Procedural macro for deriving view types from models.

This crate provides the #[derive(Views)] macro that automatically generates specialized view types for different access modes (Get, Create, Patch) from a base model struct.

Overview

The Views derive macro generates up to three view types for a model:

• {Model}Get: A read-only view for retrieving data
• {Model}Create: A view for creating new instances
• {Model}Patch: A view for partial updates using the Patch<T> wrapper

Each generated type only includes fields relevant to its access mode, based on field-level attributes that specify visibility policies.

Field Policies

Control field visibility in each view using these attributes:

• #[views(get = "policy")]: Controls field visibility in the Get view

  • "required" (default): Field is always present
  • "optional": Field is wrapped in Option<T>
  • "forbidden": Field is excluded from this view

• #[views(create = "policy")]: Controls field visibility in the Create view

  • "required" (default): Field must be provided
  • "optional": Field is wrapped in Option<T>
  • "forbidden": Field is excluded from this view

• #[views(patch = "policy")]: Controls field visibility in the Patch view

  • "patch" (default): Field is wrapped in Patch<T>
  • "optional": Field is wrapped in Patch<Option<T>>
  • "forbidden": Field is excluded from this view

Container Attributes

• #[views(crate = "path")]: Override the path to the model_views crate
• #[views(serde)]: Automatically derive Serialize/Deserialize for generated types

Example

#[derive(Views)]
#[views(serde)]
struct User {
    #[views(get = "required", create = "forbidden", patch = "forbidden")]
    id: i64,
    
    #[views(get = "required", create = "required", patch = "patch")]
    name: String,
    
    #[views(get = "optional", create = "optional", patch = "optional")]
    email: String,
}

This generates:

• UserGet with id: i64, name: String, email: Option<Option<String>>
• UserCreate with name: String, email: Option<Option<String>>
• UserPatch with name: Patch<String>, email: Patch<Option<String>>