snapshot of https://github.com/ThreeDotsLabs/watermill.git (master, 2026-09-15; blobs > 131072B omitted)

_examples/real-world-examples/server-sent-events-htmx/repository.go

@@ -0,0 +1,136 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"time"
+)
+
+const migration = `
+CREATE TABLE IF NOT EXISTS posts (
+	id serial PRIMARY KEY,
+	author VARCHAR NOT NULL,
+	content TEXT NOT NULL,
+	views INT NOT NULL DEFAULT 0,
+	reactions JSONB NOT NULL DEFAULT '{}',
+	created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+
+INSERT INTO posts (id, author, content) VALUES
+	(1, 'Miłosz', 'Oh, I remember the days when we used to write code in PHP!'),
+	(2, 'Robert', 'Back in my days, we used to write code in assembly!')
+ON CONFLICT (id) DO NOTHING;
+`
+
+func MigrateDB(db *sql.DB) error {
+	_, err := db.Exec(migration)
+	return err
+}
+
+type Repository struct {
+	db *sql.DB
+}
+
+func NewRepository(db *sql.DB) *Repository {
+	return &Repository{
+		db: db,
+	}
+}
+
+func (s *Repository) PostByID(ctx context.Context, id int) (Post, error) {
+	row := s.db.QueryRowContext(ctx, `SELECT id, author, content, views, reactions, created_at FROM posts WHERE id = $1`, id)
+	post, err := scanPost(row)
+	if err != nil {
+		return Post{}, err
+	}
+
+	return post, nil
+}
+
+func (s *Repository) AllPosts(ctx context.Context) ([]Post, error) {
+	rows, err := s.db.QueryContext(ctx, `SELECT id, author, content, views, reactions, created_at FROM posts ORDER BY id ASC`)
+	if err != nil {
+		return nil, err
+	}
+
+	var posts []Post
+	for rows.Next() {
+		post, err := scanPost(rows)
+		if err != nil {
+			return nil, err
+		}
+		posts = append(posts, post)
+	}
+
+	return posts, nil
+}
+
+func (s *Repository) UpdatePost(ctx context.Context, id int, updateFn func(post *Post)) (err error) {
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return err
+	}
+
+	defer func() {
+		if err == nil {
+			err = tx.Commit()
+		} else {
+			txErr := tx.Rollback()
+			if txErr != nil {
+				err = txErr
+			}
+		}
+	}()
+
+	row := s.db.QueryRowContext(ctx, `SELECT id, author, content, views, reactions, created_at FROM posts WHERE id = $1 FOR UPDATE`, id)
+	post, err := scanPost(row)
+	if err != nil {
+		return err
+	}
+
+	updateFn(&post)
+
+	reactionsJSON, err := json.Marshal(post.Reactions)
+	if err != nil {
+		return err
+	}
+
+	_, err = tx.ExecContext(ctx, `UPDATE posts SET views = $1, reactions = $2 WHERE id = $3`, post.Views, reactionsJSON, post.ID)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+type scanner interface {
+	Scan(dest ...any) error
+}
+
+func scanPost(s scanner) (Post, error) {
+	var id, postViews int
+	var author, content string
+	var reactions []byte
+	var createdAt time.Time
+
+	err := s.Scan(&id, &author, &content, &postViews, &reactions, &createdAt)
+	if err != nil {
+		return Post{}, err
+	}
+
+	var reactionsMap map[string]int
+	err = json.Unmarshal(reactions, &reactionsMap)
+	if err != nil {
+		return Post{}, err
+	}
+
+	return Post{
+		ID:        id,
+		Author:    author,
+		Content:   content,
+		CreatedAt: createdAt,
+		Views:     postViews,
+		Reactions: reactionsMap,
+	}, nil
+}