mattermost/server/public/plugin/http.go
Ben Cooke 07d63e7f89
Add http.Flusher support to plugin RPC layer (#34411)
* Add http.Flusher support to plugin RPC layer
2025-11-10 16:30:09 -05:00

119 lines
3.1 KiB
Go

// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.
package plugin
import (
"bufio"
"errors"
"fmt"
"io"
"maps"
"net"
"net/http"
"net/rpc"
"github.com/mattermost/mattermost/server/public/shared/mlog"
)
type hijackedResponse struct {
conn net.Conn
bufrw *bufio.ReadWriter
readBuf []byte
}
type httpResponseWriterRPCServer struct {
w http.ResponseWriter
log *mlog.Logger
hjr *hijackedResponse
}
func (w *httpResponseWriterRPCServer) Header(args struct{}, reply *http.Header) error {
*reply = w.w.Header()
return nil
}
func (w *httpResponseWriterRPCServer) Write(args []byte, reply *struct{}) error {
_, err := w.w.Write(args)
return err
}
func (w *httpResponseWriterRPCServer) WriteHeader(args int, reply *struct{}) error {
// Check if args is a valid http status code. This prevents plugins from crashing the server with a panic.
// This is a copy of the checkWriteHeaderCode function in net/http/server.go in the go source.
if args < 100 || args > 999 {
w.log.Error(fmt.Sprintf("Plugin tried to write an invalid http status code: %v. Did not write the invalid header.", args))
return errors.New("invalid http status code")
}
w.w.WriteHeader(args)
return nil
}
func (w *httpResponseWriterRPCServer) SyncHeader(args http.Header, reply *struct{}) error {
dest := w.w.Header()
for k := range dest {
if _, ok := args[k]; !ok {
delete(dest, k)
}
}
maps.Copy(dest, args)
return nil
}
func (w *httpResponseWriterRPCServer) Flush(args struct{}, reply *struct{}) error {
// Type assert to http.Flusher and flush if supported
if flusher, ok := w.w.(http.Flusher); ok {
flusher.Flush()
}
// If the underlying writer doesn't support Flusher, silently ignore
// This matches the HTTP spec's "best effort" semantics
return nil
}
type httpResponseWriterRPCClient struct {
client *rpc.Client
header http.Header
}
var _ http.ResponseWriter = (*httpResponseWriterRPCClient)(nil)
var _ http.Flusher = (*httpResponseWriterRPCClient)(nil)
func (w *httpResponseWriterRPCClient) Header() http.Header {
if w.header == nil {
w.client.Call("Plugin.Header", struct{}{}, &w.header)
}
return w.header
}
func (w *httpResponseWriterRPCClient) Write(b []byte) (int, error) {
if err := w.client.Call("Plugin.SyncHeader", w.header, nil); err != nil {
return 0, err
}
if err := w.client.Call("Plugin.Write", b, nil); err != nil {
return 0, err
}
return len(b), nil
}
func (w *httpResponseWriterRPCClient) WriteHeader(statusCode int) {
if err := w.client.Call("Plugin.SyncHeader", w.header, nil); err != nil {
return
}
w.client.Call("Plugin.WriteHeader", statusCode, nil)
}
// Flush implements http.Flusher interface
func (w *httpResponseWriterRPCClient) Flush() {
// Best-effort flush - ignore errors per HTTP spec
w.client.Call("Plugin.Flush", struct{}{}, nil)
}
func (w *httpResponseWriterRPCClient) Close() error {
return w.client.Close()
}
func connectHTTPResponseWriter(conn io.ReadWriteCloser) *httpResponseWriterRPCClient {
return &httpResponseWriterRPCClient{
client: rpc.NewClient(conn),
}
}