POC-golang-postgres-docker/internal/app/api.go

package app

import (
	"encoding/json"
	"fmt"
	uuid "github.com/nu7hatch/gouuid"
	"net/http"
	"time"
)

type User struct {
	UserID    int
	Title     string
	CreatedOn time.Time
}

type Users struct {
	users []User
}

func UserGetHandler(w http.ResponseWriter, req *http.Request) {
	if req.Method == "GET" {

		title, ok := req.URL.Query()["title"]

		if !ok || len(title[0]) < 1 {
			http.Error(w, "Url Param 'title' is missing", 400)
			return
		}

		// Query()["key"] will return an array of items,
		// we only want the single item.
		userTitle := title[0]

		users := Users{}

		err := queryRepos(&users, userTitle)
		if err != nil {
			http.Error(w, err.Error(), 500)
			return
		}

		if len(users.users) > 0 {

			out, err := json.Marshal(users.users)
			if err != nil {
				http.Error(w, err.Error(), 500)
				return
			}

			fmt.Fprintf(w, string(out))
		} else {
			fmt.Fprintf(w, "User does not exist")
		}
	} else {
		fmt.Fprintf(w, "Sorry, only Get methods are supported for thus api.")
	}
}

func UserPostHandler(w http.ResponseWriter, req *http.Request) {
	if req.Method == "POST" {
		if err := req.ParseForm(); err != nil {
			fmt.Fprintf(w, "ParseForm() err: %v", err)
			return
		}

		uuid, err := uuid.NewV4()
		if err != nil {
			http.Error(w, err.Error(), 500)

		}

		title := req.FormValue("title")
		sqlInsert := `
INSERT INTO users (title, created_on,uuid)
VALUES ($1, $2, $3)
RETURNING user_id`
		if len(title) > 0 {
			user_id := 0
			row := Db.QueryRow(sqlInsert, title, time.Now().Format(time.RFC3339), uuid.String())
			err := row.Scan(&user_id)
			if err != nil {
				panic(err)
			}
			fmt.Fprintf(w, "user created.")
		} else {
			fmt.Fprintf(w, "Invalid data")
		}
	} else {
		fmt.Fprintf(w, "Sorry, only POST methods are supported for thus api.")
	}
}

func queryRepos(users *Users, userTitle string) error {
	query := `
		SELECT
     		user_id,
			title,
			created_on
			
		FROM users
		WHERE title='` + userTitle + `';
		`

	rows, err := Db.Query(query)
	if err != nil {
		return err
	}
	defer rows.Close()
	for rows.Next() {
		user := User{}
		err = rows.Scan(
			&user.UserID,
			&user.Title,
			&user.CreatedOn,
		)
		if err != nil {
			return err
		}
		users.users = append(users.users, user)
	}

	err = rows.Err()
	if err != nil {
		return err
	}
	return nil
}