Go Crash Course 03 is done

Author: Chunting Wu

controller/post-controller.go

@@ -0,0 +1,64 @@
+package controller
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"example.com/clean-arch/entity"
+	"example.com/clean-arch/errors"
+	"example.com/clean-arch/service"
+)
+
+type controller struct{}
+
+var (
+	postService service.PostService
+)
+
+type PostController interface {
+	GetPosts(response http.ResponseWriter, request *http.Request)
+	AddPost(response http.ResponseWriter, request *http.Request)
+}
+
+func NewPostController(service service.PostService) PostController {
+	postService = service
+	return &controller{}
+}
+
+func (*controller) GetPosts(response http.ResponseWriter, request *http.Request) {
+	response.Header().Set("Content-Type", "application/json")
+	posts, err := postService.FindAll()
+	if err != nil {
+		response.WriteHeader(http.StatusInternalServerError)
+		json.NewEncoder(response).Encode(errors.ServiceError{Message: "Error getting the posts"})
+	}
+	response.WriteHeader(http.StatusOK)
+	json.NewEncoder(response).Encode(posts)
+}
+
+func (*controller) AddPost(response http.ResponseWriter, request *http.Request) {
+	response.Header().Set("Content-Type", "application/json")
+	var post entity.Post
+	err := json.NewDecoder(request.Body).Decode(&post)
+	if err != nil {
+		response.WriteHeader(http.StatusInternalServerError)
+		json.NewEncoder(response).Encode(errors.ServiceError{Message: "Error unmarshalling data"})
+		return
+	}
+
+	err = postService.Validate(&post)
+	if err != nil {
+		response.WriteHeader(http.StatusInternalServerError)
+		json.NewEncoder(response).Encode(errors.ServiceError{Message: err.Error()})
+		return
+	}
+
+	result, err := postService.Create(&post)
+	if err != nil {
+		response.WriteHeader(http.StatusInternalServerError)
+		json.NewEncoder(response).Encode(errors.ServiceError{Message: "Error saving the post"})
+		return
+	}
+	response.WriteHeader(http.StatusOK)
+	json.NewEncoder(response).Encode(result)
+}

entity/post.go

@@ -0,0 +1,7 @@
+package entity
+
+type Post struct {
+	ID    int64  `json:"id"`
+	Title string `json:"title"`
+	Text  string `json:"text"`
+}

errors/service-error.go

@@ -0,0 +1,5 @@
+package errors
+
+type ServiceError struct {
+	Message string `json:"message"`
+}

go.mod

@@ -0,0 +1,9 @@
+module example.com/clean-arch
+
+go 1.16
+
+require (
+	cloud.google.com/go/firestore v1.5.0
+	github.com/gorilla/mux v1.8.0
+	google.golang.org/api v0.49.0
+)

go.sum

@@ -0,0 +1,29 @@
+package router
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/gorilla/mux"
+)
+
+type muxRouter struct{}
+
+var (
+	muxDispatcher = mux.NewRouter()
+)
+
+func NewMuxRouter() Router {
+	return &muxRouter{}
+}
+
+func (*muxRouter) GET(uri string, f func(w http.ResponseWriter, r *http.Request)) {
+	muxDispatcher.HandleFunc(uri, f).Methods("GET")
+}
+func (*muxRouter) POST(uri string, f func(w http.ResponseWriter, r *http.Request)) {
+	muxDispatcher.HandleFunc(uri, f).Methods("POST")
+}
+func (*muxRouter) SERVE(port string) {
+	fmt.Printf("Mux HTTP server running on port %v", port)
+	http.ListenAndServe(port, muxDispatcher)
+}

http/mux-router.go

@@ -0,0 +1,9 @@
+package router
+
+import "net/http"
+
+type Router interface {
+	GET(uri string, f func(w http.ResponseWriter, r *http.Request))
+	POST(uri string, f func(w http.ResponseWriter, r *http.Request))
+	SERVE(port string)
+}

http/router.go

@@ -0,0 +1,72 @@
+package repository
+
+import (
+	"context"
+	"log"
+
+	"cloud.google.com/go/firestore"
+	"example.com/clean-arch/entity"
+	"google.golang.org/api/iterator"
+)
+
+type repo struct{}
+
+func NewFirestoreRepository() PostRepository {
+	return &repo{}
+}
+
+const (
+	projectId      string = "pragmetic-reviews"
+	collectionName string = "posts"
+)
+
+func (*repo) Save(post *entity.Post) (*entity.Post, error) {
+	ctx := context.Background()
+	client, err := firestore.NewClient(ctx, projectId)
+	if err != nil {
+		log.Fatalf("Failed to create a Firestore Client: %v", err)
+		return nil, err
+	}
+	defer client.Close()
+
+	_, _, err = client.Collection(collectionName).Add(ctx, map[string]interface{}{
+		"ID":    post.ID,
+		"Title": post.Title,
+		"Text":  post.Text,
+	})
+	if err != nil {
+		log.Fatalf("Failed adding a new post: %v", err)
+		return nil, err
+	}
+	return post, nil
+}
+
+func (*repo) FindAll() ([]entity.Post, error) {
+	ctx := context.Background()
+	client, err := firestore.NewClient(ctx, projectId)
+	if err != nil {
+		log.Fatalf("Failed to create a Firestore Client: %v", err)
+		return nil, err
+	}
+	defer client.Close()
+
+	var posts []entity.Post
+	it := client.Collection(collectionName).Documents(ctx)
+	for {
+		doc, err := it.Next()
+		if err == iterator.Done {
+			break
+		}
+		if err != nil {
+			log.Fatalf("Failed to iterate the list of posts: %v", err)
+			return nil, err
+		}
+		post := entity.Post{
+			ID:    doc.Data()["ID"].(int64),
+			Title: doc.Data()["Title"].(string),
+			Text:  doc.Data()["Text"].(string),
+		}
+		posts = append(posts, post)
+	}
+	return posts, nil
+}

repository/firestore-repo.go

@@ -0,0 +1,10 @@
+package repository
+
+import (
+	"example.com/clean-arch/entity"
+)
+
+type PostRepository interface {
+	Save(post *entity.Post) (*entity.Post, error)
+	FindAll() ([]entity.Post, error)
+}

repository/posts-repo.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+
+	"example.com/clean-arch/controller"
+	router "example.com/clean-arch/http"
+	"example.com/clean-arch/repository"
+	"example.com/clean-arch/service"
+)
+
+var (
+	httpRouter     router.Router             = router.NewMuxRouter()
+	postRepository repository.PostRepository = repository.NewFirestoreRepository()
+	postService    service.PostService       = service.NewPostService(postRepository)
+	postController controller.PostController = controller.NewPostController(postService)
+)
+
+func main() {
+	const port string = ":8000"
+
+	httpRouter.GET("/", func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintln(w, "Up and running...")
+	})
+	httpRouter.GET("/posts", postController.GetPosts)
+	httpRouter.POST("/posts", postController.AddPost)
+	httpRouter.SERVE(port)
+
+}