Initialize and configure the Flutter tracker

The package provides a single method to initialize and configure a new tracker, the Snowplow.createTracker method. It accepts configuration parameters for the tracker and returns a SnowplowTracker instance.

dart

SnowplowTracker tracker = await Snowplow.createTracker(
    namespace: 'ns1',
    endpoint: 'http://...',
    trackerConfig: const TrackerConfiguration(...),
    gdprConfig: const GdprConfiguration(...),
    subjectConfig: const SubjectConfiguration(...));
);

The method returns a SnowplowTracker instance. This can be later used for tracking events, or accessing tracker properties. However, all methods provided by the SnowplowTracker instance are also available as static functions in the Snowplow class but they require passing the tracker namespace as string.

The only required attributes of the Snowplow.createTracker method are namespace used to identify the tracker, and the Snowplow collector endpoint. Additionally, one can configure the HTTP method to be used when sending events to the collector, as well as a custom POST path, and provide configuration by instantiating classes for TrackerConfiguration, SubjectConfiguration, or GdprConfiguration. By default, events are sent by POST. The following arguments are accepted by the Snowplow.createTracker method:

Attribute	Type	Description
namespace	String	Tracker namespace to identify the tracker.
endpoint	String	URI for the Snowplow collector endpoint.
method	Method?	HTTP method to use: Method.get or Method.post (Method.post is default).
customPostPath	String?	Custom POST path.
requestHeaders	Map<String, String>?	Map of custom HTTP headers to add to requests to the collector.
trackerConfig	TrackerConfiguration?	Configuration of the tracker and the core tracker properties.
gdprConfig	GdprConfiguration?	Determines the GDPR context that will be attached to all events sent by the tracker.
subjectConfig	SubjectConfiguration?	Subject information about tracked user and device that is added to events.
emitterConfig	EmitterConfiguration?	Configuration for how the events are sent.
globalContextsConfig	GlobalContextsConfiguration?	Configuration of global context entities attached to all events.
sessionConfig	SessionConfiguration?	Configuration of session timeouts. See session tracking.

note

The ability to set customPostPath was added in v0.2.0. Setting a custom POST path can be useful in avoiding adblockers; it replaces the default "com.snowplowanalytics/snowplow/tp2". Your event collector must also be configured to accept the custom path.

note

The EmitterConfiguration class was added in v0.3.0.

Version support

The GlobalContextsConfiguration class was added in 0.9.0.

Version support

The SessionConfiguration class was added in 0.11.1.

Configuration of tracker properties: TrackerConfiguration

TrackerConfiguration provides options to configure properties and features of the tracker. In addition to setting the app identifier and device platform, the configuration enables turning several automatic context entities on and off.

Attribute	Type	Description	Android	iOS	Web	Default
appId	String?	Identifier of the app.	✔	✔	✔	null on Web, bundle identifier on iOS/Android
devicePlatform	DevicePlatform?	The device platform the tracker runs on. Available options are provided by the DevicePlatform enum.	✔	✔	✔	"web" on Web, "mob" on iOS/Android
base64Encoding	bool?	Indicates whether payload JSON data should be base64 encoded.	✔	✔	✔	true
platformContext	bool?	Indicates whether platform (mobile) entity should be attached to tracked events.	✔	✔		true
geoLocationContext	bool?	Indicates whether geo-location entity should be attached to tracked events.	✔	✔	✔	false
sessionContext	bool?	Indicates whether session entity should be attached to tracked events.	✔	✔	✔	true
webPageContext	bool?	Indicates whether a context entity about current web page should be attached to tracked events.			✔	true
screenContext	bool?	Indicates whether screen entity should be attached to tracked events.	✔	✔		true
applicationContext	bool?	Indicates whether application entity should be attached to tracked events.	✔	✔		true
webActivityTracking	WebActivityTracking?	Enables activity tracking using page views and pings on the Web.			✔	true
userAnonymisation	bool?	Anonymizes certain user identifiers.	✔	✔	✔	false
lifecycleAutotracking	bool?	Indicates whether the lifecycle entity and foreground and background events should be autotracked.	✔	✔		true
screenEngagementAutotracking	bool?	Indicates whether to enable tracking of the screen end event and the screen summary context entity.	✔	✔		true
installAutotracking	bool?	Indicates whether to track an application install event.	✔	✔		false
platformContextProperties	PlatformContextProperties?	Overrides for the values for properties of the platform context entity.	✔	✔		null

note

The ability to enable userAnonymisation, or the screen and application context entities, was added in v0.3.0.

note

The ability to enable lifecycleAutotracking was added in v0.5.0.

Version support

The ability to enable installAutotracking was added in version 0.11.1.

The optional WebActivityTracking property configures page tracking on Web. Initializing the configuration will inform SnowplowObserver observers (see section on auto-tracking in "Tracking events") to auto track PageViewEvent events instead of ScreenView events on navigation changes. Further, setting the minimumVisitLength and heartbeatDelay properties of the WebActivityTracking instance will enable activity tracking using 'page ping' events on Web.

Activity tracking monitors whether a user continues to engage with a page over time, and record how they digest content on the page over time. That is accomplished using 'page ping' events. If activity tracking is enabled, the web page is monitored to see if a user is engaging with it. (E.g. is the tab in focus, does the mouse move over the page, does the user scroll etc.) If any of these things occur in a set period of time (minimumVisitLength seconds from page load and every heartbeatDelay seconds after that), a page ping event fires, and records the maximum scroll left / right and up / down in the last ping period. If there is no activity in the page (e.g. because the user is on a different browser tab), no page ping fires.

Lifecycle autotracking is only available on mobile apps (iOS and Android). When configured (it is enabled by default), a Lifecycle context entity is attached to all events. It records whether the app was visible or not when the event was tracked. In addition, a Background event will be tracked when the app is moved to background, and a Foreground event when the app moves back to foreground (becomes visible on the screen).

Screen engagement autotracking is also only available on mobile apps (iOS and Android). When configured (it is enabled by default), a screen summary context entity will be tracked along with screen end, foreground and background events. Make sure that you have lifecycle autotracking enabled for screen summary to have complete information.

Install autotracking is also only available on mobile apps (iOS and Android), and is disabled by default in the Flutter tracker. When enabled, the tracker sends an application install event once per device, the first time a tracker is created with the option enabled.

dart

SnowplowTracker tracker = await Snowplow.createTracker(
    namespace: 'ns1',
    endpoint: 'http://...',
    trackerConfig: const TrackerConfiguration(installAutotracking: true));

Enabling install tracking in a released app

The tracker only records that the install event was sent while installAutotracking is enabled. If you enable it in an app version that is already released, each existing user sends one install event the first time they open the updated app. Account for this in any install metrics around the rollout.

See this page for information about anonymous tracking.

Configuration of emitter properties: EmitterConfiguration

The EmitterConfiguration class was added in version 0.3.0. It configures how the tracker sends events and how long it keeps events that it couldn't send yet.

Attribute	Type	Description	Android	iOS	Web	Default
serverAnonymisation	bool?	Prevents tracking of server-side user identifiers.	✔	✔	✔	false
maxEventStoreSize	int?	Maximum number of unsent events to keep in the event store.	✔	✔		1000
maxEventStoreAge	Duration?	Maximum time to keep unsent events in the event store, in whole seconds.	✔	✔		30 days

Version support

The maxEventStoreSize and maxEventStoreAge options were added in version 0.11.1.

On iOS and Android, the tracker stores events in a local database until the collector accepts them. When the device is offline for a long time, for example on poor connectivity, the stored events accumulate. The event store limits control how many of them the tracker keeps, and for how long.

Before each attempt to send events, the tracker removes events older than maxEventStoreAge. If more than maxEventStoreSize events remain, it removes the oldest ones until the number is under the limit.

dart

SnowplowTracker tracker = await Snowplow.createTracker(
    namespace: 'ns1',
    endpoint: 'http://...',
    emitterConfig: const EmitterConfiguration(
        maxEventStoreSize: 5000,
        maxEventStoreAge: Duration(days: 7)));

maxEventStoreSize must be greater than 0, and maxEventStoreAge must be at least 1 second. The tracker throws an ArgumentError for smaller values, since they would remove all unsent events. On Web, the JavaScript tracker keeps its own event queue and the event store limits have no effect.

Configuration of subject information: SubjectConfiguration

Subject information are persistent and global information about the tracked device or user. They apply to all events and are assigned as event properties.

Some of the properties are only configurable on iOS and Android and are automatically assigned on the Web.

Attribute	Type	Description	Android	iOS	Web	Default
userId	String?	Business ID of the user.	✔	✔	✔
networkUserId	String?	Network user ID (UUIDv4).	✔	✔	Non-configurable, auto-assigned.
domainUserId	String?	Domain user ID (UUIDv4).	✔	✔	Non-configurable, auto-assigned.
userAgent	String?	Custom user-agent. It overrides the user-agent used by default.	✔	✔	Non-configurable, auto-assigned.
ipAddress	String?	IP address.	✔	✔	Non-configurable, auto-assigned.
timezone	String?	The timezone label.	✔	✔	Non-configurable, auto-assigned.
language	String?	The language set on the device.	✔	✔	Non-configurable, auto-assigned.
screenResolution	Size?	The screen resolution on the device.	✔	✔	Non-configurable, auto-assigned.
screenViewport	Size?	The screen viewport.	✔	✔	Non-configurable, auto-assigned.
colorDepth	double?	The color depth.	✔	✔	Non-configurable, auto-assigned.

The configured attributes are mapped to Snowplow event properties described in the Snowplow Tracker Protocol. They are mapped as follows:

Attribute	Event Property
userId	uid
networkUserId	network_userid
domainUserId	domain_userid
userAgent	useragent
ipAddress	user_ipaddress
timezone	os_timezone
language	lang
screenResolution.width	dvce_screenwidth
screenResolution.height	dvce_screenheight
screenViewport.width	br_viewwidth
screenViewport.height	br_viewheight
colorDepth	br_colordepth

GDPR context entity configuration: GdprConfiguration

Determines the GDPR context that will be attached to all events sent by the tracker.

Attribute	Type	Description	Android	iOS	Web	Default
basisForProcessing	String	Basis for processing.	✔	✔	✔
documentId	String	ID of a GDPR basis document.	✔	✔	✔
documentVersion	String	Version of the document.	✔	✔	✔
documentDescription	String	Description of the document.	✔	✔	✔

Global context configuration: GlobalContextsConfiguration

Configures global context entities to attach to all events. Unlike per-event context entities, global context entities are sent with every event without needing to specify them on individual track() calls.

Attribute	Type	Description	Android	iOS	Web	Default
contexts	List<SelfDescribing>	List of context entities to attach to all tracked events.	✔	✔	✔	empty

See the Global context page for detailed information on configuring global contexts at initialization time and managing them dynamically at runtime.