introduce experimental adapter pattern for hdlrs

backend/internal/sys/validate/errors.go

@@ -5,7 +5,8 @@ import (
 	"errors"
 )
 
-type UnauthorizedError struct{}
+type UnauthorizedError struct {
+}
 
 func (err *UnauthorizedError) Error() string {
 	return "unauthorized"
@@ -28,7 +29,7 @@ func (err *InvalidRouteKeyError) Error() string {
 	return "invalid route key: " + err.key
 }
 
-func NewInvalidRouteKeyError(key string) error {
+func NewRouteKeyError(key string) error {
 	return &InvalidRouteKeyError{key}
 }
 

backend/internal/web/adapters/adapters.go

@@ -0,0 +1,95 @@
+// Package adapters provides functions to adapt functions to the server.Handler interface.
+package adapters
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/google/uuid"
+	"github.com/hay-kot/homebox/backend/pkgs/server"
+)
+
+type AdapterFunc[T any, Y any] func(context.Context, T) (Y, error)
+type IDFunc[T any, Y any] func(context.Context, uuid.UUID, T) (Y, error)
+
+// Query is a server.Handler that decodes a query from the request and calls the provided function.
+func Query[T any, Y any](f AdapterFunc[T, Y], ok int) server.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) error {
+		q, err := decodeQuery[T](r)
+		if err != nil {
+			return err
+		}
+
+		res, err := f(r.Context(), q)
+		if err != nil {
+			return err
+		}
+
+		return server.Respond(w, ok, res)
+	}
+}
+
+// QueryID is a server.Handler that decodes a query and an ID from the request and calls the provided function.
+func QueryID[T any, Y any](param string, f IDFunc[T, Y], ok int) server.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) error {
+		ID, err := routeUUID(r, param)
+		if err != nil {
+			return err
+		}
+
+		q, err := decodeQuery[T](r)
+		if err != nil {
+			return err
+		}
+
+		res, err := f(r.Context(), ID, q)
+		if err != nil {
+			return err
+		}
+
+		return server.Respond(w, ok, res)
+	}
+}
+
+// Action is a function that adapts a function to the server.Handler interface.
+// It decodes the request body into a value of type T and passes it to the function f.
+// The function f is expected to return a value of type Y and an error.
+//
+// Note: Action differs from Query in that it decodes the request body.
+func Action[T any, Y any](f AdapterFunc[T, Y], ok int) server.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) error {
+		v, err := decode[T](r)
+		if err != nil {
+			return err
+		}
+
+		res, err := f(r.Context(), v)
+		if err != nil {
+			return err
+		}
+
+		return server.Respond(w, ok, res)
+	}
+}
+
+// ActionID functions the same as Action, but it also decodes a UUID from the URL path.
+func ActionID[T any, Y any](param string, f IDFunc[T, Y], ok int) server.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) error {
+		ID, err := routeUUID(r, param)
+		if err != nil {
+			return err
+		}
+
+		v, err := decode[T](r)
+		if err != nil {
+			return err
+		}
+
+		res, err := f(r.Context(), ID, v)
+		if err != nil {
+			return err
+		}
+
+		return server.Respond(w, ok, res)
+	}
+}

backend/internal/web/adapters/decoders.go

@@ -0,0 +1,52 @@
+package adapters
+
+import (
+	"net/http"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/google/uuid"
+	"github.com/gorilla/schema"
+	"github.com/hay-kot/homebox/backend/internal/sys/validate"
+	"github.com/hay-kot/homebox/backend/pkgs/server"
+)
+
+var queryDecoder = schema.NewDecoder()
+
+func decodeQuery[T any](r *http.Request) (T, error) {
+	var v T
+	err := queryDecoder.Decode(&v, r.URL.Query())
+	if err != nil {
+		return v, err
+	}
+
+	err = validate.Check(v)
+	if err != nil {
+		return v, err
+	}
+
+	return v, nil
+}
+
+func decode[T any](r *http.Request) (T, error) {
+	var v T
+
+	err := server.Decode(r, &v)
+	if err != nil {
+		return v, err
+	}
+
+	err = validate.Check(v)
+	if err != nil {
+		return v, err
+	}
+
+	return v, nil
+}
+
+func routeUUID(r *http.Request, key string) (uuid.UUID, error) {
+	ID, err := uuid.Parse(chi.URLParam(r, key))
+	if err != nil {
+		return uuid.Nil, validate.NewRouteKeyError(key)
+	}
+	return ID, nil
+}