1 files changed, 93 insertions, 0 deletions
diff --git a/wrap.go b/wrap.go
new file mode 100644
index 0000000..e8ae72b
--- /dev/null
+++ b/wrap.go
@@ -0,0 +1,93 @@
+package muxtool
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+)
+
+// Wrap API handler and returns standard http.HandlerFunc function
+func Wrap[RQ any, RS any](handler func(ctx context.Context, request *RQ) (RS, error)) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		req := new(RQ)
+		richifyRequest(req, r)
+		switch r.Method {
+		case http.MethodPost, http.MethodPatch, http.MethodDelete, http.MethodPut:
+			if err := json.NewDecoder(r.Body).Decode(req); err != nil {
+				w.WriteHeader(http.StatusBadRequest)
+				_, _ = w.Write([]byte(err.Error()))
+				return
+			}
+		}
+		resp, err := handler(r.Context(), req)
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			_, _ = w.Write([]byte(err.Error()))
+			return
+		}
+
+		statusCode := http.StatusOK
+		contentType := "application/json"
+		var body []byte
+
+		if v, ok := (any)(resp).(WithContentType); ok {
+			contentType = v.ContentType()
+		}
+		if v, ok := (any)(resp).(WithHTTPStatus); ok {
+			statusCode = v.Status()
+		}
+		if v, ok := (any)(resp).(Renderer); ok {
+			body, err = v.Render()
+		} else {
+			body, err = json.Marshal(resp)
+		}
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			_, _ = w.Write([]byte(err.Error()))
+			return
+		}
+		w.WriteHeader(statusCode)
+		w.Header().Set("Content-Type", contentType)
+		w.Write(body)
+	}
+}
+
+func richifyRequest[RQ any](req *RQ, baseRequest *http.Request) {
+	if v, ok := (any)(req).(WithHeader); ok {
+		v.WithHeader(baseRequest.Header)
+	}
+	if v, ok := (any)(req).(WithMethod); ok {
+		v.WithMethod(baseRequest.Method)
+	}
+}
+
+type NilRequest struct{}
+
+// Optional interfaces for request type
+
+// WithHeader sets headers to request
+type WithHeader interface {
+	WithHeader(header http.Header)
+}
+
+// WithMethod sets method to request
+type WithMethod interface {
+	WithMethod(method string)
+}
+
+// Optional interfaces for response type
+
+// Renderer renders response to byte slice
+type Renderer interface {
+	Render() ([]byte, error)
+}
+
+// WithContentType returns custom content type for response
+type WithContentType interface {
+	ContentType() string
+}
+
+// WithHTTPStatus returns custom status code
+type WithHTTPStatus interface {
+	Status() int
+}