refactor: sha256 slug generation

app/controllers/link.cr

@@ -9,6 +9,7 @@ module App::Controllers::Link
   class Create < App::Lib::BaseController
     include App::Models
     include App::Lib
+    include App::Services
 
     def call(env)
       user = env.get("user").as(User)
@@ -29,7 +30,7 @@ module App::Controllers::Link
 
       attempts = 0
       loop do
-        slug = Random::Secure.urlsafe_base64(attempts >= 2 ? 6 : 5).gsub(/[^a-zA-Z0-9]/, "")
+        slug = SlugService.generate_base64(url, 5 + attempts)
         unless Database.get_by(Link, slug: slug)
           link.slug = slug
           break

app/services/slug.cr

@@ -0,0 +1,9 @@
+require "digest"
+
+module App::Services::SlugService
+  def self.generate_base64(link : String, size : Int32) : String
+    hash = Digest::SHA256.digest(link)
+    base64_encoded = Base64.urlsafe_encode(hash).strip.tr("+/", "")
+    base64_encoded[0, size]
+  end
+end

bit.cr

@@ -5,6 +5,7 @@ require "./app/lib/*"
 require "./app/models/*"
 require "./app/serializers/*"
 require "./app/middlewares/*"
+require "./app/services/*"
 
 require "./app/routes"