Add struct for wallet_createSession

Author: FrederikBolding

packages/snaps-simulation/src/middleware/multichain/create-session.test.ts

@@ -112,7 +112,7 @@ describe('createSessionHandler', () => {
           jsonrpc: '2.0',
           id: 1,
           method: 'wallet_createSession',
-          params: [],
+          params: { optionalScopes: { foo: {} } },
         },
         { grantPermissions, getMnemonic },
       ),

packages/snaps-simulation/src/middleware/multichain/create-session.ts

@@ -1,12 +1,24 @@
-import type { Caip25CaveatValue } from '@metamask/chain-agnostic-permission';
 import {
   Caip25CaveatType,
   Caip25EndowmentPermissionName,
   setEthAccounts,
 } from '@metamask/chain-agnostic-permission';
 import type { RequestedPermissions } from '@metamask/permission-controller';
 import { rpcErrors } from '@metamask/rpc-errors';
-import { isObject, type JsonRpcRequest } from '@metamask/utils';
+import {
+  array,
+  is,
+  object,
+  string,
+  optional,
+  record,
+} from '@metamask/superstruct';
+import {
+  CaipAccountIdStruct,
+  CaipChainIdStruct,
+  JsonStruct,
+  type JsonRpcRequest,
+} from '@metamask/utils';
 
 import { getSessionScopes } from './utils';
 import { getSimulationAccount } from '../internal-methods/accounts';
@@ -16,6 +28,21 @@ export type CreateSessionHandlerHooks = {
   getMnemonic: () => Promise<Uint8Array>;
 };
 
+const ScopesStruct = record(
+  CaipChainIdStruct,
+  object({
+    methods: array(string()),
+    accounts: array(CaipAccountIdStruct),
+    notifications: array(string()),
+  }),
+);
+
+const CreateSessionParamsStruct = object({
+  requiredScopes: optional(ScopesStruct),
+  optionalScopes: optional(ScopesStruct),
+  sessionProperties: optional(record(string(), JsonStruct)),
+});
+
 /**
  * A handler that implements a simplified version of `wallet_createSession`.
  *
@@ -27,16 +54,16 @@ export async function createSessionHandler(
   request: JsonRpcRequest,
   hooks: CreateSessionHandlerHooks,
 ) {
-  if (!isObject(request.params)) {
+  if (!is(request.params, CreateSessionParamsStruct)) {
     throw rpcErrors.invalidParams({ data: { request } });
   }
 
   const caveat = {
     requiredScopes: request.params.requiredScopes ?? {},
     optionalScopes: request.params.optionalScopes ?? {},
-    sessionProperties: {},
+    sessionProperties: request.params.sessionProperties ?? {},
     isMultichainOrigin: true,
-  } as Caip25CaveatValue;
+  };
 
   const mnemonic = await hooks.getMnemonic();
   const ethereumAccounts = [await getSimulationAccount(mnemonic)];