Add partial content request support.

go/weed/weed_server/volume_server_handlers.go

@@ -7,7 +7,9 @@ import (
 	"code.google.com/p/weed-fs/go/stats"
 	"code.google.com/p/weed-fs/go/storage"
 	"code.google.com/p/weed-fs/go/topology"
+	"io"
 	"mime"
+	"mime/multipart"
 	"net/http"
 	"strconv"
 	"strings"
@@ -20,10 +22,10 @@ func (vs *VolumeServer) storeHandler(w http.ResponseWriter, r *http.Request) {
 	switch r.Method {
 	case "GET":
 		stats.ReadRequest()
-		vs.GetOrHeadHandler(w, r, true)
+		vs.GetOrHeadHandler(w, r)
 	case "HEAD":
 		stats.ReadRequest()
-		vs.GetOrHeadHandler(w, r, false)
+		vs.GetOrHeadHandler(w, r)
 	case "DELETE":
 		stats.DeleteRequest()
 		secure(vs.whiteList, vs.DeleteHandler)(w, r)
@@ -36,7 +38,7 @@ func (vs *VolumeServer) storeHandler(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
-func (vs *VolumeServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request, isGetMethod bool) {
+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)
@@ -129,12 +131,95 @@ func (vs *VolumeServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request,
 		}
 		n.Data = images.Resized(ext, n.Data, width, height)
 	}
-	w.Header().Set("Content-Length", strconv.Itoa(len(n.Data)))
-	if isGetMethod {
+
+	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)))
 		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)
+
 }
 
 func (vs *VolumeServer) PostHandler(w http.ResponseWriter, r *http.Request) {

go/weed/weed_server/volume_server_handlers_helper.go

@@ -0,0 +1,115 @@
+package weed_server
+
+import (
+	"errors"
+	"fmt"
+	"mime/multipart"
+	"net/textproto"
+	"strconv"
+	"strings"
+)
+
+// copied from src/pkg/net/http/fs.go
+
+// httpRange specifies the byte range to be sent to the client.
+type httpRange struct {
+	start, length int64
+}
+
+func (r httpRange) contentRange(size int64) string {
+	return fmt.Sprintf("bytes %d-%d/%d", r.start, r.start+r.length-1, size)
+}
+
+func (r httpRange) mimeHeader(contentType string, size int64) textproto.MIMEHeader {
+	return textproto.MIMEHeader{
+		"Content-Range": {r.contentRange(size)},
+		"Content-Type":  {contentType},
+	}
+}
+
+// parseRange parses a Range header string as per RFC 2616.
+func parseRange(s string, size int64) ([]httpRange, error) {
+	if s == "" {
+		return nil, nil // header not present
+	}
+	const b = "bytes="
+	if !strings.HasPrefix(s, b) {
+		return nil, errors.New("invalid range")
+	}
+	var ranges []httpRange
+	for _, ra := range strings.Split(s[len(b):], ",") {
+		ra = strings.TrimSpace(ra)
+		if ra == "" {
+			continue
+		}
+		i := strings.Index(ra, "-")
+		if i < 0 {
+			return nil, errors.New("invalid range")
+		}
+		start, end := strings.TrimSpace(ra[:i]), strings.TrimSpace(ra[i+1:])
+		var r httpRange
+		if start == "" {
+			// If no start is specified, end specifies the
+			// range start relative to the end of the file.
+			i, err := strconv.ParseInt(end, 10, 64)
+			if err != nil {
+				return nil, errors.New("invalid range")
+			}
+			if i > size {
+				i = size
+			}
+			r.start = size - i
+			r.length = size - r.start
+		} else {
+			i, err := strconv.ParseInt(start, 10, 64)
+			if err != nil || i > size || i < 0 {
+				return nil, errors.New("invalid range")
+			}
+			r.start = i
+			if end == "" {
+				// If no end is specified, range extends to end of the file.
+				r.length = size - r.start
+			} else {
+				i, err := strconv.ParseInt(end, 10, 64)
+				if err != nil || r.start > i {
+					return nil, errors.New("invalid range")
+				}
+				if i >= size {
+					i = size - 1
+				}
+				r.length = i - r.start + 1
+			}
+		}
+		ranges = append(ranges, r)
+	}
+	return ranges, nil
+}
+
+// countingWriter counts how many bytes have been written to it.
+type countingWriter int64
+
+func (w *countingWriter) Write(p []byte) (n int, err error) {
+	*w += countingWriter(len(p))
+	return len(p), nil
+}
+
+// rangesMIMESize returns the nunber of bytes it takes to encode the
+// provided ranges as a multipart response.
+func rangesMIMESize(ranges []httpRange, contentType string, contentSize int64) (encSize int64) {
+	var w countingWriter
+	mw := multipart.NewWriter(&w)
+	for _, ra := range ranges {
+		mw.CreatePart(ra.mimeHeader(contentType, contentSize))
+		encSize += ra.length
+	}
+	mw.Close()
+	encSize += int64(w)
+	return
+}
+
+func sumRangesSize(ranges []httpRange) (size int64) {
+	for _, ra := range ranges {
+		size += ra.length
+	}
+	return
+}