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Beego/cache/file.go
2014-07-10 13:38:05 +08:00

261 lines
6.3 KiB
Go

// Beego (http://beego.me/)
//
// @description beego is an open-source, high-performance web framework for the Go programming language.
//
// @link http://github.com/astaxie/beego for the canonical source repository
//
// @license http://github.com/astaxie/beego/blob/master/LICENSE
//
// @authors astaxie
package cache
import (
"bytes"
"crypto/md5"
"encoding/gob"
"encoding/hex"
"encoding/json"
"fmt"
"io"
"os"
"path/filepath"
"reflect"
"strconv"
"time"
)
func init() {
Register("file", NewFileCache())
}
// FileCacheItem is basic unit of file cache adapter.
// it contains data and expire time.
type FileCacheItem struct {
Data interface{}
Lastaccess int64
Expired int64
}
var (
FileCachePath string = "cache" // cache directory
FileCacheFileSuffix string = ".bin" // cache file suffix
FileCacheDirectoryLevel int = 2 // cache file deep level if auto generated cache files.
FileCacheEmbedExpiry int64 = 0 // cache expire time, default is no expire forever.
)
// FileCache is cache adapter for file storage.
type FileCache struct {
CachePath string
FileSuffix string
DirectoryLevel int
EmbedExpiry int
}
// Create new file cache with no config.
// the level and expiry need set in method StartAndGC as config string.
func NewFileCache() *FileCache {
// return &FileCache{CachePath:FileCachePath, FileSuffix:FileCacheFileSuffix}
return &FileCache{}
}
// Start and begin gc for file cache.
// the config need to be like {CachePath:"/cache","FileSuffix":".bin","DirectoryLevel":2,"EmbedExpiry":0}
func (fc *FileCache) StartAndGC(config string) error {
var cfg map[string]string
json.Unmarshal([]byte(config), &cfg)
if _, ok := cfg["CachePath"]; !ok {
cfg["CachePath"] = FileCachePath
}
if _, ok := cfg["FileSuffix"]; !ok {
cfg["FileSuffix"] = FileCacheFileSuffix
}
if _, ok := cfg["DirectoryLevel"]; !ok {
cfg["DirectoryLevel"] = strconv.Itoa(FileCacheDirectoryLevel)
}
if _, ok := cfg["EmbedExpiry"]; !ok {
cfg["EmbedExpiry"] = strconv.FormatInt(FileCacheEmbedExpiry, 10)
}
fc.CachePath = cfg["CachePath"]
fc.FileSuffix = cfg["FileSuffix"]
fc.DirectoryLevel, _ = strconv.Atoi(cfg["DirectoryLevel"])
fc.EmbedExpiry, _ = strconv.Atoi(cfg["EmbedExpiry"])
fc.Init()
return nil
}
// Init will make new dir for file cache if not exist.
func (fc *FileCache) Init() {
app := filepath.Dir(os.Args[0])
fc.CachePath = filepath.Join(app, fc.CachePath)
if ok, _ := exists(fc.CachePath); !ok { // todo : error handle
_ = os.MkdirAll(fc.CachePath, os.ModePerm) // todo : error handle
}
}
// get cached file name. it's md5 encoded.
func (fc *FileCache) getCacheFileName(key string) string {
m := md5.New()
io.WriteString(m, key)
keyMd5 := hex.EncodeToString(m.Sum(nil))
cachePath := fc.CachePath
switch fc.DirectoryLevel {
case 2:
cachePath = filepath.Join(cachePath, keyMd5[0:2], keyMd5[2:4])
case 1:
cachePath = filepath.Join(cachePath, keyMd5[0:2])
}
if ok, _ := exists(cachePath); !ok { // todo : error handle
_ = os.MkdirAll(cachePath, os.ModePerm) // todo : error handle
}
return filepath.Join(cachePath, fmt.Sprintf("%s%s", keyMd5, fc.FileSuffix))
}
// Get value from file cache.
// if non-exist or expired, return empty string.
func (fc *FileCache) Get(key string) interface{} {
fileData, err := File_get_contents(fc.getCacheFileName(key))
if err != nil {
return ""
}
var to FileCacheItem
Gob_decode(fileData, &to)
if to.Expired < time.Now().Unix() {
return ""
}
return to.Data
}
// Put value into file cache.
// timeout means how long to keep this file, unit of ms.
// if timeout equals FileCacheEmbedExpiry(default is 0), cache this item forever.
func (fc *FileCache) Put(key string, val interface{}, timeout int64) error {
gob.Register(val)
item := FileCacheItem{Data: val}
if timeout == FileCacheEmbedExpiry {
item.Expired = time.Now().Unix() + (86400 * 365 * 10) // ten years
} else {
item.Expired = time.Now().Unix() + timeout
}
item.Lastaccess = time.Now().Unix()
data, err := Gob_encode(item)
if err != nil {
return err
}
return File_put_contents(fc.getCacheFileName(key), data)
}
// Delete file cache value.
func (fc *FileCache) Delete(key string) error {
filename := fc.getCacheFileName(key)
if ok, _ := exists(filename); ok {
return os.Remove(filename)
}
return nil
}
// Increase cached int value.
// fc value is saving forever unless Delete.
func (fc *FileCache) Incr(key string) error {
data := fc.Get(key)
var incr int
if reflect.TypeOf(data).Name() != "int" {
incr = 0
} else {
incr = data.(int) + 1
}
fc.Put(key, incr, FileCacheEmbedExpiry)
return nil
}
// Decrease cached int value.
func (fc *FileCache) Decr(key string) error {
data := fc.Get(key)
var decr int
if reflect.TypeOf(data).Name() != "int" || data.(int)-1 <= 0 {
decr = 0
} else {
decr = data.(int) - 1
}
fc.Put(key, decr, FileCacheEmbedExpiry)
return nil
}
// Check value is exist.
func (fc *FileCache) IsExist(key string) bool {
ret, _ := exists(fc.getCacheFileName(key))
return ret
}
// Clean cached files.
// not implemented.
func (fc *FileCache) ClearAll() error {
return nil
}
// check file exist.
func exists(path string) (bool, error) {
_, err := os.Stat(path)
if err == nil {
return true, nil
}
if os.IsNotExist(err) {
return false, nil
}
return false, err
}
// Get bytes to file.
// if non-exist, create this file.
func File_get_contents(filename string) (data []byte, e error) {
f, e := os.OpenFile(filename, os.O_RDWR|os.O_CREATE, os.ModePerm)
if e != nil {
return
}
defer f.Close()
stat, e := f.Stat()
if e != nil {
return
}
data = make([]byte, stat.Size())
result, e := f.Read(data)
if e != nil || int64(result) != stat.Size() {
return nil, e
}
return
}
// Put bytes to file.
// if non-exist, create this file.
func File_put_contents(filename string, content []byte) error {
fp, err := os.OpenFile(filename, os.O_RDWR|os.O_CREATE, os.ModePerm)
if err != nil {
return err
}
defer fp.Close()
_, err = fp.Write(content)
return err
}
// Gob encodes file cache item.
func Gob_encode(data interface{}) ([]byte, error) {
buf := bytes.NewBuffer(nil)
enc := gob.NewEncoder(buf)
err := enc.Encode(data)
if err != nil {
return nil, err
}
return buf.Bytes(), err
}
// Gob decodes file cache item.
func Gob_decode(data []byte, to *FileCacheItem) error {
buf := bytes.NewBuffer(data)
dec := gob.NewDecoder(buf)
return dec.Decode(&to)
}