Change structure of code to a frontend and backend one

2024-07-13 13:58:36 +02:00
parent 21fd3403b2
commit ce152a13b8
18 changed files with 197 additions and 126 deletions
--- a/cmd/backend/articles.go
+++ b/cmd/backend/articles.go
@ -0,0 +1,258 @@
+package backend
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"log"
+	"time"
+)
+
+type Article struct {
+	Title       string
+	Created     time.Time
+	Description string
+	Content     string
+	Published   bool
+	Rejected    bool
+	ID          int64
+	AuthorID    int64
+	IssueID     int64
+}
+
+func (db *DB) AddArticle(a *Article) (int64, error) {
+	var id int64
+	txOptions := &sql.TxOptions{Isolation: sql.LevelSerializable}
+	selectQuery := "SELECT id FROM issues WHERE published = false"
+	insertQuery := `
+    INSERT INTO articles
+        (title, description, content, published, rejected, author_id, issue_id)
+    VALUES (?, ?, ?, ?, ?, ?, ?)
+    `
+
+	for i := 0; i < TxMaxRetries; i++ {
+		id, err := func() (int64, error) {
+			tx, err := db.BeginTx(context.Background(), txOptions)
+			if err != nil {
+				return 0, fmt.Errorf("error starting transaction: %v", err)
+			}
+
+			if err = tx.QueryRow(selectQuery).Scan(&id); err != nil {
+				if rollbackErr := tx.Rollback(); rollbackErr != nil {
+					log.Fatalf("transaction error: %v, rollback error: %v", err, rollbackErr)
+				}
+				return 0, fmt.Errorf("error getting issue ID when adding article to DB: %v", err)
+			}
+
+			result, err := tx.Exec(insertQuery, a.Title, a.Description,
+				a.Content, a.Published, a.Rejected, a.AuthorID, id)
+			if err != nil {
+				if rollbackErr := tx.Rollback(); rollbackErr != nil {
+					log.Fatalf("transaction error: %v, rollback error: %v", err, rollbackErr)
+				}
+				return 0, fmt.Errorf("error inserting article into DB: %v", err)
+			}
+
+			id, err := result.LastInsertId()
+			if err != nil {
+				if rollbackErr := tx.Rollback(); rollbackErr != nil {
+					log.Fatalf("transaction error: %v, rollback error: %v", err, rollbackErr)
+				}
+				return 0, fmt.Errorf("error retrieving ID of added article: %v", err)
+			}
+
+			if err = tx.Commit(); err != nil {
+				return 0, fmt.Errorf("error committing transaction when adding article to DB: %v", err)
+			}
+			return id, nil
+		}()
+		if err == nil {
+			return id, nil
+		}
+
+		log.Println(err)
+		wait(i)
+	}
+
+	return 0, fmt.Errorf("error: %v unsuccessful retries for DB operation, aborting", TxMaxRetries)
+}
+
+func (db *DB) GetArticle(id int64) (*Article, error) {
+	query := `
+    SELECT title, created, description, content, published, author_id
+    FROM articles
+    WHERE id = ?
+    `
+	row := db.QueryRow(query, id)
+
+	article := new(Article)
+	var created []byte
+	var err error
+
+	if err := row.Scan(&article.Title, &created, &article.Description,
+		&article.Content, &article.Published, &article.AuthorID); err != nil {
+		return nil, fmt.Errorf("error scanning article row: %v", err)
+	}
+
+	article.ID = id
+	article.Created, err = time.Parse("2006-01-02 15:04:05", string(created))
+	if err != nil {
+		return nil, fmt.Errorf("error parsing created: %v", err)
+	}
+
+	return article, nil
+}
+
+func (db *DB) GetCertainArticles(published, rejected bool) ([]*Article, error) {
+	query := `
+    SELECT id, title, created, description, content, author_id, issue_id
+    FROM articles
+    WHERE published = ?
+    AND rejected = ?
+    `
+	rows, err := db.Query(query, published, rejected)
+	if err != nil {
+		return nil, fmt.Errorf("error querying articles: %v", err)
+	}
+
+	articleList := make([]*Article, 0)
+	for rows.Next() {
+		article := new(Article)
+		var created []byte
+
+		if err = rows.Scan(&article.ID, &article.Title, &created,
+			&article.Description, &article.Content, &article.AuthorID,
+			&article.IssueID); err != nil {
+			return nil, fmt.Errorf("error scanning article row: %v", err)
+		}
+
+		article.Published = false
+		article.Created, err = time.Parse("2006-01-02 15:04:05", string(created))
+		if err != nil {
+			return nil, fmt.Errorf("error parsing created: %v", err)
+		}
+
+		articleList = append(articleList, article)
+	}
+
+	return articleList, nil
+}
+
+func (db *DB) GetCurrentIssueArticles() ([]*Article, error) {
+	var issueID int64
+	txOptions := &sql.TxOptions{Isolation: sql.LevelSerializable}
+	issueQuery := "SELECT id FROM issues WHERE published = false"
+	articlesQuery := `
+    SELECT id, title, created, description, content, author_id
+    FROM articles
+    WHERE issue_id = ? AND published = true
+    `
+
+	for i := 0; i < TxMaxRetries; i++ {
+		id, err := func() ([]*Article, error) {
+			tx, err := db.BeginTx(context.Background(), txOptions)
+			if err != nil {
+				return nil, fmt.Errorf("error starting transaction: %v", err)
+			}
+
+			row := tx.QueryRow(issueQuery)
+			if err := row.Scan(&issueID); err != nil {
+				if rollbackErr := tx.Rollback(); rollbackErr != nil {
+					log.Fatalf("transaction error: %v, rollback error: %v", err, rollbackErr)
+				}
+				return nil, fmt.Errorf("error querying DB for unpublished issue: %v", err)
+			}
+
+			rows, err := tx.Query(articlesQuery, issueID)
+			if err != nil {
+				if rollbackErr := tx.Rollback(); rollbackErr != nil {
+					log.Fatalf("transaction error: %v, rollback error: %v", err, rollbackErr)
+				}
+				return nil, fmt.Errorf("error querying DB for articles of issue %v: %v", issueID, err)
+			}
+
+			articleList := make([]*Article, 0)
+			for rows.Next() {
+				article := new(Article)
+				var created []byte
+
+				if err = rows.Scan(&article.ID, &article.Title, &created,
+					&article.Description, &article.Content, &article.AuthorID); err != nil {
+					if rollbackErr := tx.Rollback(); rollbackErr != nil {
+						log.Fatalf("transaction error: %v, rollback error: %v", err, rollbackErr)
+					}
+					return nil, fmt.Errorf("error scanning article from issue %v: %v", issueID, err)
+				}
+
+				article.Created, err = time.Parse("2006-01-02 15:04:05", string(created))
+				if err != nil {
+					if rollbackErr := tx.Rollback(); rollbackErr != nil {
+						log.Fatalf("transaction error: %v, rollback error: %v", err, rollbackErr)
+					}
+					return nil, fmt.Errorf("error parsing created: %v", err)
+				}
+
+				articleList = append(articleList, article)
+			}
+
+			if err = tx.Commit(); err != nil {
+				return nil, fmt.Errorf("error committing transaction when getting articles of issue %v: %v", issueID, err)
+			}
+
+			return articleList, nil
+		}()
+		if err == nil {
+			return id, nil
+		}
+
+		log.Println(err)
+		wait(i)
+	}
+
+	return nil, fmt.Errorf("error: %v unsuccessful retries for DB operation, aborting", TxMaxRetries)
+}
+
+func (db *DB) AddArticleToCurrentIssue(id int64) error {
+	var issueID int64
+	txOptions := &sql.TxOptions{Isolation: sql.LevelSerializable}
+	selectQuery := "SELECT id FROM issues WHERE published = false"
+	updateQuery := "UPDATE articles SET issue_id = ? WHERE id = ?"
+
+	for i := 0; i < TxMaxRetries; i++ {
+		err := func() error {
+			tx, err := db.BeginTx(context.Background(), txOptions)
+			if err != nil {
+				return fmt.Errorf("error starting transaction: %v", err)
+			}
+
+			if err = tx.QueryRow(selectQuery).Scan(&issueID); err != nil {
+				if rollbackErr := tx.Rollback(); rollbackErr != nil {
+					log.Fatalf("transaction error: %v, rollback error: %v", err, rollbackErr)
+				}
+				return fmt.Errorf("error scanning row: %v", err)
+			}
+
+			_, err = db.Exec(updateQuery, issueID, id)
+			if err != nil {
+				if rollbackErr := tx.Rollback(); rollbackErr != nil {
+					log.Fatalf("transaction error: %v, rollback error: %v", err, rollbackErr)
+				}
+				return fmt.Errorf("error updating issueID for article: %v", err)
+			}
+
+			if err = tx.Commit(); err != nil {
+				return fmt.Errorf("error committing transaction when getting articles of issue %v: %v", issueID, err)
+			}
+
+			return nil
+		}()
+		if err == nil {
+			return nil
+		}
+
+		log.Println(err)
+		wait(i)
+	}
+
+	return fmt.Errorf("error: %v unsuccessful retries for DB operation, aborting", TxMaxRetries)
+}