Typify lets you convert JSON Schema documents into Rust types. It can be used via a macro [import_types!] or a build.rs file.

A typical use looks like this:

# use typify_macro::import_types;
# use serde::{Deserialize,Serialize};
import_types!("../example.json");

This expands to type definitions corresponding to the types from the file example.json. The types are pub and have a number of useful associated impls including [Debug], [Clone], Serialize, and Deserialize.

Alternatively, you may use the expanded form:

# use typify_macro::import_types;
# use serde::{Deserialize,Serialize};
import_types!(schema = "../example.json");

If you want to add additional derives for the generated types, you can specify them with the derives property of the expanded form:

# use typify_macro::import_types;
# use serde::{Deserialize,Serialize};
import_types!(
schema = "../example.json",
derives = [schemars::JsonSchema],
);

Macro vs. build.rs

While using the [import_types!] macro is quite a bit simpler, you can also construct output in a build.rs script. Doing so requires a little more work do process the JSON Schema document and write out the file to your intended location. The significant benefit is that the generated type definitions are significantly easier to inspect. The macro-generated types can be viewed with cargo expand and they (like build.rs-derived types) have generated documentation, but if you find that you'd like to see the actual code generated you may prefer a build.rs.

Builder interface

Typify exports a [TypeSpace] interface that is intended for programmatic construction of types. This can be for something simple like a build.rs script or something more complex like a generated that includes types as part of its definition.

Mapping JSON Schema to Rust

JSON Schema allows for extreme flexibility. As such, there are some schemas that Typify isn't able to interpret (please file an issue!). In general, though, Typify does a pretty job of mapping JSON Schema types to Rust. For more information, see the project's README.md.