filer: processing all response headers, no pass through to volume server

* filer calculate MD5 etag
* filer handle response headers, instread of pass it to volume servers

weed/server/common.go

@@ -5,6 +5,8 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
+	"mime/multipart"
 	"net/http"
 	"path/filepath"
 	"strconv"
@@ -210,3 +212,107 @@ func handleStaticResources2(r *mux.Router) {
 	r.Handle("/favicon.ico", http.FileServer(statikFS))
 	r.PathPrefix("/seaweedfsstatic/").Handler(http.StripPrefix("/seaweedfsstatic", http.FileServer(statikFS)))
 }
+
+func adjustHeadersAfterHEAD(w http.ResponseWriter, r *http.Request, filename string) {
+	if filename != "" {
+		contentDisposition := "inline"
+		if r.FormValue("dl") != "" {
+			if dl, _ := strconv.ParseBool(r.FormValue("dl")); dl {
+				contentDisposition = "attachment"
+			}
+		}
+		w.Header().Set("Content-Disposition", contentDisposition+`; filename="`+fileNameEscaper.Replace(filename)+`"`)
+	}
+}
+
+func processRangeRequst(r *http.Request, w http.ResponseWriter, totalSize int64, mimeType string, writeFn func(writer io.Writer, offset int64, size int64) error) {
+	rangeReq := r.Header.Get("Range")
+
+	if rangeReq == "" {
+		w.Header().Set("Content-Length", strconv.FormatInt(totalSize, 10))
+		if err := writeFn(w, 0, 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 = writeFn(w, ra.start, 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 = writeFn(part, ra.start, 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
+	}
+}