doc: add example to the library

README.md

@@ -1,3 +1,7 @@
 # httpwrapper [![Documentation](https://godoc.org/github.com/induzo/httpwrapper?status.svg)](http://godoc.org/github.com/induzo/httpwrapper) [![audit](https://github.com/induzo/httpwrapper/actions/workflows/audit.yml/badge.svg)](https://github.com/induzo/httpwrapper/actions/workflows/audit.yml) [![Go Report Card](https://goreportcard.com/badge/github.com/induzo/httpwrapper)](https://goreportcard.com/report/github.com/induzo/httpwrapper) [![Coverage Status](https://coveralls.io/repos/github/induzo/httpwrapper/badge.svg?branch=)](https://coveralls.io/github/induzo/httpwrapper?branch=main) [![Maintainability](https://api.codeclimate.com/v1/badges/163ea119e152dab7c834/maintainability)](https://codeclimate.com/github/induzo/httpwrapper/maintainability)
 
 wrap your API to save you from boilerplate code
+
+## Examples
+
+See doc or example_test.go

example_test.go

@@ -0,0 +1,76 @@
+package httpwrapper
+
+import (
+	"context"
+	"io"
+	"log"
+	"net/http"
+	"strconv"
+
+	"github.com/rs/zerolog"
+)
+
+// Wrapping a POST http handler.
+func Example_post() {
+	zl := zerolog.New(io.Discard).With()
+
+	type postRequest struct {
+		Name string `json:"name"`
+	}
+
+	createHandler := func() TypedHandler {
+		return func(r *http.Request) (*Response, *ErrorResponse) {
+			var pr postRequest
+
+			if err := BindBody(r, &pr); err != nil {
+				return nil, err
+			}
+
+			log.Println(pr)
+
+			return &Response{
+				Body:           pr,
+				HTTPStatusCode: http.StatusCreated,
+			}, nil
+		}
+	}
+
+	Wrapper(zl.Logger(), createHandler()).ServeHTTP(nil, nil)
+}
+
+// Wrapping a GET http handler.
+func Example_get() {
+	zl := zerolog.New(io.Discard).With()
+
+	getter := func(ctx context.Context, key string) (string, *ErrorResponse) {
+		if key == "id" {
+			return "1", nil
+		}
+
+		return "", MissingParamError{Name: key}.ToErrorResponse()
+	}
+
+	getHandler := func(nupg NamedURLParamsGetter) TypedHandler {
+		return func(r *http.Request) (*Response, *ErrorResponse) {
+			idParam, errR := nupg(r.Context(), "id")
+			if errR != nil {
+				return nil, errR
+			}
+
+			id, err := strconv.ParseInt(idParam, 10, 64)
+			if err != nil {
+				return nil, ParsingParamError{
+					Name:  "id",
+					Value: idParam,
+				}.ToErrorResponse()
+			}
+
+			return &Response{
+				Body:           id,
+				HTTPStatusCode: http.StatusOK,
+			}, nil
+		}
+	}
+
+	Wrapper(zl.Logger(), getHandler(getter)).ServeHTTP(nil, nil)
+}