Class Poco::MongoDB::OpMsgMessage

Library: MongoDB
Package: MongoDB
Header: Poco/MongoDB/OpMsgMessage.h

Description

This class represents a request/response (OP_MSG) to send requests and receive responses to/from MongoDB.

THREAD SAFETY: This class is NOT thread-safe. OpMsgMessage instances must not be accessed concurrently from multiple threads without external synchronization. Each thread should use its own message instances.

Inheritance

Direct Base Classes: Message

All Base Classes: Message

Member Summary

Member Functions: acknowledgedRequest, body, clear, collectionName, commandName, databaseName, documents, flags, read, responseOk, send, setAcknowledgedRequest, setCommandName

Inherited Functions: header, messageLength

Enumerations

Flags

MSG_FLAGS_DEFAULT = 0

MSG_CHECKSUM_PRESENT = (1 << 0)

MSG_MORE_TO_COME = (1 << 1)

Sender will send another message and is not prepared for overlapping messages

MSG_EXHAUST_ALLOWED = (1 << 16)

Client is prepared for multiple replies (using the moreToCome bit) to this request

Constructors

OpMsgMessage

OpMsgMessage();

Creates an OpMsgMessage for response.

OpMsgMessage

OpMsgMessage(
    const std::string & databaseName,
    const std::string & collectionName,
    UInt32 flags = MSG_FLAGS_DEFAULT
);

Creates an OpMsgMessage for requests.

Destructor

~OpMsgMessage

virtual ~OpMsgMessage();

Member Functions

acknowledgedRequest

[[nodiscard]]
bool acknowledgedRequest() const;

body

Document & body();

Access to body document. Additional query arguments shall be added after setting the command name.

body

[[nodiscard]]
const Document & body() const;

clear

void clear();

Clears the message.

collectionName

[[nodiscard]]
const std::string & collectionName() const;

commandName

[[nodiscard]]
const std::string & commandName() const;

Current command name.

databaseName

[[nodiscard]]
const std::string & databaseName() const;

documents

Document::Vector & documents();

Documents prepared for request or retrieved in response.

documents

[[nodiscard]]
const Document::Vector & documents() const;

Documents prepared for request or retrieved in response.

flags

[[nodiscard]]
UInt32 flags() const;

read

void read(
std::istream & istr
);

Reads the response from the stream. The message is cleared first, so that a reused message never holds parts of two responses. The message must carry an OP_MSG opcode and exactly one body section.

Only bounds are checked (see Document::read); documents may exceed BSON_MAX_DOCUMENT_SIZE, as the server returns larger ones. Throws DataFormatException if a check fails, NotImplementedException for an unsupported element type, and IOException if the stream ends early.

responseOk

[[nodiscard]]
bool responseOk() const;

Reads "ok" status from the response message.

send

void send(
std::ostream & ostr
);

Writes the request to stream.

Throws InvalidArgumentException, before anything is written, if the message exceeds MAX_MESSAGE_SIZE_BYTES, a document of the document sequence exceeds BSON_MAX_DOCUMENT_SIZE + 16 KiB, nesting is too deep, a name contains a null character or MSG_CHECKSUM_PRESENT is set, which is not supported, and RangeException for a BSONTimestamp outside 1970-2106. Other limits are left to the server.

setAcknowledgedRequest

void setAcknowledgedRequest(
bool ack
);

Set false to create request that does not return response. It has effect only for commands that write or delete documents. Default is true (request returns acknowledge response).