Trait Plugin

Source

pub trait Plugin:
    Any
    + Sized
    + Send
    + Sync {
    const CODE: &'static str;
    const MONO: bool = false;

    // Required methods
    fn call(
        &self,
        req: SgRequest,
        inner: Inner,
    ) -> impl Future<Output = Result<SgResponse, BoxError>> + Send;
    fn create(plugin_config: PluginConfig) -> Result<Self, BoxError>;

    // Provided methods
    fn meta() -> PluginMetaData { ... }
    fn create_by_spec(
        spec: JsonValue,
        name: PluginInstanceName,
    ) -> Result<Self, BoxError> { ... }
    fn register(repo: &PluginRepository) { ... }
}

Expand description

§Plugin Trait

It’s a easy way to define a plugin through this trait. You should give a unique code for the plugin, and implement the call function and the create function.

§Example

In the follow example, we add a server header for each response.

pub struct ServerHeaderPlugin {
    header_value: String,
}

impl Plugin for ServerHeaderPlugin {
    const CODE: &'static str = "server-header";
    async fn call(&self, req: SgRequest, inner: Inner) -> Result<SgResponse, BoxError> {
        let mut resp = inner.call(req).await;    
        resp.headers_mut().insert("server", self.header_value.parse()?);
        Ok(resp)
    }
    fn create(plugin_config: PluginConfig) -> Result<Self, BoxError> {
        let Some(header_value) = plugin_config.spec.get("header_value") else {
            return Err("missing header_value".into())
        };
        Ok(Self {
           header_value: header_value.as_str().unwrap_or("spacegate").to_string(),
        })
    }
}