Use only one header to send git blobs

internal/git/blob.go

@@ -2,33 +2,60 @@ package git
 
 import (
 	"../helper"
+	"encoding/base64"
+	"encoding/json"
 	"fmt"
 	"io"
 	"log"
 	"net/http"
+	"strings"
 )
 
-func SendGitBlob(w http.ResponseWriter, r *http.Request, repoPath string, blobId string) {
-	log.Printf("SendGitBlob: sending %q for %q", blobId, r.URL.Path)
+type blobParams struct {
+	RepoPath string
+	BlobId   string
+}
+
+const SendBlobPrefix = "git-blob:"
+
+func SendBlob(w http.ResponseWriter, r *http.Request, sendData string) {
+	params, err := unpackSendData(sendData)
+	if err != nil {
+		helper.Fail500(w, fmt.Errorf("SendBlob: unpack sendData: %v", err))
+		return
+	}
+	log.Printf("SendBlob: sending %q for %q", params.BlobId, r.URL.Path)
 
-	gitShowCmd := gitCommand("", "git", "--git-dir="+repoPath, "show", blobId)
+	gitShowCmd := gitCommand("", "git", "--git-dir="+params.RepoPath, "show", params.BlobId)
 	stdout, err := gitShowCmd.StdoutPipe()
 	if err != nil {
-		helper.Fail500(w, fmt.Errorf("SendGitBlob: git show stdout: %v", err))
+		helper.Fail500(w, fmt.Errorf("SendBlob: git show stdout: %v", err))
 		return
 	}
 	if err := gitShowCmd.Start(); err != nil {
-		helper.Fail500(w, fmt.Errorf("SendGitBlob: start %v: %v", gitShowCmd, err))
+		helper.Fail500(w, fmt.Errorf("SendBlob: start %v: %v", gitShowCmd, err))
 		return
 	}
 	defer helper.CleanUpProcessGroup(gitShowCmd)
 
 	if _, err := io.Copy(w, stdout); err != nil {
-		helper.LogError(fmt.Errorf("SendGitBlob: copy git show stdout: %v", err))
+		helper.LogError(fmt.Errorf("SendBlob: copy git show stdout: %v", err))
 		return
 	}
 	if err := gitShowCmd.Wait(); err != nil {
-		helper.LogError(fmt.Errorf("SendGitBlob: wait for git show: %v", err))
+		helper.LogError(fmt.Errorf("SendBlob: wait for git show: %v", err))
 		return
 	}
 }
+
+func unpackSendData(sendData string) (*blobParams, error) {
+	jsonBytes, err := base64.URLEncoding.DecodeString(strings.TrimPrefix(sendData, SendBlobPrefix))
+	if err != nil {
+		return nil, err
+	}
+	result := &blobParams{}
+	if err := json.Unmarshal([]byte(jsonBytes), result); err != nil {
+		return nil, err
+	}
+	return result, nil
+}

internal/senddata/sendfile.go

@@ -11,6 +11,7 @@ import (
 	"../helper"
 	"log"
 	"net/http"
+	"strings"
 )
 
 type sendFileResponseWriter struct {
@@ -44,6 +45,13 @@ func (s *sendFileResponseWriter) Write(data []byte) (n int, err error) {
 }
 
 func (s *sendFileResponseWriter) WriteHeader(status int) {
+	// Never pass these headers to the client
+	defer func() {
+		s.Header().Del("X-Sendfile")
+		s.Header().Del("Gitlab-Workhorse-Send-Data")
+
+	}()
+
 	if s.status != 0 {
 		return
 	}
@@ -55,27 +63,21 @@ func (s *sendFileResponseWriter) WriteHeader(status int) {
 	}
 
 	if file := s.Header().Get("X-Sendfile"); file != "" {
-		s.Header().Del("X-Sendfile")
-
 		// Mark this connection as hijacked
 		s.hijacked = true
 
 		// Serve the file
 		sendFileFromDisk(s.rw, s.req, file)
 		return
-	} else if repoPath := s.Header().Get("Gitlab-Workhorse-Repo-Path"); repoPath != "" {
+	}
+	if sendData := s.Header().Get("Gitlab-Workhorse-Send-Data"); strings.HasPrefix(sendData, "git-blob:") {
 		s.hijacked = true
-
-		s.Header().Del("Gitlab-Workhorse-Repo-Path")
-		sendBlob := s.Header().Get("Gitlab-Workhorse-Send-Blob")
-		s.Header().Del("Gitlab-Workhorse-Send-Blob")
-
-		git.SendGitBlob(s.rw, s.req, repoPath, sendBlob)
-		return
-	} else {
-		s.rw.WriteHeader(s.status)
+		git.SendBlob(s.rw, s.req, sendData)
 		return
 	}
+
+	s.rw.WriteHeader(s.status)
+	return
 }
 
 func sendFileFromDisk(w http.ResponseWriter, r *http.Request, file string) {