BSON_READER_T(3)

Streaming BSON Document Reader

SYNOPSIS

            #include <bson/bson.h>

            typedef struct _bson_reader_t bson_reader_t;

            bson_reader_t *
            bson_reader_new_from_handle (void *handle,
                                         bson_reader_read_func_t rf,
                                         bson_reader_destroy_func_t df);
            bson_reader_t *
            bson_reader_new_from_fd (int fd, bool close_on_destroy);
            bson_reader_t *
            bson_reader_new_from_file (const char *path, bson_error_t *error);
            bson_reader_t *
            bson_reader_new_from_data (const uint8_t *data, size_t length);

            void
            bson_reader_destroy (bson_reader_t *reader);

DESCRIPTION

bson_reader_t is a structure used for reading a sequence of BSON documents. The sequence can come from a file-descriptor, memory region, or custom callbacks.

EXAMPLE

            /*
             * Copyright 2013 MongoDB, Inc.
             *
             * Licensed under the Apache License, Version 2.0 (the "License");
             * you may not use this file except in compliance with the License.
             * You may obtain a copy of the License at
             *
             *   http://www.apache.org/licenses/LICENSE-2.0
             *
             * Unless required by applicable law or agreed to in writing, software
             * distributed under the License is distributed on an "AS IS" BASIS,
             * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
             * See the License for the specific language governing permissions and
             * limitations under the License.
             */

            /*
             * This program will print each BSON document contained in the provided files
             * as a JSON string to STDOUT.
             */

            #include <bson/bson.h>
            #include <stdio.h>

            int
            main (int argc, char *argv[])
            {
               bson_reader_t *reader;
               const bson_t *b;
               bson_error_t error;
               const char *filename;
               char *str;
               int i;

               /*
                * Print program usage if no arguments are provided.
                */
               if (argc == 1) {
                  fprintf (stderr, "usage: %s [FILE | -]...\nUse - for STDIN.\n", argv[0]);
                  return 1;
               }

               /*
                * Process command line arguments expecting each to be a filename.
                */
               for (i = 1; i < argc; i++) {
                  filename = argv[i];

                  if (strcmp (filename, "-") == 0) {
                     reader = bson_reader_new_from_fd (STDIN_FILENO, false);
                  } else {
                     if (!(reader = bson_reader_new_from_file (filename, &error))) {
                        fprintf (
                           stderr, "Failed to open \"%s\": %s\n", filename, error.message);
                        continue;
                     }
                  }

                  /*
                   * Convert each incoming document to JSON and print to stdout.
                   */
                  while ((b = bson_reader_read (reader, NULL))) {
                     str = bson_as_canonical_extended_json (b, NULL);
                     fprintf (stdout, "%s\n", str);
                     bson_free (str);
                  }

                  /*
                   * Cleanup after our reader, which closes the file descriptor.
                   */
                  bson_reader_destroy (reader);
               }

               return 0;
            }

AUTHOR
MongoDB, Inc

COPYRIGHT
2017-present, MongoDB, Inc