ADK - Golang API Development Kit

GoDoc Reference:

• api:
• errors:
• respond:

---

---

Common utilities to write simple apis in golang.

- Custom API Handlers
  - Custom API Request(JSON) Decoders
  - Custom API URL Query-params Decoders using gorrila schema.
- App Errors
- Response Writers

Ex: Conventional way of writing api

package main

import (
	"net/http"

	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"
)

func main() {
	r := chi.NewRouter()
	r.Use(middleware.Logger)
	r.Post("/user", CreateUserHandler)
	http.ListenAndServe(":3000", r)
}

// CreateUserHandler creates a new users
func CreateUserHandler(w http.ResponseWriter, r *http.Request) {
    ctx := r.Context()

	reqBts, err := ioutil.ReadAll(r.Body)
	if err != nil {
        w.Header().Add("Content-Type", "application/json")
		w.WriteHeader(http.StatusBadRequest)
        w.Write([]byte(`{"error": "Couldn't read request body"}`))
		return
	}

	var createReq createUserReq
	jErr := json.Unmarshal(reqBts, &createReq)
	if jErr != nil {
        w.Header().Add("Content-Type", "application/json")
		w.WriteHeader(http.StatusBadRequest)
        w.Write([]byte(`{"error": "invalid request body"}`))
		return
	}
    if err := validateCreateUserReq(&createReq); err != nil {
        w.Header().Add("Content-Type", "application/json")
		w.WriteHeader(http.StatusBadRequest)
        w.Write([]byte(`{"error": "invalid request body"}`))
		return
    }
    if err := store.CreateUser(&createReq); err != nil {
        w.Header().Add("Content-Type", "application/json")
		w.WriteHeader(http.StatusInternalServerError)
        w.Write([]byte(`{"error": "invalid request body"}`))
		return
    }

    // respond to the client
    w.Header().Add("Content-Type", "application/json")
    w.WriteHeader(http.StatusOK)
    w.Write([]byte(`{"message": "user created successfully", "id": 123}`))
}

After using custom handlers and ADK

package main

import (
	"net/http"

    "github.com/manigandand/adk/api"
    "github.com/manigandand/adk/errors"
    "github.com/manigandand/adk/middleware"
    "github.com/manigandand/adk/respond"

	"github.com/go-chi/chi/v5"
)

func main() {
	r := chi.NewRouter()
	r.Use(middleware.Logger)
    r.Use(middleware.Recoverer)

	r.Method(http.MethodPost, "/user", api.Handler(CreateUserHandler))
	http.ListenAndServe(":3000", r)
}

type createUserReq struct {
    Email string `json:"email"`
    Name  string `json:"name"`
}

func (c *createUserReq) Validate() *errors.AppError {
    if c.Email == "" {
        return errors.KeyRequired("email")
    }
    return nil
}

// CreateUserHandler creates a new users
func CreateUserHandler(w http.ResponseWriter, r *http.Request) *errors.AppError{
    ctx := r.Context()

	var createReq createUserReq

	if err := api.Decode(r, &createReq); err != nil {
		return err
	}
    if err := store.CreateUser(&createReq); err != nil {
		return err
    }

    // respond to the client
    return respond.OK(w, map[string]interface{}{
        "message": "user created successfully",
        "id": 123,
    })
}

NOTE: Decoder currently will work on only on the "application/json" body.