refactor: replace ClickController class with struct

app/controllers/click.cr

@@ -4,52 +4,55 @@ UserAgent.load_regexes(File.read("data/uap_core_regexes.yaml"))
 IpLookup.load_mmdb("data/GeoLite2-Country.mmdb")
 
 module App::Controllers
-  class ClickController
+  struct ClickController
     include App::Models
     include App::Lib
     include App::Services
 
-    def initialize(@env : HTTP::Server::Context); end
+    def self.redirect_handler
+      ->(env : HTTP::Server::Context) {
+        slug = env.params.url["slug"]
 
-    def redirect
-      slug = @env.params.url["slug"]
-
-      link_data = nil
-      Database.raw_query("SELECT id, url FROM links WHERE slug = (?) LIMIT 1", slug) do |result|
-        if result.move_next
-          link_data = {result.read(Int64), result.read(String)}
+        link_data = nil
+        Database.raw_query("SELECT id, url FROM links WHERE slug = (?) LIMIT 1", slug) do |result|
+          if result.move_next
+            link_data = {result.read(Int64), result.read(String)}
+          end
         end
-      end
-      raise App::NotFoundException.new(@env) unless link_data
+        raise App::NotFoundException.new(env) unless link_data
 
-      link_id, url = link_data
-      client_ip = IpLookup.ip_from_address(@env.request.headers["Cf-Connecting-Ip"]? || @env.request.remote_address.to_s)
+        link_id, url = link_data
+        client_ip = IpLookup.ip_from_address(env.request.headers["Cf-Connecting-Ip"]? || env.request.remote_address.to_s)
 
-      @env.response.status_code = 301
-      @env.response.headers["Location"] = url
-      @env.response.headers["X-Forwarded-For"] = client_ip.to_s
-      @env.response.headers["Connection"] = "close"
+        spawn do
+          begin
+            user_agent_str = env.request.headers["User-Agent"]?
+            referer = env.request.headers["Referer"]?.try { |r| URI.parse(r).host rescue r } || env.params.query["utm_source"]? || "Direct"
 
-      spawn do
-        begin
-          user_agent_str = @env.request.headers["User-Agent"]?
-          referer = @env.request.headers["Referer"]?.try { |r| URI.parse(r).host rescue r } || @env.params.query["utm_source"]? || "Direct"
+            ua_parser = user_agent_str ? UserAgent.new(user_agent_str) : nil
 
-          ua_parser = user_agent_str ? UserAgent.new(user_agent_str) : nil
+            click = App::Models::Click.new
+            click.link_id = link_id
+            click.country = client_ip ? IpLookup.new(client_ip).try(&.country.try(&.code)) : nil
+            click.user_agent = ua_parser.to_s
+            click.browser = ua_parser.try(&.family)
+            click.os = ua_parser.try(&.os.try(&.family))
+            click.referer = referer
 
-          click = App::Models::Click.new
-          click.link_id = link_id
-          click.country = client_ip ? IpLookup.new(client_ip).try(&.country.try(&.code)) : nil
-          click.user_agent = ua_parser.to_s
-          click.browser = ua_parser.try(&.family)
-          click.os = ua_parser.try(&.os.try(&.family))
-          click.referer = referer
-
-          Database.insert(click)
-        rescue ex
-          Log.error { "Click tracking error: #{ex.message}" }
+            Database.insert(click)
+          rescue ex
+            Log.error { "Click tracking error: #{ex.message}" }
+          end
         end
-      end
+
+        env.response.status_code = 301
+        env.response.headers.add("Location", url)
+        env.response.headers.add("X-Forwarded-For", client_ip.to_s)
+        env.response.print ""
+        env.response.close
+
+        return
+      }
     end
   end
 end

app/lib/errors.cr

@@ -55,12 +55,3 @@ module App
     end
   end
 end
-
-error 500 do |env|
-  App::InternalServerErrorException.new(env)
-  ""
-end
-
-error 404 do |env|
-  ""
-end

app/routes.cr

@@ -1,26 +1,40 @@
 require "./controllers/**"
 
-module App
-  # CORS handling middleware
-  before_all do |env|
-    if env.request.path.starts_with?("/api/")
-      env.response.headers["Access-Control-Allow-Origin"] = "*"
-      env.response.headers["Access-Control-Allow-Methods"] = "GET, POST, PUT, DELETE, OPTIONS"
-      env.response.headers["Access-Control-Allow-Headers"] = "Content-Type, Accept, Origin, X-Api-Key"
+require "kemal"
+
+class CORSHandler < Kemal::Handler
+  exclude ["/:slug"]
+
+  def initialize(
+    @allow_origin = "*",
+    @allow_methods = "GET, POST, PUT, DELETE, OPTIONS",
+    @allow_headers = "Content-Type, Accept, Origin, X-Api-Key"
+  )
+  end
+
+  def call(context)
+    return call_next(context) if exclude_match?(context)
+
+    context.response.headers["Access-Control-Allow-Origin"] = @allow_origin
+    context.response.headers["Access-Control-Allow-Methods"] = @allow_methods
+    context.response.headers["Access-Control-Allow-Headers"] = @allow_headers
+
+    # If this is a preflight OPTIONS request, we return immediately with 200
+    if context.request.method == "OPTIONS"
+      context.response.status_code = 200
+      context.response.content_type = "text/plain"
+      context.response.print("")
+      return context
     end
-  end
 
-  # Error handling middleware
-  error 404 do |env|
-    {error: "Not Found"}.to_json
-  end
-  error 500 do |env|
-    {error: "Internal Server Error"}.to_json
+    call_next(context)
   end
+end
 
-  get "/:slug" do |env|
-    Controllers::ClickController.new(env).redirect
-  end
+add_handler CORSHandler.new
+
+module App
+  get "/:slug", &App::Controllers::ClickController.redirect_handler
 
   # Namespace /api
   get "/api/ping" do |env|
@@ -50,4 +64,9 @@ module App
   delete "/api/links/:id" do |env|
     Controllers::LinkController.new(env).delete
   end
+
+  error 500 do |env|
+    App::InternalServerErrorException.new(env)
+    ""
+  end
 end