feature: add package for client sdk

.gitignore

@@ -2,4 +2,5 @@ node_modules
 .env*
 dist
 .DS_Store
-*.pem
+*.pem
+yarn-error.log

packages/relay-sdk/.gitignore

@@ -0,0 +1 @@
+index.js

packages/relay-sdk/.npmignore

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+# Ignore all files and directories starting with a dot
+.*
+
+# Build related stuff
+node_modules/

packages/relay-sdk/README.md

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+# Relay SDK
+
+## Description
+
+The Lit Network Relay SDK is a lightweight JavaScript library that can be used for setting up payment delegations using the Lit Network Relay Server. The SDK provides a simple interface to connect to the Relay server, register a new payer, and add payees.
+
+## Features
+
+- Connect to the Relay server
+- Register a new payer
+- Add payees to the payer's delegation
+
+## Installation
+
+```bash
+npm install @lit-protocol/relay-sdk
+```
+
+or
+
+```bash
+yarn add @lit-protocol/relay-sdk
+```
+
+## Usage
+
+### Registering a new payer:
+
+```javascript
+import { LitRelayClient } from '@lit-protocol/relay-sdk';
+
+const client = await LitRelayClient.register('habanero', 'you-api-key');
+const secret = client.secret;
+```
+
+### Adding a payee:
+
+```javascript
+import { LitRelayClient } from '@lit-protocol/relay-sdk';
+
+const client = await LitRelayClient.connect('habanero', 'you-api-key', 'your-payer-secret');
+await client.addPayee('user-wallet-address');
+```
+

packages/relay-sdk/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "@litnetwork/relay-sdk",
+  "version": "0.0.1",
+  "description": "Lightweight client for interacting with Lit Network relay server.",
+  "main": "index.js",
+  "scripts": {
+    "build": "esbuild src/index.ts --bundle --platform=node --target=node12 --outfile=index.js"
+  },
+  "license": "ISC",
+  "devDependencies": {
+    "esbuild": "^0.21.4"
+  },
+  "dependencies": {
+    "@lit-protocol/constants": "^6.0.1"
+  }
+}

packages/relay-sdk/src/index.ts

@@ -0,0 +1,132 @@
+
+import { RELAY_URL_HABANERO, RELAY_URL_MANZANO } from '@lit-protocol/constants';
+import { assertNotNull, assertStatus, assertString, getProp } from './util';
+
+type SupportedNetworks = 'habanero' | 'manzano';
+
+function getRelayURLByNetwork(network: SupportedNetworks): string {
+    switch (network) {
+        case 'habanero':
+            return RELAY_URL_HABANERO;
+        case 'manzano':
+            return RELAY_URL_MANZANO;
+    }
+}
+
+export class LitRelayClient {
+
+    private readonly baseUrl: string;
+    private readonly apiKey: string;
+
+    private payerSecret: string | undefined = undefined;
+
+    /**
+     * Create a new LitRelayClient instance. Requires that the payer is already registered.
+     * and the the payer secret is known.
+     * 
+     * ```typescript
+     * const client = new LitRelayClient('https://habanero.lit.dev', 'my-api-key', 'my-payer-secret');
+     * ```
+     * 
+     * @param baseUrl
+     * @param apiKey
+     * @param payerSecret
+     */
+    private constructor(baseUrl: string, apiKey: string, payerSecret: string) {
+        this.baseUrl = baseUrl;
+        this.apiKey = apiKey;
+
+        if (payerSecret) {
+            this.payerSecret = payerSecret;
+        }
+    }
+
+    /**
+     * Adds a new payee to the payer's delegation list.
+     * 
+     * ```typescript
+     * const client = await LitRelayClient.connect('habanero', 'my-api-key', 'my-payer-secret');
+     * const result = await client.addPayee('payee-wallet-address');
+     * ```
+     * @param payeeAddress
+     * 
+     * @returns Promise<{ tokenId: string } | Error>
+     */
+    public addPayee(payeeAddress: string): Promise<{ tokenId: string }> {
+        if (!this.payerSecret) {
+            return Promise.reject('Payer secret key is missing');
+        }
+
+        return fetch(`${this.baseUrl}/add-users`, {
+            method: 'POST',
+            headers: {
+                'Content-Type': 'application/json',
+                'api-key': this.apiKey,
+                'payer-secret-key': this.payerSecret,
+            },
+            body: JSON.stringify([payeeAddress]),
+        })
+            .then(assertStatus(200, 'Failed to add payee: request failed'))
+            .then(res => res.json())
+            .then(json => assertString(json.tokenId, 'Failed to add payee: missing token ID'))
+            .then(tokenId => ({ tokenId }));
+    }
+
+    /**
+     * Registers a new payer with the Lit Relay server using the provided API key. Returns
+     * a new LitRelayClient instance with the payer secret key.
+     * 
+     * ```typescript
+     * const client = await LitRelayClient.register('habanero', 'my-api-key');
+     * ```
+     * 
+     * @param network 
+     * @param apiKey 
+     * 
+     * @returns LitRelayClient
+     */
+    public static register(network: SupportedNetworks, apiKey: string): Promise<LitRelayClient {
+        if (network !== 'habanero' && network !== 'manzano') {
+            throw Promise.reject('Invalid network');
+        }
+
+        const baseUrl = getRelayURLByNetwork(network);
+
+        return fetch(`${baseUrl}/register-payer`, {
+            method: 'POST',
+            headers: {
+                'Content-Type': 'application/json',
+                'api-key': apiKey,
+            },
+        })
+            .then(assertStatus(200, 'Failed to register payer: request failed'))
+            .then(res => res.json())
+            .then(json => getProp(json, 'payerSecretKey'))
+            .then(json => assertString(json.payerSecretKey, 'Failed to register payer: missing secret key'))
+            .then(payerSecretKey => new LitRelayClient(baseUrl, apiKey, payerSecretKey));
+    }
+
+    /**
+     * Connects to the Relay server for the specified network using the provided API key and payer secret
+     * and returns a new LitRelayClient instance.
+     * 
+     * ```typescript
+     * const client = await LitRelayClient.connect('habanero', 'my-api-key', 'my-payer-secret');
+     * ```
+     * 
+     * @param network 
+     * @param apiKey 
+     * @param payerSecret 
+     * 
+     * @returns LitRelayClient
+     */
+    public static connect(network: SupportedNetworks, apiKey: string, payerSecret: string) {
+        if (network !== 'habanero' && network !== 'manzano') {
+            throw new Error('Invalid network');
+        }
+
+        const baseUrl = getRelayURLByNetwork(network);
+
+        return new LitRelayClient(baseUrl, apiKey, payerSecret);
+    }
+}

packages/relay-sdk/src/util.ts

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+export function assertStatus(code: number, error: string) {
+    return (response: Response) => {
+        if (response.status !== code) {
+            throw new Error(error);
+        }
+
+        return response;
+    };
+}
+
+export function assertNotNull(value: any, error: string) {
+    if (value === null || value === undefined) {
+        throw new Error(error);
+    }
+
+    return value;
+}
+
+export function assertString(value: any, error: string) {
+    if (typeof value !== "string") {
+        throw new Error(error);
+    }
+
+    return value as string;
+}