# Chat

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Chat is is designed to support in-session text communication. Zoom truncates messages exceeding a binary size of 10,000 bytes. As a best practice, we recommend a limit of 1000 characters per message.

While in a session, users can send chat messages to each other.

The following two main components within the SDK will help you implement in-session messaging features:

-   An instance of `ZoomVideoSDKChatHelper` provides methods to send and receive messages in a session running on your app.
-   The `onChatNewMessageNotify` callback from your `ZoomVideoSDKDelegate` confirms the delivery of a message.

> Common chat implementations in iOS use `UITableViews`. This documentation only goes over how to get information from the `ZoomVideoSDK` chat API. If you would like to use this API in a `UITableView`, see [UITableViews in iOS](https://developer.apple.com/documentation/uikit/uitableview).

## Send chat messages

Users can send a message privately to a single user or publicly to all users present in a session.

### Send a private chat message

```swift
// Get the ZoomVideoSDKChatHelper to perform chat actions.
if let chatHelper = ZoomVideoSDK.shareInstance()?.getChatHelper() {
    // Check if chat is enabled in this session.
    if !chatHelper.isChatDisabled(), !chatHelper.isPrivateChatDisabled() {
        // Send message to User.
        chatHelper.sendChat(to: user, content: message)
    }
}
```

```objectivec
// Get the ZoomVideoSDKChatHelper to perform chat actions.
ZoomVideoSDKChatHelper *chatHelper = [[ZoomVideoSDK shareInstance] getChatHelper];
// Check if chat is enabled in this session.
if (chatHelper.IsChatDisabled == NO && chatHelper.IsPrivateChatDisabled == NO) {
    // Send message to User.
    [chatHelper SendChatToUser:user Content:message];
}
```

### Send a public chat message

```swift
// Get the ZoomVideoSDKChatHelper to perform chat actions.
if let chatHelper = ZoomVideoSDK.shareInstance()?.getChatHelper() {
    // Check if chat is enabled in this session.
    if !chatHelper.isChatDisabled() {
        // Send message to all users in this session.
        chatHelper.sendChat(toAll: message)
    }
}
```

```objectivec
// Get the ZoomVideoSDKChatHelper to perform chat actions.
ZoomVideoSDKChatHelper *chatHelper = [[ZoomVideoSDK shareInstance] getChatHelper];
// Check if chat is enabled in this session.
if (chatHelper.IsChatDisabled == NO) {
    // Send message to all users in this session.
    [chatHelper SendChatToAll:message];
}
```

## Receive chat messages

Use the `onChatNewMessageNotify` callback to be notified of a new message. The parameter `chatMessage` contains information about the message including a `ZoomVideoSDKUserInfo` object for both the sender and recipient.

```swift
func onChatNewMessageNotify(_ helper: ZoomVideoSDKChatHelper?, message chatMessage: ZoomVideoSDKChatMessage?) {
    // Use helper to perform chat actions.
    // Message contains the info about a chat message.
    if let content = chatMessage?.content, let senderName = chatMessage?.senderUser?.getName() {
        print("\\(senderName) sent a message: \\(content)")
    }
}
```

```objectivec
- (void)onChatNewMessageNotify:(ZoomVideoSDKChatHelper *)helper message:(ZoomVideoSDKChatMessage *)chatMessage {
    // Use helper to perform chat actions.
    // Message contains the info about a chat message.
    NSString *content = chatMessage.content;
    ZoomVideoSDKUser *sender = chatMessage.senderUser;
    NSLog(@"%@ sent a message: %@", sender.getUserName, content);
}
```

For more information on how to use the `ZoomVideoSDKUserInfo` object, see [Sessions](/docs/video-sdk/ios/sessions/).

## Chat message details

Here are some additional considerations to make note of while using `ZoomVideoSDKChatMessage`:

```swift
let isChatToAll = chatMessage.isChatToAll // Returns false for private messages.
let currentUserIsSender = chatMessage.isSelfSend // Returns true if the current user sent the message.
let timeMessageWasSent = chatMessage.timeStamp // The time at which the message was sent.
let recipient = chatMessage.receiverUser // The recipient of a private message.
```

```objectivec
[chatMessage isChatToAll]; // Returns false for private messages.
[chatMessage isSelfSend]; // Returns true if the current user sent the message.
[chatMessage timeStamp]; // The time at which the message was sent.
[chatMessage receiverUser]; // The recipient of a private message.
```

## Callbacks

The following is an example of a chat callback.

### Get notified when a message is delivered

```swift
func onChatNewMessageNotify(_ helper: ZoomVideoSDKChatHelper?, message chatMessage: ZoomVideoSDKChatMessage?) {
    // Use helper to perform chat actions.
    // Message contains the info about a chat message.
    if let content = chatMessage?.content, let senderName = chatMessage.senderUser?.getName() {
        print("\\(senderName) sent a message: \(content)")
    }
}
```

```objectivec
- (void)onChatNewMessageNotify:(ZoomVideoSDKChatHelper *)helper message:(ZoomVideoSDKChatMessage *)chatMessage {
    // Use helper to perform chat actions.
    // Message contains the info about a chat message.
    NSString *content = chatMessage.content;
    ZoomVideoSDKUser *sender = chatMessage.senderUser;
    NSLog(@"%@ sent a message: %@", sender.getUserName, content);
}
```

## Send files in chat

Users can transfer files in chat during the session.

> Zoom deletes files sent via in-session chat when the session ends.

Enable [send files via in-session chat](/docs/build/account/#in-session-advanced) in your Video SDK account portal settings and configure the following settings.

-   **Only allow specified file types** - Select to allow only specific file types and enter the file extensions in the text box, separated by commas.
-   **Maximum file size** - Select to limit the file size to 2048 MB.

Check if the file transfer feature is enabled.

```swift
if let isFileTransferEnable = ZoomVideoSDK.shareInstance()?.getSession()?.isFileTransferEnable(), isFileTransferEnable {
    // File Transfer is enabled.
}
```

Get the list of allowed file types that you can transfer.

```swift
if let fileType = ZoomVideoSDK.shareInstance()?.getSession()?.getTransferFileTypeWhiteList() {
    // fileType consists of the string value of the allowed file types, multiple values are separated by comma. Exe files are by default forbidden from being transferred.
}
```

Get the maximum file size to transfer.

```swift
if let maxSize = ZoomVideoSDK.shareInstance()?.getSession()?.getMaxTransferFileSize() {
    // fileType consists of the long value of the max allowed file size
}
```

Send files to all users in the current session.

```swift
if let session = ZoomVideoSDK.shareInstance()?.getSession() {
    let error = session.transferFile("filePath")
    if error == .Errors_Success {
        // Transfer successfully
    } else {
        // Failed to transfer
    }
}
```

Send files to a certain user in the session.

```swift
// Get the user you want to send file to
let userToReceiveFile: ZoomVideoSDKUser
let error = userToReceiveFile.transferFile("filePath")
if error == .Errors_Success {
    // Transfer successfully
} else {
    // Failed to transfer
}
```

Cancel sending files.

```swift
// onSendFileStatus under ZoomVideoSDKDelegate
func onSendFileStatus(_ file: ZoomVideoSDKSendFile?, status: ZoomVideoSDKFileTransferStatus) {
    if status != .FileTransferState_TransferDone, let sendingFile = file {
        let error = sendingFile.cancelSend()
    }
}
```

Start receiving files.

```swift
// onReceiveFileStatus under ZoomVideoSDKDelegate
func onReceiveFileStatus(_ file: ZoomVideoSDKReceiveFile?, status: ZoomVideoSDKFileTransferStatus) {
    guard let receiveFile = file else { return }
    let error = receiveFile.startReceive(filePath)
}
```

Cancel receiving files.

```swift
// onReceiveFileStatus under ZoomVideoSDKDelegate
func onReceiveFileStatus(_ file: ZoomVideoSDKReceiveFile?, status: ZoomVideoSDKFileTransferStatus) {
    guard let receiveFile = file else { return }
    let error = receiveFile.cancelReceive()
}
```

### File transfer callbacks

Be sure that you have [set up a delegate for callback events](/docs/video-sdk/ios/integrate/#implement-a-delegate) to receive file transfer callbacks.

Get notified when you transfer a file.

```swift
func onSendFileStatus(_ file: ZoomVideoSDKSendFile?, status: ZoomVideoSDKFileTransferStatus) {

}
```

Get notified when you receive a file from other users.

```swift
func onReceiveFileStatus(_ file: ZoomVideoSDKReceiveFile?, status: ZoomVideoSDKFileTransferStatus) {

}
```