/*
此api实现复制写入操作 步骤如下:
1.先写入本地
2. 如果需要复制则 将消息投递replicate到master
3. 如果2操作成功完成则返回
4. 如果2失败,则删除本地副本并投递删除消息到master
5. 返回4的结果
同理删除
*/
func ReplicatedWrite(masterNode string, s *storage.Store, volumeId storage.VolumeId, needle *storage.Needle, r *http.Request) (size uint32, errorStatus string) {
ret, err := s.Write(volumeId, needle)
needToReplicate := !s.HasVolume(volumeId)
if err != nil {
errorStatus = "Failed to write to local disk (" + err.Error() + ")"
} else if ret > 0 { //写入成功
needToReplicate = needToReplicate || s.GetVolume(volumeId).NeedToReplicate()
} else {
errorStatus = "Failed to write to local disk"
}
//??? --lewgun
if !needToReplicate && ret > 0 {
needToReplicate = s.GetVolume(volumeId).NeedToReplicate()
}
if needToReplicate { //send to other replica locations
if r.FormValue("type") != "replicate" { //只有最原始的才会执行distributedOperation
//向master复制
if !distributedOperation(masterNode,
s,
volumeId,
func(location operation.Location) bool {
_, err := operation.Upload(
"http://"+location.Url+r.URL.Path+"?type=replicate&ts="+strconv.FormatUint(needle.LastModified, 10),
string(needle.Name),
bytes.NewReader(needle.Data),
needle.IsGzipped(),
string(needle.Mime))
return err == nil
})
{
ret = 0
errorStatus = "Failed to write to replicas for volume " + volumeId.String()
}// if !distributedOperation(masterNode,
} // if r.FormValue("type") != "replicate" {
}
//复制失败,删除本地副本
if errorStatus != "" {
if _, err = s.Delete(volumeId, needle); err != nil {
errorStatus += "\nCannot delete " + strconv.FormatUint(needle.Id, 10) + " from " +
volumeId.String() + ": " + err.Error()
} else {
distributedOperation(
masterNode,
s,
volumeId,
func(location operation.Location) bool {
return nil == util.Delete("http://"+location.Url+r.URL.Path+"?type=replicate")
}
) // distributedOperation(...)
} // if errorStatus != "" {
}
size = ret
return
}
func walker(vid storage.VolumeId, n *storage.Needle, version storage.Version) (err error) {
key := storage.NewFileIdFromNeedle(vid, n).String()
if tarFh != nil {
fnTmplBuf.Reset()
//生成文件名 bingo
if err = fnTmpl.Execute(fnTmplBuf,
nameParams{Name: string(n.Name),
Id: n.Id,
Mime: string(n.Mime),
Key: key,
},
); err != nil {
return err
}
nm := fnTmplBuf.String()
if n.IsGzipped() && path.Ext(nm) != ".gz" {
nm = nm + ".gz"
}
tarHeader.Name, tarHeader.Size = nm, int64(len(n.Data))
//写文件头
if err = tarFh.WriteHeader(&tarHeader); err != nil {
return err
}
//写文件
_, err = tarFh.Write(n.Data)
} else {
size := n.DataSize
if version == storage.Version1 {
size = n.Size
}
fmt.Printf("key=%s Name=%s Size=%d gzip=%t mime=%s\n",
key,
n.Name,
size,
n.IsGzipped(),
n.Mime,
)
}
return
}
/*
此api完成数据的返回,处理了multi-part等
*/
func (vs *VolumeServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request) {
n := new(storage.Needle)
vid, fid, filename, ext, _ := parseURLPath(r.URL.Path)
volumeId, err := storage.NewVolumeId(vid)
if err != nil {
glog.V(2).Infoln("parsing error:", err, r.URL.Path)
w.WriteHeader(http.StatusBadRequest)
return
}
err = n.ParsePath(fid)
if err != nil {
glog.V(2).Infoln("parsing fid error:", err, r.URL.Path)
w.WriteHeader(http.StatusBadRequest)
return
}
glog.V(4).Infoln("volume", volumeId, "reading", n)
if !vs.store.HasVolume(volumeId) { //自己没有
//向master查找
lookupResult, err := operation.Lookup(vs.masterNode, volumeId.String())
glog.V(2).Infoln("volume", volumeId, "found on", lookupResult, "error", err)
//重定向
if err == nil && len(lookupResult.Locations) > 0 {
http.Redirect(w, r, "http://"+lookupResult.Locations[0].PublicUrl+r.URL.Path, http.StatusMovedPermanently)
} else {
glog.V(2).Infoln("lookup error:", err, r.URL.Path)
w.WriteHeader(http.StatusNotFound)
}
return
}
cookie := n.Cookie
count, e := vs.store.Read(volumeId, n)
glog.V(4).Infoln("read bytes", count, "error", e)
//读取失败
if e != nil || count <= 0 {
glog.V(0).Infoln("read error:", e, r.URL.Path)
w.WriteHeader(http.StatusNotFound)
return
}
//文件cookie不匹配
if n.Cookie != cookie {
glog.V(0).Infoln("request", r.URL.Path, "with unmaching cookie seen:", cookie, "expected:", n.Cookie, "from", r.RemoteAddr, "agent", r.UserAgent())
w.WriteHeader(http.StatusNotFound)
return
}
if n.LastModified != 0 {
w.Header().Set("Last-Modified", time.Unix(int64(n.LastModified), 0).UTC().Format(http.TimeFormat))
if r.Header.Get("If-Modified-Since") != "" {
if t, parseError := time.Parse(http.TimeFormat, r.Header.Get("If-Modified-Since")); parseError == nil {
if t.Unix() >= int64(n.LastModified) {
w.WriteHeader(http.StatusNotModified)
return
}
}
}
}
etag := n.Etag()
if inm := r.Header.Get("If-None-Match"); inm == etag {
w.WriteHeader(http.StatusNotModified)
return
}
w.Header().Set("Etag", etag)
if n.NameSize > 0 && filename == "" {
filename = string(n.Name)
dotIndex := strings.LastIndex(filename, ".")
if dotIndex > 0 {
ext = filename[dotIndex:]
}
}
mtype := ""
if ext != "" {
mtype = mime.TypeByExtension(ext)
}
if n.MimeSize > 0 {
mt := string(n.Mime)
if mt != "application/octet-stream" {
mtype = mt
}
}
if mtype != "" {
w.Header().Set("Content-Type", mtype)
}
if filename != "" {
w.Header().Set("Content-Disposition", "filename=\""+fileNameEscaper.Replace(filename)+"\"")
}
if ext != ".gz" {
if n.IsGzipped() {
if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
w.Header().Set("Content-Encoding", "gzip")
} else {
if n.Data, err = storage.UnGzipData(n.Data); err != nil {
glog.V(0).Infoln("lookup error:", err, r.URL.Path)
}
}
}
}
if ext == ".png" || ext == ".jpg" || ext == ".gif" {
width, height := 0, 0
if r.FormValue("width") != "" {
width, _ = strconv.Atoi(r.FormValue("width"))
}
if r.FormValue("height") != "" {
height, _ = strconv.Atoi(r.FormValue("height"))
}
//获得缩略图
n.Data, _, _ = images.Resized(ext, n.Data, width, height)
}
//如果是head协议 简单返回
w.Header().Set("Accept-Ranges", "bytes")
if r.Method == "HEAD" {
w.Header().Set("Content-Length", strconv.Itoa(len(n.Data)))
return
}
rangeReq := r.Header.Get("Range")
if rangeReq == "" {
w.Header().Set("Content-Length", strconv.Itoa(len(n.Data)))
//写入实际数据
if _, e = w.Write(n.Data); e != nil {
glog.V(0).Infoln("response write error:", e)
}
return
}
//the rest is dealing with partial content request
//mostly copy from src/pkg/net/http/fs.go
size := int64(len(n.Data))
ranges, err := parseRange(rangeReq, size)
if err != nil {
http.Error(w, err.Error(), http.StatusRequestedRangeNotSatisfiable)
return
}
if sumRangesSize(ranges) > size {
// The total number of bytes in all the ranges
// is larger than the size of the file by
// itself, so this is probably an attack, or a
// dumb client. Ignore the range request.
ranges = nil
return
}
if len(ranges) == 0 {
return
}
if len(ranges) == 1 {
// RFC 2616, Section 14.16:
// "When an HTTP message includes the content of a single
// range (for example, a response to a request for a
// single range, or to a request for a set of ranges
// that overlap without any holes), this content is
// transmitted with a Content-Range header, and a
// Content-Length header showing the number of bytes
// actually transferred.
// ...
// A response to a request for a single range MUST NOT
// be sent using the multipart/byteranges media type."
ra := ranges[0]
w.Header().Set("Content-Length", strconv.FormatInt(ra.length, 10))
w.Header().Set("Content-Range", ra.contentRange(size))
w.WriteHeader(http.StatusPartialContent)
if _, e = w.Write(n.Data[ra.start : ra.start+ra.length]); e != nil {
glog.V(0).Infoln("response write error:", e)
}
return
}
// process mulitple ranges
for _, ra := range ranges {
if ra.start > size {
http.Error(w, "Out of Range", http.StatusRequestedRangeNotSatisfiable)
return
}
}
sendSize := rangesMIMESize(ranges, mtype, size)
pr, pw := io.Pipe()
mw := multipart.NewWriter(pw)
w.Header().Set("Content-Type", "multipart/byteranges; boundary="+mw.Boundary())
sendContent := pr
defer pr.Close() // cause writing goroutine to fail and exit if CopyN doesn't finish.
go func() {
for _, ra := range ranges {
part, err := mw.CreatePart(ra.mimeHeader(mtype, size))
if err != nil {
pw.CloseWithError(err)
return
}
if _, err = part.Write(n.Data[ra.start : ra.start+ra.length]); err != nil {
pw.CloseWithError(err)
return
}
}
mw.Close()
pw.Close()
}()
if w.Header().Get("Content-Encoding") == "" {
w.Header().Set("Content-Length", strconv.FormatInt(sendSize, 10))
}
w.WriteHeader(http.StatusPartialContent)
io.CopyN(w, sendContent, sendSize)
}