Join Session

Join a call session using one of two approaches: the quick start method with a session ID, or the advanced flow with manual token generation for more control.

Overview

The CometChat Calls SDK provides two ways to join a session:

Approach	Best For	Complexity
Join with Session ID	Most use cases - simple and straightforward	Low - One method call
Join with Token	Custom token management, pre-generation, caching	Medium - Two-step process

Both approaches require a container view in your layout and properly configured SessionSettings.

Container Setup

Create a container view where the call interface will be rendered. This can be done in your storyboard or programmatically:

Swift
Storyboard

// Programmatically
let callViewContainer = UIView()
callViewContainer.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(callViewContainer)

NSLayoutConstraint.activate([
    callViewContainer.topAnchor.constraint(equalTo: view.topAnchor),
    callViewContainer.bottomAnchor.constraint(equalTo: view.bottomAnchor),
    callViewContainer.leadingAnchor.constraint(equalTo: view.leadingAnchor),
    callViewContainer.trailingAnchor.constraint(equalTo: view.trailingAnchor)
])

Add a UIView to your view controller and create an @IBOutlet:

@IBOutlet weak var callViewContainer: UIView!

The call UI will be dynamically added to this container when you join the session.

Join with Session ID

The simplest way to join a session. Pass a session ID and the SDK automatically generates the token and joins the call.

let sessionId = "SESSION_ID"

let sessionSettings = CometChatCalls.sessionSettingsBuilder
    .setDisplayName("John Doe")
    .setSessionType(.video)
    .build()

CometChatCalls.joinSession(
    sessionID: sessionId,
    callSetting: sessionSettings,
    container: callViewContainer,
    onSuccess: { message in
        print("Joined session successfully")
    },
    onError: { error in
        print("Failed: \(error?.errorDescription ?? "")")
    }
)

Parameter	Type	Description
`sessionID`	String	Unique identifier for the call session
`callSetting`	SessionSettings	Configuration for the session
`container`	UIView	Container view for the call UI
`onSuccess`	Closure	Closure called on successful join
`onError`	Closure	Closure called on failure

All participants joining the same call must use the same session ID.

Join with Token

For scenarios requiring more control over token generation, such as pre-generating tokens, implementing custom caching strategies, or managing token lifecycle separately. Step 1: Generate Token Generate a call token for the session. Each token is unique to a specific session and user combination.

let sessionId = "SESSION_ID"

CometChatCalls.generateToken(sessionID: sessionId, onSuccess: { token in
    print("Token generated: \(token ?? "")")
    // Store or use the token
}, onError: { error in
    print("Token generation failed: \(error?.errorDescription ?? "")")
})

Parameter	Type	Description
`sessionID`	String	Unique identifier for the call session
`onSuccess`	Closure	Closure returning the generated token string
`onError`	Closure	Closure called on failure

Step 2: Join with Token Use the generated token to join the session. This gives you control over when and how the token is used.

let sessionSettings = CometChatCalls.sessionSettingsBuilder
    .setDisplayName("John Doe")
    .setSessionType(.video)
    .build()

// Use the previously generated token
CometChatCalls.joinSession(
    callToken: generatedToken,
    callSetting: sessionSettings,
    container: callViewContainer,
    onSuccess: { message in
        print("Joined session successfully")
    },
    onError: { error in
        print("Failed: \(error?.errorDescription ?? "")")
    }
)

Parameter	Type	Description
`callToken`	String	Previously generated token string
`callSetting`	SessionSettings	Configuration for the session
`container`	UIView	Container view for the call UI
`onSuccess`	Closure	Closure called on successful join
`onError`	Closure	Closure called on failure

Complete Example

let sessionId = "SESSION_ID"

// Step 1: Generate token
CometChatCalls.generateToken(sessionID: sessionId, onSuccess: { [weak self] token in
    guard let self = self, let token = token else { return }
    
    // Step 2: Join with token
    let sessionSettings = CometChatCalls.sessionSettingsBuilder
        .setDisplayName("John Doe")
        .setSessionType(.video)
        .build()

    CometChatCalls.joinSession(
        callToken: token,
        callSetting: sessionSettings,
        container: self.callViewContainer,
        onSuccess: { message in
            print("Joined session successfully")
        },
        onError: { error in
            print("Failed to join: \(error?.errorDescription ?? "")")
        }
    )
}, onError: { error in
    print("Token generation failed: \(error?.errorDescription ?? "")")
})

Error Handling

Common errors when joining a session:

Error Code	Description
`INIT ERROR`	SDK not initialized - call `init()` first
`AUTH TOKEN ERROR`	User not logged in or auth token invalid
`SESSION ID ERROR`	Session ID is null or empty
`API ERROR`	Invalid call token or API error

Overview

Getting Started

Call Session

Features

Advanced

Migration Guide

Resources

Overview

Container Setup

Join with Session ID

Join with Token

Error Handling

​Overview

​Container Setup

​Join with Session ID

​Join with Token

​Error Handling

Overview

Container Setup

Join with Session ID

Join with Token

Error Handling