-
Notifications
You must be signed in to change notification settings - Fork 1.8k
/
message_stream.ts
243 lines (211 loc) · 7.86 KB
/
message_stream.ts
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
import { Duplex, DuplexOptions } from 'stream';
import type { BSONSerializeOptions, Document } from '../bson';
import { MongoDecompressionError, MongoParseError } from '../error';
import type { ClientSession } from '../sessions';
import { BufferPool, Callback } from '../utils';
import { BinMsg, MessageHeader, Msg, Query, Response, WriteProtocolMessageType } from './commands';
import {
compress,
Compressor,
CompressorName,
decompress,
uncompressibleCommands
} from './wire_protocol/compression';
import { OP_COMPRESSED, OP_MSG } from './wire_protocol/constants';
const MESSAGE_HEADER_SIZE = 16;
const COMPRESSION_DETAILS_SIZE = 9; // originalOpcode + uncompressedSize, compressorID
const kDefaultMaxBsonMessageSize = 1024 * 1024 * 16 * 4;
/** @internal */
const kBuffer = Symbol('buffer');
/** @internal */
export interface MessageStreamOptions extends DuplexOptions {
maxBsonMessageSize?: number;
}
/** @internal */
export interface OperationDescription extends BSONSerializeOptions {
started: number;
cb: Callback<Document>;
command: boolean;
documentsReturnedIn?: string;
fullResult: boolean;
noResponse: boolean;
raw: boolean;
requestId: number;
session?: ClientSession;
socketTimeoutOverride?: boolean;
agreedCompressor?: CompressorName;
zlibCompressionLevel?: number;
$clusterTime?: Document;
}
/**
* A duplex stream that is capable of reading and writing raw wire protocol messages, with
* support for optional compression
* @internal
*/
export class MessageStream extends Duplex {
/** @internal */
maxBsonMessageSize: number;
/** @internal */
[kBuffer]: BufferPool;
/** @internal */
isMonitoringConnection = false;
constructor(options: MessageStreamOptions = {}) {
super(options);
this.maxBsonMessageSize = options.maxBsonMessageSize || kDefaultMaxBsonMessageSize;
this[kBuffer] = new BufferPool();
}
get buffer(): BufferPool {
return this[kBuffer];
}
override _write(chunk: Buffer, _: unknown, callback: Callback<Buffer>): void {
this[kBuffer].append(chunk);
processIncomingData(this, callback);
}
override _read(/* size */): void {
// NOTE: This implementation is empty because we explicitly push data to be read
// when `writeMessage` is called.
return;
}
writeCommand(
command: WriteProtocolMessageType,
operationDescription: OperationDescription
): void {
// TODO: agreed compressor should live in `StreamDescription`
const compressorName: CompressorName =
operationDescription && operationDescription.agreedCompressor
? operationDescription.agreedCompressor
: 'none';
if (compressorName === 'none' || !canCompress(command)) {
const data = command.toBin();
this.push(Array.isArray(data) ? Buffer.concat(data) : data);
return;
}
// otherwise, compress the message
const concatenatedOriginalCommandBuffer = Buffer.concat(command.toBin());
const messageToBeCompressed = concatenatedOriginalCommandBuffer.slice(MESSAGE_HEADER_SIZE);
// Extract information needed for OP_COMPRESSED from the uncompressed message
const originalCommandOpCode = concatenatedOriginalCommandBuffer.readInt32LE(12);
// Compress the message body
compress({ options: operationDescription }, messageToBeCompressed, (err, compressedMessage) => {
if (err || !compressedMessage) {
operationDescription.cb(err);
return;
}
// Create the msgHeader of OP_COMPRESSED
const msgHeader = Buffer.alloc(MESSAGE_HEADER_SIZE);
msgHeader.writeInt32LE(
MESSAGE_HEADER_SIZE + COMPRESSION_DETAILS_SIZE + compressedMessage.length,
0
); // messageLength
msgHeader.writeInt32LE(command.requestId, 4); // requestID
msgHeader.writeInt32LE(0, 8); // responseTo (zero)
msgHeader.writeInt32LE(OP_COMPRESSED, 12); // opCode
// Create the compression details of OP_COMPRESSED
const compressionDetails = Buffer.alloc(COMPRESSION_DETAILS_SIZE);
compressionDetails.writeInt32LE(originalCommandOpCode, 0); // originalOpcode
compressionDetails.writeInt32LE(messageToBeCompressed.length, 4); // Size of the uncompressed compressedMessage, excluding the MsgHeader
compressionDetails.writeUInt8(Compressor[compressorName], 8); // compressorID
this.push(Buffer.concat([msgHeader, compressionDetails, compressedMessage]));
});
}
}
// Return whether a command contains an uncompressible command term
// Will return true if command contains no uncompressible command terms
function canCompress(command: WriteProtocolMessageType) {
const commandDoc = command instanceof Msg ? command.command : (command as Query).query;
const commandName = Object.keys(commandDoc)[0];
return !uncompressibleCommands.has(commandName);
}
function processIncomingData(stream: MessageStream, callback: Callback<Buffer>) {
const buffer = stream[kBuffer];
if (buffer.length < 4) {
callback();
return;
}
const sizeOfMessage = buffer.peek(4).readInt32LE();
if (sizeOfMessage < 0) {
callback(new MongoParseError(`Invalid message size: ${sizeOfMessage}`));
return;
}
if (sizeOfMessage > stream.maxBsonMessageSize) {
callback(
new MongoParseError(
`Invalid message size: ${sizeOfMessage}, max allowed: ${stream.maxBsonMessageSize}`
)
);
return;
}
if (sizeOfMessage > buffer.length) {
callback();
return;
}
const message = buffer.read(sizeOfMessage);
const messageHeader: MessageHeader = {
length: message.readInt32LE(0),
requestId: message.readInt32LE(4),
responseTo: message.readInt32LE(8),
opCode: message.readInt32LE(12)
};
const monitorHasAnotherHello = () => {
if (stream.isMonitoringConnection) {
// Can we read the next message size?
if (buffer.length >= 4) {
const sizeOfMessage = buffer.peek(4).readInt32LE();
if (sizeOfMessage <= buffer.length) {
return true;
}
}
}
return false;
};
let ResponseType = messageHeader.opCode === OP_MSG ? BinMsg : Response;
if (messageHeader.opCode !== OP_COMPRESSED) {
const messageBody = message.slice(MESSAGE_HEADER_SIZE);
// If we are a monitoring connection message stream and
// there is more in the buffer that can be read, skip processing since we
// want the last hello command response that is in the buffer.
if (monitorHasAnotherHello()) {
processIncomingData(stream, callback);
} else {
stream.emit('message', new ResponseType(message, messageHeader, messageBody));
if (buffer.length >= 4) {
processIncomingData(stream, callback);
} else {
callback();
}
}
return;
}
messageHeader.fromCompressed = true;
messageHeader.opCode = message.readInt32LE(MESSAGE_HEADER_SIZE);
messageHeader.length = message.readInt32LE(MESSAGE_HEADER_SIZE + 4);
const compressorID: Compressor = message[MESSAGE_HEADER_SIZE + 8] as Compressor;
const compressedBuffer = message.slice(MESSAGE_HEADER_SIZE + 9);
// recalculate based on wrapped opcode
ResponseType = messageHeader.opCode === OP_MSG ? BinMsg : Response;
decompress(compressorID, compressedBuffer, (err, messageBody) => {
if (err || !messageBody) {
callback(err);
return;
}
if (messageBody.length !== messageHeader.length) {
callback(
new MongoDecompressionError('Message body and message header must be the same length')
);
return;
}
// If we are a monitoring connection message stream and
// there is more in the buffer that can be read, skip processing since we
// want the last hello command response that is in the buffer.
if (monitorHasAnotherHello()) {
processIncomingData(stream, callback);
} else {
stream.emit('message', new ResponseType(message, messageHeader, messageBody));
if (buffer.length >= 4) {
processIncomingData(stream, callback);
} else {
callback();
}
}
});
}