mcp_resource

The mcp_resource macro generates utility methods for static resource definitions.

#[macros::mcp_resource(
    uri = "hello.txt",
    name = "Hello Text",
    description = "A plain text greeting",
    mime_type = "text/plain",
)]
#[derive(Debug, macros::JsonSchema)]
pub struct HelloResource;

Generated methods:

• HelloResource::resource() - creates a Resource instance
• HelloResource::resource_uri() - returns the URI string
• HelloResource::RESOURCE_URI - the URI as a constant, usable in match patterns

The macro only generates metadata helpers - it does not read or produce resource content. Load the content yourself (e.g., with tokio::fs::read_to_string) in your read_resource handler and build a ReadResourceResult manually.

With Custom Logic

async fn handle_read_resource_request(
    &self, params: ReadResourceRequestParams, _runtime: Arc<dyn McpServer>,
) -> Result<ReadResourceResult, RpcError> {
    if params.uri == HelloResource::resource_uri() {
        let text = tokio::fs::read_to_string("hello.txt").await?;
        Ok(ReadResourceResult {
            contents: vec![TextResourceContents::new(text, HelloResource::resource_uri())
                .with_mime_type(HelloResource::resource_mime_type().unwrap_or("text/plain"))
                .into()],
            meta: None,
        })
    } else {
        Err(RpcError::invalid_params())
    }
}