Tsvetomir Dimitrov
7a1958ca4e
* Expose `UnknownBlock` error via `ApiError` In [certain cases](https://github.com/paritytech/polkadot/issues/5885) a runtime api is called for an unknown block. For example a block which is already pruned or on an abandon fork. In such cases the correct error is returned but it is wrapped in `ApiError::Application` and the only way to figure out what is the problem is to inspect the actual message in the error. In polkadot for example this usually happens when the runtime api version is being queried. It's beneficial to be able to clearly separate such errors so i that when they occur the client side can handle them more gracefully. E.g. log less stressful error message than `State already discarded for BlockId` or cancel any pending work related on this block. * Update primitives/api/src/lib.rs Co-authored-by: Bastian Köcher <git@kchr.de> Co-authored-by: Bastian Köcher <git@kchr.de>
Substrate runtime api
The Substrate runtime api is the crucial interface between the node and the runtime.
Every call that goes into the runtime is done with a runtime api. The runtime apis are not fixed.
Every Substrate user can define its own apis with
decl_runtime_apis and implement them in
the runtime with impl_runtime_apis.
Every Substrate runtime needs to implement the [Core] runtime api. This api provides the basic
functionality that every runtime needs to export.
Besides the macros and the [Core] runtime api, this crates provides the [Metadata] runtime
api, the [ApiExt] trait, the [CallApiAt] trait and the [ConstructRuntimeApi] trait.
On a meta level this implies, the client calls the generated API from the client perspective.
License: Apache-2.0