Feature branch: new session logic + outcomes #624

itrush · 2020-04-08T19:36:45Z

Session logic refactoring for web sdk

Motivation

Previously we were tracking sessions per tab, i.e. every new open tab was counted as a new session while page refresh was not even if page was left open in the background for a long time.

New way of session tracking should be much more similar to Android SDK and be more logical from user perspective:

it will track the session across tabs/windows
it can track how much time user spends on a site
it should allow adding time triggers later based on time spent on a page

Implementation

The refactored session tracking heavily relies on service workers (SW). Previously all api calls were performed from the page which made them somewhat fragile to page refreshes. The new approach moves api calls related to session tracking into the service worker.

Chrome and Firefox

For these browsers we already utilize SW since they are used for push notifications. It means there was no change needed to install SW as part of initialization flow. The main changes are in setting up additional messaging between page and SW to track session related events, with different handling of HTTPS and HTTP setups.
HTTP setup is implemented using the subscription workaround where we add an iframe pointing to a custom HTTPS OneSignal (OS) subdomain and install SW there. Page can talk to iframe, iframe talks to its SW and back.

Safari

Safari does not use SW for push but they became supported a few versions ago so we'll be installing SW on Safari for HTTPS sites (SW are not allowed for HTTP sites). For pure HTTP sites SW is not allowed at all so session is reported the old way on the first page load for a new tab/window.

General flow

When user is not subscribed, session is not tracked.
When user is subscribed
- and opens the page for the first time, page notifies SW to start a new session. SW creates a new session object and saves it in IndexedDb then sends an api call to on_session api endpoint to notify OneSignal.
- when page becomes out of focus (blur event) or is hidden (visibilitychange event) or page is closed (beforeunload event), page notifies SW of session change
- when page becomes focused (focus event) or becomes visible after being hidden (visibilitychange event), page notifies SW of session change
- when SW gets a message about possible session change, it sets up a debounce for session refresh function. Debounce can help with situations when multiple events are incoming, e.g. 2 tabs are open pointing to the pages on the same origin and user switches between them, multiple tabs are closed when browser closes, etc.
- session refresh logic queries the focused state of all controlled pages and decides whether to mark session as active or inactive
- if session stays inactive for longer than 30 seconds, SW finalized the session (reports it to OS api to on_focus endpoint and cleans it up from IndexedDb)
When user unsubscribes, page notifies SW of session change

Outcomes

Motivation

Outcomes is a feature recently introduced in OneSignal dashboard and currently supported by ios and android only. This PR adds outcomes support to Web SDK.

General flow

Browser tracks all incoming notifications saving them to local db table with timestamps.
Browser tracks all clicked notifications. If a clicked notification results in a new session to be created, it's considered direct.
Each app can configure its own attribution window for outcomes. I believe the default is now 1 hour. If a new session is created within that time frame since getting a notif, the session is considered indirectly attributed to 1 or more notifications.
If session is not directly attributed and there are no notifications within outcomes attribution time frame, session is considered unattributed.
Session reports both attribution and duration of the session which is translated into weighted outcome.
Same logic applies to custom outcomes. The only difference is that they have to be triggered by user's code via OneSignal.sendOutcome(value, optional_value). The attribution is decided the same way as described above.

New session logic and outcomes implementation heavily rely on service worker (SW) and having push as part of SW so it's best supported by browsers that implemented push via SW events.

Safari's way of handling push makes it impossible to track direct and indirect outcomes making all of them to be unattributed.

This branch also includes improvements and bug fixes for session logic that became obvious during testing.

This change is

…s in config

Added types for DeviceRecord serialization.

instead of direct api calls from the page

1. Perform validation for all required params to be present 2. If no session exists, create a new one with current moment as its start 3. If there is an existing session 3.1. check if it's already active, theoretically should never get to this point and should be safe to continue with no extra action; 3.2. for inactive session we verify when it was last marked as inactive. if it's been less than THRESHOLD seconds, mark as active 3.3. last case should not occur often, it should cover the case if we failed to report it on the previous attempt. May need extra thought.

1. If there is no existing session, invalid use case -> early return 2. If the session is already in inactive state -> invalid use case -> early return 3. Otherwise - mark as inactive - calculate total session time since last activated - update the record in the database - set up timeout to report session to on_focus and cleanup

It tracks switching to a different tab, fully covering page with another window, screen lock/unlock.

Don't have much time when tab is closing, skipping device record and directly notify SW for https. Does not include http support yet. Had to change SessionPayload interface to reflect optional device record fields.

Don't add focus and blur when page's visibility is hidden, i.e. rendered in background. As soon as becomes visible, set both blur and focus. If becomes hidden again, clear out event listeners. Done so to avoid double-firing of session events.

or deactivate the session. Currently done for https only. Http support to follow. Unfortunately, safari is special and would not give the correct focused status for its pages to the service worker as chrome does. Had to work around it with a messaging to the page: 1. sending a request to all active pages to return their focused states 2. setting a timeout of 500ms to wait for responses 3. added a handler on the page and in SW to react to the new events 4. after timeout goes off, check current clientsStatus in SW to trigger session update

to account for multiple session update requests, e.g. - closing several tabs fast - switching between tabs

It had wrong assumption about payload structure.

1. Including push token on service worker side if missing 2. Implementing or rather skipping implementation on page for getting push token.

and not using subscription workaround and first page view

Had to introduce an interface for SessionManager and use it in context instead of actual classed. By doing this each type of context can rely on its specific implementation while still complying with general interface.

when cancel happens.

regardless of notificationOpensLink flag value.

to not use page Context

in order not to break tests

until we finish splitting all managers clearly for page and sw

if sw got killed before carrying out finalize

itrush added 30 commits April 8, 2020 12:26

Defining the model and base operations for new session table in index db

91efd0f

Rename SessionManager into PageViewManager

f133d32

Minor refactoring to give a descriptive name to the function

bd9f9e2

Adding support for sessionThreshold and enableSessionDuration setting…

b633cb0

…s in config

Added origin header for CORS requests

91ae84a

Adding a new field on OneSignal for local memory cache

6990e9a

Updated TestEnvironment config with new properties

7b43c33

Moved createDeviceRecord out of UpdateManager into a helper.

a8fee9c

Added types for DeviceRecord serialization.

New session initialization logic

5d0f81d

Added SessionOrigin metadata to request payload

28cd422

New commands for worker messenger for session updates

4309cdf

ServiceWorkerHelper: upsert and deactivate session placeholders

958488e

ServiceWorker: placeholder handlers for new upsert and deactivate event

a6d120c

Added SessionManager class and plugged it into contexts

51f7556

SessionManager: initial implementation of session tracking logic

b24c6dc

Switching to use SessionManager for session updates

6c7ba5b

instead of direct api calls from the page

Added on_session call to SW api client

e8441b0

Refactored SW.getActiveClients with better types

6f437b3

Added page event for visibility change.

46806ff

It tracks switching to a different tab, fully covering page with another window, screen lock/unlock.

Moved code for SW messaging into a separate function to reuse

7df5fd8

Added before unload event handler for session tracking.

bf613de

Don't have much time when tab is closing, skipping device record and directly notify SW for https. Does not include http support yet. Had to change SessionPayload interface to reflect optional device record fields.

Added blur and focus event handlers

2bed05b

Don't add focus and blur when page's visibility is hidden, i.e. rendered in background. As soon as becomes visible, set both blur and focus. If becomes hidden again, clear out event listeners. Done so to avoid double-firing of session events.

Installing SW on safari

b1b1902

on_focus api call implementation in api client for SW

a68b7f5

Reporting session duration to OS public api -> on_focus

8dc041f

Added debounce logic for session refresh in Service Worker

fc88220

to account for multiple session update requests, e.g. - closing several tabs fast - switching between tabs

HTTP Support: setting up visibility events on the host page

6ff97b6

itrush added 28 commits April 8, 2020 12:26

Fixed PageVisibility request in Safari

2b6a034

It had wrong assumption about payload structure.

Fixing http flow

0b0d70e

1. Including push token on service worker side if missing 2. Implementing or rather skipping implementation on page for getting push token.

Fixed Database.getAll for http integration

38ab80f

Installing SW on safari https

7f64d15

Changing initialization order to expose environmentInfo in context

2311d3f

Send old-school on_session from page if SW not supported

79ed316

and not using subscription workaround and first page view

Not setting up SW session related events if no SW possible

8338629

Exposing custom link in the web page

19208d7

Removed accidentally left console.log's

268b8ab

Cleaned up TODO messages

a97bfd3

Updated server config to match outcomes on android

9c5894e

Fixed linter issue with SessionManager in Context file

e1ac6ec

Had to introduce an interface for SessionManager and use it in context instead of actual classed. By doing this each type of context can rely on its specific implementation while still complying with general interface.

Bump up version of IndexedDb

56ce4ef

Swapping reject to resolve for cancelable timeout

a5efb8b

when cancel happens.

PR Feedback: Always saving clicked notification to local db

4930b22

regardless of notificationOpensLink flag value.

Using const instead of var in IndexedDb

a2e67e7

One more var -> const and deleted unused function

1413349

Upgrade session to direct if notif clicked when out of focus

3814f85

Fixed linter errors in tests

67e38a3

Fixing tests that supposed to run in SW context

a2f1d68

to not use page Context

Initializing OneSignal.environmentInfo as part of TestEnvironment

dde9cb2

Updated import of cancelableTimeout module to relative

ca9cbfc

in order not to break tests

Fixed ServiceWorkerManager test that is relying on presence of envInfo

48b099f

Have to keep envInfo in context as optional

0a0b0ca

until we finish splitting all managers clearly for page and sw

Bumping up max bundle sizes for worker and page js

f477724

Warning user about outcomes not working on free accounts

03895ff

Updated intialization of Remote Frame to include environment info

1fc15d1

Sending on_session after finalize

324e3fa

if sw got killed before carrying out finalize

itrush merged commit 250055d into master Apr 13, 2020

jkasten2 deleted the feat-session-outcomes branch November 27, 2023 19:02

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Feature branch: new session logic + outcomes #624

Feature branch: new session logic + outcomes #624

itrush commented Apr 8, 2020 •

edited

Loading

Feature branch: new session logic + outcomes #624

Feature branch: new session logic + outcomes #624

Conversation

itrush commented Apr 8, 2020 • edited Loading

Session logic refactoring for web sdk

Motivation

Implementation

Chrome and Firefox

Safari

General flow

Outcomes

Motivation

General flow

itrush commented Apr 8, 2020 •

edited

Loading