Export validate siwf response function (#178)

# Problem

Export a part of a function for easier validation when receiving a
payload only.

docs/src/Delegations.md

@@ -18,5 +18,5 @@ Staging-Testnet and Production-Mainnet have the same delegation Schema Ids avail
 | [`dsnp.reply@v2`](https://spec.dsnp.org/DSNP/Types/Reply.html)                                                | Reply to a content                                                 | 18        |
 | [`dsnp.tombstone@v2`](https://spec.dsnp.org/DSNP/Types/Tombstone.html)                                        | Mark content for deletion                                          | 16        |
 | [`dsnp.update@v2`](https://spec.dsnp.org/DSNP/Types/Update.html)                                              | Update an existing post or reply                                   | 19        |
-| [`dsnp.user-attribute-set@v1`](https://spec.dsnp.org/DSNP/Types/UserAttributeSet.html)                        | Create an authenticated attribute set for a DSNP User              | 13        |
+| [`dsnp.user-attribute-set@v2`](https://spec.dsnp.org/DSNP/Types/UserAttributeSet.html)                        | Create an authenticated attribute set for a DSNP User              | 20        |
 | [`frequency.default-token-address@v1`](https://github.com/frequency-chain/schemas)                            | List one or more default token receiving addresses                 | 21        |

libraries/js/README.md

@@ -19,6 +19,7 @@ See [Markdown/GitHub Docs](../../docs/src/QuickStart.md) or
 | `generateAuthenticationUrl`    | Generates the signed request for the authentication flow                                 |
 | `getLoginResult`               | Fetch and extract the Result of the Login                                                |
 | `hasChainSubmissions`          | Checks to see if there are any chain submissions in the given result                     |
+| `validateSiwfResponse`         | Takes a response payload and validates it                                                |
 | `generateSignedRequest`        | Generates the signed payload for the authentication flow using a keypair                 |
 | `buildSignedRequest`           | Builds the signed request for the authentication flow using the signature and public key |
 | `generateEncodedSignedRequest` | Generates the encoded signed payload for the authentication flow using a keypair         |

libraries/js/src/response.test.ts

@@ -1,7 +1,8 @@
 import { describe, it, vi, expect, beforeAll } from 'vitest';
-import { ExampleLogin, ExampleNewProvider, ExampleNewUser } from './mocks/index.js';
-import { getLoginResult, hasChainSubmissions } from './response.js';
 import { cryptoWaitReady } from '@polkadot/util-crypto';
+import base64url from 'base64url';
+import { ExampleLogin, ExampleNewProvider, ExampleNewUser } from './mocks/index.js';
+import { getLoginResult, hasChainSubmissions, validateSiwfResponse } from './response.js';
 
 global.fetch = vi.fn();
 
@@ -57,3 +58,28 @@ describe('hasChainSubmissions', () => {
     expect(hasChainSubmissions(loginResponse)).toBe(false);
   });
 });
+
+describe('validateSiwfResponse', () => {
+  it('can handle a JSON strigified base64url encoded value', async () => {
+    const example = await ExampleLogin();
+    await expect(validateSiwfResponse(base64url(JSON.stringify(example)))).to.resolves.toMatchObject(example);
+  });
+
+  it('can handle an object value', async () => {
+    const example = await ExampleLogin();
+    await expect(validateSiwfResponse(example)).to.resolves.toMatchObject(example);
+  });
+
+  it('throws on a null value', async () => {
+    await expect(validateSiwfResponse(null)).to.rejects.toThrowError(
+      'Response failed to correctly parse or invalid content: null'
+    );
+  });
+
+  it('throws on a bad string value', async () => {
+    const value = base64url(JSON.stringify({ foo: 'bad' }));
+    await expect(validateSiwfResponse(value)).to.rejects.toThrowError(
+      'Response failed to correctly parse or invalid content: {"foo":"bad"}'
+    );
+  });
+});

libraries/js/src/response.ts

@@ -1,4 +1,5 @@
 import { cryptoWaitReady } from '@polkadot/util-crypto';
+import base64url from 'base64url';
 import { SiwfOptions } from './types/general.js';
 import { isSiwfResponse, SiwfResponse } from './types/response.js';
 import { parseEndpoint } from './util.js';
@@ -17,6 +18,39 @@ export function hasChainSubmissions(result: SiwfResponse): boolean {
   return !!result.payloads.find((x) => !!x.endpoint);
 }
 
+/**
+ * Validate a possible SIWF Response
+ *
+ * @param {unknown} response - A possible SIWF Response.
+ *
+ * @returns {Promise<SiwfResponse>} The validated response
+ */
+export async function validateSiwfResponse(response: unknown): Promise<SiwfResponse> {
+  await cryptoWaitReady();
+
+  let body = response;
+  if (typeof response === 'string') {
+    try {
+      body = JSON.parse(base64url.decode(response));
+    } catch (_e) {
+      throw new Error(`Response failed to correctly parse: ${response}`);
+    }
+  }
+
+  // This also validates that userPublicKey is a valid address
+  if (!isSiwfResponse(body)) {
+    throw new Error(`Response failed to correctly parse or invalid content: ${JSON.stringify(body)}`);
+  }
+
+  // Validate Payloads
+  await validatePayloads(body);
+
+  // Validate Credentials (if any), but trust DIDs from frequencyAccess
+  await validateCredentials(body.credentials, ['did:web:frequencyaccess.com', 'did:web:testnet.frequencyaccess.com']);
+
+  return body;
+}
+
 /**
  * Fetch and extract the Result of the Login from Frequency Access
  *
@@ -27,7 +61,6 @@ export function hasChainSubmissions(result: SiwfResponse): boolean {
  * @returns {Promise<SiwfResponse>} The parsed and validated response
  */
 export async function getLoginResult(authorizationCode: string, options?: SiwfOptions): Promise<SiwfResponse> {
-  await cryptoWaitReady();
   const endpoint = new URL(
     `${parseEndpoint(options?.endpoint, '/api/payload')}?authorizationCode=${authorizationCode}`
   );
@@ -39,16 +72,5 @@ export async function getLoginResult(authorizationCode: string, options?: SiwfOp
 
   const body = await response.json();
 
-  // This also validates that userPublicKey is a valid address
-  if (!isSiwfResponse(body)) {
-    throw new Error(`Response failed to correctly parse or invalid content: ${await response.text()}`);
-  }
-
-  // Validate Payloads
-  await validatePayloads(body);
-
-  // Validate Credentials (if any), but trust DIDs from frequencyAccess
-  await validateCredentials(body.credentials, ['did:web:frequencyaccess.com', 'did:web:testnet.frequencyaccess.com']);
-
-  return body;
+  return validateSiwfResponse(body);
 }