store.go

package main

import (
	"database/sql"
	"github.com/eyan422/Blog/CommonStruct"
	"log"
)

type Store interface {
	CreateArticle(article *CommonStruct.Article) (int64, error)
	GetArticles() (articles []*CommonStruct.Article, err error)
	GetArticle(id uint64) (articles *CommonStruct.Article, err error)
}

type dbStore struct {
	db *sql.DB
}

func (store *dbStore) CreateArticle(article *CommonStruct.Article) (int64, error) {

	res, err := store.db.Query("SELECT id, title, content, author from article where title = ? and content = ? and author = ?",
		article.Title,
		article.Content,
		article.Author,
	)
	defer res.Close()
	if err != nil {
		return 0, err
	}

	var articleRetrieved *CommonStruct.Article
	if res.Next() {
		articleRetrieved = &CommonStruct.Article{}
		if err := res.Scan(&articleRetrieved.Id, &articleRetrieved.Title, &articleRetrieved.Content, &articleRetrieved.Author); err != nil {
			return 0, err
		}
	}

	if articleRetrieved != nil && articleRetrieved.Id > 0 {
		return -1, nil
	}

	query := "INSERT INTO article(title, content, author) VALUES (?, ?, ?)"

	stmt, err := store.db.Prepare(query)
	if err != nil {
		log.Printf("Error %s when preparing SQL statement", err)
		return 0, err
	}
	defer stmt.Close()

	res1, err := stmt.Exec(article.Title, article.Content, article.Author)
	rows, err := res1.RowsAffected()
	if err != nil {
		log.Printf("Error %s when finding rows affected", err)
		return 0, err
	}
	log.Printf("%d record created ", rows)

	lastId, err := res1.LastInsertId()
	if err != nil {
		return 0, err
	}

	return lastId, err
}

func (store *dbStore) GetArticles() (articles []*CommonStruct.Article, err error) {
	rows, err := store.db.Query("SELECT id, title, content, author from article order by id")
	defer rows.Close()
	if err != nil {
		return nil, err
	}

	for rows.Next() {
		article := &CommonStruct.Article{}
		if err := rows.Scan(&article.Id, &article.Title, &article.Content, &article.Author); err != nil {
			return nil, err
		}
		articles = append(articles, article)
	}
	return articles, nil
}

func (store *dbStore) GetArticle(id uint64) (article *CommonStruct.Article, err error) {
	res, err := store.db.Query("SELECT id, title, content, author from article where id = ?", id)
	defer res.Close()
	if err != nil {
		return nil, err
	}

	if res.Next() {
		article = &CommonStruct.Article{}
		if err := res.Scan(&article.Id, &article.Title, &article.Content, &article.Author); err != nil {
			return nil, err
		}
	}

	return article, nil
}

var store Store

func InitStore(s Store) {
	store = s
}