Golang util.MarshalResponse函数代码示例

// getConfig retrieves the configuration for the specified key. If the
// key is empty, all configurations are returned. Otherwise, the
// leading "/" path delimiter is stripped and the configuration
// matching the remainder is retrieved. Note that this will retrieve
// the default config if "key" is equal to "/", and will list all
// configs if "key" is equal to "". The body result contains a listing
// of keys and retrieval of a config. The output format is determined
// by the request header.
func getConfig(db *client.DB, configPrefix proto.Key, config gogoproto.Message,
	path string, r *http.Request) (body []byte, contentType string, err error) {
	// Scan all configs if the key is empty.
	if len(path) == 0 {
		var rows []client.KeyValue
		if rows, err = db.Scan(configPrefix, configPrefix.PrefixEnd(), maxGetResults); err != nil {
			return
		}
		if len(rows) == maxGetResults {
			log.Warningf("retrieved maximum number of results (%d); some may be missing", maxGetResults)
		}
		var prefixes []string
		for _, row := range rows {
			trimmed := bytes.TrimPrefix(row.Key, configPrefix)
			prefixes = append(prefixes, url.QueryEscape(string(trimmed)))
		}
		// Encode the response.
		body, contentType, err = util.MarshalResponse(r, prefixes, util.AllEncodings)
	} else {
		configkey := keys.MakeKey(configPrefix, proto.Key(path[1:]))
		if err = db.GetProto(configkey, config); err != nil {
			return
		}
		body, contentType, err = util.MarshalResponse(r, config, util.AllEncodings)
	}

	return
}

// handleStoreStatus handles GET requests for a single node's status. If no id
// is available, it calls handleStoresStatus to return all store's statuses.
func (s *statusServer) handleStoreStatus(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
	id, err := strconv.ParseInt(ps.ByName("id"), 10, 32)
	if err != nil {
		log.Error(err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	key := keys.StoreStatusKey(int32(id))

	storeStatus := &storage.StoreStatus{}
	if err := s.db.GetProto(key, storeStatus); err != nil {
		log.Error(err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	b, contentType, err := util.MarshalResponse(r, storeStatus, []util.EncodingType{util.JSONEncoding})
	if err != nil {
		log.Error(err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	w.Header().Set(util.ContentTypeHeader, contentType)
	w.Write(b)
}

// handleLocalLogFile handles GET requests for a single log. If no filename is
// available, it returns 404. The log contents are returned in structured
// format as JSON.
func (s *statusServer) handleLocalLogFile(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
	log.Flush()
	file := ps.ByName("file")
	reader, err := log.GetLogReader(file, false /* !allowAbsolute */)
	if reader == nil || err != nil {
		log.Errorf("unable to open log file %s: %s", file, err)
		http.NotFound(w, r)
		return
	}
	defer reader.Close()

	entry := log.LogEntry{}
	var entries []log.LogEntry
	decoder := log.NewEntryDecoder(reader)
	for {
		if err := decoder.Decode(&entry); err != nil {
			if err == io.EOF {
				break
			}
			log.Error(err)
			w.WriteHeader(http.StatusInternalServerError)
			return
		}
		entries = append(entries, entry)
	}

	b, contentType, err := util.MarshalResponse(r, entries, []util.EncodingType{util.JSONEncoding})
	if err != nil {
		log.Error(err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	w.Header().Set(util.ContentTypeHeader, contentType)
	w.Write(b)
}

// Verify that marshal response protects against returning
// unguarded slice or array types.
func TestMarshalResponseSlice(t *testing.T) {
	// We expect the array to be wrapped in a struct with data key "d".
	expBody := []byte(`{
  "d": [
    1,
    2,
    3
  ]
}`)
	// Respond with JSON versions of a slice and an array of integers from 1,2,3.
	for i, value := range []interface{}{[]int{1, 2, 3}, [3]int{1, 2, 3}} {
		req, err := http.NewRequest("GET", "http://foo.com", nil)
		if err != nil {
			t.Fatal(err)
		}
		req.Header.Add(util.ContentTypeHeader, util.JSONContentType)
		req.Header.Add(util.AcceptHeader, util.JSONContentType)
		body, _, err := util.MarshalResponse(req, value, util.AllEncodings)
		if err != nil {
			t.Fatalf("%d: %s", i, err)
		}
		if !bytes.Equal(body, expBody) {
			t.Errorf("%d: expected %q; got %q", i, expBody, body)
		}
	}
}

// TestProtoEncodingError verifies that MarshalResponse and
// UnmarshalRequest gracefully handles a protocol message type error.
func TestProtoEncodingError(t *testing.T) {
	req, err := http.NewRequest("GET", "http://foo.com", nil)
	if err != nil {
		t.Fatal(err)
	}
	req.Header.Add(util.ContentTypeHeader, util.ProtoContentType)
	reqBody := []byte("foo")
	var value string
	err = util.UnmarshalRequest(req, reqBody, value, []util.EncodingType{util.ProtoEncoding})
	if err == nil {
		t.Errorf("unexpected success")
	}

	req.Header.Add(util.AcceptHeader, util.ProtoContentType)
	body, cType, err := util.MarshalResponse(req, value, []util.EncodingType{util.ProtoEncoding})
	if err != nil {
		t.Fatal(err)
	}
	if cType != util.JSONContentType {
		t.Errorf("unexpected content type; got %s", cType)
	}
	if !bytes.Equal(body, body) {
		t.Errorf("unexpected boy; got %s", body)
	}
}

// handleStoresStatus handles GET requests for all store statuses.
func (s *statusServer) handleStoresStatus(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
	startKey := keys.StatusStorePrefix
	endKey := startKey.PrefixEnd()

	rows, err := s.db.Scan(startKey, endKey, 0)
	if err != nil {
		log.Error(err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	storeStatuses := []storage.StoreStatus{}
	for _, row := range rows {
		storeStatus := &storage.StoreStatus{}
		if err := row.ValueProto(storeStatus); err != nil {
			log.Error(err)
			w.WriteHeader(http.StatusInternalServerError)
			return
		}
		storeStatuses = append(storeStatuses, *storeStatus)
	}
	b, contentType, err := util.MarshalResponse(r, storeStatuses, []util.EncodingType{util.JSONEncoding})
	if err != nil {
		log.Error(err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	w.Header().Set(util.ContentTypeHeader, contentType)
	w.Write(b)
}

// ServeHTTP serves the SQL API by treating the request URL path
// as the method, the request body as the arguments, and sets the
// response body as the method reply. The request body is unmarshalled
// into arguments based on the Content-Type request header. Protobuf
// and JSON-encoded requests are supported. The response body is
// encoded according to the request's Accept header, or if not
// present, in the same format as the request's incoming Content-Type
// header.
func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	defer r.Body.Close()
	method := r.URL.Path
	if !strings.HasPrefix(method, driver.Endpoint) {
		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
		return
	}

	// Check TLS settings.
	authenticationHook, err := security.AuthenticationHook(s.context.Insecure, r.TLS)
	if err != nil {
		http.Error(w, err.Error(), http.StatusUnauthorized)
		return
	}

	method = strings.TrimPrefix(method, driver.Endpoint)
	if method != driver.Execute.String() {
		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
		return
	}

	// Unmarshal the request.
	reqBody, err := ioutil.ReadAll(r.Body)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	var args driver.Request
	if err := util.UnmarshalRequest(r, reqBody, &args, allowedEncodings); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	// Check request user against client certificate user.
	if err := authenticationHook(&args); err != nil {
		http.Error(w, err.Error(), http.StatusUnauthorized)
		return
	}

	// Send the Request for SQL execution and set the application-level error
	// on the reply.
	reply, err := s.exec(args)
	if err != nil {
		errProto := proto.Error{}
		errProto.SetResponseGoError(err)
		reply.Error = &errProto
	}

	// Marshal the response.
	body, contentType, err := util.MarshalResponse(r, &reply, allowedEncodings)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	w.Header().Set(util.ContentTypeHeader, contentType)
	w.Write(body)
}

// TestHTTPSenderSend verifies sending posts.
func TestHTTPSenderSend(t *testing.T) {
	defer leaktest.AfterTest(t)
	server, addr := startTestHTTPServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Make sure SSL certs were properly specified.
		authenticationHook, err := security.AuthenticationHook(false /* !insecure */, r.TLS)
		if err != nil {
			t.Error(err)
		}

		if r.Method != "POST" {
			t.Errorf("expected method POST; got %s", r.Method)
		}
		if r.URL.Path != KVDBEndpoint+"Put" {
			t.Errorf("expected url %s; got %s", KVDBEndpoint+"Put", r.URL.Path)
		}
		// Unmarshal the request.
		reqBody, err := ioutil.ReadAll(r.Body)
		if err != nil {
			t.Errorf("unexpected error reading body: %s", err)
		}

		args := &proto.PutRequest{}
		if err := util.UnmarshalRequest(r, reqBody, args, util.AllEncodings); err != nil {
			t.Errorf("unexpected error unmarshalling request: %s", err)
		}

		// Validate request against incoming user.
		if err := authenticationHook(args, false /*not public*/); err != nil {
			t.Error(err)
		}

		if !args.Key.Equal(testPutReq.Key) || !args.Timestamp.Equal(testPutReq.Timestamp) {
			t.Errorf("expected parsed %+v to equal %+v", args, testPutReq)
		}
		body, contentType, err := util.MarshalResponse(r, testPutResp, util.AllEncodings)
		if err != nil {
			t.Errorf("failed to marshal response: %s", err)
		}
		w.Header().Set(util.ContentTypeHeader, contentType)
		w.Write(body)
	}))
	defer server.Close()

	sender, err := newHTTPSender(addr, testutils.NewNodeTestBaseContext(), defaultRetryOptions)
	if err != nil {
		t.Fatal(err)
	}
	reply := &proto.PutResponse{}
	sender.Send(context.Background(), proto.Call{Args: testPutReq, Reply: reply})
	if reply.GoError() != nil {
		t.Errorf("expected success; got %s", reply.GoError())
	}
	if !reply.Timestamp.Equal(testPutResp.Timestamp) {
		t.Errorf("expected received %+v to equal %+v", reply, testPutResp)
	}
}

// ServeHTTP serves the SQL API by treating the request URL path
// as the method, the request body as the arguments, and sets the
// response body as the method reply. The request body is unmarshalled
// into arguments based on the Content-Type request header. Protobuf
// and JSON-encoded requests are supported. The response body is
// encoded according to the request's Accept header, or if not
// present, in the same format as the request's incoming Content-Type
// header.
func (s Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	defer r.Body.Close()
	method := r.URL.Path
	if !strings.HasPrefix(method, driver.Endpoint) {
		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
		return
	}

	// Check TLS settings.
	authenticationHook, err := security.ProtoAuthHook(s.context.Insecure, r.TLS)
	if err != nil {
		http.Error(w, err.Error(), http.StatusUnauthorized)
		return
	}

	method = strings.TrimPrefix(method, driver.Endpoint)
	if method != driver.Execute.String() {
		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
		return
	}

	// Unmarshal the request.
	reqBody, err := ioutil.ReadAll(r.Body)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	var args driver.Request
	if err := util.UnmarshalRequest(r, reqBody, &args, allowedEncodings); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	// Check request user against client certificate user.
	if err := authenticationHook(&args, true /* public */); err != nil {
		http.Error(w, err.Error(), http.StatusUnauthorized)
		return
	}

	reply, code, err := s.Execute(args)
	if err != nil {
		http.Error(w, err.Error(), code)
	}

	// Marshal the response.
	body, contentType, err := util.MarshalResponse(r, &reply, allowedEncodings)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	w.Header().Set(util.ContentTypeHeader, contentType)
	if _, err := w.Write(body); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}

// ServeHTTP serves the key-value API by treating the request URL path
// as the method, the request body as the arguments, and sets the
// response body as the method reply. The request body is unmarshalled
// into arguments based on the Content-Type request header. Protobuf
// and JSON-encoded requests are supported. The response body is
// encoded according the the request's Accept header, or if not
// present, in the same format as the request's incoming Content-Type
// header.
func (s *DBServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	// Check TLS settings before anything else.
	authenticationHook, err := security.AuthenticationHook(s.context.Insecure, r.TLS)
	if err != nil {
		http.Error(w, err.Error(), http.StatusUnauthorized)
		return
	}

	method := r.URL.Path
	if !strings.HasPrefix(method, DBPrefix) {
		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
		return
	}
	method = strings.TrimPrefix(method, DBPrefix)
	args, reply := createArgsAndReply(method)
	if args == nil {
		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
		return
	}

	// Unmarshal the request.
	reqBody, err := ioutil.ReadAll(r.Body)
	defer r.Body.Close()
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	if err := util.UnmarshalRequest(r, reqBody, args, allowedEncodings); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	// Verify the request for public API.
	if err := verifyRequest(args); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	// Check request user against client certificate user.
	if err := authenticationHook(args); err != nil {
		http.Error(w, err.Error(), http.StatusUnauthorized)
		return
	}

	// Create a call and invoke through sender.
	s.sender.Send(context.TODO(), proto.Call{Args: args, Reply: reply})

	// Marshal the response.
	body, contentType, err := util.MarshalResponse(r, reply, allowedEncodings)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	w.Header().Set(util.ContentTypeHeader, contentType)
	w.Write(body)
}

// handleQuery handles an incoming HTTP query request. Each query requests data
// for one or more metrics over a specific time span. Query requests have a
// significant body and thus are POST requests.
func (s *Server) handleQuery(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
	request := &TimeSeriesQueryRequest{}

	// Unmarshal query request.
	reqBody, err := ioutil.ReadAll(r.Body)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	if err := util.UnmarshalRequest(r, reqBody, request, util.AllEncodings); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	if len(request.Queries) == 0 {
		http.Error(w, "time series query requests must specify at least one query.", http.StatusBadRequest)
		return
	}

	response := &TimeSeriesQueryResponse{
		Results: make([]*TimeSeriesQueryResponse_Result, 0, len(request.Queries)),
	}
	for _, q := range request.Queries {
		datapoints, sources, err := s.db.Query(q, Resolution10s, request.StartNanos, request.EndNanos)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		result := &TimeSeriesQueryResponse_Result{
			Query:      q,
			Datapoints: datapoints,
		}
		// TODO(tamird): Remove this (and all other) explicit setting of defaults.
		// It is currently required because the client side doesn't know about
		// proto defaults.
		result.SourceAggregator = q.GetSourceAggregator().Enum()
		result.Downsampler = q.GetDownsampler().Enum()
		result.Derivative = q.GetDerivative().Enum()

		result.Sources = sources
		response.Results = append(response.Results, result)
	}

	// Marshal and return response.
	b, contentType, err := util.MarshalResponse(r, response, util.AllEncodings)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	w.Header().Set(util.ContentTypeHeader, contentType)
	if _, err := w.Write(b); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
}

// Get retrieves the perm configuration for the specified key. If the
// key is empty, all perm configurations are returned. Otherwise, the
// leading "/" path delimiter is stripped and the perm configuration
// matching the remainder is retrieved. Note that this will retrieve
// the default perm config if "key" is equal to "/", and will list all
// configs if "key" is equal to "". The body result contains
// JSON-formatted output for a listing of keys and JSON-formatted
// output for retrieval of a perm config.
func (ph *permHandler) Get(path string, r *http.Request) (body []byte, contentType string, err error) {
	// Scan all perms if the key is empty.
	if len(path) == 0 {
		sr := &proto.ScanResponse{}
		if err = ph.db.Call(proto.Scan, &proto.ScanRequest{
			RequestHeader: proto.RequestHeader{
				Key:    engine.KeyConfigPermissionPrefix,
				EndKey: engine.KeyConfigPermissionPrefix.PrefixEnd(),
				User:   storage.UserRoot,
			},
			MaxResults: maxGetResults,
		}, sr); err != nil {
			return
		}
		if len(sr.Rows) == maxGetResults {
			log.Warningf("retrieved maximum number of results (%d); some may be missing", maxGetResults)
		}
		var prefixes []string
		for _, kv := range sr.Rows {
			trimmed := bytes.TrimPrefix(kv.Key, engine.KeyConfigPermissionPrefix)
			prefixes = append(prefixes, url.QueryEscape(string(trimmed)))
		}
		// Encode the response.
		body, contentType, err = util.MarshalResponse(r, prefixes, util.AllEncodings)
	} else {
		permKey := engine.MakeKey(engine.KeyConfigPermissionPrefix, proto.Key(path[1:]))
		var ok bool
		config := &proto.PermConfig{}
		if ok, _, err = ph.db.GetProto(permKey, config); err != nil {
			return
		}
		// On get, if there's no perm config for the requested prefix,
		// return a not found error.
		if !ok {
			err = util.Errorf("no config found for key prefix %q", path)
			return
		}
		body, contentType, err = util.MarshalResponse(r, config, util.AllEncodings)
	}

	return
}

// ServeHTTP serves the key-value API by treating the request URL path
// as the method, the request body as the arguments, and sets the
// response body as the method reply. The request body is unmarshalled
// into arguments based on the Content-Type request header. Protobuf
// and JSON-encoded requests are supported. The response body is
// encoded according the the request's Accept header, or if not
// present, in the same format as the request's incoming Content-Type
// header.
func (s *DBServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	method := r.URL.Path
	if !strings.HasPrefix(method, DBPrefix) {
		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
		return
	}
	method = strings.TrimPrefix(method, DBPrefix)
	if !proto.IsPublic(method) {
		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
		return
	}

	// Unmarshal the request.
	reqBody, err := ioutil.ReadAll(r.Body)
	defer r.Body.Close()
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	args, reply, err := proto.CreateArgsAndReply(method)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	if err := util.UnmarshalRequest(r, reqBody, args, allowedEncodings); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	// Verify the request for public API.
	if err := verifyRequest(args); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	// Create a call and invoke through sender.
	call := &client.Call{
		Method: method,
		Args:   args,
		Reply:  reply,
	}
	s.sender.Send(call)

	// Marshal the response.
	body, contentType, err := util.MarshalResponse(r, reply, allowedEncodings)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type", contentType)
	w.Write(body)
}

// TestHTTPSenderRetryHTTPSendError verifies that send is retried
// on all errors sending HTTP requests.
func TestHTTPSenderRetryHTTPSendError(t *testing.T) {
	defer leaktest.AfterTest(t)
	retryOptions := defaultRetryOptions
	retryOptions.InitialBackoff = 1 * time.Millisecond

	testCases := []func(*httptest.Server, http.ResponseWriter){
		// Send back an unparseable response but a success code on first try.
		func(s *httptest.Server, w http.ResponseWriter) {
			fmt.Fprintf(w, "\xff\xfe\x23\x44")
		},
		// Close the client connection.
		func(s *httptest.Server, w http.ResponseWriter) {
			s.CloseClientConnections()
		},
	}

	for i, testFunc := range testCases {
		count := 0
		var s *httptest.Server
		server, addr := startTestHTTPServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			count++
			if count == 1 {
				// On first retry, invoke the error function.
				testFunc(s, w)
				return
			}
			// Success on second try.
			body, contentType, err := util.MarshalResponse(r, testPutResp, util.AllEncodings)
			if err != nil {
				t.Errorf("%d: failed to marshal response: %s", i, err)
			}
			w.Header().Set(util.ContentTypeHeader, contentType)
			w.Write(body)
		}))

		s = server
		sender, err := newHTTPSender(addr, testutils.NewRootTestBaseContext(), retryOptions)
		if err != nil {
			t.Fatal(err)
		}
		reply := &proto.PutResponse{}
		sender.Send(context.Background(), proto.Call{Args: testPutReq, Reply: reply})
		if reply.GoError() != nil {
			t.Errorf("%d: expected success; got %s", i, reply.GoError())
		}
		if count != 2 {
			t.Errorf("%d: expected retry", i)
		}
		server.Close()
	}
}

// handleQuery handles an incoming HTTP query request. Each query requests data
// for one or more metrics over a specific time span. Query requests have a
// significant body and thus are POST requests.
func (s *Server) handleQuery(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
	request := &TimeSeriesQueryRequest{}

	// Unmarshal query request.
	reqBody, err := ioutil.ReadAll(r.Body)
	defer r.Body.Close()
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	if err := util.UnmarshalRequest(r, reqBody, request, util.AllEncodings); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	if len(request.Queries) == 0 {
		http.Error(w, "time series query requests must specify at least one query.", http.StatusBadRequest)
		return
	}

	response := &TimeSeriesQueryResponse{
		Results: make([]*TimeSeriesQueryResponse_Result, 0, len(request.Queries)),
	}
	for _, q := range request.Queries {
		datapoints, sources, err := s.db.Query(q, Resolution10s, request.StartNanos, request.EndNanos)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		response.Results = append(response.Results, &TimeSeriesQueryResponse_Result{
			Name:       q.Name,
			Sources:    sources,
			Datapoints: datapoints,
			Aggregator: q.Aggregator,
		})
	}

	// Marshal and return response.
	b, contentType, err := util.MarshalResponse(r, response, util.AllEncodings)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	w.Header().Set(util.ContentTypeHeader, contentType)
	if _, err := w.Write(b); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
}