func (fs *FilerServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request, isGetMethod bool) {
//只返回目录
if strings.HasSuffix(r.URL.Path, "/") {
fs.listDirectoryHandler(w, r)
return
}
fileId, err := fs.filer.FindFile(r.URL.Path)
if err == leveldb.ErrNotFound {
glog.V(3).Infoln("Not found in db", r.URL.Path)
w.WriteHeader(http.StatusNotFound)
return
}
parts := strings.Split(fileId, ",") //3,12345
if len(parts) != 2 {
glog.V(1).Infoln("Invalid fileId", fileId)
w.WriteHeader(http.StatusNotFound)
return
}
lookup, lookupError := operation.Lookup(fs.master, parts[0])
if lookupError != nil {
glog.V(1).Infoln("Invalid lookup", lookupError.Error())
w.WriteHeader(http.StatusNotFound)
return
}
if len(lookup.Locations) == 0 {
glog.V(1).Infoln("Can not find location for volume", parts[0])
w.WriteHeader(http.StatusNotFound)
return
}
//从合适的DataNode中随机选择一个 从中读取fileId指定的文件
urlLocation := lookup.Locations[rand.Intn(len(lookup.Locations))].PublicUrl
u, _ := url.Parse("http://" + urlLocation + "/" + fileId)
request := &http.Request{
Method: r.Method,
URL: u,
Proto: r.Proto,
ProtoMajor: r.ProtoMajor,
ProtoMinor: r.ProtoMinor,
Header: r.Header,
Body: r.Body,
Host: r.Host,
ContentLength: r.ContentLength,
}
glog.V(3).Infoln("retrieving from", u)
resp, do_err := util.Do(request)
if do_err != nil {
glog.V(0).Infoln("failing to connect to volume server", do_err.Error())
writeJsonError(w, r, do_err)
return
}
defer resp.Body.Close()
for k, v := range resp.Header {
w.Header()[k] = v
}
w.WriteHeader(resp.StatusCode)
io.Copy(w, resp.Body)
}
func (fs *FilerServer) PostHandler(w http.ResponseWriter, r *http.Request) {
query := r.URL.Query()
//获得一个fileId
assignResult, ae := operation.Assign(fs.master, 1, query.Get("replication"), fs.collection, query.Get("ttl"))
if ae != nil {
glog.V(0).Infoln("failing to assign a file id", ae.Error())
writeJsonError(w, r, ae)
return
}
u, _ := url.Parse("http://" + assignResult.PublicUrl + "/" + assignResult.Fid)
glog.V(4).Infoln("post to", u)
request := &http.Request{
Method: r.Method,
URL: u,
Proto: r.Proto,
ProtoMajor: r.ProtoMajor,
ProtoMinor: r.ProtoMinor,
Header: r.Header,
Body: r.Body,
Host: r.Host,
ContentLength: r.ContentLength,
}
//执行写入操作
resp, do_err := util.Do(request)
if do_err != nil {
glog.V(0).Infoln("failing to connect to volume server", r.RequestURI, do_err.Error())
writeJsonError(w, r, do_err)
return
}
defer resp.Body.Close()
resp_body, ra_err := ioutil.ReadAll(resp.Body)
//读取失败消息
if ra_err != nil {
glog.V(0).Infoln("failing to upload to volume server", r.RequestURI, ra_err.Error())
writeJsonError(w, r, ra_err)
return
}
glog.V(4).Infoln("post result", string(resp_body))
var ret operation.UploadResult
unmarshal_err := json.Unmarshal(resp_body, &ret)
if unmarshal_err != nil {
glog.V(0).Infoln("failing to read upload resonse", r.RequestURI, string(resp_body))
writeJsonError(w, r, unmarshal_err)
return
}
if ret.Error != "" {
glog.V(0).Infoln("failing to post to volume server", r.RequestURI, ret.Error)
writeJsonError(w, r, errors.New(ret.Error))
return
}
path := r.URL.Path
if strings.HasSuffix(path, "/") { //文件夹
if ret.Name != "" { //有文件名
path += ret.Name
} else {
operation.DeleteFile(fs.master, assignResult.Fid) //clean up
glog.V(0).Infoln("Can not to write to folder", path, "without a file name!")
writeJsonError(w, r, errors.New("Can not to write to folder "+path+" without a file name"))
return
}
}
glog.V(4).Infoln("saving", path, "=>", assignResult.Fid)
//向目录服务添加一新项
if db_err := fs.filer.CreateFile(path, assignResult.Fid); db_err != nil {
operation.DeleteFile(fs.master, assignResult.Fid) //clean up
glog.V(0).Infoln("failing to write to filer server", r.RequestURI, db_err.Error())
writeJsonError(w, r, db_err)
return
}
w.WriteHeader(http.StatusCreated)
}