add tag scoped search

app/models/search.rb

@@ -53,15 +53,26 @@ class Search
     end
   end
 
+  def with_tags(base, tag_scopes)
+    base
+      .joins({ :taggings => :tag }, :user)
+      .where(:tags => { :tag => tag_scopes })
+      .having("COUNT(stories.id) = ?", tag_scopes.length)
+      .group("stories.id")
+  end
+
   def search_for_user!(user)
     self.results = []
     self.total_results = 0
 
     # extract domain query since it must be done separately
     domain = nil
+    tag_scopes = []
     words = self.q.to_s.split(" ").reject{|w|
       if m = w.match(/^domain:(.+)$/)
         domain = m[1]
+      elsif m = w.match(/^tag:(.+)$/)
+        tag_scopes << m[1]
       end
     }.join(" ")
 
@@ -71,9 +82,7 @@ class Search
 
     case self.what
     when "stories"
-      base = Story.unmerged.where(:is_expired => false).
-        includes({ :taggings => :tag }, :user)
-
+      base = Story.unmerged.where(:is_expired => false)
       if domain.present?
         begin
           reg = Regexp.new("//([^/]*\.)?#{domain}/")
@@ -84,36 +93,49 @@ class Search
         end
       end
 
+      title_match_sql = "MATCH(stories.title) AGAINST('#{qwords}' IN BOOLEAN MODE)"
+      description_match_sql = "MATCH(stories.description) AGAINST('#{qwords}' IN BOOLEAN MODE)"
+      story_cache_match_sql = "MATCH(stories.story_cache) AGAINST('#{qwords}' IN BOOLEAN MODE)"
+
       if qwords.present?
         base.where!(
-          "(MATCH(title) AGAINST('#{qwords}' IN BOOLEAN MODE) OR " +
-          "MATCH(description) AGAINST('#{qwords}' IN BOOLEAN MODE) OR " +
-          "MATCH(story_cache) AGAINST('#{qwords}' IN BOOLEAN MODE))"
+          "(#{title_match_sql} OR " +
+          "#{description_match_sql} OR " +
+          "#{story_cache_match_sql})"
         )
 
-        self.results = base.select(
-          "stories.*, " +
-          "MATCH(title) AGAINST('#{qwords}' IN BOOLEAN MODE) AS rel_title, " +
-          "MATCH(description) AGAINST('#{qwords}' IN BOOLEAN MODE) AS rel_description, " +
-          "MATCH(story_cache) AGAINST('#{qwords}' IN BOOLEAN MODE) AS rel_story_cache"
-        )
+        if tag_scopes.present?
+          self.results = with_tags(base, tag_scopes)
+        else
+          base = base.includes({ :taggings => :tag }, :user)
+          self.results = base.select(
+            "stories.*, " +
+            "#{title_match_sql}, " +
+            "#{description_match_sql}, " +
+            "#{story_cache_match_sql}"
+          )
+        end
       else
-        self.results = base
+        if tag_scopes.present?
+          self.results = with_tags(base, tag_scopes)
+        else
+          self.results = base.includes({ :taggings => :tag }, :user)
+        end
       end
 
       case self.order
       when "relevance"
         if qwords.present?
           self.results.order!(
-            "(rel_title * 2) DESC, " +
-            "(rel_description * 1.5) DESC, " +
-            "(rel_story_cache) DESC"
+            "((#{title_match_sql}) * 2) DESC, " +
+            "((#{description_match_sql}) * 1.5) DESC, " +
+            "(#{story_cache_match_sql}) DESC"
           )
         else
-          self.results.order!("created_at DESC")
+          self.results.order!("stories.created_at DESC")
         end
       when "newest"
-        self.results.order!("created_at DESC")
+        self.results.order!("stories.created_at DESC")
       when "points"
         self.results.order!("#{Story.score_sql} DESC")
       end
@@ -138,7 +160,11 @@ class Search
       end
     end
 
-    self.total_results = base.count
+    if tag_scopes.present?
+      self.total_results = self.results.length
+    else
+      self.total_results = base.count
+    end
 
     if self.page > self.page_count
       self.page = self.page_count

spec/models/search_spec.rb

@@ -0,0 +1,107 @@
+require "spec_helper"
+
+describe Search do
+
+  # We need to set up and then teardown the environment
+  # outside of the typical RSpec transaction because
+  # the search module uses custom SQL that doesn't
+  # work inside the transaction
+  before(:all) do
+    @user = User.make!
+
+    @multi_tag = Story.make!(:title => "multitag term1 t1 t2",
+                             :url => "https://example.com/3",
+                             :user_id => @user.id,
+                             :tags_a => ["tag1", "tag2"])
+    @stories = [
+      Story.make!(:title => "unique",
+                  :url => "https://example.com/unique",
+                  :user_id => @user.id,
+                  :tags_a => ["tag1"]),
+      Story.make!(:title => "term1 domain1",
+                  :url => "https://example.com/1",
+                  :user_id => @user.id,
+                  :tags_a => ["tag1"]),
+      Story.make!(:title => "term1 t2",
+                  :url => "https://example.com/2",
+                  :user_id => @user.id,
+                  :tags_a => ["tag2"]),
+      @multi_tag,
+      Story.make!(:title => "term1 domain2",
+                  :url => "https://lobste.rs/1",
+                  :user_id => @user.id,
+                  :tags_a => ["tag1"]),
+    ]
+  end
+
+  after(:all) do
+    @user.destroy!
+    @stories.each { |s| s.destroy! }
+  end
+
+  it "can search for stories" do
+    search = Search.new
+    search.q = "unique"
+
+    search.search_for_user!(@user)
+
+    expect(search.results.length).to eq(1)
+    expect(search.results.first.title).to eq("unique")
+  end
+
+  it "can search for multitaged stories" do
+    search = Search.new
+    search.q = "multitag"
+
+    search.search_for_user!(@user)
+
+    expect(search.results.length).to eq(1)
+    expect(search.results.first.title).to eq("multitag term1 t1 t2")
+  end
+
+  it "can search for stories by domain" do
+    search = Search.new
+    search.q = "term1 domain:lobste.rs"
+
+    search.search_for_user!(@user)
+
+    expect(search.results.length).to eq(1)
+    expect(search.results.first.title).to eq("term1 domain2")
+  end
+
+  it "can search for stories by tag" do
+    search = Search.new
+    search.q = "term1 tag:tag1"
+
+    search.search_for_user!(@user)
+
+    expect(search.results.length).to eq(3)
+
+    # Stories with multiple tags should return all the tags
+    multi_tag_res = search.results.select do |res|
+      res.id == @multi_tag.id
+    end
+
+    expect(multi_tag_res.length).to eq(1)
+    expect(multi_tag_res.first.sorted_taggings.first.tag.tag).to eq("tag1")
+    expect(multi_tag_res.first.sorted_taggings.second.tag.tag).to eq("tag2")
+  end
+
+  it "should return only stories with both tags if multiple tags are present" do
+    search = Search.new
+    search.q = "term1 tag:tag1 tag:tag2"
+
+    search.search_for_user!(@user)
+
+    expect(search.results.length).to eq(1)
+  end
+
+  it "can search for stories with only tags" do
+    search = Search.new
+    search.q = "tag:tag2"
+
+    search.search_for_user!(@user)
+
+    expect(search.results.length).to eq(2)
+  end
+end