seaweedfs/weed/util/compression.go
2020-06-20 08:01:00 -07:00

119 lines
2.4 KiB
Go

package util
import (
"bytes"
"compress/flate"
"compress/gzip"
"fmt"
"io/ioutil"
"strings"
"golang.org/x/tools/godoc/util"
"github.com/chrislusf/seaweedfs/weed/glog"
)
func GzipData(input []byte) ([]byte, error) {
buf := new(bytes.Buffer)
w, _ := gzip.NewWriterLevel(buf, flate.BestSpeed)
if _, err := w.Write(input); err != nil {
glog.V(2).Infoln("error compressing data:", err)
return nil, err
}
if err := w.Close(); err != nil {
glog.V(2).Infoln("error closing compressed data:", err)
return nil, err
}
return buf.Bytes(), nil
}
func UnCompressData(input []byte) ([]byte, error) {
if IsGzippedContent(input) {
return ungzipData(input)
}
return nil, fmt.Errorf("unsupported compression")
}
func ungzipData(input []byte) ([]byte, error) {
buf := bytes.NewBuffer(input)
r, _ := gzip.NewReader(buf)
defer r.Close()
output, err := ioutil.ReadAll(r)
if err != nil {
glog.V(2).Infoln("error uncompressing data:", err)
}
return output, err
}
/*
* Default more not to gzip since gzip can be done on client side.
*/
func IsGzippable(ext, mtype string, data []byte) bool {
shouldBeZipped, iAmSure := IsGzippableFileType(ext, mtype)
if iAmSure {
return shouldBeZipped
}
isMostlyText := util.IsText(data)
return isMostlyText
}
func IsGzippedContent(data []byte) bool {
if len(data) < 2 {
return false
}
return data[0] == 31 && data[1] == 139
}
/*
* Default more not to gzip since gzip can be done on client side.
*/func IsGzippableFileType(ext, mtype string) (shouldBeZipped, iAmSure bool) {
// text
if strings.HasPrefix(mtype, "text/") {
return true, true
}
// images
switch ext {
case ".svg", ".bmp", ".wav":
return true, true
}
if strings.HasPrefix(mtype, "image/") {
return false, true
}
// by file name extension
switch ext {
case ".zip", ".rar", ".gz", ".bz2", ".xz":
return false, true
case ".pdf", ".txt", ".html", ".htm", ".css", ".js", ".json":
return true, true
case ".php", ".java", ".go", ".rb", ".c", ".cpp", ".h", ".hpp":
return true, true
case ".png", ".jpg", ".jpeg":
return false, true
}
// by mime type
if strings.HasPrefix(mtype, "application/") {
if strings.HasSuffix(mtype, "xml") {
return true, true
}
if strings.HasSuffix(mtype, "script") {
return true, true
}
}
if strings.HasPrefix(mtype, "audio/") {
switch strings.TrimPrefix(mtype, "audio/") {
case "wave", "wav", "x-wav", "x-pn-wav":
return true, true
}
}
return false, false
}