--- name: "bson_json" section: "3" platform: "linux" package: "libbson-doc" version: "1.23.1-1+deb12u3" release: "Debian 12 (Bookworm)" platforms: ["linux"] url: "https://new.carta.tech/bson_json" --- # bson\_json(3) JSON Libbson provides routines for converting to and from the JSON format. In particular, it supports the MongoDB extended JSON format. ## NAME bson\_json - JSON Libbson provides routines for converting to and from the JSON format. In particular, it supports the *MongoDB extended JSON* format. ## CONVERTING BSON TO JSON There are often times where you might want to convert a BSON document to JSON. It is convenient for debugging as well as an interchange format. To help with this, Libbson contains the functions *bson\_as\_canonical\_extended\_json()* and *bson\_as\_relaxed\_extended\_json()*. The canonical format preserves BSON type information for values that may have ambiguous representations in JSON (e.g. numeric types). ``` bson_t *b; size_t len; char *str; b = BCON_NEW ("a", BCON_INT32 (1)); str = bson_as_canonical_extended_json (b, &len); printf ("%s\n", str); bson_free (str); bson_destroy (b); ``` ``` { "a" : { "$numberInt": "1" } } ``` The relaxed format prefers JSON primitives for numeric values and may be used if type fidelity is not required. ``` bson_t *b; size_t len; char *str; b = BCON_NEW ("a", BCON_INT32 (1)); str = bson_as_relaxed_extended_json (b, &len); printf ("%s\n", str); bson_free (str); bson_destroy (b); ``` ``` { "a" : 1 } ``` ## CONVERTING JSON TO BSON Converting back from JSON is also useful and common enough that we added *bson\_init\_from\_json()* and *bson\_new\_from\_json()*. The following example creates a new *bson\_t* from the JSON string **{"a":1}**. ``` bson_t *b; bson_error_t error; b = bson_new_from_json ("{\"a\":1}", -1, &error); if (!b) { printf ("Error: %s\n", error.message); } else { bson_destroy (b); } ``` ## STREAMING JSON PARSING Libbson provides *bson\_json\_reader\_t* to allow for parsing a sequence of JSON documents into BSON. The interface is similar to *bson\_reader\_t* but expects the input to be in the *MongoDB extended JSON* format. ``` /* * 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 JSON document contained in the provided files * as a BSON string to STDOUT. */ #include #include #include int main (int argc, char *argv[]) { bson_json_reader_t *reader; bson_error_t error; const char *filename; bson_t doc = BSON_INITIALIZER; int i; int b; /* * Print program usage if no arguments are provided. */ if (argc == 1) { fprintf (stderr, "usage: %s FILE...\n", argv[0]); return 1; } /* * Process command line arguments expecting each to be a filename. */ for (i = 1; i < argc; i++) { filename = argv[i]; /* * Open the filename provided in command line arguments. */ if (0 == strcmp (filename, "-")) { reader = bson_json_reader_new_from_fd (STDIN_FILENO, false); } else { if (!(reader = bson_json_reader_new_from_file (filename, &error))) { fprintf ( stderr, "Failed to open \"%s\": %s\n", filename, error.message); continue; } } /* * Convert each incoming document to BSON and print to stdout. */ while ((b = bson_json_reader_read (reader, &doc, &error))) { if (b < 0) { fprintf (stderr, "Error in json parsing:\n%s\n", error.message); abort (); } if (fwrite (bson_get_data (&doc), 1, doc.len, stdout) != doc.len) { fprintf (stderr, "Failed to write to stdout, exiting.\n"); exit (1); } bson_reinit (&doc); } bson_json_reader_destroy (reader); bson_destroy (&doc); } return 0; } ``` ## EXAMPLES The following example reads BSON documents from **stdin** and prints them to **stdout** as JSON. ``` /* * 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 #include 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