feat: add api context to handlers and add middlewares with Builder.With()

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"
@@ -14,6 +15,7 @@ import (
 type Builder struct {
 	conf        *config.Server
 	handlers    []*apiHandler
+	middlewares []api.Middleware
 }
 
 // represents an api handler (method-pattern combination)
@@ -34,6 +36,14 @@ func (b *Builder) AddType(t datatype.T) {
 	b.conf.Types = append(b.conf.Types, t)
 }
 
+// With adds a middleware that will be used for each request
+func (b *Builder) With(mw api.Middleware) {
+	if b.conf == nil {
+		b.conf = &config.Server{}
+	}
+	b.middlewares = append(b.middlewares, mw)
+}
+
 // Setup the builder with its api definition file
 // panics if already setup
 func (b *Builder) Setup(r io.Reader) error {

handler.go

@@ -51,10 +51,20 @@ func (s Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// 5. pass execution to the handler
-	var outData, outErr = handler.dyn.Handle(input.Data)
+	// 5. create context and run middlewares
+	var ctx = &api.Context{
+		Context:  r.Context(),
+		Request:  r,
+		Response: w,
+	}
+	for _, mw := range s.middlewares {
+		ctx = mw.Handle(ctx)
+	}
 
-	// 6. build res from returned data
+	// 6. pass execution to the handler
+	var outData, outErr = handler.dyn.Handle(ctx, input.Data)
+
+	// 7. build res from returned data
 	var res = api.EmptyResponse().WithError(outErr)
 	for key, value := range outData {
 
@@ -66,7 +76,7 @@ func (s Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	// 7. apply headers
+	// 8. apply headers
 	w.Header().Set("Content-Type", "application/json; charset=utf-8")
 	for key, values := range res.Headers {
 		for _, value := range values {

internal/dynfunc/errors.go

@@ -19,6 +19,9 @@ const errMissingHandlerArgumentParam = cerr("missing handler argument : paramete
 // errUnexpectedInput - input argument is not expected
 const errUnexpectedInput = cerr("unexpected input struct")
 
+// errMissingContext - first input argument is missing
+const errMissingContext = cerr("missing first input argument (*api.Context)")
+
 // errMissingHandlerOutput - missing output for handler
 const errMissingHandlerOutput = cerr("handler must have at least 1 output")
 

internal/dynfunc/handler.go

@@ -46,7 +46,7 @@ func Build(fn interface{}, service config.Service) (*Handler, error) {
 }
 
 // Handle binds input @data into the dynamic function and returns map output
-func (h *Handler) Handle(data map[string]interface{}) (map[string]interface{}, api.Err) {
+func (h *Handler) Handle(ctx *api.Context, data map[string]interface{}) (map[string]interface{}, api.Err) {
 	var ert = reflect.TypeOf(api.Err{})
 	var fnv = reflect.ValueOf(h.fn)
 

internal/dynfunc/spec.go

@@ -47,20 +47,31 @@ func makeSpec(service config.Service) spec {
 func (s spec) checkInput(fnv reflect.Value) error {
 	fnt := fnv.Type()
 
+	// fail on missing context (first arg)
+	if fnt.NumIn() < 1 {
+		return errMissingContext
+	}
+
+	// fail on invalid context argument
+	ctxArg := fnt.In(0)
+	if ctxArg != reflect.TypeOf(&api.Context{}) {
+		return errMissingContext
+	}
+
 	// no input -> ok
 	if len(s.Input) == 0 {
-		if fnt.NumIn() > 0 {
+		if fnt.NumIn() != 1 {
 			return errUnexpectedInput
 		}
 		return nil
 	}
 
-	if fnt.NumIn() != 1 {
+	if fnt.NumIn() != 2 {
 		return errMissingHandlerArgumentParam
 	}
 
 	// arg must be a struct
-	structArg := fnt.In(0)
+	structArg := fnt.In(1)
 	if structArg.Kind() != reflect.Struct {
 		return errMissingParamArgument
 	}

internal/dynfunc/spec_test.go

@@ -11,74 +11,109 @@ import (
 
 func TestInputCheck(t *testing.T) {
 	tcases := []struct {
+		Name  string
 		Input map[string]reflect.Type
 		Fn    interface{}
 		Err   error
 	}{
-		// no input
 		{
+			Name:  "no argument required, missing context",
 			Input: map[string]reflect.Type{},
 			Fn:    func() {},
+			Err:   errMissingContext,
+		},
+		{
+			Name:  "no argument required, invalid context",
+			Input: map[string]reflect.Type{},
+			Fn:    func(int) {},
+			Err:   errMissingContext,
+		},
+		{
+			Name:  "no argument required, valid context",
+			Input: map[string]reflect.Type{},
+			Fn:    func(*api.Context) {},
 			Err:   nil,
 		},
-		// func must have noarguments if none specified
 		{
+			Name:  "argument but none required",
 			Input: map[string]reflect.Type{},
-			Fn:    func(int, string) {},
+			Fn:    func(*api.Context, int) {},
 			Err:   errUnexpectedInput,
 		},
-		// missing input struct in func
 		{
+			Name:  "arguments but none required",
+			Input: map[string]reflect.Type{},
+			Fn:    func(*api.Context, int, string) {},
+			Err:   errUnexpectedInput,
+		},
+		{
+			Name: "int required, no context",
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(int(0)),
 			},
 			Fn:  func() {},
-			Err: errMissingHandlerArgumentParam,
+			Err: errMissingContext,
 		},
-		// input not a struct
 		{
+			Name: "int required, invalid context",
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(int(0)),
 			},
 			Fn:  func(int) {},
+			Err: errMissingContext,
+		},
+		{
+			Name: "int required, only context provided",
+			Input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			Fn:  func(*api.Context) {},
+			Err: errMissingHandlerArgumentParam,
+		},
+		{
+			Name: "non-struct second argument",
+			Input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			Fn:  func(*api.Context, int) {},
 			Err: errMissingParamArgument,
 		},
-		// unexported param name
 		{
+			Name: "fail on unexported param",
 			Input: map[string]reflect.Type{
 				"test1": reflect.TypeOf(int(0)),
 			},
-			Fn:  func(struct{}) {},
+			Fn:  func(*api.Context, struct{}) {},
 			Err: errUnexportedName,
 		},
-		// input field missing
 		{
+			Name: "struct with missing field",
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(int(0)),
 			},
-			Fn:  func(struct{}) {},
+			Fn:  func(*api.Context, struct{}) {},
 			Err: errMissingParamFromConfig,
 		},
-		// input field invalid type
 		{
+			Name: "field with missing type",
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(int(0)),
 			},
-			Fn:  func(struct{ Test1 string }) {},
+			Fn:  func(*api.Context, struct{ Test1 string }) {},
 			Err: errWrongParamTypeFromConfig,
 		},
-		// input field valid type
 		{
+			Name: "valid input",
 			Input: map[string]reflect.Type{
 				"Test1": reflect.TypeOf(int(0)),
 			},
-			Fn:  func(struct{ Test1 int }) {},
+			Fn:  func(*api.Context, struct{ Test1 int }) {},
 			Err: nil,
 		},
 	}
 
-	for i, tcase := range tcases {
-		t.Run(fmt.Sprintf("case.%d", i), func(t *testing.T) {
+	for _, tcase := range tcases {
+		t.Run(tcase.Name, func(t *testing.T) {
 			// mock spec
 			s := spec{
 				Input:  tcase.Input,