Derive Macro JsonSchema

#[derive(JsonSchema)]

Derives a JSON Schema representation for a struct.

This procedural macro generates a json_schema() method for the annotated struct, returning a serde_json::Map<String, serde_json::Value> that represents the struct as a JSON Schema object. The schema includes the struct’s fields as properties, with support for basic types, Option<T>, Vec<T>, and nested structs that also derive JsonSchema.

Features

• Basic Types: Maps String to "string", i32 to "integer", bool to "boolean", etc.
• Option<T>: Adds "nullable": true to the schema of the inner type, indicating the field is optional.
• Vec<T>: Generates an "array" schema with an "items" field describing the inner type.
• Nested Structs: Recursively includes the schema of nested structs (assumed to derive JsonSchema), embedding their "properties" and "required" fields.
• Required Fields: Adds a top-level "required" array listing field names not wrapped in Option.

Notes

It’s designed as a straightforward solution to meet the basic needs of this package, supporting common types and simple nested structures. For more advanced features or robust JSON Schema generation, consider exploring established crates like schemars on crates.io

Limitations

• Supports only structs with named fields (e.g., struct S { field: Type }).
• Nested structs must also derive JsonSchema, or compilation will fail.
• Unknown types are mapped to {"type": "unknown"}.
• Type paths must be in scope (e.g., fully qualified paths like my_mod::InnerStruct work if imported).

Panics

• If the input is not a struct with named fields (e.g., tuple structs or enums).

Dependencies

Relies on serde_json for Map and Value types.