Class representing a client connection to MongoDB. More...

#include <client.hpp>

Public Member Functions
	client () noexcept
	Default constructs a new client. More...

	client (const class uri &mongodb_uri, const options::client &options=options::client())
	Creates a new client connection to MongoDB. More...

	client (client &&) noexcept
	Move constructs a client.

client &	operator= (client &&) noexcept
	Move assigns a client.

	~client ()
	Destroys a client.

	operator bool () const noexcept
	Returns true if the client is valid, meaning it was not default constructed or moved from.

MONGOCXX_DEPRECATED void	read_concern (class read_concern rc)
	Sets the read concern for this client. More...

class read_concern	read_concern () const
	Returns the current read concern for this client. More...

MONGOCXX_DEPRECATED void	read_preference (class read_preference rp)
	Sets the read preference for this client. More...

class read_preference	read_preference () const
	Returns the current read preference for this client. More...

class uri	uri () const
	Returns the current uri for this client. More...

MONGOCXX_DEPRECATED void	write_concern (class write_concern wc)
	Sets the write concern for this client. More...

class write_concern	write_concern () const
	Returns the current write concern for this client. More...

class database	database (bsoncxx::string::view_or_value name) const &
	Obtains a database that represents a logical grouping of collections on a MongoDB server. More...

class database	operator[] (bsoncxx::string::view_or_value name) const &
	Allows the syntax `client`["db_name"] as a convenient shorthand for the client::database() method by implementing the array subscript operator. More...

client_session	start_session (const options::client_session &options={})
	Create a client session for a sequence of operations. More...

void	reset ()
	Prevents resource cleanup in the child process from interfering with the parent process after forking. More...


cursor	list_databases () const
	Enumerates the databases in the client. More...

cursor	list_databases (const client_session &session) const
	Enumerates the databases in the client. More...

cursor	list_databases (const bsoncxx::document::view_or_value opts) const
	Enumerates the databases in the client. More...

std::vector< std::string >	list_database_names (const bsoncxx::document::view_or_value filter={}) const
	Queries the MongoDB server for a list of known databases. More...


change_stream	watch (const options::change_stream &options={})
	Gets a change stream on this client with an empty pipeline. More...

change_stream	watch (const client_session &session, const options::change_stream &options={})

change_stream	watch (const pipeline &pipe, const options::change_stream &options={})
	Gets a change stream on this client. More...

change_stream	watch (const client_session &session, const pipeline &pipe, const options::change_stream &options={})
	Gets a change stream on this client. More...

Detailed Description

Class representing a client connection to MongoDB.

Acts as a logical gateway for working with databases contained within a MongoDB server.

Databases that are created via this client inherit the read_concern, read_preference, and write_concern settings of this client when they are created. The lifetimes of objects created via a client object (databases, collections, cursors, etc...) must be a subset of the lifetime of the client that created them.

Example:

mongocxx::client mongo_client{mongocxx::uri{}};

mongocxx::client mongo_client{mongocxx::uri{"mongodb://localhost:27017"}};

Note that client is not thread-safe. See https://mongodb.github.io/mongo-cxx-driver/mongocxx-v3/thread-safety/ for more details.

Examples: examples/mongocxx/client_session.cpp.

Constructor & Destructor Documentation

◆ client() [1/2]

mongocxx::client::client ( )

noexcept

Default constructs a new client.

The client is not connected and is equivalent to the state of a moved-from client. The only valid actions to take with a default constructed 'client' are to assign to it, or destroy it.

◆ client() [2/2]

mongocxx::client::client	(	const class uri &	mongodb_uri,
		const options::client &	options = `options::client()`
	)

Creates a new client connection to MongoDB.

Parameters

mongodb_uri	A MongoDB URI representing the connection parameters
options	Additional options that cannot be specified via the mongodb_uri

Exceptions

mongocxx::exception if invalid options are provided (whether from the URI or provided client options).

Member Function Documentation

◆ database()

class database mongocxx::client::database ( bsoncxx::string::view_or_value name ) const &

Obtains a database that represents a logical grouping of collections on a MongoDB server.

Note: A database cannot be obtained from a temporary client object.

Parameters

name	The name of the database to get

Returns: The database

◆ list_database_names()

std::vector<std::string> mongocxx::client::list_database_names ( const bsoncxx::document::view_or_value filter = {} ) const

Queries the MongoDB server for a list of known databases.

Parameters

filter An optional query expression to filter the returned database names.

Returns: std::vector<std::string> containing the database names.

Exceptions

mongocxx::operation_exception if the underlying 'listDatabases' command fails.

See also: https://docs.mongodb.com/manual/reference/command/listDatabases

◆ list_databases() [1/3]

cursor mongocxx::client::list_databases ( ) const

Enumerates the databases in the client.

Returns: A mongocxx::cursor containing a BSON document for each database. Each document contains a name field with the database name, a sizeOnDisk field with the total size of the database file on disk in bytes, and an empty field specifying whether the database has any data.

Exceptions

mongocxx::operation_exception if the underlying 'listDatabases' command fails.

See also: https://docs.mongodb.com/manual/reference/command/listDatabases

◆ list_databases() [2/3]

cursor mongocxx::client::list_databases ( const bsoncxx::document::view_or_value opts ) const

Enumerates the databases in the client.

Parameters

opts	Options passed directly to the 'listDatabases' command.

Returns: A mongocxx::cursor containing a BSON document for each database. Each document contains a name field with the database name, a sizeOnDisk field with the total size of the database file on disk in bytes, and an empty field specifying whether the database has any data.

Exceptions

mongocxx::operation_exception if the underlying 'listDatabases' command fails.

See also: https://docs.mongodb.com/manual/reference/command/listDatabases

◆ list_databases() [3/3]

cursor mongocxx::client::list_databases ( const client_session & session ) const

Enumerates the databases in the client.

Parameters

session The mongocxx::client_session with which to perform the aggregation.

Returns: A mongocxx::cursor containing a BSON document for each database. Each document contains a name field with the database name, a sizeOnDisk field with the total size of the database file on disk in bytes, and an empty field specifying whether the database has any data.

Exceptions

mongocxx::operation_exception if the underlying 'listDatabases' command fails.

See also: https://docs.mongodb.com/manual/reference/command/listDatabases

◆ operator[]()

database mongocxx::client::operator[] ( bsoncxx::string::view_or_value name ) const &

Allows the syntax client["db_name"] as a convenient shorthand for the client::database() method by implementing the array subscript operator.

Note: A database cannot be obtained from a temporary client object.

Parameters

name	The name of the database.

Returns: Client side representation of a server side database

◆ read_concern() [1/2]

class read_concern mongocxx::client::read_concern ( ) const

Returns the current read concern for this client.

Returns: The current read_concern

◆ read_concern() [2/2]

MONGOCXX_DEPRECATED void mongocxx::client::read_concern ( class read_concern rc )

Sets the read concern for this client.

Modifications at this level do not affect existing database instances that have been created by this client but do affect new ones as databases inherit the read_concern settings of their parent upon instantiation.

Deprecated:: This method is deprecated. Read concerns should be set either in the URI or directly on database or collection objects.

Parameters

rc	The new `read_concern`

See also: https://docs.mongodb.com/manual/reference/read-concern/

◆ read_preference() [1/2]

class read_preference mongocxx::client::read_preference ( ) const

Returns the current read preference for this client.

Returns: The current read_preference

See also: https://docs.mongodb.com/manual/core/read-preference/

◆ read_preference() [2/2]

MONGOCXX_DEPRECATED void mongocxx::client::read_preference ( class read_preference rp )

Sets the read preference for this client.

Modifications at this level do not affect existing database instances that have been created by this client but do affect new ones as databases inherit the read_preference settings of their parent upon instantiation.

Deprecated:: This method is deprecated. Read preferences should be set either in the URI or directly on database or collection objects.

Parameters

rp	The new `read_preference`

See also: https://docs.mongodb.com/manual/core/read-preference/

◆ reset()

void mongocxx::client::reset ( )

Prevents resource cleanup in the child process from interfering with the parent process after forking.

Clients should not be reused after forking. Call this method in the child after forking to safely destroy the client. This method should not be used with multi-threaded clients.

This method causes the client to clear its session pool without sending endSessions. It also increments an internal generation counter on the given client. After this method is called, cursors from previous generations will not issue a killCursors command when they are destroyed. Client sessions from previous generations cannot be used and should be destroyed.

◆ start_session()

client_session mongocxx::client::start_session ( const options::client_session & options = {} )

Create a client session for a sequence of operations.

Returns: A client_session object. See mongocxx::client_session for more information.

Exceptions

mongocxx::operation_exception if the driver is not built with crypto support, if options is misconfigured, or if the session is configured with options that the server does not support.

◆ uri()

class uri mongocxx::client::uri ( ) const

Returns the current uri for this client.

Returns: The uri that this client was created with.

◆ watch() [1/4]

change_stream mongocxx::client::watch	(	const client_session &	session,
		const options::change_stream &	options = `{}`
	)

Parameters

session	The mongocxx::client_session with which to perform the watch operation.
options	The options to use when creating the change stream.

Returns: A change stream on this client.

See also: https://docs.mongodb.com/manual/changeStreams/

◆ watch() [2/4]

change_stream mongocxx::client::watch	(	const client_session &	session,
		const pipeline &	pipe,
		const options::change_stream &	options = `{}`
	)

Gets a change stream on this client.

Parameters

session	The mongocxx::client_session with which to perform the watch operation.
pipe	The aggregation pipeline to be used on the change notifications.
options	The options to use when creating the change stream.

Returns: A change stream on this client.

See also: https://docs.mongodb.com/manual/changeStreams/

◆ watch() [3/4]

change_stream mongocxx::client::watch ( const options::change_stream & options = {} )

Gets a change stream on this client with an empty pipeline.

Change streams are only supported with a "majority" read concern or no read concern.

Parameters

options The options to use when creating the change stream.

Returns: A change stream on this client.

See also: https://docs.mongodb.com/manual/changeStreams/

◆ watch() [4/4]

change_stream mongocxx::client::watch	(	const pipeline &	pipe,
		const options::change_stream &	options = `{}`
	)

Gets a change stream on this client.

Change streams are only supported with a "majority" read concern or no read concern.

Parameters

pipe	The aggregation pipeline to be used on the change notifications. Only a subset of pipeline operations are supported for change streams. For more information see the change streams documentation.
options	The options to use when creating the change stream.

Returns: A change stream on this client.

See also: https://docs.mongodb.com/manual/changeStreams/

◆ write_concern() [1/2]

class write_concern mongocxx::client::write_concern ( ) const

Returns the current write concern for this client.

Returns: the current write_concern

◆ write_concern() [2/2]

MONGOCXX_DEPRECATED void mongocxx::client::write_concern ( class write_concern wc )

Sets the write concern for this client.

Note: Modifications at this level do not affect existing databases or collection instances that have come from this client but do affect new ones as databases will receive a copy of this client's write_concern upon instantiation.

Deprecated:: This method is deprecated. Write concerns should be set either in the URI or directly on database or collection objects.

Parameters

wc	The new write concern

The documentation for this class was generated from the following file:

src/mongocxx/client.hpp

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ client() [1/2]

◆ client() [2/2]

Member Function Documentation

◆ database()

◆ list_database_names()

◆ list_databases() [1/3]

◆ list_databases() [2/3]

◆ list_databases() [3/3]

◆ operator[]()

◆ read_concern() [1/2]

◆ read_concern() [2/2]

◆ read_preference() [1/2]

◆ read_preference() [2/2]

◆ reset()

◆ start_session()

◆ uri()

◆ watch() [1/4]

◆ watch() [2/4]

◆ watch() [3/4]

◆ watch() [4/4]

◆ write_concern() [1/2]

◆ write_concern() [2/2]