README.md

@@ -107,17 +107,12 @@ func main() {
         log.Fatalf("invalid config: %s", err)
     }
 
-    // add http middlewares (logger)
-    builder.With(func(next http.Handler) http.Handler{ /* ... */ })
-
-    // add contextual middlewares (authentication)
-    builder.WithContext(func(next http.Handler) http.Handler{ /* ... */ })
-
     // bind handlers
     err = builder.Bind(http.MethodGet, "/user/{id}", getUserById)
     if err != nil {
         log.Fatalf("cannog bind GET /user/{id}: %s", err)
     }
+    // ...
 
     // build your services
     handler, err := builder.Build()
@@ -266,7 +261,7 @@ type res struct{
     Output2 bool
 }
 
-func myHandler(ctx context.Context, r req) (*res, api.Err) {
+func myHandler(r req) (*res, api.Err) {
     err := doSomething()
     if err != nil {
         return nil, api.ErrFailure

api/adapter.go

@@ -0,0 +1,13 @@
+package api
+
+import "net/http"
+
+// Adapter to encapsulate incoming requests
+type Adapter func(http.HandlerFunc) http.HandlerFunc
+
+// AuthHandlerFunc is http.HandlerFunc with additional Authorization information
+type AuthHandlerFunc func(Auth, http.ResponseWriter, *http.Request)
+
+// AuthAdapter to encapsulate incoming request with access to api.Auth
+// to manage permissions
+type AuthAdapter func(AuthHandlerFunc) AuthHandlerFunc

api/auth.go

@@ -21,7 +21,7 @@ type Auth struct {
 
 // Granted returns whether the authorization is granted
 // i.e. Auth.Active fulfills Auth.Required
-func (a *Auth) Granted() bool {
+func (a Auth) Granted() bool {
 	var nothingRequired = true
 
 	// first dimension: OR ; at least one is valid
@@ -43,7 +43,7 @@ func (a *Auth) Granted() bool {
 }
 
 // returns whether Auth.Active fulfills (contains) all @required roles
-func (a *Auth) fulfills(required []string) bool {
+func (a Auth) fulfills(required []string) bool {
 	for _, requiredRole := range required {
 		var found = false
 		for _, activeRole := range a.Active {

api/context.go

@@ -1,44 +1,17 @@
 package api
 
 import (
-	"context"
 	"net/http"
-
-	"git.xdrm.io/go/aicra/internal/ctx"
 )
 
-// GetRequest extracts the current request from a context.Context
+// Ctx contains additional information for handlers
-func GetRequest(c context.Context) *http.Request {
+//
-	var (
+// usually input/output arguments built by aicra are sufficient
-		raw      = c.Value(ctx.Request)
+// but the Ctx lets you manage your request from scratch if required
-		cast, ok = raw.(*http.Request)
+//
-	)
+// If required, set api.Ctx as the first argument of your handler; if you
-	if !ok {
+// don't need it, only use standard input arguments and it will be ignored
-		return nil
+type Ctx struct {
-	}
+	Res http.ResponseWriter
-	return cast
+	Req *http.Request
-}
-
-// GetResponseWriter extracts the response writer from a context.Context
-func GetResponseWriter(c context.Context) http.ResponseWriter {
-	var (
-		raw      = c.Value(ctx.Response)
-		cast, ok = raw.(http.ResponseWriter)
-	)
-	if !ok {
-		return nil
-	}
-	return cast
-}
-
-// GetAuth returns the api.Auth associated with this request from a context.Context
-func GetAuth(c context.Context) *Auth {
-	var (
-		raw      = c.Value(ctx.Auth)
-		cast, ok = raw.(*Auth)
-	)
-	if !ok {
-		return nil
-	}
-	return cast
 }

builder.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"net/http"
 
+	"git.xdrm.io/go/aicra/api"
 	"git.xdrm.io/go/aicra/datatype"
 	"git.xdrm.io/go/aicra/internal/config"
 	"git.xdrm.io/go/aicra/internal/dynfunc"
@@ -12,16 +13,10 @@ import (
 
 // Builder for an aicra server
 type Builder struct {
-	// the server configuration defining available services
 	conf         *config.Server
-	// user-defined handlers bound to services from the configuration
 	handlers     []*apiHandler
-	// http middlewares wrapping the entire http connection (e.g. logger)
+	adapters     []api.Adapter
-	middlewares []func(http.Handler) http.Handler
+	authAdapters []api.AuthAdapter
-	// custom middlewares only wrapping the service handler of a request
-	// they will benefit from the request's context that contains service-specific
-	// information (e.g. required permisisons from the configuration)
-	ctxMiddlewares []func(http.Handler) http.Handler
 }
 
 // represents an api handler (method-pattern combination)
@@ -46,36 +41,26 @@ func (b *Builder) AddType(t datatype.T) error {
 	return nil
 }
 
-// With adds an http middleware on top of the http connection
+// With adds an http adapter (middleware)
-//
+func (b *Builder) With(adapter api.Adapter) {
-// Authentication management can only be done with the WithContext() methods as
-// the service associated with the request has not been found at this stage.
-// This stage is perfect for logging or generic request management.
-func (b *Builder) With(mw func(http.Handler) http.Handler) {
 	if b.conf == nil {
 		b.conf = &config.Server{}
 	}
-	if b.middlewares == nil {
+	if b.adapters == nil {
-		b.middlewares = make([]func(http.Handler) http.Handler, 0)
+		b.adapters = make([]api.Adapter, 0)
 	}
-	b.middlewares = append(b.middlewares, mw)
+	b.adapters = append(b.adapters, adapter)
 }
 
-// WithContext adds an http middleware with the fully loaded context
+// WithAuth adds an http adapter with auth capabilities (middleware)
-//
+func (b *Builder) WithAuth(adapter api.AuthAdapter) {
-// Logging or generic request management should be done with the With() method as
-// it wraps the full http connection. Middlewares added through this method only
-// wrap the user-defined service handler. The context.Context is filled with useful
-// data that can be access with api.GetRequest(), api.GetResponseWriter(),
-// api.GetAuth(), etc methods.
-func (b *Builder) WithContext(mw func(http.Handler) http.Handler) {
 	if b.conf == nil {
 		b.conf = &config.Server{}
 	}
-	if b.ctxMiddlewares == nil {
+	if b.authAdapters == nil {
-		b.ctxMiddlewares = make([]func(http.Handler) http.Handler, 0)
+		b.authAdapters = make([]api.AuthAdapter, 0)
 	}
-	b.ctxMiddlewares = append(b.ctxMiddlewares, mw)
+	b.authAdapters = append(b.authAdapters, adapter)
 }
 
 // Setup the builder with its api definition file

builder_test.go

@@ -1,7 +1,6 @@
 package aicra
 
 import (
-	"context"
 	"errors"
 	"net/http"
 	"strings"
@@ -73,7 +72,7 @@ func TestBind(t *testing.T) {
 			Config:        "[]",
 			HandlerMethod: "",
 			HandlerPath:   "",
-			HandlerFn:     func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			HandlerFn:     func() (*struct{}, api.Err) { return nil, api.ErrSuccess },
 			BindErr:       errUnknownService,
 			BuildErr:      nil,
 		},
@@ -109,7 +108,7 @@ func TestBind(t *testing.T) {
 			]`,
 			HandlerMethod: http.MethodPost,
 			HandlerPath:   "/path",
-			HandlerFn:     func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			HandlerFn:     func() (*struct{}, api.Err) { return nil, api.ErrSuccess },
 			BindErr:       errUnknownService,
 			BuildErr:      errMissingHandler,
 		},
@@ -127,7 +126,7 @@ func TestBind(t *testing.T) {
 			]`,
 			HandlerMethod: http.MethodGet,
 			HandlerPath:   "/paths",
-			HandlerFn:     func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			HandlerFn:     func() (*struct{}, api.Err) { return nil, api.ErrSuccess },
 			BindErr:       errUnknownService,
 			BuildErr:      errMissingHandler,
 		},
@@ -145,7 +144,7 @@ func TestBind(t *testing.T) {
 			]`,
 			HandlerMethod: http.MethodGet,
 			HandlerPath:   "/path",
-			HandlerFn:     func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			HandlerFn:     func() (*struct{}, api.Err) { return nil, api.ErrSuccess },
 			BindErr:       nil,
 			BuildErr:      nil,
 		},
@@ -165,7 +164,7 @@ func TestBind(t *testing.T) {
 			]`,
 			HandlerMethod: http.MethodGet,
 			HandlerPath:   "/path",
-			HandlerFn:     func(context.Context, struct{ Name int }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			HandlerFn:     func(struct{ Name int }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
 			BindErr:       nil,
 			BuildErr:      nil,
 		},
@@ -185,7 +184,7 @@ func TestBind(t *testing.T) {
 			]`,
 			HandlerMethod: http.MethodGet,
 			HandlerPath:   "/path",
-			HandlerFn:     func(context.Context, struct{ Name uint }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			HandlerFn:     func(struct{ Name uint }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
 			BindErr:       nil,
 			BuildErr:      nil,
 		},
@@ -205,7 +204,7 @@ func TestBind(t *testing.T) {
 			]`,
 			HandlerMethod: http.MethodGet,
 			HandlerPath:   "/path",
-			HandlerFn:     func(context.Context, struct{ Name string }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			HandlerFn:     func(struct{ Name string }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
 			BindErr:       nil,
 			BuildErr:      nil,
 		},
@@ -225,7 +224,7 @@ func TestBind(t *testing.T) {
 			]`,
 			HandlerMethod: http.MethodGet,
 			HandlerPath:   "/path",
-			HandlerFn:     func(context.Context, struct{ Name bool }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			HandlerFn:     func(struct{ Name bool }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
 			BindErr:       nil,
 			BuildErr:      nil,
 		},

handler.go

@@ -1,14 +1,12 @@
 package aicra
 
 import (
-	"context"
 	"fmt"
 	"net/http"
 	"strings"
 
 	"git.xdrm.io/go/aicra/api"
 	"git.xdrm.io/go/aicra/internal/config"
-	"git.xdrm.io/go/aicra/internal/ctx"
 	"git.xdrm.io/go/aicra/internal/reqdata"
 )
 
@@ -17,31 +15,30 @@ type Handler Builder
 
 // ServeHTTP implements http.Handler and wraps it in middlewares (adapters)
 func (s Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	var h http.Handler = http.HandlerFunc(s.resolve)
+	var h = http.HandlerFunc(s.resolve)
 
-	for _, mw := range s.middlewares {
+	for _, adapter := range s.adapters {
-		h = mw(h)
+		h = adapter(h)
 	}
-	h.ServeHTTP(w, r)
+	h(w, r)
 }
 
-// ServeHTTP implements http.Handler and wraps it in middlewares (adapters)
 func (s Handler) resolve(w http.ResponseWriter, r *http.Request) {
-	// 1ind a matching service from config
+	// 1. find a matching service from config
 	var service = s.conf.Find(r)
 	if service == nil {
 		handleError(api.ErrUnknownService, w, r)
 		return
 	}
 
-	// extract request data
+	// 2. extract request data
 	var input, err = extractInput(service, *r)
 	if err != nil {
 		handleError(api.ErrMissingParam, w, r)
 		return
 	}
 
-	// find a matching handler
+	// 3. find a matching handler
 	var handler *apiHandler
 	for _, h := range s.handlers {
 		if h.Method == service.Method && h.Path == service.Pattern {
@@ -49,50 +46,59 @@ func (s Handler) resolve(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	// fail on no matching handler
+	// 4. fail on no matching handler
 	if handler == nil {
 		handleError(api.ErrUncallableService, w, r)
 		return
 	}
 
-	// build context with builtin data
+	// replace format '[a]' in scope where 'a' is an existing input's name
-	c := r.Context()
+	scope := make([][]string, len(service.Scope))
-	c = context.WithValue(c, ctx.Request, r)
+	for a, list := range service.Scope {
-	c = context.WithValue(c, ctx.Response, w)
+		scope[a] = make([]string, len(list))
-	c = context.WithValue(c, ctx.Auth, buildAuth(service.Scope, input.Data))
+		for b, perm := range list {
+			scope[a][b] = perm
+			for name, value := range input.Data {
+				var (
+					token       = fmt.Sprintf("[%s]", name)
+					replacement = ""
+				)
+				if value != nil {
+					replacement = fmt.Sprintf("[%v]", value)
+				}
+				scope[a][b] = strings.ReplaceAll(scope[a][b], token, replacement)
+			}
+		}
+	}
 
-	// create http handler
+	var auth = api.Auth{
-	var h http.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		Required: scope,
-		auth := api.GetAuth(r.Context())
+		Active:   []string{},
-		if auth == nil {
+	}
+
+	// 5. run auth-aware middlewares
+	var h = api.AuthHandlerFunc(func(a api.Auth, w http.ResponseWriter, r *http.Request) {
+		if !a.Granted() {
 			handleError(api.ErrPermission, w, r)
 			return
 		}
 
-		// reject non granted requests
+		s.handle(input, handler, service, w, r)
-		if !auth.Granted() {
-			handleError(api.ErrPermission, w, r)
-			return
-		}
-
-		// use context defined in the request
-		s.handle(r.Context(), input, handler, service, w, r)
 	})
 
-	// run middlewares the handler
+	for _, adapter := range s.authAdapters {
-	for _, mw := range s.ctxMiddlewares {
+		h = adapter(h)
-		h = mw(h)
 	}
+	h(auth, w, r)
 
-	// serve using the context with values
-	h.ServeHTTP(w, r.WithContext(c))
 }
 
-func (s *Handler) handle(c context.Context, input *reqdata.T, handler *apiHandler, service *config.Service, w http.ResponseWriter, r *http.Request) {
+func (s *Handler) handle(input *reqdata.T, handler *apiHandler, service *config.Service, w http.ResponseWriter, r *http.Request) {
-	// pass execution to the handler
+	// 5. pass execution to the handler
-	var outData, outErr = handler.dyn.Handle(c, input.Data)
+	ctx := api.Ctx{Res: w, Req: r}
+	var outData, outErr = handler.dyn.Handle(ctx, input.Data)
 
-	// build response from returned arguments
+	// 6. build res from returned data
 	var res = api.EmptyResponse().WithError(outErr)
 	for key, value := range outData {
 
@@ -143,35 +149,3 @@ func extractInput(service *config.Service, req http.Request) (*reqdata.T, error)
 
 	return dataset, nil
 }
-
-// buildAuth builds the api.Auth struct from the service scope configuration
-//
-// it replaces format '[a]' in scope where 'a' is an existing input argument's
-// name with its value
-func buildAuth(scope [][]string, in map[string]interface{}) *api.Auth {
-	updated := make([][]string, len(scope))
-
-	// replace '[arg_name]' with the 'arg_name' value if it is a known variable
-	// name
-	for a, list := range scope {
-		updated[a] = make([]string, len(list))
-		for b, perm := range list {
-			updated[a][b] = perm
-			for name, value := range in {
-				var (
-					token       = fmt.Sprintf("[%s]", name)
-					replacement = ""
-				)
-				if value != nil {
-					replacement = fmt.Sprintf("[%v]", value)
-				}
-				updated[a][b] = strings.ReplaceAll(updated[a][b], token, replacement)
-			}
-		}
-	}
-
-	return &api.Auth{
-		Required: updated,
-		Active:   []string{},
-	}
-}

handler_test.go

@@ -3,7 +3,6 @@ package aicra_test
 import (
 	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
 	"net/http"
 	"net/http/httptest"
@@ -49,15 +48,15 @@ func TestWith(t *testing.T) {
 	type ckey int
 	const key ckey = 0
 
-	middleware := func(next http.Handler) http.Handler {
+	middleware := func(next http.HandlerFunc) http.HandlerFunc {
-		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		return func(w http.ResponseWriter, r *http.Request) {
 			newr := r
 
 			// first time -> store 1
 			value := r.Context().Value(key)
 			if value == nil {
 				newr = r.WithContext(context.WithValue(r.Context(), key, int(1)))
-				next.ServeHTTP(w, newr)
+				next(w, newr)
 				return
 			}
 
@@ -68,8 +67,8 @@ func TestWith(t *testing.T) {
 			}
 			cast++
 			newr = r.WithContext(context.WithValue(r.Context(), key, cast))
-			next.ServeHTTP(w, newr)
+			next(w, newr)
-		})
+		}
 	}
 
 	// add middleware @n times
@@ -83,9 +82,9 @@ func TestWith(t *testing.T) {
 		t.Fatalf("setup: unexpected error <%v>", err)
 	}
 
-	pathHandler := func(ctx context.Context) (*struct{}, api.Err) {
+	pathHandler := func(ctx api.Ctx) (*struct{}, api.Err) {
 		// write value from middlewares into response
-		value := ctx.Value(key)
+		value := ctx.Req.Context().Value(key)
 		if value == nil {
 			t.Fatalf("nothing found in context")
 		}
@@ -94,7 +93,7 @@ func TestWith(t *testing.T) {
 			t.Fatalf("cannot cast context data to int")
 		}
 		// write to response
-		api.GetResponseWriter(ctx).Write([]byte(fmt.Sprintf("#%d#", cast)))
+		ctx.Res.Write([]byte(fmt.Sprintf("#%d#", cast)))
 
 		return nil, api.ErrSuccess
 	}
@@ -213,13 +212,8 @@ func TestWithAuth(t *testing.T) {
 			}
 
 			// tester middleware (last executed)
-			builder.WithContext(func(next http.Handler) http.Handler {
+			builder.WithAuth(func(next api.AuthHandlerFunc) api.AuthHandlerFunc {
-				return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				return func(a api.Auth, w http.ResponseWriter, r *http.Request) {
-					a := api.GetAuth(r.Context())
-					if a == nil {
-						t.Fatalf("cannot access api.Auth form request context")
-					}
-
 					if a.Granted() == tc.granted {
 						return
 					}
@@ -228,20 +222,14 @@ func TestWithAuth(t *testing.T) {
 					} else {
 						t.Fatalf("expected granted auth")
 					}
-					next.ServeHTTP(w, r)
-				})
-			})
-
-			builder.WithContext(func(next http.Handler) http.Handler {
-				return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-					a := api.GetAuth(r.Context())
-					if a == nil {
-						t.Fatalf("cannot access api.Auth form request context")
 				}
-
-					a.Active = tc.permissions
-					next.ServeHTTP(w, r)
 			})
+
+			builder.WithAuth(func(next api.AuthHandlerFunc) api.AuthHandlerFunc {
+				return func(a api.Auth, w http.ResponseWriter, r *http.Request) {
+					a.Active = tc.permissions
+					next(a, w, r)
+				}
 			})
 
 			err := builder.Setup(strings.NewReader(tc.manifest))
@@ -249,7 +237,7 @@ func TestWithAuth(t *testing.T) {
 				t.Fatalf("setup: unexpected error <%v>", err)
 			}
 
-			pathHandler := func(ctx context.Context) (*struct{}, api.Err) {
+			pathHandler := func(ctx api.Ctx) (*struct{}, api.Err) {
 				return nil, api.ErrNotImplemented
 			}
 
@@ -276,97 +264,6 @@ func TestWithAuth(t *testing.T) {
 
 }
 
-func TestPermissionError(t *testing.T) {
-
-	tt := []struct {
-		name        string
-		manifest    string
-		permissions []string
-		granted     bool
-	}{
-		{
-			name:        "permission fulfilled",
-			manifest:    `[ { "method": "GET", "path": "/path", "scope": [["A"]], "info": "info", "in": {}, "out": {} } ]`,
-			permissions: []string{"A"},
-			granted:     true,
-		},
-		{
-			name:        "missing permission",
-			manifest:    `[ { "method": "GET", "path": "/path", "scope": [["A"]], "info": "info", "in": {}, "out": {} } ]`,
-			permissions: []string{},
-			granted:     false,
-		},
-	}
-
-	for _, tc := range tt {
-		t.Run(tc.name, func(t *testing.T) {
-			builder := &aicra.Builder{}
-			if err := addBuiltinTypes(builder); err != nil {
-				t.Fatalf("unexpected error <%v>", err)
-			}
-
-			// add active permissions
-			builder.WithContext(func(next http.Handler) http.Handler {
-				return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-					a := api.GetAuth(r.Context())
-					if a == nil {
-						t.Fatalf("cannot access api.Auth form request context")
-					}
-
-					a.Active = tc.permissions
-					next.ServeHTTP(w, r)
-				})
-			})
-
-			err := builder.Setup(strings.NewReader(tc.manifest))
-			if err != nil {
-				t.Fatalf("setup: unexpected error <%v>", err)
-			}
-
-			pathHandler := func(ctx context.Context) (*struct{}, api.Err) {
-				return nil, api.ErrNotImplemented
-			}
-
-			if err := builder.Bind(http.MethodGet, "/path", pathHandler); err != nil {
-				t.Fatalf("bind: unexpected error <%v>", err)
-			}
-
-			handler, err := builder.Build()
-			if err != nil {
-				t.Fatalf("build: unexpected error <%v>", err)
-			}
-
-			response := httptest.NewRecorder()
-			request := httptest.NewRequest(http.MethodGet, "/path", &bytes.Buffer{})
-
-			// test request
-			handler.ServeHTTP(response, request)
-			if response.Body == nil {
-				t.Fatalf("response has no body")
-			}
-			type jsonResponse struct {
-				Err api.Err `json:"error"`
-			}
-			var res jsonResponse
-			err = json.Unmarshal(response.Body.Bytes(), &res)
-			if err != nil {
-				t.Fatalf("cannot unmarshal response: %s", err)
-			}
-
-			expectedError := api.ErrNotImplemented
-			if !tc.granted {
-				expectedError = api.ErrPermission
-			}
-
-			if res.Err.Code != expectedError.Code {
-				t.Fatalf("expected error code %d got %d", expectedError.Code, res.Err.Code)
-			}
-
-		})
-	}
-
-}
-
 func TestDynamicScope(t *testing.T) {
 	tt := []struct {
 		name        string
@@ -393,7 +290,7 @@ func TestDynamicScope(t *testing.T) {
 				}
 			]`,
 			path:        "/path/{id}",
-			handler:     func(context.Context, struct{ Input1 uint }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			handler:     func(struct{ Input1 uint }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
 			url:         "/path/123",
 			body:        ``,
 			permissions: []string{"user[123]"},
@@ -414,7 +311,7 @@ func TestDynamicScope(t *testing.T) {
 				}
 			]`,
 			path:        "/path/{id}",
-			handler:     func(context.Context, struct{ Input1 uint }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			handler:     func(struct{ Input1 uint }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
 			url:         "/path/666",
 			body:        ``,
 			permissions: []string{"user[123]"},
@@ -435,7 +332,7 @@ func TestDynamicScope(t *testing.T) {
 				}
 			]`,
 			path:        "/path/{id}",
-			handler:     func(context.Context, struct{ User uint }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			handler:     func(struct{ User uint }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
 			url:         "/path/123",
 			body:        ``,
 			permissions: []string{"prefix.user[123].suffix"},
@@ -457,7 +354,7 @@ func TestDynamicScope(t *testing.T) {
 				}
 			]`,
 			path: "/prefix/{pid}/user/{uid}",
-			handler: func(context.Context, struct {
+			handler: func(struct {
 				Prefix uint
 				User   uint
 			}) (*struct{}, api.Err) {
@@ -484,7 +381,7 @@ func TestDynamicScope(t *testing.T) {
 				}
 			]`,
 			path: "/prefix/{pid}/user/{uid}",
-			handler: func(context.Context, struct {
+			handler: func(struct {
 				Prefix uint
 				User   uint
 			}) (*struct{}, api.Err) {
@@ -512,7 +409,7 @@ func TestDynamicScope(t *testing.T) {
 				}
 			]`,
 			path: "/prefix/{pid}/user/{uid}/suffix/{sid}",
-			handler: func(context.Context, struct {
+			handler: func(struct {
 				Prefix uint
 				User   uint
 				Suffix uint
@@ -541,7 +438,7 @@ func TestDynamicScope(t *testing.T) {
 				}
 			]`,
 			path: "/prefix/{pid}/user/{uid}/suffix/{sid}",
-			handler: func(context.Context, struct {
+			handler: func(struct {
 				Prefix uint
 				User   uint
 				Suffix uint
@@ -563,12 +460,8 @@ func TestDynamicScope(t *testing.T) {
 			}
 
 			// tester middleware (last executed)
-			builder.WithContext(func(next http.Handler) http.Handler {
+			builder.WithAuth(func(next api.AuthHandlerFunc) api.AuthHandlerFunc {
-				return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				return func(a api.Auth, w http.ResponseWriter, r *http.Request) {
-					a := api.GetAuth(r.Context())
-					if a == nil {
-						t.Fatalf("cannot access api.Auth form request context")
-					}
 					if a.Granted() == tc.granted {
 						return
 					}
@@ -577,20 +470,15 @@ func TestDynamicScope(t *testing.T) {
 					} else {
 						t.Fatalf("expected granted auth")
 					}
-					next.ServeHTTP(w, r)
+				}
-				})
 			})
 
 			// update permissions
-			builder.WithContext(func(next http.Handler) http.Handler {
+			builder.WithAuth(func(next api.AuthHandlerFunc) api.AuthHandlerFunc {
-				return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				return func(a api.Auth, w http.ResponseWriter, r *http.Request) {
-					a := api.GetAuth(r.Context())
-					if a == nil {
-						t.Fatalf("cannot access api.Auth form request context")
-					}
 					a.Active = tc.permissions
-					next.ServeHTTP(w, r)
+					next(a, w, r)
-				})
+				}
 			})
 
 			err := builder.Setup(strings.NewReader(tc.manifest))

internal/ctx/ctx.go

@@ -1,13 +0,0 @@
-package ctx
-
-// Key defines a custom context key type
-type Key int
-
-const (
-	// Request is the key for the current *http.Request
-	Request Key = iota
-	// Response is the key for the associated http.ResponseWriter
-	Response
-	// Auth is the key for the request's authentication information
-	Auth
-)

internal/dynfunc/errors.go

@@ -14,19 +14,16 @@ const errHandlerNotFunc = cerr("handler must be a func")
 const errNoServiceForHandler = cerr("no service found for this handler")
 
 // errMissingHandlerArgumentParam - missing params arguments for handler
-const errMissingHandlerContextArgument = cerr("missing handler first argument of type context.Context")
+const errMissingHandlerArgumentParam = cerr("missing handler argument : parameter struct")
-
-// errMissingHandlerInputArgument - missing params arguments for handler
-const errMissingHandlerInputArgument = cerr("missing handler argument: input struct")
 
 // errUnexpectedInput - input argument is not expected
 const errUnexpectedInput = cerr("unexpected input struct")
 
-// errMissingHandlerOutputArgument - missing output for handler
+// errMissingHandlerOutput - missing output for handler
-const errMissingHandlerOutputArgument = cerr("missing handler first output argument: output struct")
+const errMissingHandlerOutput = cerr("handler must have at least 1 output")
 
 // errMissingHandlerOutputError - missing error output for handler
-const errMissingHandlerOutputError = cerr("missing handler last output argument of type api.Err")
+const errMissingHandlerOutputError = cerr("handler must have its last output of type api.Err")
 
 // errMissingRequestArgument - missing request argument for handler
 const errMissingRequestArgument = cerr("handler first argument must be of type api.Request")
@@ -37,14 +34,17 @@ const errMissingParamArgument = cerr("handler second argument must be a struct")
 // errUnexportedName - argument is unexported in struct
 const errUnexportedName = cerr("unexported name")
 
-// errWrongOutputArgumentType - wrong type for output first argument
+// errMissingParamOutput - missing output argument for handler
-const errWrongOutputArgumentType = cerr("handler first output argument must be a *struct")
+const errMissingParamOutput = cerr("handler first output must be a *struct")
 
-// errMissingConfigArgument - missing an input/output argument in handler struct
+// errMissingParamFromConfig - missing a parameter in handler struct
-const errMissingConfigArgument = cerr("missing an argument from the configuration")
+const errMissingParamFromConfig = cerr("missing a parameter from configuration")
+
+// errMissingOutputFromConfig - missing a parameter in handler struct
+const errMissingOutputFromConfig = cerr("missing a parameter from configuration")
 
 // errWrongParamTypeFromConfig - a configuration parameter type is invalid in the handler param struct
 const errWrongParamTypeFromConfig = cerr("invalid struct field type")
 
-// errMissingHandlerErrorArgument - missing handler output error
+// errMissingHandlerErrorOutput - missing handler output error
-const errMissingHandlerErrorArgument = cerr("last output must be of type api.Err")
+const errMissingHandlerErrorOutput = cerr("last output must be of type api.Err")

internal/dynfunc/handler.go

@@ -1,7 +1,6 @@
 package dynfunc
 
 import (
-	"context"
 	"fmt"
 	"log"
 	"reflect"
@@ -10,69 +9,73 @@ import (
 	"git.xdrm.io/go/aicra/internal/config"
 )
 
-// Handler represents a dynamic aicra service handler
+// Handler represents a dynamic api handler
 type Handler struct {
-	// signature defined from the service configuration
+	spec *signature
-	signature *Signature
-	// fn provided function that will be the service's handler
 	fn   interface{}
+	// whether fn uses api.Ctx as 1st argument
+	hasContext bool
+	// index in input arguments where the data struct must be
+	dataIndex int
 }
 
-// Build a handler from a dynamic function and checks its signature against a
+// Build a handler from a service configuration and a dynamic function
-// service configuration
+//
-//e
+// @fn must have as a signature : `func(inputStruct) (*outputStruct, api.Err)`
-// `fn` must have as a signature : `func(*api.Context, in) (*out, api.Err)`
+//  - `inputStruct` is a struct{} containing a field for each service input (with valid reflect.Type)
-//  - `in` is a struct{} containing a field for each service input (with valid reflect.Type)
+//  - `outputStruct` is a struct{} containing a field for each service output (with valid reflect.Type)
-//  - `out` is a struct{} containing a field for each service output (with valid reflect.Type)
 //
 // Special cases:
-//  - it there is no input, `in` MUST be omitted
+//  - a first optional input parameter of type `api.Ctx` can be added
-//  - it there is no output, `out` MUST be omitted
+//  - it there is no input, `inputStruct` must be omitted
+//  - it there is no output, `outputStruct` must be omitted
 func Build(fn interface{}, service config.Service) (*Handler, error) {
-	var (
+	h := &Handler{
-		h = &Handler{
+		spec: signatureFromService(service),
-			signature: BuildSignature(service),
 		fn:   fn,
 	}
-		fnType = reflect.TypeOf(fn)
-	)
 
-	if fnType.Kind() != reflect.Func {
+	impl := reflect.TypeOf(fn)
+
+	if impl.Kind() != reflect.Func {
 		return nil, errHandlerNotFunc
 	}
-	if err := h.signature.ValidateInput(fnType); err != nil {
+
+	h.hasContext = impl.NumIn() >= 1 && reflect.TypeOf(api.Ctx{}).AssignableTo(impl.In(0))
+	if h.hasContext {
+		h.dataIndex = 1
+	}
+
+	if err := h.spec.checkInput(impl, h.dataIndex); err != nil {
 		return nil, fmt.Errorf("input: %w", err)
 	}
-	if err := h.signature.ValidateOutput(fnType); err != nil {
+	if err := h.spec.checkOutput(impl); err != nil {
 		return nil, fmt.Errorf("output: %w", err)
 	}
 
 	return h, nil
 }
 
-// Handle binds input `data` into the dynamic function and returns an output map
+// Handle binds input @data into the dynamic function and returns map output
-func (h *Handler) Handle(ctx context.Context, data map[string]interface{}) (map[string]interface{}, api.Err) {
+func (h *Handler) Handle(ctx api.Ctx, data map[string]interface{}) (map[string]interface{}, api.Err) {
-	var (
+	var ert = reflect.TypeOf(api.Err{})
-		ert      = reflect.TypeOf(api.Err{})
+	var fnv = reflect.ValueOf(h.fn)
-		fnv      = reflect.ValueOf(h.fn)
-		callArgs = make([]reflect.Value, 0)
-	)
 
-	// bind context
+	callArgs := []reflect.Value{}
+
+	// bind context if used in handler
+	if h.hasContext {
 		callArgs = append(callArgs, reflect.ValueOf(ctx))
+	}
 
-	inputStructRequired := fnv.Type().NumIn() > 1
+	// bind input data
-
+	if fnv.Type().NumIn() > h.dataIndex {
-	// bind input arguments
-	if inputStructRequired {
 		// create zero value struct
-		var (
+		callStructPtr := reflect.New(fnv.Type().In(0))
-			callStructPtr = reflect.New(fnv.Type().In(1))
+		callStruct := callStructPtr.Elem()
-			callStruct    = callStructPtr.Elem()
-		)
 
 		// set each field
-		for name := range h.signature.Input {
+		for name := range h.spec.Input {
 			field := callStruct.FieldByName(name)
 			if !field.CanSet() {
 				continue
@@ -112,12 +115,12 @@ func (h *Handler) Handle(ctx context.Context, data map[string]interface{}) (map[
 		callArgs = append(callArgs, callStruct)
 	}
 
-	// call the handler
+	// call the HandlerFn
 	output := fnv.Call(callArgs)
 
 	// no output OR pointer to output struct is nil
 	outdata := make(map[string]interface{})
-	if len(h.signature.Output) < 1 || output[0].IsNil() {
+	if len(h.spec.Output) < 1 || output[0].IsNil() {
 		var structerr = output[len(output)-1].Convert(ert)
 		return outdata, api.Err{
 			Code:   int(structerr.FieldByName("Code").Int()),
@@ -129,7 +132,7 @@ func (h *Handler) Handle(ctx context.Context, data map[string]interface{}) (map[
 	// extract struct from pointer
 	returnStruct := output[0].Elem()
 
-	for name := range h.signature.Output {
+	for name := range h.spec.Output {
 		field := returnStruct.FieldByName(name)
 		outdata[name] = field.Interface()
 	}

internal/dynfunc/handler_test.go

@@ -1,7 +1,6 @@
 package dynfunc
 
 import (
-	"context"
 	"fmt"
 	"reflect"
 	"testing"
@@ -9,7 +8,7 @@ import (
 	"git.xdrm.io/go/aicra/api"
 )
 
-type testsignature Signature
+type testsignature signature
 
 // builds a mock service with provided arguments as Input and matched as Output
 func (s *testsignature) withArgs(dtypes ...reflect.Type) *testsignature {
@@ -53,7 +52,7 @@ func TestInput(t *testing.T) {
 		{
 			Name:           "none required none provided",
 			Spec:           (&testsignature{}).withArgs(),
-			Fn:             func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			Fn:             func() (*struct{}, api.Err) { return nil, api.ErrSuccess },
 			HasContext:     false,
 			Input:          []interface{}{},
 			ExpectedOutput: []interface{}{},
@@ -62,7 +61,7 @@ func TestInput(t *testing.T) {
 		{
 			Name: "int proxy (0)",
 			Spec: (&testsignature{}).withArgs(reflect.TypeOf(int(0))),
-			Fn: func(ctx context.Context, in intstruct) (*intstruct, api.Err) {
+			Fn: func(in intstruct) (*intstruct, api.Err) {
 				return &intstruct{P1: in.P1}, api.ErrSuccess
 			},
 			HasContext:     false,
@@ -73,7 +72,7 @@ func TestInput(t *testing.T) {
 		{
 			Name: "int proxy (11)",
 			Spec: (&testsignature{}).withArgs(reflect.TypeOf(int(0))),
-			Fn: func(ctx context.Context, in intstruct) (*intstruct, api.Err) {
+			Fn: func(in intstruct) (*intstruct, api.Err) {
 				return &intstruct{P1: in.P1}, api.ErrSuccess
 			},
 			HasContext:     false,
@@ -84,7 +83,7 @@ func TestInput(t *testing.T) {
 		{
 			Name: "*int proxy (nil)",
 			Spec: (&testsignature{}).withArgs(reflect.TypeOf(new(int))),
-			Fn: func(ctx context.Context, in intptrstruct) (*intptrstruct, api.Err) {
+			Fn: func(in intptrstruct) (*intptrstruct, api.Err) {
 				return &intptrstruct{P1: in.P1}, api.ErrSuccess
 			},
 			HasContext:     false,
@@ -95,7 +94,7 @@ func TestInput(t *testing.T) {
 		{
 			Name: "*int proxy (28)",
 			Spec: (&testsignature{}).withArgs(reflect.TypeOf(new(int))),
-			Fn: func(ctx context.Context, in intptrstruct) (*intstruct, api.Err) {
+			Fn: func(in intptrstruct) (*intstruct, api.Err) {
 				return &intstruct{P1: *in.P1}, api.ErrSuccess
 			},
 			HasContext:     false,
@@ -106,7 +105,7 @@ func TestInput(t *testing.T) {
 		{
 			Name: "*int proxy (13)",
 			Spec: (&testsignature{}).withArgs(reflect.TypeOf(new(int))),
-			Fn: func(ctx context.Context, in intptrstruct) (*intstruct, api.Err) {
+			Fn: func(in intptrstruct) (*intstruct, api.Err) {
 				return &intstruct{P1: *in.P1}, api.ErrSuccess
 			},
 			HasContext:     false,
@@ -120,9 +119,16 @@ func TestInput(t *testing.T) {
 		t.Run(tcase.Name, func(t *testing.T) {
 			t.Parallel()
 
+			var dataIndex = 0
+			if tcase.HasContext {
+				dataIndex = 1
+			}
+
 			var handler = &Handler{
-				signature: &Signature{Input: tcase.Spec.Input, Output: tcase.Spec.Output},
+				spec:       &signature{Input: tcase.Spec.Input, Output: tcase.Spec.Output},
 				fn:         tcase.Fn,
+				dataIndex:  dataIndex,
+				hasContext: tcase.HasContext,
 			}
 
 			// build input
@@ -132,7 +138,7 @@ func TestInput(t *testing.T) {
 				input[key] = val
 			}
 
-			var output, err = handler.Handle(context.Background(), input)
+			var output, err = handler.Handle(api.Ctx{}, input)
 			if err != tcase.ExpectedErr {
 				t.Fatalf("expected api error <%v> got <%v>", tcase.ExpectedErr, err)
 			}

internal/dynfunc/signature.go

@@ -1,7 +1,6 @@
 package dynfunc
 
 import (
-	"context"
 	"fmt"
 	"reflect"
 	"strings"
@@ -10,17 +9,15 @@ import (
 	"git.xdrm.io/go/aicra/internal/config"
 )
 
-// Signature represents input/output arguments for service from the aicra configuration
+// signature represents input/output arguments for a dynamic function
-type Signature struct {
+type signature struct {
-	// Input arguments of the service
 	Input  map[string]reflect.Type
-	// Output arguments of the service
 	Output map[string]reflect.Type
 }
 
-// BuildSignature builds a signature for a service configuration
+// builds a spec from the configuration service
-func BuildSignature(service config.Service) *Signature {
+func signatureFromService(service config.Service) *signature {
-	s := &Signature{
+	s := &signature{
 		Input:  make(map[string]reflect.Type),
 		Output: make(map[string]reflect.Type),
 	}
@@ -47,37 +44,31 @@ func BuildSignature(service config.Service) *Signature {
 	return s
 }
 
-// ValidateInput validates a handler's input arguments against the service signature
+// checks for HandlerFn input arguments
-func (s *Signature) ValidateInput(handlerType reflect.Type) error {
+func (s *signature) checkInput(impl reflect.Type, index int) error {
-	ctxType := reflect.TypeOf((*context.Context)(nil)).Elem()
+	var requiredInput, structIndex = index, index
-
+	if len(s.Input) > 0 { // arguments struct
-	// missing or invalid first arg: context.Context
+		requiredInput++
-	if handlerType.NumIn() < 1 {
-		return errMissingHandlerContextArgument
-	}
-	firstArgType := handlerType.In(0)
-
-	if !firstArgType.Implements(ctxType) {
-		return fmt.Errorf("fock")
 	}
 
-	// no input required
+	// missing arguments
-	if len(s.Input) == 0 {
+	if impl.NumIn() > requiredInput {
-		// input struct provided
-		if handlerType.NumIn() > 1 {
 		return errUnexpectedInput
 	}
+
+	// none required
+	if len(s.Input) == 0 {
 		return nil
 	}
 
 	// too much arguments
-	if handlerType.NumIn() > 2 {
+	if impl.NumIn() != requiredInput {
-		return errMissingHandlerInputArgument
+		return errMissingHandlerArgumentParam
 	}
 
 	// arg must be a struct
-	inStruct := handlerType.In(1)
+	structArg := impl.In(structIndex)
-	if inStruct.Kind() != reflect.Struct {
+	if structArg.Kind() != reflect.Struct {
 		return errMissingParamArgument
 	}
 
@@ -87,9 +78,9 @@ func (s *Signature) ValidateInput(handlerType reflect.Type) error {
 			return fmt.Errorf("%s: %w", name, errUnexportedName)
 		}
 
-		field, exists := inStruct.FieldByName(name)
+		field, exists := structArg.FieldByName(name)
 		if !exists {
-			return fmt.Errorf("%s: %w", name, errMissingConfigArgument)
+			return fmt.Errorf("%s: %w", name, errMissingParamFromConfig)
 		}
 
 		if !ptype.AssignableTo(field.Type) {
@@ -100,18 +91,16 @@ func (s *Signature) ValidateInput(handlerType reflect.Type) error {
 	return nil
 }
 
-// ValidateOutput validates a handler's output arguments against the service signature
+// checks for HandlerFn output arguments
-func (s Signature) ValidateOutput(handlerType reflect.Type) error {
+func (s signature) checkOutput(impl reflect.Type) error {
-	errType := reflect.TypeOf(api.ErrUnknown)
+	if impl.NumOut() < 1 {
-
+		return errMissingHandlerOutput
-	if handlerType.NumOut() < 1 {
-		return errMissingHandlerErrorArgument
 	}
 
 	// last output must be api.Err
-	lastArgType := handlerType.Out(handlerType.NumOut() - 1)
+	errOutput := impl.Out(impl.NumOut() - 1)
-	if !lastArgType.AssignableTo(errType) {
+	if !errOutput.AssignableTo(reflect.TypeOf(api.ErrUnknown)) {
-		return errMissingHandlerErrorArgument
+		return errMissingHandlerErrorOutput
 	}
 
 	// no output -> ok
@@ -119,19 +108,19 @@ func (s Signature) ValidateOutput(handlerType reflect.Type) error {
 		return nil
 	}
 
-	if handlerType.NumOut() < 2 {
+	if impl.NumOut() != 2 {
-		return errMissingHandlerOutputArgument
+		return errMissingParamOutput
 	}
 
 	// fail if first output is not a pointer to struct
-	outStructPtr := handlerType.Out(0)
+	structOutputPtr := impl.Out(0)
-	if outStructPtr.Kind() != reflect.Ptr {
+	if structOutputPtr.Kind() != reflect.Ptr {
-		return errWrongOutputArgumentType
+		return errMissingParamOutput
 	}
 
-	outStruct := outStructPtr.Elem()
+	structOutput := structOutputPtr.Elem()
-	if outStruct.Kind() != reflect.Struct {
+	if structOutput.Kind() != reflect.Struct {
-		return errWrongOutputArgumentType
+		return errMissingParamOutput
 	}
 
 	// fail on invalid output
@@ -140,9 +129,9 @@ func (s Signature) ValidateOutput(handlerType reflect.Type) error {
 			return fmt.Errorf("%s: %w", name, errUnexportedName)
 		}
 
-		field, exists := outStruct.FieldByName(name)
+		field, exists := structOutput.FieldByName(name)
 		if !exists {
-			return fmt.Errorf("%s: %w", name, errMissingConfigArgument)
+			return fmt.Errorf("%s: %w", name, errMissingOutputFromConfig)
 		}
 
 		// ignore types evalutating to nil

internal/dynfunc/signature_test.go

@@ -1,7 +1,6 @@
 package dynfunc
 
 import (
-	"context"
 	"errors"
 	"fmt"
 	"reflect"
@@ -21,22 +20,22 @@ func TestInputCheck(t *testing.T) {
 		{
 			Name:  "no input 0 given",
 			Input: map[string]reflect.Type{},
-			Fn:    func(context.Context) {},
+			Fn:    func() {},
-			FnCtx: func(context.Context) {},
+			FnCtx: func(api.Ctx) {},
 			Err:   nil,
 		},
 		{
 			Name:  "no input 1 given",
 			Input: map[string]reflect.Type{},
-			Fn:    func(context.Context, int) {},
+			Fn:    func(int) {},
-			FnCtx: func(context.Context, int) {},
+			FnCtx: func(api.Ctx, int) {},
 			Err:   errUnexpectedInput,
 		},
 		{
 			Name:  "no input 2 given",
 			Input: map[string]reflect.Type{},
-			Fn:    func(context.Context, int, string) {},
+			Fn:    func(int, string) {},
-			FnCtx: func(context.Context, int, string) {},
+			FnCtx: func(api.Ctx, int, string) {},
 			Err:   errUnexpectedInput,
 		},
 		{
@@ -44,17 +43,17 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(int(0)),
 			},
-			Fn:    func(context.Context) {},
+			Fn:    func() {},
-			FnCtx: func(context.Context) {},
+			FnCtx: func(api.Ctx) {},
-			Err:   errMissingHandlerInputArgument,
+			Err:   errMissingHandlerArgumentParam,
 		},
 		{
 			Name: "1 input non-struct given",
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(int(0)),
 			},
-			Fn:    func(context.Context, int) {},
+			Fn:    func(int) {},
-			FnCtx: func(context.Context, int) {},
+			FnCtx: func(api.Ctx, int) {},
 			Err:   errMissingParamArgument,
 		},
 		{
@@ -62,8 +61,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"test1": reflect.TypeOf(int(0)),
 			},
-			Fn:    func(context.Context, struct{}) {},
+			Fn:    func(struct{}) {},
-			FnCtx: func(context.Context, struct{}) {},
+			FnCtx: func(api.Ctx, struct{}) {},
 			Err:   errUnexportedName,
 		},
 		{
@@ -71,17 +70,17 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(int(0)),
 			},
-			Fn:    func(context.Context, struct{}) {},
+			Fn:    func(struct{}) {},
-			FnCtx: func(context.Context, struct{}) {},
+			FnCtx: func(api.Ctx, struct{}) {},
-			Err:   errMissingConfigArgument,
+			Err:   errMissingParamFromConfig,
 		},
 		{
 			Name: "1 input invalid given",
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(int(0)),
 			},
-			Fn:    func(context.Context, struct{ Test1 string }) {},
+			Fn:    func(struct{ Test1 string }) {},
-			FnCtx: func(context.Context, struct{ Test1 string }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 string }) {},
 			Err:   errWrongParamTypeFromConfig,
 		},
 		{
@@ -89,8 +88,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(int(0)),
 			},
-			Fn:    func(context.Context, struct{ Test1 int }) {},
+			Fn:    func(struct{ Test1 int }) {},
-			FnCtx: func(context.Context, struct{ Test1 int }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 int }) {},
 			Err:   nil,
 		},
 		{
@@ -98,17 +97,17 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(new(int)),
 			},
-			Fn:    func(context.Context, struct{}) {},
+			Fn:    func(struct{}) {},
-			FnCtx: func(context.Context, struct{}) {},
+			FnCtx: func(api.Ctx, struct{}) {},
-			Err:   errMissingConfigArgument,
+			Err:   errMissingParamFromConfig,
 		},
 		{
 			Name: "1 input ptr invalid given",
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(new(int)),
 			},
-			Fn:    func(context.Context, struct{ Test1 string }) {},
+			Fn:    func(struct{ Test1 string }) {},
-			FnCtx: func(context.Context, struct{ Test1 string }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 string }) {},
 			Err:   errWrongParamTypeFromConfig,
 		},
 		{
@@ -116,8 +115,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(new(int)),
 			},
-			Fn:    func(context.Context, struct{ Test1 *string }) {},
+			Fn:    func(struct{ Test1 *string }) {},
-			FnCtx: func(context.Context, struct{ Test1 *string }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 *string }) {},
 			Err:   errWrongParamTypeFromConfig,
 		},
 		{
@@ -125,8 +124,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(new(int)),
 			},
-			Fn:    func(context.Context, struct{ Test1 *int }) {},
+			Fn:    func(struct{ Test1 *int }) {},
-			FnCtx: func(context.Context, struct{ Test1 *int }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 *int }) {},
 			Err:   nil,
 		},
 		{
@@ -134,8 +133,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(string("")),
 			},
-			Fn:    func(context.Context, struct{ Test1 string }) {},
+			Fn:    func(struct{ Test1 string }) {},
-			FnCtx: func(context.Context, struct{ Test1 string }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 string }) {},
 			Err:   nil,
 		},
 		{
@@ -143,8 +142,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(uint(0)),
 			},
-			Fn:    func(context.Context, struct{ Test1 uint }) {},
+			Fn:    func(struct{ Test1 uint }) {},
-			FnCtx: func(context.Context, struct{ Test1 uint }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 uint }) {},
 			Err:   nil,
 		},
 		{
@@ -152,8 +151,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(float64(0)),
 			},
-			Fn:    func(context.Context, struct{ Test1 float64 }) {},
+			Fn:    func(struct{ Test1 float64 }) {},
-			FnCtx: func(context.Context, struct{ Test1 float64 }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 float64 }) {},
 			Err:   nil,
 		},
 		{
@@ -161,8 +160,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf([]byte("")),
 			},
-			Fn:    func(context.Context, struct{ Test1 []byte }) {},
+			Fn:    func(struct{ Test1 []byte }) {},
-			FnCtx: func(context.Context, struct{ Test1 []byte }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 []byte }) {},
 			Err:   nil,
 		},
 		{
@@ -170,8 +169,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf([]rune("")),
 			},
-			Fn:    func(context.Context, struct{ Test1 []rune }) {},
+			Fn:    func(struct{ Test1 []rune }) {},
-			FnCtx: func(context.Context, struct{ Test1 []rune }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 []rune }) {},
 			Err:   nil,
 		},
 		{
@@ -179,8 +178,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(new(string)),
 			},
-			Fn:    func(context.Context, struct{ Test1 *string }) {},
+			Fn:    func(struct{ Test1 *string }) {},
-			FnCtx: func(context.Context, struct{ Test1 *string }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 *string }) {},
 			Err:   nil,
 		},
 		{
@@ -188,8 +187,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(new(uint)),
 			},
-			Fn:    func(context.Context, struct{ Test1 *uint }) {},
+			Fn:    func(struct{ Test1 *uint }) {},
-			FnCtx: func(context.Context, struct{ Test1 *uint }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 *uint }) {},
 			Err:   nil,
 		},
 		{
@@ -197,8 +196,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(new(float64)),
 			},
-			Fn:    func(context.Context, struct{ Test1 *float64 }) {},
+			Fn:    func(struct{ Test1 *float64 }) {},
-			FnCtx: func(context.Context, struct{ Test1 *float64 }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 *float64 }) {},
 			Err:   nil,
 		},
 		{
@@ -206,8 +205,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(new([]byte)),
 			},
-			Fn:    func(context.Context, struct{ Test1 *[]byte }) {},
+			Fn:    func(struct{ Test1 *[]byte }) {},
-			FnCtx: func(context.Context, struct{ Test1 *[]byte }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 *[]byte }) {},
 			Err:   nil,
 		},
 		{
@@ -215,8 +214,8 @@ func TestInputCheck(t *testing.T) {
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(new([]rune)),
 			},
-			Fn:    func(context.Context, struct{ Test1 *[]rune }) {},
+			Fn:    func(struct{ Test1 *[]rune }) {},
-			FnCtx: func(context.Context, struct{ Test1 *[]rune }) {},
+			FnCtx: func(api.Ctx, struct{ Test1 *[]rune }) {},
 			Err:   nil,
 		},
 	}
@@ -226,12 +225,13 @@ func TestInputCheck(t *testing.T) {
 			t.Parallel()
 
 			// mock spec
-			s := Signature{
+			s := signature{
 				Input:  tcase.Input,
 				Output: nil,
 			}
 
-			err := s.ValidateInput(reflect.TypeOf(tcase.FnCtx))
+			t.Run("with-context", func(t *testing.T) {
+				err := s.checkInput(reflect.TypeOf(tcase.FnCtx), 1)
 				if err == nil && tcase.Err != nil {
 					t.Errorf("expected an error: '%s'", tcase.Err.Error())
 					t.FailNow()
@@ -248,6 +248,25 @@ func TestInputCheck(t *testing.T) {
 					}
 				}
 			})
+			t.Run("without-context", func(t *testing.T) {
+				err := s.checkInput(reflect.TypeOf(tcase.Fn), 0)
+				if err == nil && tcase.Err != nil {
+					t.Errorf("expected an error: '%s'", tcase.Err.Error())
+					t.FailNow()
+				}
+				if err != nil && tcase.Err == nil {
+					t.Errorf("unexpected error: '%s'", err.Error())
+					t.FailNow()
+				}
+
+				if err != nil && tcase.Err != nil {
+					if !errors.Is(err, tcase.Err) {
+						t.Errorf("expected the error <%s> got <%s>", tcase.Err, err)
+						t.FailNow()
+					}
+				}
+			})
+		})
 	}
 }
 
@@ -260,37 +279,25 @@ func TestOutputCheck(t *testing.T) {
 		// no input -> missing api.Err
 		{
 			Output: map[string]reflect.Type{},
-			Fn:     func(context.Context) {},
+			Fn:     func() {},
-			Err:    errMissingHandlerOutputArgument,
+			Err:    errMissingHandlerOutput,
 		},
 		// no input -> with last type not api.Err
 		{
 			Output: map[string]reflect.Type{},
-			Fn:     func(context.Context) bool { return true },
+			Fn:     func() bool { return true },
-			Err:    errMissingHandlerErrorArgument,
+			Err:    errMissingHandlerErrorOutput,
 		},
 		// no input -> with api.Err
 		{
 			Output: map[string]reflect.Type{},
-			Fn:     func(context.Context) api.Err { return api.ErrSuccess },
+			Fn:     func() api.Err { return api.ErrSuccess },
 			Err:    nil,
 		},
-		// no input -> missing context.Context
-		{
-			Output: map[string]reflect.Type{},
-			Fn:     func(context.Context) api.Err { return api.ErrSuccess },
-			Err:    errMissingHandlerContextArgument,
-		},
-		// no input -> invlaid context.Context type
-		{
-			Output: map[string]reflect.Type{},
-			Fn:     func(context.Context, int) api.Err { return api.ErrSuccess },
-			Err:    errMissingHandlerContextArgument,
-		},
 		// func can have output if not specified
 		{
 			Output: map[string]reflect.Type{},
-			Fn:     func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			Fn:     func() (*struct{}, api.Err) { return nil, api.ErrSuccess },
 			Err:    nil,
 		},
 		// missing output struct in func
@@ -299,7 +306,7 @@ func TestOutputCheck(t *testing.T) {
 				"Test1": reflect.TypeOf(int(0)),
 			},
 			Fn:  func() api.Err { return api.ErrSuccess },
-			Err: errWrongOutputArgumentType,
+			Err: errMissingParamOutput,
 		},
 		// output not a pointer
 		{
@@ -307,7 +314,7 @@ func TestOutputCheck(t *testing.T) {
 				"Test1": reflect.TypeOf(int(0)),
 			},
 			Fn:  func() (int, api.Err) { return 0, api.ErrSuccess },
-			Err: errWrongOutputArgumentType,
+			Err: errMissingParamOutput,
 		},
 		// output not a pointer to struct
 		{
@@ -315,7 +322,7 @@ func TestOutputCheck(t *testing.T) {
 				"Test1": reflect.TypeOf(int(0)),
 			},
 			Fn:  func() (*int, api.Err) { return nil, api.ErrSuccess },
-			Err: errWrongOutputArgumentType,
+			Err: errMissingParamOutput,
 		},
 		// unexported param name
 		{
@@ -331,7 +338,7 @@ func TestOutputCheck(t *testing.T) {
 				"Test1": reflect.TypeOf(int(0)),
 			},
 			Fn:  func() (*struct{}, api.Err) { return nil, api.ErrSuccess },
-			Err: errMissingConfigArgument,
+			Err: errMissingParamFromConfig,
 		},
 		// output field invalid type
 		{
@@ -364,12 +371,12 @@ func TestOutputCheck(t *testing.T) {
 			t.Parallel()
 
 			// mock spec
-			s := Signature{
+			s := signature{
 				Input:  nil,
 				Output: tcase.Output,
 			}
 
-			err := s.ValidateOutput(reflect.TypeOf(tcase.Fn))
+			err := s.checkOutput(reflect.TypeOf(tcase.Fn))
 			if err == nil && tcase.Err != nil {
 				t.Errorf("expected an error: '%s'", tcase.Err.Error())
 				t.FailNow()