Create memzipfile.go

memzipfile.go

@@ -0,0 +1,202 @@
+package beego
+
+import (
+	"bytes"
+	"compress/flate"
+	"compress/gzip"
+	"errors"
+	//"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+)
+
+var gmfim map[string]*MemFileInfo = make(map[string]*MemFileInfo)
+
+//TODO: 加锁保证数据完整性
+func OpenMemZipFile(path string, zip string) (*MemFile, error) {
+	osfile, e := os.Open(path)
+	if e != nil {
+		return nil, e
+	}
+	defer osfile.Close()
+
+	osfileinfo, e := osfile.Stat()
+	if e != nil {
+		return nil, e
+	}
+
+	modtime := osfileinfo.ModTime()
+	fileSize := osfileinfo.Size()
+
+	cfi, ok := gmfim[zip+":"+path]
+	if ok && cfi.ModTime() == modtime && cfi.fileSize == fileSize {
+		//fmt.Printf("read %s file %s from cache\n", zip, path)
+	} else {
+		//fmt.Printf("NOT read %s file %s from cache\n", zip, path)
+		var content []byte
+		if zip == "gzip" {
+			//将文件内容压缩到zipbuf中
+			var zipbuf bytes.Buffer
+			gzipwriter, e := gzip.NewWriterLevel(&zipbuf, gzip.BestCompression)
+			if e != nil {
+				return nil, e
+			}
+			_, e = io.Copy(gzipwriter, osfile)
+			gzipwriter.Close()
+			if e != nil {
+				return nil, e
+			}
+			//读zipbuf到content
+			content, e = ioutil.ReadAll(&zipbuf)
+			if e != nil {
+				return nil, e
+			}
+		} else if zip == "deflate" {
+			//将文件内容压缩到zipbuf中
+			var zipbuf bytes.Buffer
+			deflatewriter, e := flate.NewWriter(&zipbuf, flate.BestCompression)
+			if e != nil {
+				return nil, e
+			}
+			_, e = io.Copy(deflatewriter, osfile)
+			deflatewriter.Close()
+			if e != nil {
+				return nil, e
+			}
+			//将zipbuf读入到content
+			content, e = ioutil.ReadAll(&zipbuf)
+			if e != nil {
+				return nil, e
+			}
+		} else {
+			content, e = ioutil.ReadAll(osfile)
+			if e != nil {
+				return nil, e
+			}
+		}
+
+		cfi = &MemFileInfo{osfileinfo, modtime, content, int64(len(content)), fileSize}
+		gmfim[zip+":"+path] = cfi
+		//fmt.Printf("%s file %s to %d, cache it\n", zip, path, len(content))
+	}
+	return &MemFile{fi: cfi, offset: 0}, nil
+}
+
+type MemFileInfo struct {
+	os.FileInfo
+	modTime     time.Time
+	content     []byte
+	contentSize int64
+	fileSize    int64
+}
+
+func (fi *MemFileInfo) Name() string {
+	return fi.Name()
+}
+
+func (fi *MemFileInfo) Size() int64 {
+	return fi.contentSize
+}
+
+func (fi *MemFileInfo) Mode() os.FileMode {
+	return fi.Mode()
+}
+
+func (fi *MemFileInfo) ModTime() time.Time {
+	return fi.modTime
+}
+
+func (fi *MemFileInfo) IsDir() bool {
+	return fi.IsDir()
+}
+
+func (fi *MemFileInfo) Sys() interface{} {
+	return nil
+}
+
+type MemFile struct {
+	fi     *MemFileInfo
+	offset int64
+}
+
+func (f *MemFile) Close() error {
+	return nil
+}
+
+func (f *MemFile) Stat() (os.FileInfo, error) {
+	return f.fi, nil
+}
+
+func (f *MemFile) Readdir(count int) ([]os.FileInfo, error) {
+	infos := []os.FileInfo{}
+
+	return infos, nil
+}
+
+func (f *MemFile) Read(p []byte) (n int, err error) {
+	if len(f.fi.content)-int(f.offset) >= len(p) {
+		n = len(p)
+	} else {
+		n = len(f.fi.content) - int(f.offset)
+		err = io.EOF
+	}
+	copy(p, f.fi.content[f.offset:f.offset+int64(n)])
+	f.offset += int64(n)
+	return
+}
+
+var errWhence = errors.New("Seek: invalid whence")
+var errOffset = errors.New("Seek: invalid offset")
+
+func (f *MemFile) Seek(offset int64, whence int) (ret int64, err error) {
+	switch whence {
+	default:
+		return 0, errWhence
+	case os.SEEK_SET:
+	case os.SEEK_CUR:
+		offset += f.offset
+	case os.SEEK_END:
+		offset += int64(len(f.fi.content))
+	}
+	if offset < 0 || int(offset) > len(f.fi.content) {
+		return 0, errOffset
+	}
+	f.offset = offset
+	return f.offset, nil
+}
+
+//返回: gzip, deflate, 优先gzip
+//返回空, 表示不zip
+func GetAcceptEncodingZip(r *http.Request) string {
+	ss := r.Header.Get("Accept-Encoding")
+	ss = strings.ToLower(ss)
+	if strings.Contains(ss, "gzip") {
+		return "gzip"
+	} else if strings.Contains(ss, "deflate") {
+		return "deflate"
+	} else {
+		return ""
+	}
+}
+
+func CloseZWriter(zwriter io.Writer) {
+	if zwriter == nil {
+		return
+	}
+
+	switch zwriter.(type) {
+	case *gzip.Writer:
+		zwriter.(*gzip.Writer).Close()
+	case *flate.Writer:
+		zwriter.(*flate.Writer).Close()
+		//其他情况不close, 保持和默认(非压缩)行为一致
+		/*
+			case io.WriteCloser:
+				zwriter.(io.WriteCloser).Close()
+		*/
+	}
+}