# @ucanto/server

`@ucanto/server` provides the necessary components to build a UCAN-based RPC server. It enables services to define capabilities, validate UCANs, and process invocations securely and efficiently. This package builds on `ucanto/core` and integrates seamlessly with other `ucanto` modules.

## What It Provides
- **UCAN-Based Authorization**: Ensures that all invocations are securely verified before execution.
- **Capability Handling**: Allows services to define and manage capabilities with fine-grained access control.
- **Pluggable Transport Layer**: Supports multiple encoding and transport options.
- **Batch Invocation Processing**: Enables efficient handling of multiple invocations in a single request.

## How It Fits with Other Modules
- [`@ucanto/core`](../core/README.md): Provides the fundamental capability execution and validation logic.
- [`@ucanto/interface`](../interface/README.md): Defines shared type definitions and contracts.
- [`@ucanto/transport`](../transport/README.md): Implements encoding and transport mechanisms.
- [`@ucanto/principal`](../principal/README.md): Handles identity management and cryptographic operations.

For an overview and detailed usage information, refer to the [main `ucanto` README](../../Readme.md).

## Installation
```sh
npm install @ucanto/server
```

## Example Usage
```ts
import * as Server from '@ucanto/server';
import * as CAR from '@ucanto/transport/car';
import * as CBOR from '@ucanto/transport/cbor';
import { ed25519 } from '@ucanto/principal';
import { capability, URI } from '@ucanto/core';

const ReadFile = capability({
  can: 'file/read',
  with: URI.match({ protocol: 'file:' })
});

export const createServer = () => {
  const read = Server.provide(ReadFile, ({ capability }) => {
    return { path: capability.with };
  });

  return Server.create({
    id: ed25519.Signer.parse(process.env.SERVICE_SECRET),
    service: { file: { read } },
    decoder: CAR,
    encoder: CBOR
  });
};
```

For more details, see the [`ucanto` documentation](https://github.com/storacha/ucanto).