Events

Batch allows you to track events that happen in your application. They automatically keep track of their count, the last time it happened and their value.

Important
- Please read our guide on custom data before tagging your app.
- Newly tracked events are hidden by default. You will need to manually display them from the dashboard settings > "Custom data" tab.

Tracking events

Events are easy to use, but have some rules:

• Event names are strings. They should be made of letters, numbers or underscores ([a-z0-9_]) and can't be longer than 30 characters.
• A custom data object can be attached. See the section "Event Attributes", right under this one.
• Custom attributes have some reserved keys. See the section "Reserved event attributes" under "Event Attributes" for more info.

Here are some examples:

// Simple event
BatchProfile.trackEvent(name: "ad_seen")

// Event with custom attributes
BatchProfile.trackEvent(name: "add_to_cart", attributes: BatchEventAttributes { data in
  // Custom attribute
  data.put("sub_category", forKey: "nickname")
  // Compatibility reserved key
  data.put("$label", forKey: "activity")
 })

Important
Please test your implementation using our debug tool and profile view before releasing your app on the store.

Event attributes

Custom attributes can be attached to events using BatchEventAttributes. You will then use them when calling BatchProfile.trackEvent().

Attribute name

They should be made of letters, numbers or underscores ([a-z0-9_]) and can't be longer than 30 characters (e.g. has_premium). They will be automatically lowercased, so trying to use the same key with different casing will overwrite the previously set value.

Attribute value

Values must be any of the following types:

• NSString, must not be longer than 200 characters and can't be empty. For better results, you should make them upper/lowercase and trim the whitespaces.
• Bool
• Floats/Doubles
• NSInteger
• NSDate
• NSURL, not longer than 2048 characters and must follow the format scheme://[authority][path][?query][#fragment].
• NSArray<NSString | BatchEventAttributes>, You can set array of strings (max 200chars) and array of objects. Max 25 items. You cannot mix several attribute types in one array. Arrays can't be nested.
• Object (using BatchEventAttributes, Objects cannot have more than 3 levels of nesting.

Note: Setting a value for an existing key will overwrite it. Any attempt to add an invalid attribute will fail and the event will NOT be tracked. You can use the validateWithError method which return a list of human-readable errors to ensure your event is valid before sending it.

Reserved event attributes

Some event attributes have reserved keys, and are all prefixed by a $ sign. This is the list of currently reserved event attributes. You cannot set an event attribute starting by a $ sign.

In Batch SDK v1 you were able to set a label and tags at the root of an event, with the limit of 1 label and 10 tags.

Batch SDK v2 introduced Object and Array types in event attributes. You can set more than one array on profiles events. This is only supported for profiles, and not on the install-centric data model, which currently powers push notification and In-App messages.

However, it's still possible to set a label and tags on events in the install-centric data model by using $label and $tags, and activate compatibility flows. This way, you will be able to use this data for your push and in-app communications.

Example

let attributes = BatchEventAttributes { data in
    data.put("man_clothes", forKey: "sub_category")
    data.put(Date(timeIntervalSince1970: 1713432899086), forKey: "end_of_sale_date")
    data.put([
        BatchEventAttributes { itemData in
            itemData.put("Basic Tee", forKey: "name")
            itemData.put("M", forKey: "size")
            itemData.put(23.99, forKey: "price")
            itemData.put(URL(string: "https://batch-store.com/basic-tee")!, forKey: "item_url")
            itemData.put(URL(string: "https://batch-store.com/basic-tee/black/image.png")!, forKey: "item_image")
            itemData.put(true, forKey: "in_sales")
        },
        BatchEventAttributes { itemData in
            itemData.put("Short socks pack x3", forKey: "name")
            itemData.put("38-40", forKey: "size")
            itemData.put(15.99, forKey: "price")
            itemData.put(URL(string: "https://batch-store.com/short-socks-pack-x3")!, forKey: "item_url")
            itemData.put(URL(string: "https://batch-store.com/short-socks-pack-x3/image.png")!, forKey: "item_image")
            itemData.put(false, forKey: "in_sales")
        }
    ], forKey: "items_list")
    data.put("accessories", forKey: "$label")
    data.put(["first_purchase", "in_promo"], forKey: "$tags")
}
do {
    let _ = try attributes.validate()
    BatchProfile.trackEvent(name: "purchased", attributes: attributes)
} catch let error {
    print("Event validation error: \(error.localizedDescription)")
}

Tracking user location

You can now natively track a user location. This uses CoreLocation's standard CLLocation object, which you usually get from the CoreLocation itself. You can also instanciate one manually from a latitude/longitude.

Here's an example:

// let location: CLLocation = [...]
BatchUser.trackLocation(location)

This data will allow you to send geo-targeted push notifications from the dashboard or the Campaigns API.

The SDK will throttle location tracking to optimize network and battery usage. You can track one location event every 30 seconds, any attempt at updating the location sooner will be ignored by the SDK.

Background events

Events can be sent while the application is in the background by asking UIApplication to begin a background task. Once the event has been sent to the server, Batch will emit a BatchEventTrackerFinishedNotification NSNotification.

Please note that this notification might be sent multiple times: you may want to dynamically add the observer and remove it once your event has been tracked.

Here is a sample implementation:

@objc
class BackgroundEventSender : NSObject {
    var eventBackgroundEventTaskID: UIBackgroundTaskIdentifier?
    
    override init() {
        super.init()
        NotificationCenter.default.addObserver(self, selector: #selector(finishBackgroundTask), name: Notification.Name.BatchEventTrackerFinished, object: nil)
    }
    
    func trackBackgroundEvent() {
        guard eventBackgroundEventTaskID == nil else {
            // This sample code doesn't support tracking multiple events at once
            return
        }
        
        eventBackgroundEventTaskID = UIApplication.shared.beginBackgroundTask(withName: "batch_background_event", expirationHandler: self.finishBackgroundTask)
        
        BatchUser.trackEvent("SAMPLE_BACKGROUND_EVENT")
    }
    
    @objc
    func finishBackgroundTask() {
        guard let task = eventBackgroundEventTaskID else {
            return
        }
        self.eventBackgroundEventTaskID = nil
        UIApplication.shared.endBackgroundTask(task)
    }
}