golang rest api helper

A set of small data structure that help to write rest API response.

OK response format

  {
      "status": "ok",
      "data":
      {
          "firstName": "Jon",
          "lastName": "Snow"
      }
  }

Error response format

  {
      "status": "error",
      "code": "some_error_code",
      "msg": "some error message"
  }

Example

package main

import (
    "encoding/json"
    "github.com/hongjundu/go-rest-api-helper"
    "log"
    "net/http"
)

func main() {
    log.Printf("server starts...")

    http.HandleFunc("/ok", wrapHandler(handlerReturnsOK))
    http.HandleFunc("/error", wrapHandler(handlerReturnsError))

    log.Fatal(http.ListenAndServe(":8080", nil))

    log.Printf("server exists")
}

func handlerReturnsOK(r *http.Request) (response interface{}, err error) {
    type Resp struct {
        FirstName string `json:"firstName"`
        LastName  string `json:"lastName"`
    }
    response = &Resp{FirstName: "Jon", LastName: "Snow"}
    return
}

func handlerReturnsError(r *http.Request) (response interface{}, err error) {
    err = apihelper.NewError("some_error_code", "some error message")
    return
}

func wrapHandler(handler func(r *http.Request) (interface{}, error)) func(w http.ResponseWriter, r *http.Request) {
    return func(w http.ResponseWriter, r *http.Request) {
        var err error
        var response interface{}
        var responseBody []byte

        if response, err = handler(r); err == nil {
            responseBody, err = json.Marshal(response)
        }

        if err != nil {
            responseBody, _ = json.Marshal(apihelper.NewErrorResponse(err))
        }

        w.Write(responseBody)
    }
}