Tracking specific events

As a Snowplow user, you have the access to a wide selection of event types and associated methods for tracking as well as the ability to define your own event types:

Function	Description
`track_page_view()`	Track views of web pages
`track_page_ping()`	Track engagement on web pages over time
`track_link_click()`	Track link clicks
`track_form_change()`	Track form changes
`track_form_submit()`	Track that a form was submitted
`track_site_search()`	Track when a user searches your site
`track_screen_view()`	Track screen views (non-web e.g. in-app)
`track_mobile_screen_view()`	Track mobile screen views
`track_ecommerce_transaction()`	Track ecommerce transaction
`track_ecommerce_transaction_item()`	Track an item of an ecommerce transaction
`track_add_to_cart()`	Track an add to cart event
`track_remove_from_cart()`	Track a remove from cart event
`track_struct_event()`	Track a Snowplow custom structured event
`track_self_describing_event()`	Track an event that you have defined yourself

Common tracking parameters

All events are tracked with specific methods on the tracker instance, of the form track_XXX(), where XXX is the name of the event to track. The parameters that are common for all track methods are:

context
tstamp
event_subject (**New to v0.9.0)

1. Custom context

Custom context can be used to augment any standard Snowplow event type, including self describing events, with additional data.

Custom context can be added as an extra argument to any of Snowplow’s track..() methods.

When you track an event, some of the data that you track will be specific to that event. A lot of the data you want to record, however, will describe entities that are tracked across multiple events. For example, a media company might want to track the following events:

User views video listing
User plays video
User pauses video
User shares video
User favorites video
User reviews video

Whilst each of those events is a different type, all of them involve capturing data about the user and the video. Both the 'user' and 'video' are entities that are tracked across multiple event types. Both are candidates to be "custom context". You as a Snowplow user can define your own custom contexts (including associated schemas) and then send data for as many custom contexts as you wish with any Snowplow event. So if you want, you can define your own "user context", and then send additional user data in that object with any event. Other examples of context include:

articles
videos
products
categories
pages / page_types
environments

Each tracking method accepts an additional optional context parameter after all the parameters specific to that method:

The context argument should consist of an array of one or more instances of SelfDescribingJson class. This class isomorphic to self-describing JSON, to be more precisely - it has Iglu URI attribute and data itself.

For example, if a server-side Python application can determine visitor's geoposition, this can be attached to the event, using the geolocation_context that is predefined on Iglu Central:

from snowplow_tracker import SelfDescribingJson

geo_context = SelfDescribingJson(
  "iglu:com.snowplowanalytics.snowplow/geolocation_context/jsonschema/1-0-0",
  {
    "latitude": -23.2,
    "longitude": 43.0
  }
)

As another example, if a visitor arrives on a page advertising a movie, the context object might look like this (movie_poster is custom context, not predefined):

poster_context = SelfDescribingJson(
  "iglu:com.acme_company/movie_poster/jsonschema/2-1-1",
  {
    "movie_name": "Solaris",
    "poster_country": "JP",
    "poster_year": "1978-01-01"
  }
)

This is how to fire a page view event with both above contexts:

t.track_page_view("http://www.films.com", "Homepage", context=[poster_context, geo_context])

Important: Even if only one custom context is being attached to an event, it still needs to be wrapped in an array.

Note also that you should not pass in an empty array of contexts as this will fail validation. Instead of an empty array, you can pass in None.

2. Timestamp argument

Each track...() method supports an optional timestamp as an argument. The timestamp should be in milliseconds since the Unix epoch, the same format as generated by time.time() * 1000 .

Generally, according to the Snowplow Tracker Protocol, every event tracked will be recorded with two timestamps:

the dvce_created_tstamp, which is the timestamp when the event was created
the dvce_sent_tstamp, which is the timestamp when the event was sent

These are going to be used downstream, to calculate the derived_tstamp for the event, which takes also into account the collector timestamp, in order to best approximate the exact time the event occured.

The optional timestamp argument is for the cases where you might want to set the event timestamp yourself. If this argument is not provided or set to None, then the Python Tracker will use the current time to be the dvce_created_tstamp for the event.

Here is an example tracking a structured event and supplying the optional timestamp argument. We can explicitly supply None for the intervening arguments which are empty:

t.track_struct_event("some cat", "save action", None, None, None, 1368725287000)

Alternatively, we can use the argument name:

t.track_struct_event("some cat", "save action", tstamp=1368725287000)

**Prior to v0.9.0

Before version 0.9.0 of the Python Tracker, providing a snowplow_tracker.timestamp.TrueTimestamp object as the timestamp argument will attach a true timestamp to the event, replacing the device timestamp. For example:

from snowplow_tracker.tracker import TrueTimestamp
t.track_struct_event("some cat", "save action", tstamp=TrueTimestamp(1368725287000))

Above will attach ttm(true_tstamp) parameter instead of default dtm. You can also use, plain integer, DeviceTimestamp or None to send device_sent_timestamp.

**New to v0.9.0

Since version 0.9.0, providing the optional timestamp argument will only set the true timestamp (true_tstamp) of the event. The type of this argument can only be the unix time in milliseconds. If you migrate from previous version, make sure to replace any references to Timestamp objects, since the Timestamp class (along with the TrueTimestamp and DeviceTimestamp subclasses) do not exist.

t.track_struct_event("some cat", "save action", tstamp=1368725287000)

3. Event subject (since v0.9.0)

Since version 0.9.0, it is possible to set the Subject per-event, in order to augment the event with extra information without having to change the Subject at the Tracker level. This provides a thread safe way to track multiple subjects.

This is supported as an optional keyword argument by all track methods. For example:

evSubject = Subject().set_user_id("1234")
t.track_page_view("www.example.com", event_subject=evSubject)

Tracker method return values

All tracker methods will return the tracker instance, allowing tracker methods to be chained:

e = AsyncEmitter("d3rkrsqld9gmqf.cloudfront.net")
t = Tracker(e)

t.track_page_view("http://www.example.com").track_screen_view("title screen")x

Track self-describing event

Use track_self_describing_event() to track an event types that you have defined yourself.

This method's arguments are:

Argument	Description	Required?	Type
`event_json`	The properties of the event	Yes	SelfDescribingJson
`context`	Custom context for the event	No	List(SelfDescribingJson)
`tstamp`	When the unstructured event occurred	No	Positive integer
`event_subject` (since v0.9.0)	The subject for the event	No	Subject

Example:

from snowplow_tracker import SelfDescribingJson

t.track_self_describing_event(SelfDescribingJson(
  "iglu:com.example_company/save-game/jsonschema/1-0-2",
  {
    "save_id": "4321",
    "level": 23,
    "difficultyLevel": "HARD",
    "dl_content": True
  }
))

The event_json is represented using the SelfDescribingJson class. It has two fields: schema and data. data is a dictionary containing the properties of the unstructured event. schema identifies the JSON schema against which data should be validated. This schema should be available in your Iglu schema registry and your Snowplow pipeline configured so that that that registry is included in your Iglu resolver.

For more on JSON schema, see the blog post.

Many Snowplow users use the above method to track all their events i.e. only record event types that they have defined. However, there are a number of "out of the box" events that have dedicated tracking methods. These are detailed below:

Track page view

Use track_page_view() to track a user viewing a page within your app or website. The arguments are:

Argument	Description	Required?	**Type**
`page_url`	The URL of the page	Yes	Non-empty string
`page_title`	The title of the page	No	String
`referrer`	The address which linked to the page	No	String
`context`	Custom context for the event	No	List(SelfDescribingJson)
`tstamp`	When the pageview occurred	No	Positive integer
`event_subject` (since v0.9.0)	The subject for the event	No	Subject

Example:

t.track_page_view("www.example.com", "example", "www.referrer.com")

Track page pings

Use track_page_ping() to track engagement with a web page over time, via a heartbeat event. (Each ping represents a single heartbeat.)

Arguments are:

Argument	Description	Required?	Type
`page_url`	The URL of the page	Yes	Non-empty string
`page_title`	The title of the page	No	String
`referrer`	The address which linked to the page	No	String
`min_x`	Minimum page X offset seen in the last ping period	No	Positive integer
`max_x`	Maximum page X offset seen in the last ping period	No	Positive integer
`min_y`	Minimum page Y offset seen in the last ping period	No	Positive integer
`max_y`	Maximum page Y offset seen in the last ping period	No	Positive integer
`context`	Custom context for the event	No	List(SelfDescribingJson)
`tstamp`	When the pageview occurred	No	Positive integer
`event_subject` (since v0.9.0)	The subject for the event	No	Subject

Example:

t.track_page_ping("http://mytesturl/test2", "Page title 2", "http://myreferrer.com", 0, 100, 0, 500, None)

Track screen view

Use track_mobile_screen_view() to track a user viewing a screen (or equivalent) within your app.

Argument	Description	Required?	Type
`id_`	Unique identifier for this screen (UUID)	No	string
`name`	Human-readable name for this screen	No	Non-empty string
`type`	The type of screen that was viewed e.g feed / carousel.	No	string
`previous_name`	The name of the previous screenview.	No	string
`previous_id`	The id of the previous screenview.	No	string
`previous_type`	The type of the previous screenview.	No	string
`transition_type`	The type of transition that led to the screen being viewed.	No	string
`context`	Custom context for the event	No	List(SelfDescribingJson)
`tstamp`	When the screen was viewed	No	Positive integer
`event_subject` (since v0.9.0)	The subject for the event	No	Subject

Example:

t.track_mobile_screen_view(id_="1368725287001", name="Profile Page", type="feed", previous_name="Home Page", previous_id="1368725287000", previous_type="feed")

note

Since v0.13.0 we recommend using track_mobile_screen_view() instead of the deprecated track_screen_view() method.

Track ecommerce transactions

Use track_ecommerce_transaction() to track an ecommerce transaction. Arguments:

Argument	Description	Required?	Type
`order_id`	ID of the eCommerce transaction	Yes	Non-empty string
`total_value`	Total transaction value	Yes	Int or Float
`affiliation`	Transaction affiliation	No	String
`tax_value`	Transaction tax value	No	Int or Float
`shipping`	Delivery cost charged	No	Int or Float
`city`	Delivery address city	No	String
`state`	Delivery address state	No	String
`country`	Delivery address country	No	String
`currency`	Transaction currency	No	String
`items`	Items in the transaction	Yes	List
`context`	Custom context for the event	No	List(SelfDescribingJson)
`tstamp`	When the transaction event occurred	No	Positive integer
`event_subject` (since v0.9.0)	The subject for the event	No	Subject

The items argument is an array of Python dictionaries representing the items in the transaction. track_ecommerce_transaction fires multiple events: one "transaction" event for the transaction as a whole, and one "transaction item" event for each element of the items array. Each transaction item event will have the same timestamp, order_id, currency (and event_subject, since v0.9.0) as the main transaction event.

These are the fields that can appear in a transaction item dictionary:

Field	Description	Required?	Type
`"sku"`	Item SKU	Yes	Non-empty string
`"price"`	Item price	Yes	Int or Float
`"quantity"`	Item quantity	Yes	Int
`"name"`	Item name	No	String
`"category"`	Item category	No	String
`"context"`	Custom context for the event	No	List

Example of tracking a transaction containing two items:

t.track_ecommerce_transaction("6a8078be", 35, city="London", currency="GBP", items=
    [{
        "sku": "pbz0026",
        "price": 20,
        "quantity": 1
    },
    {
        "sku": "pbz0038",
        "price": 15,
        "quantity": 1
    }])

Track ecommerce transaction items

Use track_ecommerce_transaction_item() to track an individual line item.

Arguments:

Argument	Description	Required?	Type
`id`	Order ID	Yes	Non-empty string
`sku`	Item SKU	Yes	Non-empty string
`price`	Item price	Yes	Int or Float
`quantity`	Item quantity	Yes	Int
`name`	Item name	No	String
`category`	Item category	No	String
`context`	Custom context for the event	No	List(SelfDescribingJson)
`tstamp`	When the transaction event occurred	No	Positive integer
`event_subject` (since v0.9.0)	The subject for the event	No	Subject

Example:

t.track_ecommerce_transaction_item("order-789", "2001", 49.99, 1, "Green shoes", "clothing")

Track structured events

Use track_struct_event() to track a custom event happening in your app which fits the Google Analytics-style structure of having up to five fields (with only the first two required):

Argument	Description	Required?	Type
`category`	The grouping of structured events which this `action` belongs to	Yes	Non-empty string
`action`	Defines the type of user interaction which this event involves	Yes	Non-empty string
`label`	A string to provide additional dimensions to the event data	No	String
`property`	A string describing the object or the action performed on it	No	String
`value`	A value to provide numerical data about the event	No	Int or Float
`context`	Custom context for the event	No	List(SelfDescribingJson)
`tstamp`	When the structured event occurred	No	Positive integer
`event_subject` (since v0.9.0)	The subject for the event	No	Subject

Example:

t.track_struct_event("shop", "add-to-basket", None, "pcs", 2)

Track link clicks

Use track_link_click() to track individual link click events. Arguments are:

Argument	Description	Required?	Type
`target_url`	The URL of the page	Yes	Non-empty string
`element_id`	ID attribute of the HTML element	No	String
`element_classes`	Classes of the HTML element	No	List(string)
`element_target`	Target element	No	String
`element_content`	The content of the HTML element	No	String
`context`	Custom context for the event	No	List(SelfDescribingJson)
`tstamp`	When the pageview occurred	No	Positive integer
`event_subject` (since v0.9.0)	The subject for the event	No	Subject

Basic example:

t.track_link_click("http://my-target-url2/path")

Advanced example:

t.track_link_click("http://my-target-url2/path", "element id 2", None, "element target", "element content")

Track add-to-cart events

Use track_add_to_cart() to track adding items to a cart on an ecommerce site. Arguments are:

Argument	Description	Required?	Type
`sku`	Item SKU or ID	Yes	Non-empty string
`quantity`	Number of items added to cart	Yes	Integer
`name`	Item's name	No	String
`category`	Item's category	No	String
`unit_price`	Item's price	No	Int or Float
`currency`	Currency	No	String
`context`	Custom context for the event	No	List(SelfDescribingJson)
`tstamp`	When the pageview occurred	No	Positive integer
`event_subject` (since v0.9.0)	The subject for the event	No	Subject

Example:

t.track_add_to_cart("123", 2, "The Devil's Dance", "Books", 23.99, "USD", None )

Track remove-from-cart events

Use track_remove_from_cart() to track removing items from a cart on an ecommerce site. Arguments are:

Argument	Description	Required?	Type
`sku`	Item SKU or ID	Yes	Non-empty string
`quantity`	Number of items added to cart	Yes	Integer
`name`	Item's name	No	String
`category`	Item's category	No	String
`unit_price`	Item's price	No	Int or Float
`currency`	Currency	No	String
`context`	Custom context for the event	No	List(SelfDescribingJson)
`tstamp`	When the pageview occurred	No	Positive integer
`event_subject` (since v0.9.0)	The subject for the event	No	Subject

Basic example:

t.track_remove_from_cart("123", 1)

Advanced example:

t.track_remove_from_cart("123", 2, "The Devil's Dance", "Books", 23.99, "USD")

Track form change

Use track_from_change() to track changes in website form inputs over session. Arguments are:

Argument	Description	Required?	Type
`form_id`	ID attribute of the HTML form	Yes	Non-empty string
`element_id`	ID attribute of the HTML element	Yes	String
`node_name`	Type of input element	Yes	Valid node_name
`value`	Value of input element	Yes	String
`type_`	Type of data the element represents	No	Non-empty string
`element_classes`	Classes of the HTML element	No	List(string)
`context`	Custom context for the event	No	List(SelfDescribingJson)
`tstamp`	When the pageview occurred	No	Positive integer
`event_subject` (since v0.9.0)	The subject for the event	No	Subject

Basic example:

t.track_form_change("signupForm", "ageInput", "age", "24")

Advanced example:

t.track_form_change("signupForm", "ageInput", "age", "24", "number", ["signup__number", "form__red"])

Track submitted forms

Use track_form_submit() to track sumbitted forms. Arguments are:

Argument	Description	Required?	Type
`form_id`	ID attribute of the HTML form	Yes	Non-empty string
`form_classes`	Classes of the HTML form	No	List(str)
`elements`	Value of input element	No	List(dict)
`context`	Custom context for the event	No	List(SelfDescribingJson)
`tstamp`	When the pageview occurred	No	Positive integer
`event_subject` (since v0.9.0)	The subject for the event	No	Subject

Basic example:

t.track_form_submit("registrationForm")

Advanced example:

t.track_form_submit("signupForm", ["signup__warning"], {"name": "email", "value": "tracker@example.com", "nodeName": "INPUT", "type": "email"})

Track site searches

Use track_site_search() to track a what user searches on your website. Arguments are:

Argument	Description	Required?	Type
`terms`	Search terms	Yes	List(str)
`filters`	Filters applied to search	No	List(dict{str:str
`total_results`	Total number of results	No	Integer
`page_results`	Number of pages of results	No	Integer
`context`	Custom context for the event	No	List(SelfDescribingJson)
`tstamp`	When the pageview occurred	No	Positive integer
`event_subject` (since v0.9.0)	The subject for the event	No	Subject

Basic example:

t.track_site_search(["analytics", "snowplow", "tracker"])

Advanced example:

t.track_site_search(["pulp fiction", "reviews"], {"nswf": true}, 215, 22)

`truck_unstruct_event`

This functionally is equivalent to track_self_describing_event. We believe that the method name is misleading: this method is used to track events that are structured in nature (they have an associated schema), which is why we believe referring to them as self-describing events makes more sense than referring to them as unstructured events.

The method is provided for reasons of backwards compatibility.

Common tracking parameters​

1. Custom context​

2. Timestamp argument​

3. Event subject (since v0.9.0)​

Tracker method return values​

Track self-describing event​

Track page view​

Track page pings​

Track screen view​

Track ecommerce transactions​

Track ecommerce transaction items​

Track structured events​

Track link clicks​

Track add-to-cart events​

Track remove-from-cart events​

Track form change​

Track submitted forms​

Track site searches​

truck_unstruct_event​

Common tracking parameters

1. Custom context

2. Timestamp argument

3. Event subject (since v0.9.0)

Tracker method return values

Track self-describing event

Track page view

Track page pings

Track screen view

Track ecommerce transactions

Track ecommerce transaction items

Track structured events

Track link clicks

Track add-to-cart events

Track remove-from-cart events

Track form change

Track submitted forms

Track site searches

`truck_unstruct_event`