created_at2015-06-09 16:18:02.257532
updated_at2024-04-02 17:28:05.853743
descriptionEncoding and decoding support for BSON in Rust



# bson [![](]( [![](]( [![](]( Encoding and decoding support for BSON in Rust ## Index - [Installation](#installation) - [Requirements](#requirements) - [Importing](#importing) - [Feature flags](#feature-flags) - [Useful links](#useful-links) - [Overview of BSON Format](#overview-of-the-bson-format) - [Usage](#usage) - [BSON Values](#bson-values) - [BSON Documents](#bson-documents) - [Modeling BSON with strongly typed data structures](#modeling-bson-with-strongly-typed-data-structures) - [Working with datetimes](#working-with-datetimes) - [Working with UUIDs](#working-with-uuids) - [WASM support](#wasm-support) - [Contributing](#contributing) - [Running the Tests](#running-the-tests) - [Continuous Integration](#continuous-integration) ## Useful links - [API Documentation]( - [Serde Documentation]( ## Installation ### Requirements - Rust 1.48+ ### Importing This crate is available on []( To use it in your application, simply add it to your project's `Cargo.toml`. ```toml [dependencies] bson = "2.10.0" ``` Note that if you are using `bson` through the `mongodb` crate, you do not need to specify it in your `Cargo.toml`, since the `mongodb` crate already re-exports it. #### Feature Flags | Feature | Description | Extra dependencies | Default | | :----------- | :---------------------------------------------------------------------------------------------------------- | :----------------- | :------ | | `chrono-0_4` | Enable support for v0.4 of the [`chrono`]( crate in the public API. | n/a | no | | `uuid-0_8` | Enable support for v0.8 of the [`uuid`]( crate in the public API. | n/a | no | | `uuid-1` | Enable support for v1.x of the [`uuid`]( crate in the public API. | n/a | no | | `serde_with` | Enable [`serde_with`]( 1.x integrations for `bson::DateTime` and `bson::Uuid`.| serde_with | no | | `serde_with-3` | Enable [`serde_with`]( 3.x integrations for `bson::DateTime` and `bson::Uuid`.| serde_with | no | ## Overview of the BSON Format BSON, short for Binary JSON, is a binary-encoded serialization of JSON-like documents. Like JSON, BSON supports the embedding of documents and arrays within other documents and arrays. BSON also contains extensions that allow representation of data types that are not part of the JSON spec. For example, BSON has a datetime type and a binary data type. ```text // JSON equivalent {"hello": "world"} // BSON encoding \x16\x00\x00\x00 // total document size \x02 // 0x02 = type String hello\x00 // field name \x06\x00\x00\x00world\x00 // field value \x00 // 0x00 = type EOO ('end of object') ``` BSON is the primary data representation for [MongoDB](, and this crate is used in the [`mongodb`]( driver crate in its API and implementation. For more information about BSON itself, see []( ## Usage ### BSON values Many different types can be represented as a BSON value, including 32-bit and 64-bit signed integers, 64 bit floating point numbers, strings, datetimes, embedded documents, and more. To see a full list of possible BSON values, see the [BSON specification]( The various possible BSON values are modeled in this crate by the [`Bson`]( enum. #### Creating [`Bson`]( instances [`Bson`]( values can be instantiated directly or via the [`bson!`]( macro: ```rust let string = Bson::String("hello world".to_string()); let int = Bson::Int32(5); let array = Bson::Array(vec![Bson::Int32(5), Bson::Boolean(false)]); let string: Bson = "hello world".into(); let int: Bson = 5i32.into(); let string = bson!("hello world"); let int = bson!(5); let array = bson!([5, false]); ``` [`bson!`]( supports both array and object literals, and it automatically converts any values specified to [`Bson`](, provided they are `Into`. #### [`Bson`]( value unwrapping [`Bson`]( has a number of helper methods for accessing the underlying native Rust types. These helpers can be useful in circumstances in which the specific type of a BSON value is known ahead of time. e.g.: ```rust let value = Bson::Int32(5); let int = value.as_i32(); // Some(5) let bool = value.as_bool(); // None let value = bson!([true]); let array = value.as_array(); // Some(&Vec) ``` ### BSON documents BSON documents are ordered maps of UTF-8 encoded strings to BSON values. They are logically similar to JSON objects in that they can contain subdocuments, arrays, and values of several different types. This crate models BSON documents via the [`Document`]( struct. #### Creating [`Document`]( [`Document`]( can be created directly either from a byte reader containing BSON data or via the `doc!` macro: ```rust let mut bytes = hex::decode("0C0000001069000100000000").unwrap(); let doc = Document::from_reader(&mut bytes.as_slice()).unwrap(); // { "i": 1 } let doc = doc! { "hello": "world", "int": 5, "subdoc": { "cat": true }, }; ``` [`doc!`]( works similarly to [`bson!`](, except that it always returns a [`Document`]( rather than a [`Bson`]( #### [`Document`]( member access [`Document`]( has a number of methods on it to facilitate member access: ```rust let doc = doc! { "string": "string", "bool": true, "i32": 5, "doc": { "x": true }, }; // attempt get values as untyped Bson let none = doc.get("asdfadsf"); // None let value = doc.get("string"); // Some(&Bson::String("string")) // attempt to get values with explicit typing let string = doc.get_str("string"); // Ok("string") let subdoc = doc.get_document("doc"); // Some(Document({ "x": true })) let error = doc.get_i64("i32"); // Err(...) ``` ### Modeling BSON with strongly typed data structures While it is possible to work with documents and BSON values directly, it will often introduce a lot of boilerplate for verifying the necessary keys are present and their values are the correct types. [`serde`]( provides a powerful way of mapping BSON data into Rust data structures largely automatically, removing the need for all that boilerplate. e.g.: ```rust #[derive(Serialize, Deserialize)] struct Person { name: String, age: i32, phones: Vec, } // Some BSON input data as a `Bson`. let bson_data: Bson = bson!({ "name": "John Doe", "age": 43, "phones": [ "+44 1234567", "+44 2345678" ] }); // Deserialize the Person struct from the BSON data, automatically // verifying that the necessary keys are present and that they are of // the correct types. let mut person: Person = bson::from_bson(bson_data).unwrap(); // Do things just like with any other Rust data structure. println!("Redacting {}'s record.",; = "REDACTED".to_string(); // Get a serialized version of the input data as a `Bson`. let redacted_bson = bson::to_bson(&person).unwrap(); ``` Any types that implement `Serialize` and `Deserialize` can be used in this way. Doing so helps separate the "business logic" that operates over the data from the (de)serialization logic that translates the data to/from its serialized form. This can lead to more clear and concise code that is also less error prone. ### Working with datetimes The BSON format includes a datetime type, which is modeled in this crate by the [`bson::DateTime`]( struct, and the `Serialize` and `Deserialize` implementations for this struct produce and parse BSON datetimes when serializing to or deserializing from BSON. The popular crate [`chrono`]( also provides a `DateTime` type, but its `Serialize` and `Deserialize` implementations operate on strings instead, so when using it with BSON, the BSON datetime type is not used. To work around this, the `chrono-0_4` feature flag can be enabled. This flag exposes a number of convenient conversions between `bson::DateTime` and `chrono::DateTime`, including the [`chrono_datetime_as_bson_datetime`]( serde helper, which can be used to (de)serialize `chrono::DateTime`s to/from BSON datetimes, and the `From` implementation for `Bson`, which allows `chrono::DateTime` values to be used in the `doc!` and `bson!` macros. e.g. ``` rust use serde::{Serialize, Deserialize}; #[derive(Serialize, Deserialize)] struct Foo { // serializes as a BSON datetime. date_time: bson::DateTime, // serializes as an RFC 3339 / ISO-8601 string. chrono_datetime: chrono::DateTime, // serializes as a BSON datetime. // this requires the "chrono-0_4" feature flag #[serde(with = "bson::serde_helpers::chrono_datetime_as_bson_datetime")] chrono_as_bson: chrono::DateTime, } // this automatic conversion also requires the "chrono-0_4" feature flag let query = doc! { "created_at": chrono::Utc::now(), }; ``` ### Working with UUIDs See the module-level documentation for the [`bson::uuid` module]( ### WASM support This crate compiles to the `wasm32-unknown-unknown` target; when doing so, the `js-sys` crate is used for the current timestamp component of `ObjectId` generation. ## Minimum supported Rust version (MSRV) The MSRV for this crate is currently 1.64.0. This will be rarely be increased, and if it ever is, it will only happen in a minor or major version release. ## Contributing We encourage and would happily accept contributions in the form of GitHub pull requests. Before opening one, be sure to run the tests locally; check out the [testing section](#running-the-tests) for information on how to do that. Once you open a pull request, your branch will be run against the same testing matrix that we use for our [continuous integration](#continuous-integration) system, so it is usually sufficient to only run the integration tests locally against a standalone. Remember to always run the linter tests before opening a pull request. ## Running the tests ### Integration and unit tests To actually run the tests, you can use `cargo` like you would in any other crate: ```bash cargo test --verbose # runs against localhost:27017 ``` ### Linter Tests Our linter tests use the nightly version of `rustfmt` to verify that the source is formatted properly and the stable version of `clippy` to statically detect any common mistakes. You can use `rustup` to install them both: ```bash rustup component add clippy --toolchain stable rustup component add rustfmt --toolchain nightly ``` To run the linter tests, run the `` and `` scripts in the `.evergreen` directory: ```bash bash .evergreen/ && bash .evergreen/ ``` ## Continuous Integration Commits to main are run automatically on [evergreen](
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cargo fmt