Adding extra data: The Subject class

You may have additional information about your application’s environment, current user and so on, which you want to send to Snowplow with each event.

Create a subject like this:

subject := sp.InitSubject()

The Subject class has a set of Set...() methods to attach extra data relating to the user to all tracked events:

• SetUserId
• SetScreenResolution
• SetViewport
• SetColorDepth
• SetTimezone
• SetLanguage
• SetIpAddress
• SetUseragent
• SetDomainUserId
• SetNetworkUserId

We will discuss each of these in turn below:

Set user ID with SetUserId

You can set the user ID to any string:

s.SetUserId( "{{USER ID}}" );

Example:

s.SetUserId("alexd");

Set screen resolution with SetScreenResolution

If your code has access to the device’s screen resolution, then you can pass this in to Snowplow too:

s.SetScreenResolution( {{WIDTH}}, {{HEIGHT}} );

Both numbers should be positive integers; note the order is width followed by height. Example:

s.SetScreenResolution(1366, 768);

Set viewport dimensions with SetViewport

If your code has access to the viewport dimensions, then you can pass this in to Snowplow too:

s.SetViewport( {{WIDTH}}, {{HEIGHT}} );

Both numbers should be positive integers; note the order is width followed by height. Example:

s.SetViewport(300, 200);

Set color depth with SetColorDepth

If your code has access to the bit depth of the device’s color palette for displaying images, then you can pass this in to Snowplow too:

s.SetColorDepth( {{BITS PER PIXEL}} );

The number should be a positive integer, in bits per pixel. Example:

s.SetColorDepth(32);

Set timezone with SetTimezone

This method lets you pass a user’s timezone in to Snowplow:

s.timezone( {{TIMEZONE}} );

The timezone should be a string:

s.SetColorDepth("Europe/London");

Set the language with SetLang

This method lets you pass a user’s language in to Snowplow:

s.SetLang( {{LANGUAGE}} );

The language should be a string:

s.SetLang('en');

Set the IP Address with SetIpAddress

This method lets you pass a user’s IP Address in to Snowplow:

s.SetIpAddress( {{IP ADDRESS}} );

The IP Address should be a string:

s.SetIpAddress('127.0.0.1');

Set the useragent with SetUseragent

This method lets you pass a user’s useragent string in to Snowplow:

s.SetUseragent( {{USERAGENT}} );

The useragent should be a string:

s.SetUseragent('some useragent');

Set the Domain User ID with SetDomainUserId

This method lets you pass a user’s Domain User ID string in to Snowplow:

s.SetDomainUserId( {{DOMAIN USER ID}} );

The Domain User ID should be a string:

s.SetDomainUserId('domain-uid-12');

Set the Domain User ID with SetNetworkUserId

This method lets you pass a user’s Network User ID string in to Snowplow:

s.SetNetworkUserId( {{DOMAIN USER ID}} );

The Network User ID should be a string:

s.SetNetworkUserId('domain-uid-12');