mongoc_collection_read_write_command_with_opts()

Synopsis

bool
mongoc_collection_read_write_command_with_opts (
   mongoc_collection_t *collection,
   const bson_t *command,
   const mongoc_read_prefs_t *read_prefs /* UNUSED */,
   const bson_t *opts,
   bson_t *reply,
   bson_error_t *error);

Execute a command on the server, applying logic for commands that both read and write, and taking the MongoDB server version into account. To send a raw command to the server without any of this logic, use mongoc_collection_command_simple().

Use this function for commands that both read and write, such as “mapReduce” with an output collection.

Read and write concern and collation can be overridden by various sources. In a transaction, read concern and write concern are prohibited in opts. The highest-priority sources for these options are listed first in the following table. Read preferences are not applied. The write concern is omitted for MongoDB before 3.4.

Read Concern	Write Concern	Collation
opts	opts	opts
Transaction	Transaction
collection	collection

See the example for transactions and for the “distinct” command with opts.

reply is always initialized, and must be freed with bson_destroy().

(The mongoc_read_prefs_t parameter was included by mistake when this function was introduced in libmongoc 1.5. A command that writes must not obey a read preference.)

Parameters

• collection: A mongoc_collection_t.

• command: A bson_t containing the command specification.

• read_prefs: Ignored.

• opts: A bson_t containing additional options.

• reply: A location for the resulting document.

• error: An optional location for a bson_error_t or NULL.

opts may be NULL or a BSON document with additional command options:

• readConcern: Construct a mongoc_read_concern_t and use mongoc_read_concern_append() to add the read concern to opts. See the example code for mongoc_client_read_command_with_opts(). Read concern requires MongoDB 3.2 or later, otherwise an error is returned.

• writeConcern: Construct a mongoc_write_concern_t and use mongoc_write_concern_append() to add the write concern to opts. See the example code for mongoc_client_write_command_with_opts().

• sessionId: First, construct a mongoc_client_session_t with mongoc_client_start_session(). You can begin a transaction with mongoc_client_session_start_transaction(), optionally with a mongoc_transaction_opt_t that overrides the options inherited from collection, and use mongoc_client_session_append() to add the session to opts. See the example code for mongoc_client_session_t.

• collation: Configure textual comparisons. See Setting Collation Order, and the MongoDB Manual entry on Collation. Collation requires MongoDB 3.2 or later, otherwise an error is returned.

• serverId: To target a specific server, include an int32 “serverId” field. Obtain the id by calling mongoc_client_select_server(), then mongoc_server_description_id() on its return value.

Consult the MongoDB Manual entry on Database Commands for each command’s arguments.

Errors

Errors are propagated via the error parameter.

Returns

Returns true if successful. Returns false and sets error if there are invalid arguments or a server or network error.

A write concern timeout or write concern error is considered a failure.

Example

See the example code for mongoc_client_read_command_with_opts().