[CIS-1771] Expose method for clearing local DB data (#2241)

* Add logout method for properly disconnecting users and clearing local data.

* Update documentation on logout, remove completion from logout and add test.

* Update change log

* Code review fixes

* Update docusaurus/docs/iOS/uikit/getting-started.md

Co-authored-by: Nuno Vieira <nuno.fcvieira93@gmail.com>

Co-authored-by: Nuno Vieira <nuno.fcvieira93@gmail.com>

CHANGELOG.md

@@ -4,6 +4,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 # Upcoming
 
 ## StreamChat
+### ✅ Added
+- From now on, if you want to logout the user from the app, especially when switching users, you should call the `client.logout()` method instead of `client.disconnect()`. Read more [here](https://getstream.io/chat/docs/sdk/ios/uikit/getting-started/#disconnect--logout) [#2241](https://github.com/GetStream/stream-chat-swift/pull/2241)
 ### 🐞 Fixed
 - Fix hidden channels showing past history [#2216](https://github.com/GetStream/stream-chat-swift/pull/2216)
 

DemoApp/StreamChat/StreamChatWrapper.swift

@@ -127,7 +127,8 @@ extension StreamChatWrapper {
             }
         }
 
-        client.disconnect()
+        client.logout()
+
         self.client = nil
     }
 }

Sources/StreamChat/ChatClient.swift

@@ -373,6 +373,19 @@ public class ChatClient {
         }
         userConnectionProvider = nil
     }
+
+    /// Disconnects the chat client form the chat servers and removes all the local data related.
+    public func logout() {
+        disconnect()
+        databaseContainer.removeAllData(force: true) { error in
+            if let error = error {
+                log.error("Logging out current user failed with error \(error)", subsystems: .all)
+                return
+            } else {
+                log.debug("Logging out current user successfully.", subsystems: .all)
+            }
+        }
+    }
 
     func fetchCurrentUserIdFromDatabase() -> UserId? {
         var currentUserId: UserId?

Tests/StreamChatTests/StreamChat/ChatClient_Tests.swift

@@ -572,6 +572,21 @@ final class ChatClient_Tests: XCTestCase {
         XCTAssertEqual(testEnv.clientUpdater!.disconnect_source, .userInitiated)
     }
 
+    func test_logout_disconnectsAndRemovesLocalData() {
+        // GIVEN
+        let client = ChatClient(
+            config: inMemoryStorageConfig,
+            environment: testEnv.environment
+        )
+
+        // WHEN
+        client.logout()
+
+        // THEN
+        XCTAssertTrue(testEnv.clientUpdater!.disconnect_called)
+        XCTAssertTrue(testEnv.databaseContainer!.removeAllData_called)
+    }
+
     // MARK: - Background workers tests
 
     func test_productionClientIsInitalizedWithAllMandatoryBackgroundWorkers() {

docusaurus/docs/iOS/uikit/getting-started.md

@@ -72,6 +72,19 @@ ChatClient.shared.connectUser(userInfo: userInfo, tokenProvider: tokenProvider)
 }
 ```
 
+### Disconnect & Logout
+
+Whenever your users leave the chat component, you should use disconnect to stop receiving chat updates and events while using other features of your app. You disconnect by calling:
+```swift
+chatClient.disconnect()
+```
+
+If your users logout form their account you should use logout instead for completely logging out from the session. You logout by calling:
+
+```swift
+chatClient.logout()
+```
+
 ### Show Channel List
 
 Once the `ChatClient` is connected, we can show the list of channels.