crowsnest/internal/model/database/articles.go

package database

import (
	"crowsnest/internal/model"
	"database/sql"
)

type ArticleModel struct {
	DB *sql.DB
}

// Gets all the article objects from the database. This may throw an error if
// the connection to the database fails.
func (m *ArticleModel) All(limit int) ([]model.Article, error) {
	stmt := `
        SELECT id, title, sourceUrl, content, publishDate, fetchDate 
        FROM articles 
        ORDER BY publishDate DESC
		LIMIT $1
    `
	rows, err := m.DB.Query(stmt, limit)
	if err != nil {
		return nil, err
	}

	articles := []model.Article{}
	for rows.Next() {
		a := model.Article{}
		err := rows.Scan(&a.Identifier, &a.Title, &a.SourceUrl, &a.Content, &a.PublishDate, &a.FetchDate)
		if err != nil {
			return nil, err
		}

		articles = append(articles, a)
	}

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

	return articles, nil
}

// Will use the full-text search features of the underlying database to search
// articles for a given search query. This may fail if the connection to the
// database fails.
func (m *ArticleModel) Search(query string) ([]model.Article, error) {
	stmt := `
		SELECT id, title, sourceurl, content, publishdate, fetchDate
		FROM articles
		WHERE fts_vector @@ to_tsquery('german', $1)
		ORDER BY ts_rank(fts_vector, to_tsquery('german', $1)) DESC
		LIMIT 10
	`

	rows, err := m.DB.Query(stmt, query)
	if err != nil {
		return nil, err
	}

	articles := []model.Article{}
	for rows.Next() {
		a := model.Article{}
		err := rows.Scan(&a.Identifier, &a.Title, &a.SourceUrl, &a.Content, &a.PublishDate, &a.FetchDate)
		if err != nil {
			return nil, err
		}

		articles = append(articles, a)
	}

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

// Inserts a new article into the database. The id attribute of the given
// article will be ignored. May throw an error if the execution of the database
// query fails.
func (m *ArticleModel) Insert(a *model.Article) error {
	// insert article
	stmt := `INSERT INTO articles (title, sourceUrl, content, publishDate, fetchDate)
             VALUES ($1, $2, $3, $4, $5)
    `
	_, err := m.DB.Exec(stmt, a.Title, a.SourceUrl, a.Content, a.PublishDate, a.FetchDate)
	return err
}

// TODO docstring
func (m *ArticleModel) Update(a *model.Article) error {
	stmt := `UPDATE articles 
             SET title = $1, sourceUrl = $2, content = $4, publishDate = $5, fetchDate = $6
             WHERE id = $7
    `
	_, err := m.DB.Exec(stmt, a.Title, a.SourceUrl, a.Content, a.PublishDate, a.FetchDate, a.Identifier)
	return err
}