server/prpc: updated server according to protocol

server/prpc/decoding.go

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package prpc
 
 import (
         "bytes"
         "encoding/base64"
         "fmt"
@@ skipping 46 matching lines @@
         case formatBinary, formatJSONPB, formatText:
                 return f, nil
 
         default:
                 panic("cannot happen")
         }
 }
 
 // readMessage decodes a protobuf message from an HTTP request.
 // Does not close the request body.
-func readMessage(r *http.Request, msg proto.Message) *httpError {
+func readMessage(r *http.Request, msg proto.Message) *protocolError {
         if msg == nil {
                 panicf("cannot decode to nil")
         }
         format, err := requestFormat(r.Header.Get(headerContentType))
         if err != nil {
                 // Spec: http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.16
                 return errorf(http.StatusUnsupportedMediaType, "Content-Type header: %s", err)
         }
 
         buf, err := ioutil.ReadAll(r.Body)
@@ skipping 79 matching lines @@
                                 }
                                 md[trimmedName] = append(md[trimmedName], string(decoded))
                         }
                 }
         }
         if addedMeta {
                 c = metadata.NewContext(c, md)
         }
         return c, nil
 }