| 1 | // Copyright 2018 The Go Authors. All rights reserved. |
|---|---|
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | package jsonrpc2 |
| 6 | |
| 7 | import ( |
| 8 | "bufio" |
| 9 | "context" |
| 10 | "encoding/json" |
| 11 | "fmt" |
| 12 | "io" |
| 13 | "net" |
| 14 | "strconv" |
| 15 | "strings" |
| 16 | ) |
| 17 | |
| 18 | // Stream abstracts the transport mechanics from the JSON RPC protocol. |
| 19 | // A Conn reads and writes messages using the stream it was provided on |
| 20 | // construction, and assumes that each call to Read or Write fully transfers |
| 21 | // a single message, or returns an error. |
| 22 | // A stream is not safe for concurrent use, it is expected it will be used by |
| 23 | // a single Conn in a safe manner. |
| 24 | type Stream interface { |
| 25 | // Read gets the next message from the stream. |
| 26 | Read(context.Context) (Message, int64, error) |
| 27 | // Write sends a message to the stream. |
| 28 | Write(context.Context, Message) (int64, error) |
| 29 | // Close closes the connection. |
| 30 | // Any blocked Read or Write operations will be unblocked and return errors. |
| 31 | Close() error |
| 32 | } |
| 33 | |
| 34 | // Framer wraps a network connection up into a Stream. |
| 35 | // It is responsible for the framing and encoding of messages into wire form. |
| 36 | // NewRawStream and NewHeaderStream are implementations of a Framer. |
| 37 | type Framer func(conn net.Conn) Stream |
| 38 | |
| 39 | // NewRawStream returns a Stream built on top of a net.Conn. |
| 40 | // The messages are sent with no wrapping, and rely on json decode consistency |
| 41 | // to determine message boundaries. |
| 42 | func NewRawStream(conn net.Conn) Stream { |
| 43 | return &rawStream{ |
| 44 | conn: conn, |
| 45 | in: json.NewDecoder(conn), |
| 46 | } |
| 47 | } |
| 48 | |
| 49 | type rawStream struct { |
| 50 | conn net.Conn |
| 51 | in *json.Decoder |
| 52 | } |
| 53 | |
| 54 | func (s *rawStream) Read(ctx context.Context) (Message, int64, error) { |
| 55 | select { |
| 56 | case <-ctx.Done(): |
| 57 | return nil, 0, ctx.Err() |
| 58 | default: |
| 59 | } |
| 60 | var raw json.RawMessage |
| 61 | if err := s.in.Decode(&raw); err != nil { |
| 62 | return nil, 0, err |
| 63 | } |
| 64 | msg, err := DecodeMessage(raw) |
| 65 | return msg, int64(len(raw)), err |
| 66 | } |
| 67 | |
| 68 | func (s *rawStream) Write(ctx context.Context, msg Message) (int64, error) { |
| 69 | select { |
| 70 | case <-ctx.Done(): |
| 71 | return 0, ctx.Err() |
| 72 | default: |
| 73 | } |
| 74 | data, err := json.Marshal(msg) |
| 75 | if err != nil { |
| 76 | return 0, fmt.Errorf("marshaling message: %v", err) |
| 77 | } |
| 78 | n, err := s.conn.Write(data) |
| 79 | return int64(n), err |
| 80 | } |
| 81 | |
| 82 | func (s *rawStream) Close() error { |
| 83 | return s.conn.Close() |
| 84 | } |
| 85 | |
| 86 | // NewHeaderStream returns a Stream built on top of a net.Conn. |
| 87 | // The messages are sent with HTTP content length and MIME type headers. |
| 88 | // This is the format used by LSP and others. |
| 89 | func NewHeaderStream(conn net.Conn) Stream { |
| 90 | return &headerStream{ |
| 91 | conn: conn, |
| 92 | in: bufio.NewReader(conn), |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | type headerStream struct { |
| 97 | conn net.Conn |
| 98 | in *bufio.Reader |
| 99 | } |
| 100 | |
| 101 | func (s *headerStream) Read(ctx context.Context) (Message, int64, error) { |
| 102 | select { |
| 103 | case <-ctx.Done(): |
| 104 | return nil, 0, ctx.Err() |
| 105 | default: |
| 106 | } |
| 107 | var total, length int64 |
| 108 | // read the header, stop on the first empty line |
| 109 | for { |
| 110 | line, err := s.in.ReadString('\n') |
| 111 | total += int64(len(line)) |
| 112 | if err != nil { |
| 113 | return nil, total, fmt.Errorf("failed reading header line: %w", err) |
| 114 | } |
| 115 | line = strings.TrimSpace(line) |
| 116 | // check we have a header line |
| 117 | if line == "" { |
| 118 | break |
| 119 | } |
| 120 | colon := strings.IndexRune(line, ':') |
| 121 | if colon < 0 { |
| 122 | return nil, total, fmt.Errorf("invalid header line %q", line) |
| 123 | } |
| 124 | name, value := line[:colon], strings.TrimSpace(line[colon+1:]) |
| 125 | switch name { |
| 126 | case "Content-Length": |
| 127 | if length, err = strconv.ParseInt(value, 10, 32); err != nil { |
| 128 | return nil, total, fmt.Errorf("failed parsing Content-Length: %v", value) |
| 129 | } |
| 130 | if length <= 0 { |
| 131 | return nil, total, fmt.Errorf("invalid Content-Length: %v", length) |
| 132 | } |
| 133 | default: |
| 134 | // ignoring unknown headers |
| 135 | } |
| 136 | } |
| 137 | if length == 0 { |
| 138 | return nil, total, fmt.Errorf("missing Content-Length header") |
| 139 | } |
| 140 | data := make([]byte, length) |
| 141 | if _, err := io.ReadFull(s.in, data); err != nil { |
| 142 | return nil, total, err |
| 143 | } |
| 144 | total += length |
| 145 | msg, err := DecodeMessage(data) |
| 146 | return msg, total, err |
| 147 | } |
| 148 | |
| 149 | func (s *headerStream) Write(ctx context.Context, msg Message) (int64, error) { |
| 150 | select { |
| 151 | case <-ctx.Done(): |
| 152 | return 0, ctx.Err() |
| 153 | default: |
| 154 | } |
| 155 | data, err := json.Marshal(msg) |
| 156 | if err != nil { |
| 157 | return 0, fmt.Errorf("marshaling message: %v", err) |
| 158 | } |
| 159 | n, err := fmt.Fprintf(s.conn, "Content-Length: %v\r\n\r\n", len(data)) |
| 160 | total := int64(n) |
| 161 | if err == nil { |
| 162 | n, err = s.conn.Write(data) |
| 163 | total += int64(n) |
| 164 | } |
| 165 | return total, err |
| 166 | } |
| 167 | |
| 168 | func (s *headerStream) Close() error { |
| 169 | return s.conn.Close() |
| 170 | } |
| 171 |
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