,7 +47,22 @@ module KnowledgeExplorer
 
       # filter results by search term
       if @filters[:search_term].present?
-        results = results.where('lower(title) LIKE ?', "%#{@filters[:search_term].downcase}%")
+        term = Search.prepare_data(@filters[:search_term])
+        escaped_ts_query = Search.ts_query(term: term)
+
+        results = results.where(<<~SQL)
+          topics.id IN (
+            SELECT pp.topic_id FROM post_search_data pd
+            JOIN posts pp ON pp.id = pd.post_id AND pp.post_number = 1
+            JOIN topics tt ON pp.topic_id = tt.id
+            WHERE
+              tt.id = topics.id AND
+              pp.deleted_at IS NULL AND
+              tt.deleted_at IS NULL AND
+              pp.post_type <> #{Post.types[:whisper].to_i} AND
+              pd.search_data @@ #{escaped_ts_query}
+          )
+        SQL
       end
 
       if @filters[:order] == "title"

spec/requests/knowledge_explorer_controller_spec.rb

@@ -3,10 +3,10 @@
 require 'rails_helper'
 
 describe KnowledgeExplorer::KnowledgeExplorerController do
-  let!(:category) { Fabricate(:category) }
-  let!(:topic) { Fabricate(:topic, category: category) }
-  let!(:topic2) { Fabricate(:topic, category: category) }
-  let!(:tag) { Fabricate(:tag, topics: [topic], name: 'test') }
+  fab!(:category) { Fabricate(:category) }
+  fab!(:topic) { Fabricate(:topic, category: category) }
+  fab!(:topic2) { Fabricate(:topic, category: category) }
+  fab!(:tag) { Fabricate(:tag, topics: [topic], name: 'test') }
 
   before do
     SiteSetting.tagging_enabled = true
@@ -100,15 +100,43 @@ describe KnowledgeExplorer::KnowledgeExplorerController do
     end
 
     context 'when searching' do
-      it 'should return a list filtered by search term in title' do
-        get "/knowledge-explorer.json?search=topic 1"
+      before do
+        SearchIndexer.enable
+      end
+
+      # no fab here otherwise will be missing from search
+      let!(:post) do
+        topic = Fabricate(:topic, title: "I love banana today", category: category)
+        Fabricate(:post, topic: topic, raw: "walking and running is fun")
+      end
+
+      let!(:post2) do
+        topic = Fabricate(:topic, title: "I love the amazing tomorrow", category: category)
+        Fabricate(:post, topic: topic, raw: "I also eat bananas")
+      end
+
+      it 'should correctly filter topics' do
+        get "/knowledge-explorer.json?search=banana"
 
         expect(response.status).to eq(200)
 
         json = JSON.parse(response.body)
         topics = json['topics']['topic_list']['topics']
 
+        # ordered by latest for now
+
+        expect(topics[0]["id"]).to eq(post2.topic_id)
+        expect(topics[1]["id"]).to eq(post.topic_id)
+
+        expect(topics.size).to eq(2)
+
+        get "/knowledge-explorer.json?search=walk"
+
+        json = JSON.parse(response.body)
+        topics = json['topics']['topic_list']['topics']
+
         expect(topics.size).to eq(1)
+
       end
     end
   end