refactor: unexport api.Response into aicra.response

api/response.go

@@ -1,63 +0,0 @@
-package api
-
-import (
-	"encoding/json"
-	"net/http"
-)
-
-// ResponseData defines format for response parameters to return
-type ResponseData map[string]interface{}
-
-// Response represents an API response to be sent
-type Response struct {
-	Data    ResponseData
-	Status  int
-	Headers http.Header
-	err     Err
-}
-
-// EmptyResponse creates an empty response.
-func EmptyResponse() *Response {
-	return &Response{
-		Status:  http.StatusOK,
-		Data:    make(ResponseData),
-		err:     ErrFailure,
-		Headers: make(http.Header),
-	}
-}
-
-// WithError sets the error
-func (res *Response) WithError(err Err) *Response {
-	res.err = err
-	return res
-}
-
-func (res *Response) Error() string {
-	return res.err.Error()
-}
-
-// SetData adds/overrides a new response field
-func (res *Response) SetData(name string, value interface{}) {
-	res.Data[name] = value
-}
-
-// MarshalJSON implements the 'json.Marshaler' interface and is used
-// to generate the JSON representation of the response
-func (res *Response) MarshalJSON() ([]byte, error) {
-	fmt := make(map[string]interface{})
-	for k, v := range res.Data {
-		fmt[k] = v
-	}
-	fmt["error"] = res.err
-	return json.Marshal(fmt)
-}
-
-func (res *Response) ServeHTTP(w http.ResponseWriter, r *http.Request) error {
-	w.WriteHeader(res.err.Status)
-	encoded, err := json.Marshal(res)
-	if err != nil {
-		return err
-	}
-	w.Write(encoded)
-	return nil
-}

handler.go

@@ -27,21 +27,21 @@ func (s Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 // 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
+	// match service from config
 	var service = s.conf.Find(r)
 	if service == nil {
-		handleError(api.ErrUnknownService, w, r)
+		newResponse().WithError(api.ErrUnknownService).ServeHTTP(w, r)
 		return
 	}
 
 	// extract request data
 	var input, err = extractInput(service, *r)
 	if err != nil {
-		handleError(api.ErrMissingParam, w, r)
+		newResponse().WithError(api.ErrMissingParam).ServeHTTP(w, r)
 		return
 	}
 
-	// find a matching handler
+	// match handler
 	var handler *apiHandler
 	for _, h := range s.handlers {
 		if h.Method == service.Method && h.Path == service.Pattern {
@@ -49,13 +49,13 @@ func (s Handler) resolve(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	// fail on no matching handler
+	// no handler found
 	if handler == nil {
-		handleError(api.ErrUncallableService, w, r)
+		newResponse().WithError(api.ErrUncallableService).ServeHTTP(w, r)
 		return
 	}
 
-	// build context with builtin data
+	// add info into context
 	c := r.Context()
 	c = context.WithValue(c, ctx.Request, r)
 	c = context.WithValue(c, ctx.Response, w)
@@ -63,63 +63,55 @@ func (s Handler) resolve(w http.ResponseWriter, r *http.Request) {
 
 	// create http handler
 	var h http.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// should not happen
 		auth := api.GetAuth(r.Context())
 		if auth == nil {
-			handleError(api.ErrPermission, w, r)
+			newResponse().WithError(api.ErrPermission).ServeHTTP(w, r)
 			return
 		}
 
 		// reject non granted requests
 		if !auth.Granted() {
-			handleError(api.ErrPermission, w, r)
+			newResponse().WithError(api.ErrPermission).ServeHTTP(w, r)
 			return
 		}
 
-		// use context defined in the request
+		// execute the service handler
 		s.handle(r.Context(), input, handler, service, w, r)
 	})
 
-	// run middlewares the handler
+	// run contextual middlewares
 	for _, mw := range s.ctxMiddlewares {
 		h = mw(h)
 	}
 
-	// serve using the context with values
+	// serve using the pre-filled context
 	h.ServeHTTP(w, r.WithContext(c))
 }
 
+// handle the service request with the associated handler func and respond using
+// the handler func output
 func (s *Handler) handle(c context.Context, input *reqdata.T, handler *apiHandler, service *config.Service, w http.ResponseWriter, r *http.Request) {
-	// pass execution to the handler
+	// pass execution to the handler function
 	var outData, outErr = handler.dyn.Handle(c, input.Data)
 
-	// build response from returned arguments
+	// build response from output arguments
-	var res = api.EmptyResponse().WithError(outErr)
+	var res = newResponse().WithError(outErr)
 	for key, value := range outData {
 
 		// find original name from 'rename' field
 		for name, param := range service.Output {
 			if param.Rename == key {
-				res.SetData(name, value)
+				res.SetValue(name, value)
 			}
 		}
 	}
 
-	// 7. apply headers
+	// write response and close request
 	w.Header().Set("Content-Type", "application/json; charset=utf-8")
-	for key, values := range res.Headers {
-		for _, value := range values {
-			w.Header().Add(key, value)
-		}
-	}
-
 	res.ServeHTTP(w, r)
 }
 
-func handleError(err api.Err, w http.ResponseWriter, r *http.Request) {
-	var response = api.EmptyResponse().WithError(err)
-	response.ServeHTTP(w, r)
-}
-
 func extractInput(service *config.Service, req http.Request) (*reqdata.T, error) {
 	var dataset = reqdata.New(service)
 

response.go

@@ -0,0 +1,62 @@
+package aicra
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/xdrm-io/aicra/api"
+)
+
+// response for an service call
+type response struct {
+	Data    map[string]interface{}
+	Status  int
+	Headers http.Header
+	err     api.Err
+}
+
+// newResponse creates an empty response.
+func newResponse() *response {
+	return &response{
+		Status:  http.StatusOK,
+		Data:    make(map[string]interface{}),
+		err:     api.ErrFailure,
+		Headers: make(http.Header),
+	}
+}
+
+// WithError sets the response error
+func (res *response) WithError(err api.Err) *response {
+	res.err = err
+	return res
+}
+
+// SetValue sets a response value
+func (res *response) SetValue(name string, value interface{}) {
+	res.Data[name] = value
+}
+
+// MarshalJSON generates the JSON representation of the response
+//
+// implements json.Marshaler
+func (res *response) MarshalJSON() ([]byte, error) {
+	fmt := make(map[string]interface{})
+	for k, v := range res.Data {
+		fmt[k] = v
+	}
+	fmt["error"] = res.err
+	return json.Marshal(fmt)
+}
+
+// ServeHTTP writes the response representation back to the http.ResponseWriter
+//
+// implements http.Handler
+func (res *response) ServeHTTP(w http.ResponseWriter, r *http.Request) error {
+	w.WriteHeader(res.err.Status)
+	encoded, err := json.Marshal(res)
+	if err != nil {
+		return err
+	}
+	w.Write(encoded)
+	return nil
+}