Supports custom robots tags

README.md

@@ -183,6 +183,9 @@ Use these options to customize the title format:
 | `:og`          | add Open Graph tags (Hash)                                                                                           |
 | `:twitter`     | add Twitter tags (Hash)                                                                                              |
 | `:refresh`     | refresh interval and optionally url to redirect to                                                                   |
+| `:robots`      | add custom robots tags (Hash)                                                                                        |
+| `:googlebot`   | add custom googlebot tags (Hash)                                                                                        |
+| `:bingbot`     | add custom bingbot tags (Hash)                                                                                        |
 
 And here are a few examples to give you ideas.
 
@@ -758,6 +761,36 @@ Further reading:
 
 - [App Links Documentation](https://developers.facebook.com/docs/applinks)
 
+### Robots
+
+Besides using noindex, there's still other custom robots met tags options to instruct search engine to serve crawled site content in specific ways.
+
+```ruby
+set_meta_tags robots: {
+  "max-snippet": -1,
+  "max-video-preview": -1
+}
+
+#　<meta name="robots" content="max-snippet:-1, max-video-preview:-1">
+
+set_meta_tags googlebot: {
+  "unavailable_after": "2020-09-21"
+}
+
+#　<meta name="googlebot" content="unavailable_after:2020-09-21">
+
+set_meta_tags bingbot: {
+  "max-image-preview": "large"
+}
+
+# <meta name="bingbot" content="max-image-preview:large" />
+```
+
+Further reading:
+
+* [Robots meta tag, data-nosnippet, and X-Robots-Tag specifications](https://developers.google.com/search/reference/robots_meta_tag)
+* [Robots Metatags](https://www.bing.com/webmasters/help/which-robots-metatags-does-bing-support-5198d240)
+
 ### Custom meta tags
 
 Starting from version 1.3.1, you can specify arbitrary meta tags, and they will

lib/meta_tags/meta_tags_collection.rb

@@ -164,6 +164,13 @@ def extract_robots
         calculate_robots_attributes(result, attributes)
       end
 
+      [:robots, :googlebot, :bingbot].each do |bot|
+        values = extract(bot).presence
+        if values
+          result[bot.to_s].concat(values.map { |k, v| "#{k}:#{v}" })
+        end
+      end
+
       result.transform_values { |v| v.join(", ") }
     end
 

lib/meta_tags/view_helper.rb

@@ -169,6 +169,9 @@ def refresh(refresh)
     # @option default [String, Integer] :refresh (nil) meta refresh tag;
     # @option default [Hash] :open_graph ({}) add Open Graph meta tags.
     # @option default [Hash] :open_search ({}) add Open Search link tag.
+    # @option default [Hash] :robots ({}) add robots meta tags.
+    # @option default [Hash] :googlebot ({}) add googlebot meta tags.
+    # @option default [Hash] :googlebot ({}) add bingbot meta tags.
     # @return [String] HTML meta tags to render in HEAD section of the
     #   HTML document.
     #

sig/lib/meta_tags/view_helper.rbs

@@ -30,6 +30,9 @@ module MetaTags
     #     open_search: Hash[Renderer::meta_key, Renderer::meta_value],
     #     article: Hash[Renderer::meta_key, Renderer::meta_value],
     #     al: Hash[Renderer::meta_key, Renderer::meta_value],
+    #     robots: Hash[Renderer::meta_key, Renderer::meta_value],
+    #     googlebot: Hash[Renderer::meta_key, Renderer::meta_value],
+    #     bingbot: Hash[Renderer::meta_key, Renderer::meta_value],
     #     refresh: Integer | String | nil,
     #   } & Hash[Renderer::meta_key, Renderer::meta_value]
     type meta_tags = Hash[Renderer::meta_key, Renderer::meta_value]

spec/view_helper/robots_spec.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe MetaTags::ViewHelper, "displaying robots meta tags" do
+  it "displays meta tags specified with :robots" do
+    subject.display_meta_tags(robots: { "max-snippet": -1 }).tap do |meta|
+      expect(meta).to have_tag("meta", with: { content: "max-snippet:-1", name: "robots" })
+    end
+  end
+
+  it "displays meta tags specified with :googlebot" do
+    subject.display_meta_tags(googlebot: { "unavailable_after": "2020-09-21" }).tap do |meta|
+      expect(meta).to have_tag("meta", with: { content: "unavailable_after:2020-09-21", name: "googlebot" })
+    end
+  end
+
+  it "displays meta tags specified with :bingbot" do
+    subject.display_meta_tags(bingbot: { "max-image-preview": "large" }).tap do |meta|
+      expect(meta).to have_tag("meta", with: { content: "max-image-preview:large", name: "bingbot" })
+    end
+  end
+
+
+  it "displays multiple custom robots tags in a hash" do
+    subject.display_meta_tags(robots: { "max-snippet": -1, "max-video-preview": -1 }).tap do |meta|
+      expect(meta).to have_tag("meta", with: { content: "max-snippet:-1, max-video-preview:-1", name: "robots" })
+    end
+  end
+
+  it "displays custom robots tags along with noindex" do
+    subject.noindex(true)
+    subject.display_meta_tags(robots: { "max-snippet": -1, "max-video-preview": -1 }).tap do |meta|
+      expect(meta).to have_tag("meta", with: { content: "noindex, max-snippet:-1, max-video-preview:-1", name: "robots" })
+    end
+  end
+end