#include <mongoc/mongoc.h>

typedef struct _mongoc_gridfs_bucket_t mongoc_gridfs_bucket_t;


mongoc_gridfs_bucket_t provides a spec-compliant MongoDB GridFS implementation, superseding mongoc_gridfs_t. See the GridFS MongoDB documentation.

Thread Safety

mongoc_gridfs_bucket_t is NOT thread-safe and should only be used in the same thread as the owning mongoc_client_t.


It is an error to free a mongoc_gridfs_bucket_t before freeing all derived instances of mongoc_stream_t. The owning mongoc_client_t must outlive the mongoc_gridfs_bucket_t.


#include <stdio.h>
#include <stdlib.h>

#include <mongoc/mongoc.h>

main (int argc, char *argv[])
   const char *uri_string =
   mongoc_client_t *client;
   mongoc_database_t *db;
   mongoc_stream_t *file_stream;
   mongoc_gridfs_bucket_t *bucket;
   mongoc_cursor_t *cursor;
   bson_t filter;
   bool res;
   bson_value_t file_id;
   bson_error_t error;
   const bson_t *doc;
   char *str;
   mongoc_init ();

   if (argc != 3) {
      fprintf (stderr, "usage: %s SOURCE_FILE_PATH FILE_COPY_PATH\n", argv[0]);
      return EXIT_FAILURE;

   /* 1. Make a bucket. */
   client = mongoc_client_new (uri_string);
   db = mongoc_client_get_database (client, "test");
   bucket = mongoc_gridfs_bucket_new (db, NULL, NULL, &error);
   if (!bucket) {
      printf ("Error creating gridfs bucket: %s\n", error.message);
      return EXIT_FAILURE;

   /* 2. Insert a file.  */
   file_stream = mongoc_stream_file_new_for_path (argv[1], O_RDONLY, 0);
   res = mongoc_gridfs_bucket_upload_from_stream (
      bucket, "my-file", file_stream, NULL, &file_id, &error);
   if (!res) {
      printf ("Error uploading file: %s\n", error.message);
      return EXIT_FAILURE;

   mongoc_stream_close (file_stream);
   mongoc_stream_destroy (file_stream);

   /* 3. Download the file in GridFS to a local file. */
   file_stream = mongoc_stream_file_new_for_path (argv[2], O_CREAT | O_RDWR, 0);
   if (!file_stream) {
      perror ("Error opening file stream");
      return EXIT_FAILURE;

   res = mongoc_gridfs_bucket_download_to_stream (
      bucket, &file_id, file_stream, &error);
   if (!res) {
      printf ("Error downloading file to stream: %s\n", error.message);
      return EXIT_FAILURE;
   mongoc_stream_close (file_stream);
   mongoc_stream_destroy (file_stream);

   /* 4. List what files are available in GridFS. */
   bson_init (&filter);
   cursor = mongoc_gridfs_bucket_find (bucket, &filter, NULL);

   while (mongoc_cursor_next (cursor, &doc)) {
      str = bson_as_canonical_extended_json (doc, NULL);
      printf ("%s\n", str);
      bson_free (str);

   /* 5. Delete the file that we added. */
   res = mongoc_gridfs_bucket_delete_by_id (bucket, &file_id, &error);
   if (!res) {
      printf ("Error deleting the file: %s\n", error.message);
      return EXIT_FAILURE;

   /* 6. Cleanup. */
   mongoc_stream_close (file_stream);
   mongoc_stream_destroy (file_stream);
   mongoc_cursor_destroy (cursor);
   bson_destroy (&filter);
   mongoc_gridfs_bucket_destroy (bucket);
   mongoc_database_destroy (db);
   mongoc_client_destroy (client);
   mongoc_cleanup ();

   return EXIT_SUCCESS;

See also

The non spec-compliant mongoc_gridfs_t.