introduce experimental adapter pattern for hdlrs

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)
+	}
+}