Use MIME in HTTP::StaticFileHandler

src/http/server/handlers/static_file_handler.cr

@@ -1,6 +1,7 @@
 require "ecr/macros"
 require "html"
 require "uri"
+require "mime"
 
 # A simple handler that lists directories and serves files under a given public directory.
 class HTTP::StaticFileHandler
@@ -80,7 +81,7 @@ class HTTP::StaticFileHandler
         end
       end
 
-      context.response.content_type = mime_type(file_path)
+      context.response.content_type = MIME.fetch(File.extname(file_path), "application/octet-stream")
       context.response.content_length = File.size(file_path)
       File.open(file_path) do |file|
         IO.copy(file, context.response)
@@ -103,17 +104,6 @@ class HTTP::StaticFileHandler
     context.response.headers.add "Location", url
   end
 
-  private def mime_type(path)
-    case File.extname(path)
-    when ".txt"          then "text/plain"
-    when ".htm", ".html" then "text/html"
-    when ".css"          then "text/css"
-    when ".js"           then "application/javascript"
-    when ".svg"          then "image/svg+xml"
-    else                      "application/octet-stream"
-    end
-  end
-
   record DirectoryListing, request_path : String, path : String do
     @escaped_request_path : String?