Isolate http specific parts to minimal

internal/handlers/single.go

@@ -0,0 +1,47 @@
+package handlers
+
+import (
+	"context"
+	"errors"
+	"io"
+
+	"git.defalsify.org/vise.git/engine"
+	"git.defalsify.org/vise.git/resource"
+	"git.defalsify.org/vise.git/persist"
+
+	"git.grassecon.net/urdt/ussd/internal/storage"
+)
+
+var (
+	ErrInvalidRequest = errors.New("invalid request for context")
+	ErrSessionMissing = errors.New("missing session")
+	ErrInvalidInput = errors.New("invalid input")
+	ErrStorage = errors.New("storage retrieval fail")
+	ErrEngineType = errors.New("incompatible engine")
+	ErrEngineInit = errors.New("engine init fail")
+	ErrEngineExec = errors.New("engine exec fail")
+)
+
+type RequestSession struct {
+	Ctx context.Context
+	Config engine.Config
+	Engine engine.Engine
+	Input []byte
+	Storage storage.Storage
+	Writer io.Writer
+}
+
+type engineMaker func(cfg engine.Config, rs resource.Resource, pr *persist.Persister) engine.Engine
+
+type RequestParser interface {
+	GetSessionId(rq any) (string, error)
+	GetInput(rq any) ([]byte, error)
+}
+
+type RequestHandler interface {
+	GetEngine(cfg engine.Config, rs resource.Resource, pe *persist.Persister) engine.Engine 
+	Process(rs RequestSession) (RequestSession, error)
+	Output(rs RequestSession) (RequestSession, error)
+	Reset(rs RequestSession) (RequestSession, error)
+	ShutDown()
+}