fix(signin): accept application/x-www-form-urlencoded bodies

The legacy Ruby service accepts browser login forms posted as
application/x-www-form-urlencoded, but action-controller only registers
a JSON body parser by default, so POST /auth/signin returned 415 for
form posts. SigninBody already defined .from_form; wire it up by
registering a form-urlencoded body parser on the Application base
controller so form logins are accepted (202 + Set-Cookie), matching the
legacy behaviour.

Author: chillfox

spec/controllers/sessions_spec.cr

@@ -30,6 +30,25 @@ module PlaceOS::Auth
         user.try &.destroy
       end
 
+      it "accepts an application/x-www-form-urlencoded body (browser login form)", tags: "signin-form" do
+        password = "ok-password-1234"
+        user = create_user.call(password)
+
+        body = URI::Params.build do |fp|
+          fp.add("email", user.email.to_s)
+          fp.add("password", password)
+        end
+        headers = HTTP::Headers{
+          "Host"         => "localhost",
+          "Content-Type" => "application/x-www-form-urlencoded",
+        }
+        result = client.post("/auth/signin", headers: headers, body: body)
+        result.status_code.should eq 202
+        result.headers["Set-Cookie"]?.should_not be_nil
+      ensure
+        user.try &.destroy
+      end
+
       it "redirects to a safe `continue` target when supplied" do
         password = "ok-password-1234"
         user = create_user.call(password)

src/placeos-auth/controllers/application.cr

@@ -11,6 +11,17 @@ module PlaceOS::Auth
       Log = ::PlaceOS::Auth::Log.for(self)
     end
 
+    # The legacy Ruby service accepts browser login forms posted as
+    # `application/x-www-form-urlencoded`; action-controller only ships a
+    # JSON body parser out of the box. Register a form parser so typed
+    # body arguments can be built from form posts. Body structs opt in by
+    # defining `self.from_form(URI::Params)`.
+    add_parser("application/x-www-form-urlencoded") do |klass, body_io, request|
+      request_charset = ActionController::Support.charset(request.headers)
+      body_io.set_encoding(request_charset) if request_charset
+      klass.from_form(URI::Params.parse(body_io.gets_to_end))
+    end
+
     include Utils::CurrentUser
     include Utils::SessionHelper