diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 43a1c0e..7925fc6 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -15,9 +15,10 @@ jobs:
       matrix:
         ruby:
           - '3.3.7'
+          - '3.4'
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 68419b3..40c8b38 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## [0.1.3] - 2026-08-19
+
+- Add `Gslide::Presentation::PRESENTATION_ID_PATTERN` and `Gslide::Presentation.file_id_in`, so callers can validate a presentation id without repeating the pattern
+
 ## [0.1.2] - 2025-05-09
 
 - Add `Gslide::HTTPError`, `Gslide::UnauthorizedError` and `Gslide::QuotaExceededError` #10
diff --git a/Gemfile.lock b/Gemfile.lock
index 2008a09..0d81694 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    gslide (0.1.2)
+    gslide (0.1.3)
 
 GEM
   remote: https://rubygems.org/
diff --git a/lib/gslide/models/presentation.rb b/lib/gslide/models/presentation.rb
index 055dd4c..824afea 100644
--- a/lib/gslide/models/presentation.rb
+++ b/lib/gslide/models/presentation.rb
@@ -7,10 +7,17 @@ class Presentation
 
       attr_reader :id
 
-      PRESENTATION_PATTERN = %r[/presentation/d/([a-zA-Z0-9\-_]+)?]
+      PRESENTATION_ID_PATTERN = /[a-zA-Z0-9\-_]+/
+      PRESENTATION_PATTERN = %r[/presentation/d/(#{PRESENTATION_ID_PATTERN})?]
+
+      # @param [String] id_or_url a presentation id, or a sharing url holding one.
+      # @return [String] the presentation id, or the argument when it is not a url.
+      def self.file_id_in(id_or_url)
+        (url_id = id_or_url.match(PRESENTATION_PATTERN)) ? url_id[1] : id_or_url
+      end
 
       def initialize(id_or_url, auth: nil)
-        @id = (url_id = id_or_url.match(PRESENTATION_PATTERN)) ? url_id[1] : id_or_url
+        @id = self.class.file_id_in(id_or_url)
         @auth = auth
       end
 
diff --git a/lib/gslide/version.rb b/lib/gslide/version.rb
index 85d7498..e6000cd 100644
--- a/lib/gslide/version.rb
+++ b/lib/gslide/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Gslide
-  VERSION = "0.1.2"
+  VERSION = "0.1.3"
 end
diff --git a/test/test_gslide.rb b/test/test_gslide.rb
index e3be75f..93d177f 100644
--- a/test/test_gslide.rb
+++ b/test/test_gslide.rb
@@ -20,4 +20,21 @@ def test_initialized_with_presentation_id
     presentation = Gslide::Presentation.new(presentation_id, auth: nil)
     assert_equal "1W11pzmSEH7EoZXiMITa-cOM1y9Ym6Yby9pj_2l5NPm8", presentation.id
   end
+
+  def test_file_id_in_url
+    url = "https://docs.google.com/presentation/d/1W11pzmSEH7EoZXiMITa-cOM1y9Ym6Yby9pj_2l5NPm8/edit?usp=sharing"
+
+    assert_equal "1W11pzmSEH7EoZXiMITa-cOM1y9Ym6Yby9pj_2l5NPm8", Gslide::Presentation.file_id_in(url)
+  end
+
+  def test_file_id_in_id
+    presentation_id = "1W11pzmSEH7EoZXiMITa-cOM1y9Ym6Yby9pj_2l5NPm8"
+
+    assert_equal presentation_id, Gslide::Presentation.file_id_in(presentation_id)
+  end
+
+  def test_presentation_id_pattern_matches_a_file_id
+    assert_match(/\A#{Gslide::Presentation::PRESENTATION_ID_PATTERN}\z/, "1W11pzmSEH7EoZ-XiMITa_cOM")
+    refute_match(/\A#{Gslide::Presentation::PRESENTATION_ID_PATTERN}\z/, "javascript:alert(1)")
+  end
 end