MONGOC_COLLECTION_COMMAND(3)

💅 MONGOC_COLLECTION_COMMAND 💅

okay so bestie, we're in libmongoc territory and this one is literally called MONGOC_COLLECTION_COMMAND(3). she's an icon, she's a legend, but she's also… retired. let's get into it 🫶

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⚠️ WARNING: Deprecated since version 1.29.0 — this function is deprecated and should not be used in new code. use mongoc_collection_command_simple() instead, fr fr. this is giving "please stop calling me" energy 😭

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✨ SYNOPSIS ✨

mongoc_cursor_t *
mongoc_collection_command (mongoc_collection_t *collection,
                           mongoc_query_flags_t flags,
                           uint32_t skip,
                           uint32_t limit,
                           uint32_t batch_size,
                           const bson_t *command,
                           const bson_t *fields,
                           const mongoc_read_prefs_t *read_prefs);

heads up bestie: this function is not considered a retryable read operation. like, she will not try again for you. she said one shot, one opportunity 🎤

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🎀 PARAMETERS 🎀

• collection: A mongoc_collection_t. your girl, your target, your main character.
• flags: Unused. literally just sitting there. decor.
• skip: Unused. napping.
• limit: Unused. also napping.
• batch_size: Unused. you guessed it — napping.
• command: A bson_t containing the command to execute. this one actually does something 💖
• fields: Unused. girl is on her break.
• read_prefs: An optional mongoc_read_prefs_t. otherwise, the command uses mode MONGOC_READ_PRIMARY. (yes, that's the fallback. no cap.)

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🦋 MIGRATING 🦋

so mongoc_collection_command() is deprecated. periodt. here's how to move on gracefully 🧚

the following example uses mongoc_collection_command():

Before

const bson_t *reply;
bson_t *cmd = BCON_NEW ("find", "foo", "filter", "{", "}");
mongoc_cursor_t *cursor = mongoc_collection_command (coll,
                                                     MONGOC_QUERY_NONE /* unused */,
                                                     0 /* unused */,
                                                     0 /* unused */,
                                                     0 /* unused */,
                                                     cmd,
                                                     NULL /* unused */,
                                                     NULL /* read prefs */);
// Expect cursor to return exactly one document for the command reply.
EXPECT (mongoc_cursor_next (cursor, &reply));

bson_error_t error;
if (mongoc_cursor_error (cursor, &error)) {
   FAIL ("Expected no error, got: %s\n", error.message);
}

// Expect successful reply to contain "ok": 1
bson_iter_t iter;
EXPECT (bson_iter_init_find (&iter, reply, "ok") && bson_iter_as_int64 (&iter) == 1);

// Expect cursor to return no other documents.
EXPECT (!mongoc_cursor_next (cursor, &reply));
mongoc_cursor_destroy (cursor);
bson_destroy (cmd);

the above code block may be rewritten to use mongoc_collection_command_simple() instead, as shown below 👇

After

bson_t reply;
bson_error_t error;
bson_t *cmd = BCON_NEW ("find", "foo", "filter", "{", "}");
if (!mongoc_collection_command_simple (coll, cmd, NULL /* read prefs */, &reply, &error)) {
   FAIL ("Expected no error, got: %s\n", error.message);
}

// Expect successful reply to contain "ok": 1
bson_iter_t iter;
EXPECT (bson_iter_init_find (&iter, reply, "ok") && bson_iter_as_int64 (&iter) == 1);

bson_destroy (&reply);
bson_destroy (cmd);

glow up complete ✨

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🌸 RETURNS 🌸

this function returns a newly allocated mongoc_cursor_t that should be freed with mongoc_cursor_destroy() when no longer in use. the returned mongoc_cursor_t is never NULL, even on error — she shows up no matter what, queen behavior 👑. the user must call mongoc_cursor_next() on the returned mongoc_cursor_t to execute the initial command. don't forget, or she just sits there 🙈

cursor errors can be checked with mongoc_cursor_error_document(). it always fills out the bson_error_t if an error occurred, and optionally includes a server reply document if the error occurred server-side.

⚠️ WARNING: failure to handle the result of this function is a programming error. like, a real one. handle your business bestie 💀

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💜 AUTHOR 💜

MongoDB, Inc

⭐ COPYRIGHT ⭐

2009-present, MongoDB, Inc.

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and that's the whole page, bestie!! this was MONGOC_COLLECTION_COMMAND(3) from libmongoc, version 1.30.13, dated Oct 09, 2026. mwah 💋 go use mongoc_collection_command_simple() and thrive 🦋💖