mongoc_handshake_data_append - Man Page

mongoc_handshake_data_append()

Synopsis

bool
mongoc_handshake_data_append (const char *driver_name,
                              const char *driver_version,
                              const char *platform);

Appends the given strings to the handshake data for the underlying C Driver.

Description

This function is intended for use by drivers which wrap the C Driver. Calling this function will store the given strings as handshake data about the system and driver by appending them to the handshake data for the underlying C Driver. These values, along with other handshake data collected during mongoc_init will be sent to the server as part of the initial connection handshake in the "client" document. This function must not be called more than once, or after server monitoring begins. For a single-threaded mongoc_client_t, server monitoring begins on the first operation requiring a server. For a mongoc_client_pool_t, server monitoring begins on the first call to :symbol:`mongoc_client_pool_pop.

The passed in strings are copied, and don't have to remain valid after the call to mongoc_handshake_data_append(). The driver may store truncated versions of the passed in strings.

NOTE:

This function allocates memory, and therefore caution should be used when using this in conjunction with bson_mem_set_vtable(). If this function is called before bson_mem_set_vtable(), then bson_mem_restore_vtable() must be called before calling mongoc_cleanup(). Failure to do so will result in memory being freed by the wrong allocator.

Parameters

Returns

true if the given fields are set successfully. Otherwise, it returns false and logs an error.

The default handshake data the driver sends with "hello" looks something like:

client: {
  driver: {
    name: "mongoc",
    version: "1.5.0"
  },
  os: {...},
  platform: "CC=gcc CFLAGS=-Wall -pedantic"
}

If we call mongoc_handshake_data_append() ("phongo", "1.1.8", "CC=clang / ") and it returns true, the driver sends handshake data like:

client: {
  driver: {
    name: "mongoc / phongo",
    version: "1.5.0 / 1.1.8"
  },
  os: {...},
  platform: "CC=clang / gcc CFLAGS=-Wall -pedantic"
}

Author

MongoDB, Inc

Info

Sep 08, 2022 1.23.0 libmongoc