rfc8114: prefer return minimal

changelog/unreleased/prefer-return-minimal.md

@@ -0,0 +1,5 @@
+Enhancement: support Prefer: return=minimal in PROPFIND
+
+To reduce HTTP body size when listing folders we implemented https://datatracker.ietf.org/doc/html/rfc8144#section-2.1 to omit the 404 propstat part when a `Prefer: return=minimal` header is present.
+
+https://github.com/cs3org/reva/pull/3222

internal/http/services/owncloud/ocdav/net/headers.go

@@ -33,6 +33,9 @@ const (
 	HeaderLocation                   = "Location"
 	HeaderRange                      = "Range"
 	HeaderIfMatch                    = "If-Match"
+	HeaderPrefer                     = "Prefer"
+	HeaderPreferenceApplied          = "Preference-Applied"
+	HeaderVary                       = "Vary"
 )
 
 // webdav headers
@@ -66,3 +69,8 @@ const (
 	HeaderLitmus               = "X-Litmus"
 	HeaderTransferAuth         = "TransferHeaderAuthorization"
 )
+
+// HTTP Prefer header values
+const (
+	HeaderPreferReturn = "return" // eg. return=representation / return=minimal, depth-noroot
+)

internal/http/services/owncloud/ocdav/net/net.go

@@ -129,3 +129,18 @@ func ParseDestination(baseURI, s string) (string, error) {
 
 	return urlSplit[1], nil
 }
+
+// ParsePrefer parses the prefer header value defined in https://datatracker.ietf.org/doc/html/rfc8144
+func ParsePrefer(s string) map[string]string {
+	parts := strings.Split(s, ",")
+	m := make(map[string]string, len(parts))
+	for _, part := range parts {
+		kv := strings.SplitN(strings.ToLower(strings.Trim(part, " ")), "=", 2)
+		if len(kv) == 2 {
+			m[kv[0]] = kv[1]
+		} else {
+			m[kv[0]] = "1" // mark it as set
+		}
+	}
+	return m
+}

internal/http/services/owncloud/ocdav/publicfile.go

@@ -111,7 +111,10 @@ func (s *svc) handlePropfindOnToken(w http.ResponseWriter, r *http.Request, ns s
 
 	infos := s.getPublicFileInfos(onContainer, depth == net.DepthZero, tokenStatInfo)
 
-	propRes, err := propfind.MultistatusResponse(ctx, &pf, infos, s.c.PublicURL, ns, nil)
+	prefer := net.ParsePrefer(r.Header.Get("prefer"))
+	returnMinimal := prefer[net.HeaderPreferReturn] == "minimal"
+
+	propRes, err := propfind.MultistatusResponse(ctx, &pf, infos, s.c.PublicURL, ns, nil, returnMinimal)
 	if err != nil {
 		sublog.Error().Err(err).Msg("error formatting propfind")
 		w.WriteHeader(http.StatusInternalServerError)
@@ -120,6 +123,10 @@ func (s *svc) handlePropfindOnToken(w http.ResponseWriter, r *http.Request, ns s
 
 	w.Header().Set(net.HeaderDav, "1, 3, extended-mkcol")
 	w.Header().Set(net.HeaderContentType, "application/xml; charset=utf-8")
+	w.Header().Set(net.HeaderVary, net.HeaderPrefer)
+	if returnMinimal {
+		w.Header().Set(net.HeaderPreferenceApplied, "return=minimal")
+	}
 	w.WriteHeader(http.StatusMultiStatus)
 	if _, err := w.Write(propRes); err != nil {
 		sublog.Err(err).Msg("error writing response")

internal/http/services/owncloud/ocdav/report.go

@@ -110,14 +110,21 @@ func (s *svc) doFilterFiles(w http.ResponseWriter, r *http.Request, ff *reportFi
 			infos = append(infos, statRes.Info)
 		}
 
-		responsesXML, err := propfind.MultistatusResponse(ctx, &propfind.XML{Prop: ff.Prop}, infos, s.c.PublicURL, namespace, nil)
+		prefer := net.ParsePrefer(r.Header.Get("prefer"))
+		returnMinimal := prefer[net.HeaderPreferReturn] == "minimal"
+
+		responsesXML, err := propfind.MultistatusResponse(ctx, &propfind.XML{Prop: ff.Prop}, infos, s.c.PublicURL, namespace, nil, returnMinimal)
 		if err != nil {
 			log.Error().Err(err).Msg("error formatting propfind")
 			w.WriteHeader(http.StatusInternalServerError)
 			return
 		}
 		w.Header().Set(net.HeaderDav, "1, 3, extended-mkcol")
 		w.Header().Set(net.HeaderContentType, "application/xml; charset=utf-8")
+		w.Header().Set(net.HeaderVary, net.HeaderPrefer)
+		if returnMinimal {
+			w.Header().Set(net.HeaderPreferenceApplied, "return=minimal")
+		}
 		w.WriteHeader(http.StatusMultiStatus)
 		if _, err := w.Write(responsesXML); err != nil {
 			log.Err(err).Msg("error writing response")

internal/http/services/owncloud/ocdav/versions.go

@@ -191,14 +191,21 @@ func (h *VersionsHandler) doListVersions(w http.ResponseWriter, r *http.Request,
 		infos = append(infos, vi)
 	}
 
-	propRes, err := propfind.MultistatusResponse(ctx, &pf, infos, s.c.PublicURL, "", nil)
+	prefer := net.ParsePrefer(r.Header.Get("prefer"))
+	returnMinimal := prefer[net.HeaderPreferReturn] == "minimal"
+
+	propRes, err := propfind.MultistatusResponse(ctx, &pf, infos, s.c.PublicURL, "", nil, returnMinimal)
 	if err != nil {
 		sublog.Error().Err(err).Msg("error formatting propfind")
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
 	w.Header().Set(net.HeaderDav, "1, 3, extended-mkcol")
 	w.Header().Set(net.HeaderContentType, "application/xml; charset=utf-8")
+	w.Header().Set(net.HeaderVary, net.HeaderPrefer)
+	if returnMinimal {
+		w.Header().Set(net.HeaderPreferenceApplied, "return=minimal")
+	}
 	w.WriteHeader(http.StatusMultiStatus)
 	_, err = w.Write(propRes)
 	if err != nil {