GoBlog/persistentCache.go

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package main
import (
"database/sql"
"time"
)
func (db *database) cachePersistently(key string, data []byte) error {
date, _ := toLocal(time.Now().String())
_, err := db.exec("insert or replace into persistent_cache(key, data, date) values(@key, @data, @date)", sql.Named("key", key), sql.Named("data", data), sql.Named("date", date))
return err
}
func (db *database) retrievePersistentCache(key string) (data []byte, err error) {
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d, err, _ := db.pc.Do(key, func() (interface{}, error) {
if row, err := db.queryRow("select data from persistent_cache where key = @key", sql.Named("key", key)); err == sql.ErrNoRows {
return nil, nil
} else if err != nil {
return nil, err
} else {
err = row.Scan(&data)
return data, err
}
})
if err != nil {
return nil, err
}
return d.([]byte), nil
}
func (db *database) clearPersistentCache(pattern string) error {
_, err := db.exec("delete from persistent_cache where key like @pattern", sql.Named("pattern", pattern))
return err
}