128 lines
2.9 KiB
Go
128 lines
2.9 KiB
Go
package server
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import (
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"database/sql"
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"errors"
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_ "github.com/mattn/go-sqlite3" // SQLite driver
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"time"
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)
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const (
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createTableQuery = `
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BEGIN;
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CREATE TABLE IF NOT EXISTS messages (
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id VARCHAR(20) PRIMARY KEY,
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time INT NOT NULL,
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topic VARCHAR(64) NOT NULL,
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message VARCHAR(1024) NOT NULL
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);
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CREATE INDEX IF NOT EXISTS idx_topic ON messages (topic);
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COMMIT;
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`
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insertMessageQuery = `INSERT INTO messages (id, time, topic, message) VALUES (?, ?, ?, ?)`
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pruneMessagesQuery = `DELETE FROM messages WHERE time < ?`
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selectMessagesSinceTimeQuery = `
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SELECT id, time, message
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FROM messages
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WHERE topic = ? AND time >= ?
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ORDER BY time ASC
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`
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selectMessageCountQuery = `SELECT count(*) FROM messages WHERE topic = ?`
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selectTopicsQuery = `SELECT topic, MAX(time) FROM messages GROUP BY TOPIC`
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)
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type sqliteCache struct {
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db *sql.DB
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}
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var _ cache = (*sqliteCache)(nil)
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func newSqliteCache(filename string) (*sqliteCache, error) {
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db, err := sql.Open("sqlite3", filename)
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if err != nil {
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return nil, err
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}
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if _, err := db.Exec(createTableQuery); err != nil {
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return nil, err
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}
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return &sqliteCache{
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db: db,
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}, nil
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}
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func (c *sqliteCache) AddMessage(m *message) error {
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_, err := c.db.Exec(insertMessageQuery, m.ID, m.Time, m.Topic, m.Message)
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return err
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}
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func (c *sqliteCache) Messages(topic string, since time.Time) ([]*message, error) {
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rows, err := c.db.Query(selectMessagesSinceTimeQuery, topic, since.Unix())
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if err != nil {
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return nil, err
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}
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defer rows.Close()
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messages := make([]*message, 0)
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for rows.Next() {
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var timestamp int64
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var id, msg string
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if err := rows.Scan(&id, ×tamp, &msg); err != nil {
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return nil, err
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}
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messages = append(messages, &message{
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ID: id,
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Time: timestamp,
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Event: messageEvent,
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Topic: topic,
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Message: msg,
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})
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}
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if err := rows.Err(); err != nil {
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return nil, err
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}
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return messages, nil
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}
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func (c *sqliteCache) MessageCount(topic string) (int, error) {
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rows, err := c.db.Query(selectMessageCountQuery, topic)
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if err != nil {
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return 0, err
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}
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defer rows.Close()
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var count int
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if !rows.Next() {
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return 0, errors.New("no rows found")
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}
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if err := rows.Scan(&count); err != nil {
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return 0, err
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} else if err := rows.Err(); err != nil {
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return 0, err
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}
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return count, nil
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}
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func (s *sqliteCache) Topics() (map[string]*topic, error) {
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rows, err := s.db.Query(selectTopicsQuery)
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if err != nil {
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return nil, err
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}
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defer rows.Close()
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topics := make(map[string]*topic, 0)
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for rows.Next() {
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var id string
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var last int64
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if err := rows.Scan(&id, &last); err != nil {
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return nil, err
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}
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topics[id] = newTopic(id, time.Unix(last, 0))
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}
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if err := rows.Err(); err != nil {
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return nil, err
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}
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return topics, nil
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}
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func (c *sqliteCache) Prune(keep time.Duration) error {
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_, err := c.db.Exec(pruneMessagesQuery, time.Now().Add(-1*keep).Unix())
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return err
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}
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