Derive Macro GraphQLInputObject

#[derive(GraphQLInputObject)]
{
    // Attributes available to this derive:
    #[graphql]
}

#[derive(GraphQLInputObject)] macro for deriving a GraphQL input object implementation for a Rust struct. Each non-ignored field type must itself be GraphQL input object or a GraphQL scalar.

The #[graphql] helper attribute is used for configuring the derived implementation. Specifying multiple #[graphql] attributes on the same definition is totally okay. They all will be treated as a single attribute.

use juniper::GraphQLInputObject;

#[derive(GraphQLInputObject)]
struct Point2D {
    x: f64,
    y: f64,
}

Custom name and description

The name of a GraphQL input object or its fields may be overridden with the name attribute’s argument. By default, a type name or a struct field name is used in a camelCase.

The description of a GraphQL input object or its fields may be specified either with the description/desc attribute’s argument, or with a regular Rust doc comment.

#[derive(GraphQLInputObject)]
#[graphql(
    // Rename the type for GraphQL by specifying the name here.
    name = "Point",
    // You may also specify a description here.
    // If present, doc comments will be ignored.
    desc = "A point is the simplest two-dimensional primitive.",
)]
struct Point2D {
    /// Abscissa value.
    x: f64,

    #[graphql(name = "y", desc = "Ordinate value")]
    y_coord: f64,
}

Renaming policy

By default, all GraphQL input object fields are renamed in a camelCase manner (so a y_coord Rust struct field becomes a yCoord value in GraphQL schema, and so on). This complies with default GraphQL naming conventions as demonstrated in spec.

However, if you need for some reason another naming convention, it’s possible to do so by using the rename_all attribute’s argument. At the moment, it supports the following policies only: SCREAMING_SNAKE_CASE, camelCase, none (disables any renaming).

#[derive(GraphQLInputObject)]
#[graphql(rename_all = "none")] // disables renaming
struct Point2D {
    x: f64,
    y_coord: f64, // will be `y_coord` instead of `yCoord` in GraphQL schema
}

Ignoring fields

To omit exposing a Rust field in a GraphQL schema, use the ignore attribute’s argument directly on that field. Ignored fields must implement [Default] or have the default = <expression> attribute’s argument.

enum System {
    Cartesian,
}

#[derive(GraphQLInputObject)]
struct Point2D {
    x: f64,
    y: f64,
    #[graphql(ignore, default = System::Cartesian)]
    //                ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    // This attribute is required, as we need to be able to construct
    // a `Point2D` value from the `{ x: 0.0, y: 0.0 }` GraphQL input value,
    // received from client-side.
    system: System,
    // `Default::default()` value is used, if no
    // `#[graphql(default = <expression>)]` is specified.
    #[graphql(skip)]
    //        ^^^^ alternative naming, up to your preference
    shift: f64,
}