Struct Extension 

pub struct Extension<T = Value> {
    pub info: T,
    pub schema: Value,
    pub extra: HashMap<String, Value>,
}

Represents an extension in the X402 protocol.

An extension has:

• info: Extension-specific data provided by the server
• schema: JSON Schema defining the expected structure of info
• extra: Additional extension-specific fields (flattened during serialization)

The generic parameter T defaults to AnyJson for transport/type-erased use. Use a concrete type implementing ExtensionInfo for typed extension construction.

Fields

info: T

The information about the extension.

schema: Value

The schema defining the extension’s structure.

extra: HashMap<String, Value>

Additional extension-specific fields, flattened during serialization.

Implementations

impl Extension

pub fn new(info: Value, schema: Value) -> Extension

Create a new type-erased extension.

pub fn into_typed<T>(self) -> Result<Extension<T>, Error>

where T: DeserializeOwned,

Convert a type-erased extension into a typed extension.

This deserializes the info field from JSON into the concrete type T.

impl<T> Extension<T>

pub fn with_extra( self, key: impl Into<String>, value: impl Into<Value>, ) -> Extension<T>

Add an extra field to the extension.

Extra fields are flattened alongside info and schema during serialization.

impl<T> Extension<T>

where T: ExtensionInfo,

pub fn typed(info: T) -> Extension<T>

Create a typed extension with auto-generated schema from T’s ExtensionInfo implementation.

pub fn into_pair(self) -> (String, Extension)

where T: Serialize,

Convert this typed extension into a key-value pair for insertion into Record<Extension>.

The key is T::ID and the value is the type-erased Extension.

Trait Implementations

impl<T> Clone for Extension<T>

where T: Clone,

fn clone(&self) -> Extension<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T> Debug for Extension<T>

where T: Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'de, T> Deserialize<'de> for Extension<T>

where T: DeserializeOwned,

fn deserialize<D>( deserializer: D, ) -> Result<Extension<T>, <D as Deserializer<'de>>::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T> Serialize for Extension<T>

where T: Serialize,

fn serialize<S>( &self, serializer: S, ) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.