feat: extract auth into provider (#663)

* extract auth into provider

* bump go version

* use pointer

* rebase

Former-commit-id: 8538877f52b9aae43b38afb37e5c69d99cb4827c

backend/app/api/providers/extractors.go

@@ -0,0 +1,55 @@
+package providers
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/hay-kot/homebox/backend/internal/sys/validate"
+	"github.com/hay-kot/httpkit/server"
+	"github.com/rs/zerolog/log"
+)
+
+type LoginForm struct {
+	Username     string `json:"username"`
+	Password     string `json:"password"`
+	StayLoggedIn bool   `json:"stayLoggedIn"`
+}
+
+func getLoginForm(r *http.Request) (LoginForm, error) {
+	loginForm := LoginForm{}
+
+	switch r.Header.Get("Content-Type") {
+	case "application/x-www-form-urlencoded":
+		err := r.ParseForm()
+		if err != nil {
+			return loginForm, errors.New("failed to parse form")
+		}
+
+		loginForm.Username = r.PostFormValue("username")
+		loginForm.Password = r.PostFormValue("password")
+		loginForm.StayLoggedIn = r.PostFormValue("stayLoggedIn") == "true"
+	case "application/json":
+		err := server.Decode(r, &loginForm)
+		if err != nil {
+			log.Err(err).Msg("failed to decode login form")
+			return loginForm, errors.New("failed to decode login form")
+		}
+	default:
+		return loginForm, errors.New("invalid content type")
+	}
+
+	if loginForm.Username == "" || loginForm.Password == "" {
+		return loginForm, validate.NewFieldErrors(
+			validate.FieldError{
+				Field: "username",
+				Error: "username or password is empty",
+			},
+			validate.FieldError{
+				Field: "password",
+				Error: "username or password is empty",
+			},
+		)
+	}
+
+	return loginForm, nil
+}