filer support reading multiple chunks, with range support

weed/server/filer_server_handlers_read.go

@@ -10,6 +10,10 @@ import (
 	"github.com/chrislusf/seaweedfs/weed/glog"
 	"github.com/chrislusf/seaweedfs/weed/operation"
 	"github.com/chrislusf/seaweedfs/weed/util"
+	"strconv"
+	"mime/multipart"
+	"mime"
+	"path"
 )
 
 func (fs *FilerServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request, isGetMethod bool) {
@@ -40,20 +44,37 @@ func (fs *FilerServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request,
 		return
 	}
 
-	// FIXME pick the right fid
+	w.Header().Set("Accept-Ranges", "bytes")
+	if r.Method == "HEAD" {
+		w.Header().Set("Content-Length", strconv.FormatInt(int64(filer2.TotalSize(entry.Chunks)), 10))
+		return
+	}
+
+	if len(entry.Chunks) == 1 {
+		fs.handleSingleChunk(w, r, entry)
+		return
+	}
+
+	fs.handleMultipleChunks(w, r, entry)
+
+}
+
+func (fs *FilerServer) handleSingleChunk(w http.ResponseWriter, r *http.Request, entry *filer2.Entry) {
+
 	fileId := entry.Chunks[0].FileId
 
-	urlLocation, err := operation.LookupFileId(fs.getMasterNode(), fileId)
+	urlString, err := operation.LookupFileId(fs.getMasterNode(), fileId)
 	if err != nil {
-		glog.V(1).Infoln("operation LookupFileId %s failed, err is %s", fileId, err.Error())
+		glog.V(1).Infof("operation LookupFileId %s failed, err: %v", fileId, err)
 		w.WriteHeader(http.StatusNotFound)
 		return
 	}
-	urlString := urlLocation
+
 	if fs.redirectOnRead {
 		http.Redirect(w, r, urlString, http.StatusFound)
 		return
 	}
+
 	u, _ := url.Parse(urlString)
 	q := u.Query()
 	for key, values := range r.URL.Query() {
@@ -86,5 +107,141 @@ func (fs *FilerServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request,
 	}
 	w.WriteHeader(resp.StatusCode)
 	io.Copy(w, resp.Body)
+}
+
+func (fs *FilerServer) handleMultipleChunks(w http.ResponseWriter, r *http.Request, entry *filer2.Entry) {
+
+	mimeType := ""
+	if ext := path.Ext(entry.Name()); ext != "" {
+		mimeType = mime.TypeByExtension(ext)
+	}
+	if mimeType != "" {
+		w.Header().Set("Content-Type", mimeType)
+	}
+
+	println("mime type:", mimeType)
+
+	totalSize := int64(filer2.TotalSize(entry.Chunks))
+
+	rangeReq := r.Header.Get("Range")
+
+	if rangeReq == "" {
+		w.Header().Set("Content-Length", strconv.FormatInt(totalSize, 10))
+		if err := fs.writeContent(w, entry, 0, int(totalSize)); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		return
+	}
+
+	//the rest is dealing with partial content request
+	//mostly copy from src/pkg/net/http/fs.go
+	ranges, err := parseRange(rangeReq, totalSize)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusRequestedRangeNotSatisfiable)
+		return
+	}
+	if sumRangesSize(ranges) > totalSize {
+		// 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.
+		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(totalSize))
+		w.WriteHeader(http.StatusPartialContent)
+
+		err = fs.writeContent(w, entry, ra.start, int(ra.length))
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		return
+	}
+
+	// process multiple ranges
+	for _, ra := range ranges {
+		if ra.start > totalSize {
+			http.Error(w, "Out of Range", http.StatusRequestedRangeNotSatisfiable)
+			return
+		}
+	}
+	sendSize := rangesMIMESize(ranges, mimeType, totalSize)
+	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, e := mw.CreatePart(ra.mimeHeader(mimeType, totalSize))
+			if e != nil {
+				pw.CloseWithError(e)
+				return
+			}
+			if e = fs.writeContent(part, entry, ra.start, int(ra.length)); e != nil {
+				pw.CloseWithError(e)
+				return
+			}
+		}
+		mw.Close()
+		pw.Close()
+	}()
+	if w.Header().Get("Content-Encoding") == "" {
+		w.Header().Set("Content-Length", strconv.FormatInt(sendSize, 10))
+	}
+	w.WriteHeader(http.StatusPartialContent)
+	if _, err := io.CopyN(w, sendContent, sendSize); err != nil {
+		http.Error(w, "Internal Error", http.StatusInternalServerError)
+		return
+	}
+
+}
+
+func (fs *FilerServer) writeContent(w io.Writer, entry *filer2.Entry, offset int64, size int) error {
+
+	chunkViews := filer2.ViewFromChunks(entry.Chunks, offset, size)
+
+	fileId2Url := make(map[string]string)
+
+	for _, chunkView := range chunkViews {
+
+		urlString, err := operation.LookupFileId(fs.getMasterNode(), chunkView.FileId)
+		if err != nil {
+			glog.V(1).Infof("operation LookupFileId %s failed, err: %v", chunkView.FileId, err)
+			return err
+		}
+		fileId2Url[chunkView.FileId] = urlString
+	}
+
+	for _, chunkView := range chunkViews {
+		urlString := fileId2Url[chunkView.FileId]
+		_, err := util.ReadUrlAsStream(urlString, chunkView.Offset, int(chunkView.Size), func(data []byte) {
+			w.Write(data)
+		})
+		if err != nil {
+			glog.V(1).Infof("read %s failed, err: %v", chunkView.FileId, err)
+			return err
+		}
+	}
+
+	return nil
 
 }