[native/web] make findUserIdentities RPC available to native and web

Summary:
Implements `FindUserIdentities` RPC for web and native

Depends on D11999

Test Plan:
On both web/native successfully called the `FindUserIdentities` rpc on
1. ethereum user
2. username user
3. user with farcaster id
4. non-existent user (resulting in no entry in the identities result)

Reviewers: kamil, bartek

Reviewed By: bartek

Subscribers: inka, ashoat, tomek

Differential Revision: https://phab.comm.dev/D12000

lib/types/identity-service-types.js

@@ -172,6 +172,7 @@ export interface IdentityServiceClient {
   ) => Promise<$ReadOnlyArray<FarcasterUser>>;
   +linkFarcasterAccount: (farcasterID: string) => Promise<void>;
   +unlinkFarcasterAccount: () => Promise<void>;
+  +findUserIdentities: (userIDs: $ReadOnlyArray<string>) => Promise<Identities>;
 }
 
 export type IdentityServiceAuthLayer = {
@@ -230,6 +231,37 @@ export type UsersRawDeviceLists = {
   +[userID: string]: RawDeviceList,
 };
 
+// User Identity types
+
+export type EthereumIdentity = {
+  walletAddress: string,
+  siweMessage: string,
+  siweSignature: string,
+};
+export type Identity = {
+  +username: string,
+  +ethIdentity: ?EthereumIdentity,
+  +farcasterID: ?string,
+};
+export type Identities = {
+  +[userID: string]: Identity,
+};
+export const ethereumIdentityValidator: TInterface<EthereumIdentity> =
+  tShape<EthereumIdentity>({
+    walletAddress: t.String,
+    siweMessage: t.String,
+    siweSignature: t.String,
+  });
+export const identityValidator: TInterface<Identity> = tShape<Identity>({
+  username: t.String,
+  ethIdentity: t.maybe(ethereumIdentityValidator),
+  farcasterID: t.maybe(t.String),
+});
+export const identitiesValidator: TDict<Identities> = t.dict(
+  t.String,
+  identityValidator,
+);
+
 export type SignedDeviceList = {
   // JSON-stringified RawDeviceList
   +rawDeviceList: string,

native/identity-service/identity-service-context-provider.react.js

@@ -27,6 +27,7 @@ import {
   type UserDevicesOlmOutboundKeys,
   type UsersSignedDeviceLists,
   usersSignedDeviceListsValidator,
+  identitiesValidator,
 } from 'lib/types/identity-service-types.js';
 import { getContentSigningKey } from 'lib/utils/crypto-utils.js';
 import { assertWithValidator } from 'lib/utils/validation-utils.js';
@@ -615,6 +616,21 @@ function IdentityServiceContextProvider(props: Props): React.Node {
         } = await getAuthMetadata();
         return commRustModule.unlinkFarcasterAccount(userID, deviceID, token);
       },
+      findUserIdentities: async (userIDs: $ReadOnlyArray<string>) => {
+        const {
+          deviceID,
+          userID,
+          accessToken: token,
+        } = await getAuthMetadata();
+        const result = await commRustModule.findUserIdentities(
+          userID,
+          deviceID,
+          token,
+          userIDs,
+        );
+        const identities = JSON.parse(result);
+        return assertWithValidator(identities, identitiesValidator);
+      },
     }),
     [getAuthMetadata],
   );

web/grpc/identity-service-client-wrapper.js

@@ -30,6 +30,8 @@ import {
   farcasterUsersValidator,
   type UsersSignedDeviceLists,
   usersSignedDeviceListsValidator,
+  type Identities,
+  identitiesValidator,
 } from 'lib/types/identity-service-types.js';
 import { getMessageForException } from 'lib/utils/errors.js';
 import { assertWithValidator } from 'lib/utils/validation-utils.js';
@@ -615,6 +617,32 @@ class IdentityServiceClientWrapper implements IdentityServiceClient {
     }
     await client.unlinkFarcasterAccount(new Empty());
   };
+
+  findUserIdentities: (userIDs: $ReadOnlyArray<string>) => Promise<Identities> =
+    async userIDs => {
+      const client = this.authClient;
+      if (!client) {
+        throw new Error('Identity service client is not initialized');
+      }
+      const request = new IdentityAuthStructs.UserIdentitiesRequest();
+      request.setUserIdsList([...userIDs]);
+      const response = await client.findUserIdentities(request);
+      const identityObjects = response.toObject()?.identitiesMap;
+
+      let identities: Identities = {};
+      identityObjects.forEach(([userID, identityObject]) => {
+        identities = {
+          ...identities,
+          [userID]: {
+            ethIdentity: identityObject.ethIdentity,
+            username: identityObject.username,
+            farcasterID: identityObject.farcasterId,
+          },
+        };
+      });
+
+      return assertWithValidator(identities, identitiesValidator);
+    };
 }
 
 function authNewDeviceKeyUpload(

web/grpc/identity-service-context-provider.react.js

@@ -138,6 +138,7 @@ function IdentityServiceContextProvider(props: Props): React.Node {
       getFarcasterUsers: proxyMethodToWorker('getFarcasterUsers'),
       linkFarcasterAccount: proxyMethodToWorker('linkFarcasterAccount'),
       unlinkFarcasterAccount: proxyMethodToWorker('unlinkFarcasterAccount'),
+      findUserIdentities: proxyMethodToWorker('findUserIdentities'),
     };
   }, [proxyMethodToWorker]);