working filer server!

go/weed/weed_server/filer_server.go

@@ -0,0 +1,157 @@
+package weed_server
+
+import (
+	"code.google.com/p/weed-fs/go/glog"
+	"errors"
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/util"
+	"net/http"
+	"strings"
+)
+
+/*
+1. level db is only for local instance
+2. db stores two types of pairs
+ <path/to/dir, sub folder names>
+ <path/to/file, file id>
+ So, to list a directory, just get the directory entry, and iterate the current directory files
+ Care must be taken to maintain the <dir, sub dirs> and <file, fileid> pairs.
+3.
+*/
+type FilerServer struct {
+	port       string
+	master     string
+	collection string
+	db         *leveldb.DB
+}
+
+func NewFilerServer(r *http.ServeMux, master string, dir string) (fs *FilerServer, err error) {
+	fs = &FilerServer{
+		master:     master,
+		collection: "",
+		port:       ":8888",
+	}
+
+	if fs.db, err = leveldb.OpenFile(dir, nil); err != nil {
+		return
+	}
+
+	r.HandleFunc("/", fs.filerHandler)
+
+	glog.V(0).Infoln("file server started on port ", fs.port)
+
+	return fs, nil
+}
+
+func (fs *FilerServer) CreateFile(fullFileName string, fid string) (err error) {
+	fs.ensureFileFolder(fullFileName)
+	return fs.db.Put([]byte(fullFileName), []byte(fid), nil)
+}
+
+func (fs *FilerServer) FindFile(fullFileName string) (fid string, err error) {
+	return fs.findEntry(fullFileName)
+}
+
+func (fs *FilerServer) ListDirectories(fullpath string) (dirs []string, err error) {
+	data, e := fs.db.Get([]byte(fullpath), nil)
+	if e != nil {
+		return nil, e
+	}
+	return strings.Split(string(data), ":"), nil
+}
+
+func (fs *FilerServer) ListFiles(fullpath string, start, limit int) (files []string) {
+	if !strings.HasSuffix(fullpath, "/") {
+		fullpath += "/"
+	}
+	iter := fs.db.NewIterator(&util.Range{Start: []byte(fullpath)}, nil)
+	startCounter, limitCounter := -1, 0
+	for iter.Next() {
+		startCounter++
+		if startCounter < start {
+			continue
+		}
+		limitCounter++
+		if limit > 0 {
+			if limitCounter > limit {
+				break
+			}
+		}
+		key := string(iter.Key())
+		if !strings.HasPrefix(key, fullpath) {
+			break
+		}
+		fileName := key[len(fullpath):]
+		if strings.Contains(fileName, "/") {
+			break
+		}
+		files = append(files, fileName)
+	}
+	iter.Release()
+	return
+}
+
+func (fs *FilerServer) Delete(fullpath string, isForceDirectoryRemoval bool) (fid string, isFile bool, err error) {
+	val, e := fs.findEntry(fullpath)
+	if e != nil {
+		return "", false, e
+	}
+	if strings.Contains(val, ",") {
+		return val, true, fs.db.Delete([]byte(fullpath), nil)
+	}
+	// deal with directory
+	if !strings.HasSuffix(fullpath, "/") {
+		fullpath += "/"
+	}
+	iter := fs.db.NewIterator(&util.Range{Start: []byte(fullpath)}, nil)
+	counter := 0
+	for iter.Next() {
+		counter++
+		if counter > 0 {
+			break
+		}
+	}
+	iter.Release()
+	if counter > 0 {
+		return "", false, errors.New("Force Deletion Not Supported Yet")
+	}
+	return "", false, fs.db.Delete([]byte(fullpath), nil)
+}
+
+func (fs *FilerServer) findEntry(fullpath string) (value string, err error) {
+	data, e := fs.db.Get([]byte(fullpath), nil)
+	if e != nil {
+		return "", e
+	}
+	return string(data), nil
+}
+
+func (fs *FilerServer) ensureFileFolder(fullFileName string) (err error) {
+	parts := strings.Split(fullFileName, "/")
+	path := "/"
+	for i := 1; i < len(parts)-1; i++ {
+		sub := parts[i]
+		if sub == "" {
+			continue
+		}
+		if err = fs.ensureFolderHasEntry(path, sub); err != nil {
+			return
+		}
+		path = path + sub + "/"
+	}
+	return nil
+}
+func (fs *FilerServer) ensureFolderHasEntry(path string, sub string) (err error) {
+	val, e := fs.findEntry(path)
+	if e == leveldb.ErrNotFound {
+		return fs.db.Put([]byte(path), []byte(sub), nil)
+	} else if e != nil {
+		return e
+	}
+	for _, v := range strings.Split(val, ":") {
+		if v == sub {
+			return nil
+		}
+	}
+	return fs.db.Put([]byte(path), []byte(val+":"+sub), nil)
+}