github.com/haalcala/mattermost-server-change-repo@v0.0.0-20210713015153-16753fbeee5f/plugin/http.go (about)

     1  // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
     2  // See LICENSE.txt for license information.
     3  
     4  package plugin
     5  
     6  import (
     7  	"bufio"
     8  	"errors"
     9  	"fmt"
    10  	"io"
    11  	"net"
    12  	"net/http"
    13  	"net/rpc"
    14  
    15  	"github.com/mattermost/mattermost-server/v5/mlog"
    16  )
    17  
    18  type hijackedResponse struct {
    19  	conn    net.Conn
    20  	bufrw   *bufio.ReadWriter
    21  	readBuf []byte
    22  }
    23  
    24  type httpResponseWriterRPCServer struct {
    25  	w   http.ResponseWriter
    26  	log *mlog.Logger
    27  	hjr *hijackedResponse
    28  }
    29  
    30  func (w *httpResponseWriterRPCServer) Header(args struct{}, reply *http.Header) error {
    31  	*reply = w.w.Header()
    32  	return nil
    33  }
    34  
    35  func (w *httpResponseWriterRPCServer) Write(args []byte, reply *struct{}) error {
    36  	_, err := w.w.Write(args)
    37  	return err
    38  }
    39  
    40  func (w *httpResponseWriterRPCServer) WriteHeader(args int, reply *struct{}) error {
    41  	// Check if args is a valid http status code. This prevents plugins from crashing the server with a panic.
    42  	// This is a copy of the checkWriteHeaderCode function in net/http/server.go in the go source.
    43  	if args < 100 || args > 999 {
    44  		w.log.Error(fmt.Sprintf("Plugin tried to write an invalid http status code: %v. Did not write the invalid header.", args))
    45  		return errors.New("invalid http status code")
    46  	}
    47  	w.w.WriteHeader(args)
    48  	return nil
    49  }
    50  
    51  func (w *httpResponseWriterRPCServer) SyncHeader(args http.Header, reply *struct{}) error {
    52  	dest := w.w.Header()
    53  	for k := range dest {
    54  		if _, ok := args[k]; !ok {
    55  			delete(dest, k)
    56  		}
    57  	}
    58  	for k, v := range args {
    59  		dest[k] = v
    60  	}
    61  	return nil
    62  }
    63  
    64  type httpResponseWriterRPCClient struct {
    65  	client *rpc.Client
    66  	header http.Header
    67  }
    68  
    69  var _ http.ResponseWriter = (*httpResponseWriterRPCClient)(nil)
    70  
    71  func (w *httpResponseWriterRPCClient) Header() http.Header {
    72  	if w.header == nil {
    73  		w.client.Call("Plugin.Header", struct{}{}, &w.header)
    74  	}
    75  	return w.header
    76  }
    77  
    78  func (w *httpResponseWriterRPCClient) Write(b []byte) (int, error) {
    79  	if err := w.client.Call("Plugin.SyncHeader", w.header, nil); err != nil {
    80  		return 0, err
    81  	}
    82  	if err := w.client.Call("Plugin.Write", b, nil); err != nil {
    83  		return 0, err
    84  	}
    85  	return len(b), nil
    86  }
    87  
    88  func (w *httpResponseWriterRPCClient) WriteHeader(statusCode int) {
    89  	if err := w.client.Call("Plugin.SyncHeader", w.header, nil); err != nil {
    90  		return
    91  	}
    92  	w.client.Call("Plugin.WriteHeader", statusCode, nil)
    93  }
    94  
    95  func (w *httpResponseWriterRPCClient) Close() error {
    96  	return w.client.Close()
    97  }
    98  
    99  func connectHTTPResponseWriter(conn io.ReadWriteCloser) *httpResponseWriterRPCClient {
   100  	return &httpResponseWriterRPCClient{
   101  		client: rpc.NewClient(conn),
   102  	}
   103  }