booklet2019b

main.go

package main

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"log"
	"net/http"

	"github.com/go-chi/chi"
	_ "github.com/go-sql-driver/mysql"
)

type Question struct {
	Id         int    `json:"id"`
	Title      string `json:"title"`
	Body       string `json:"body"`
	Category   string `json:"category"`
	Created_at string `json:"created_at"`
}

var Db *sql.DB

func init() {
	var err error
	Db, err = sql.Open("mysql", "user:dbpassword@/heap_overflow")
	if err != nil {
		log.Fatal(err)
	}
}

func main() {
	defer Db.Close()

	r := chi.NewRouter()

	r.Route("/questions", func(r chi.Router) {
		r.Get("/", getAllQuestions) // GET /questions/
		r.Post("/", createQuestion) // POST /questions
		r.Route("/{questionID}", func(r chi.Router) {
			r.Get("/", getQuestion)       // GET /questions/{qustionID}
			r.Delete("/", deleteQuestion) // DELETE /questions{questionID}
			r.Put("/", updateQuestion)    // PUT /questions{questionID}
		})
	})

	http.ListenAndServe(":3000", r)
}

func updateQuestion(w http.ResponseWriter, r *http.Request) {
	questionID := chi.URLParam(r, "questionID")
	var q Question

	err := json.NewDecoder(r.Body).Decode(&q)
	if err != nil {
		log.Fatal(err)
	}

	stmt, err := Db.Prepare("UPDATE `questions` set title=?, body=?, category=? WHERE id=?")
	if err != nil {
		log.Fatal(err)
	}
	defer stmt.Close()

	_, err = stmt.Exec(q.Title, q.Body, q.Category, questionID)
	if err != nil {
		log.Fatal(err)
	}
}

func deleteQuestion(w http.ResponseWriter, r *http.Request) {
	questionID := chi.URLParam(r, "questionID")

	rows, err := Db.Query("DELETE FROM questions WHERE id = ?", questionID)
	if err != nil {
		log.Fatal(err)
	}
	defer rows.Close()
}

func createQuestion(w http.ResponseWriter, r *http.Request) {
	var q Question

	err := json.NewDecoder(r.Body).Decode(&q)
	if err != nil {
		log.Fatal(err)
	}

	stmt, err := Db.Prepare("INSERT INTO `questions`(`title`, `body`, `category`, `created_at`) VALUES(?, ?, ?, NOW())")
	if err != nil {
		log.Fatal(err)
	}
	defer stmt.Close()

	_, err = stmt.Exec(q.Title, q.Body, q.Category)
	if err != nil {
		log.Fatal(err)
	}
}

func getAllQuestions(w http.ResponseWriter, r *http.Request) {
	rows, err := Db.Query("SELECT * FROM questions")
	if err != nil {
		log.Fatal(err)
	}
	defer rows.Close()

	var id int
	var title, body, category, created_at string
	var jsonStr string

	qs := make([]Question, 0)

	for rows.Next() {
		err := rows.Scan(&id, &category, &title, &body, &created_at)
		if err != nil {
			log.Fatal(err)
		}
		q := Question{}

		q.Id = id
		q.Title = title
		q.Body = body
		q.Category = category
		q.Created_at = created_at

		qs = append(qs, q)
	}
	jsonBytes, err := json.MarshalIndent(qs, "", "  ")
	if err != nil {
		log.Fatal(err)
	}
	jsonStr = string(jsonBytes)
	w.Write([]byte(fmt.Sprintf(jsonStr)))
}

func getQuestion(w http.ResponseWriter, r *http.Request) {
	questionID := chi.URLParam(r, "questionID")
	q := Question{}

	err := Db.QueryRow("SELECT * FROM questions WHERE id = ?", questionID).Scan(&(q.Id), &(q.Category), &(q.Title), &(q.Body), &(q.Created_at))
	if err != nil {
		log.Fatal(err)
	}

	jsonBytes, err := json.MarshalIndent(q, "", "  ")
	if err != nil {
		log.Fatal(err)
	}

	jsonStr := string(jsonBytes)
	w.Write([]byte(fmt.Sprintf(jsonStr)))
}