For both open and group channels, users can send messages of the following types to the channel they are in.
A text message sent by a user.
A binary file message sent by a user.
In addition to these message types, you can further subclassify a message by specifying its custom type. This custom type takes on the form of
String and can be used to search or filter messages. It allows you to append information to your message and customize message categorization.
The following code shows several types of parameters that you can configure to customize text messages by using
UserMessageCreateParams. Under the
UserMessageCreateParams object, you can assign values to
data, and other properties. By assigning arbitrary string to the
data property, you can set custom font size, font type or
JSON object. To send your messages, you need to pass the
UserMessageCreateParams object as an argument to the parameter in the
completionHandler parameter of the
sendUserMessage(params:completionHandler:) method, the Sendbird server always notifies whether your message has been successfully sent to the channel. When there is a delivery failure due to network issues, an exception is returned through the callback method.
A user can also send binary files through the Chat SDK. The two ways to send a binary file are: sending the file itself, or sending a URL.
Sending a raw file means you're uploading it to the Sendbird server where it can be downloaded on client apps. When you upload a file directly to the server, there is a size limit imposed on the file depending on your plan. You can see the limit on your dashboard and contact our sales team to change the limit.
The other option is to send a file hosted on your server. You can pass the file's URL, which represents its location, as an argument to a parameter. In this case, your file is not hosted on the Sendbird server and it can only be downloaded from your own server. When you send a file message with a URL, there is no limit on the file size since it isn't directly uploaded to the Sendbird server.
Note: You can use
sendFileMessages(params:progressHandler:sentMessageHandler:completionHandler:), which is another method that allows you to send up to 20 file messages per one method call. Refer to our API Reference to learn more.
The following code shows several types of parameters that you can configure to customize your file messages by using
FileMessageCreateParams. Under the
FileMessageCreateParams object, you can assign specific values to
customType, and other properties. To send your messages, you need to pass the
FileMessageCreateParams object as an argument to the parameter in the
completionHandler parameter of the
sendFileMessage(params:completionHandler:) method, the Sendbird server always notifies whether your message has been successfully sent to the channel. When there is a delivery failure due to network issues, an exception is returned through the callback method.
If your app goes to the background while uploading a file such as a profile image or picture, the app can complete the upload process using the
application(_:handleEventsForBackgroundURLSession:completionHandler:) method in your
AppDelegate. To complete a file upload in progress in the background, a background event delegate should be added and implemented in
AppDelegate. If you don't want to upload a file while the app is in the background, remove the following delegation in