From 3f7c8b45772cbc5c5459d8a4f5ee501e917f2457 Mon Sep 17 00:00:00 2001
From: Serdar Dogruyol <dogruyolserdar@gmail.com>
Date: Fri, 26 Oct 2018 15:00:24 +0300
Subject: [PATCH] Add Kemal::OverrideMethodHandler

---
 spec/override_method_handler_spec.cr | 29 ++++++++++++++++++++++++++++
 src/kemal/override_method_handler.cr | 24 +++++++++++++++++++++++
 2 files changed, 53 insertions(+)
 create mode 100644 spec/override_method_handler_spec.cr
 create mode 100644 src/kemal/override_method_handler.cr

diff --git a/spec/override_method_handler_spec.cr b/spec/override_method_handler_spec.cr
new file mode 100644
index 0000000..2b34e29
--- /dev/null
+++ b/spec/override_method_handler_spec.cr
@@ -0,0 +1,29 @@
+require "./spec_helper"
+
+describe "Kemal::OverrideMethodHandler" do
+  it "does not override method without _method for POST requests" do
+    request = HTTP::Request.new(
+      "POST",
+      "/",
+      body: "_not_method=PATCH",
+      headers: HTTP::Headers{"Content-Type" => "application/x-www-form-urlencoded; charset=UTF-8"}
+    )
+
+    context = create_request_and_return_io_and_context(Kemal::OverrideMethodHandler::INSTANCE, request)[1]
+
+    context.request.method.should eq "POST"
+  end
+
+  it "overrides method with _method for POST requests" do
+    request = HTTP::Request.new(
+      "POST",
+      "/",
+      body: "_method=PATCH",
+      headers: HTTP::Headers{"Content-Type" => "application/x-www-form-urlencoded; charset=UTF-8"}
+    )
+
+    context = create_request_and_return_io_and_context(Kemal::OverrideMethodHandler::INSTANCE, request)[1]
+
+    context.request.method.should eq "PATCH"
+  end
+end
diff --git a/src/kemal/override_method_handler.cr b/src/kemal/override_method_handler.cr
new file mode 100644
index 0000000..097dee9
--- /dev/null
+++ b/src/kemal/override_method_handler.cr
@@ -0,0 +1,24 @@
+module Kemal
+  class OverrideMethodHandler
+    include HTTP::Handler
+    INSTANCE = new
+
+    ALLOWED_METHODS           = ["PUT", "PATCH", "DELETE"]
+    OVERRIDE_METHOD           = "POST"
+    OVERRIDE_METHOD_PARAM_KEY = "_method"
+
+    def call(context)
+      request = context.request
+      if request.method == OVERRIDE_METHOD
+        if context.params.body.has_key?(OVERRIDE_METHOD_PARAM_KEY) && override_method_valid?(context.params.body["_method"])
+          request.method = context.params.body["_method"].upcase
+        end
+      end
+      call_next(context)
+    end
+
+    def override_method_valid?(override_method : String)
+      ALLOWED_METHODS.includes?(override_method.upcase)
+    end
+  end
+end