feat: get and post comments

Author: rileychh

go.mod

@@ -0,0 +1,3 @@
+module vue-css-course-backend
+
+go 1.22.0

main.go

@@ -0,0 +1,95 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+	"os"
+	"time"
+)
+
+type Comment struct {
+	Author  string    `json:"author"`
+	Content string    `json:"content"`
+	Created time.Time `json:"created"`
+}
+
+type Comments []Comment
+
+const commentsFile = "comments.json"
+
+func loadComments() (Comments, error) {
+	if _, err := os.Stat(commentsFile); os.IsNotExist(err) {
+		return Comments{}, nil
+	}
+
+	data, err := os.ReadFile(commentsFile)
+	if err != nil {
+		return nil, err
+	}
+
+	var comments []Comment
+	err = json.Unmarshal(data, &comments)
+	if err != nil {
+		return nil, err
+	}
+
+	return comments, nil
+}
+
+func writeComments(comments Comments) error {
+	data, err := json.Marshal(comments)
+	if err != nil {
+		return err
+	}
+
+	err = os.WriteFile(commentsFile, data, 0644)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func handleComments(writer http.ResponseWriter, request *http.Request) {
+	comments, err := loadComments()
+	if err != nil {
+		log.Print("loadComments:", err)
+		writer.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	switch request.Method {
+	case http.MethodGet:
+		writer.Header().Set("Content-Type", "application/json")
+
+		err := json.NewEncoder(writer).Encode(comments)
+		if err != nil {
+			log.Print("json.NewEncoder.Encode:", err)
+			writer.WriteHeader(http.StatusInternalServerError)
+		}
+
+	case http.MethodPost:
+		var comment Comment
+		err := json.NewDecoder(request.Body).Decode(&comment)
+		if err != nil {
+			log.Print("json.NewDecoder.Decode:", err)
+			writer.WriteHeader(http.StatusBadRequest)
+			return
+		}
+
+		comments = append(comments, comment)
+
+		err = writeComments(comments)
+		if err != nil {
+			log.Print("writeComments:", err)
+			writer.WriteHeader(http.StatusInternalServerError)
+		}
+	}
+}
+
+func main() {
+	http.HandleFunc("/comments", handleComments)
+
+	log.Fatal(http.ListenAndServe(":8080", nil))
+}