Crate py_rs

py-rs

Generate python type declarations from rust types

Why?

When building an api in rust, data structures have to be shared between backend and client. Using this library, you can easily generate python bindings to your rust structs & enums so that you can keep your types in one place.

Note: This is a work in progress. There are still some features of ts-rs that are not tested or converted.

How?

py-rs exposes a single trait, PY. Using a derive macro, you can implement this interface for your types. Then, you can use this trait to obtain the Python bindings. We recommend doing this in your tests. See the example and the docs.

Get started

[dependencies]
py-rs = "0.1.0"

use py_rs::PY;

#[derive(PY)]
#[py(export)]
struct User {
    user_id: i32,
    first_name: String,
    last_name: String,
}

When running cargo test or cargo test export_bindings, the Python bindings will be exported to the file bindings/User.py and will contain the following code:

from pydanic import BaseModel

class User(BaseModel):
    user_id: int
    first_name: str
    last_name: str

Features

• generate type declarations from rust structs
• generate union declarations from rust enums
• generate necessary imports when exporting to multiple files
• serde compatibility
• generic types
• support for ESM imports

Note: not all the features are tested for Python.

cargo features

Feature	Description
serde-compat	Enabled by default See the “serde compatibility” section below for more information.
format	Enables formatting of the generated Python bindings. Currently, this unfortunately adds quite a few dependencies.
no-serde-warnings	By default, warnings are printed during build if unsupported serde attributes are encountered. Enabling this feature silences these warnings.
serde-json-impl	Implement PY for types from serde_json
chrono-impl	Implement PY for types from chrono
bigdecimal-impl	Implement PY for types from bigdecimal
url-impl	Implement PY for types from url
uuid-impl	Implement PY for types from uuid
bson-uuid-impl	Implement PY for bson::oid::ObjectId and bson::uuid
bytes-impl	Implement PY for types from bytes
indexmap-impl	Implement PY for types from indexmap
ordered-float-impl	Implement PY for types from ordered_float
heapless-impl	Implement PY for types from heapless
semver-impl	Implement PY for types from semver
smol_str-impl	Implement PY for types from smol_str
tokio-impl	Implement PY for types from tokio

If there’s a type you’re dealing with which doesn’t implement PY, use either #[py(as = "..")] or #[py(type = "..")], or open a PR.

serde compatability

With the serde-compat feature (enabled by default), serde attributes can be parsed for enums and structs. Supported serde attributes:

• rename
• rename-all
• rename-all-fields
• tag
• content
• untagged
• skip
• flatten
• default

Note: skip_serializing and skip_deserializing are ignored. If you wish to exclude a field from the generated type, but cannot use #[serde(skip)], use #[py(skip)] instead.

When py-rs encounters an unsupported serde attribute, a warning is emitted, unless the feature no-serde-warnings is enabled.

Contributing

Contributions are always welcome! Feel free to open an issue, discuss using GitHub discussions or open a PR. See CONTRIBUTING.md

MSRV

The Minimum Supported Rust Version for this crate is 1.63.0

Structs

Dependency

A python type which is depended upon by other types. This information is required for generating the correct import statements.

Enums

ExportError

An error which may occur when exporting a type

Traits

PY

A type which can be represented in Python.
Most of the time, you’d want to derive this trait instead of implementing it manually.
py-rs comes with implementations for all primitives, most collections, tuples, arrays and containers.

TypeVisitor

A visitor used to iterate over all dependencies or generics of a type. When an instance of TypeVisitor is passed to PY::visit_dependencies or PY::visit_generics, the TypeVisitor::visit method will be invoked for every dependency or generic parameter respectively.

Derive Macros

PY

Derives PY for a struct or enum. Please take a look at PY for documentation.