Overview

Types of hit attributes

Discover supports five basic types of hit attributes. Hit attributes may be configured to match:

Data in the request or data in the response
Data between start and end tags or exact data
Note: Discover maintains a hidden, fifth set of hit attributes, which is derived from other hit attributes, system attributes, and events. These types are defined by the system and cannot be created or edited by users.
Values that are stored in JSON message nodes that are submitted by Discover client-side frameworks
- See "Step-Based Eventing" in the Unica Discover Event Manager Manual.

The following matrix indicates the four kinds of hit attributes and how they interact with the example data listed below:

Request data:
```
REMOTE_ADDR=63.194.158.158
```
Response data:
```
You have no items in your cart
```

Table 1. Overview
REQTEXT
	Request Tags	Request Match	Response Tags	Response Match
Start Tag/End Tag	Start Tag: `\r\nREMOTE_ADDR=` End Tag: `\r\n` (denotes end of line)	`63.194.158.158`	Start Tag: `\r\nYou have` End Tag: `items in your cart\r\n`	`no`
Exact Match	Start Tag: `63.194.158.158` End Tag: (nothing)	`63.194.158.158`	Start Tag: `You have no items in your cart` End Tag: (nothing)	`You have no items in your cart`

Hit Attribute Evaluation

When a hit attribute defined with a start tag and an end tag is evaluated against a text buffer, the results are returned according to the following criteria:

Table 2. Overview
REQTEXT
Start Tag	End Tag	Returns
found	found	correct value is returned
not found	found	returns: `Not found`
found	not found	returns: `Not found`
not found	not found	returns: `Not found`

How Patterns Are Matched

When the event engine is evaluated, a pattern is compared against the request or response buffer to look for start tag/end tag patterns. Matches are found only for the innermost tags. For each found start tag, matching text is found only if the nearest end tag appears before another start tag.

For exact matches that use start tags only, the following does not apply.

Suppose you have defined a pattern definition with the following tags:

Start Tag: foo=
End Tag: bar

Suppose the text in the buffer looks like the following:


foo=1foo=2foo=3barfoo=4bar

In the above example, match values are the following:

3
4
The number of matches is 2.

Note that other potential matches (e.g. foo=3barfoo=4bar) are not recorded because the end tag overlaps another start tag.

Note: Using well-defined start and end tags enables efficient extraction of data from the hit. Using common start and end tags such as < and /> impacts hit processing performance because of the numerous matches. To reduce the number of returned matches, additional processing of the data is likely to be required.

Hit Attribute Availability

Hit attributes and any values recorded for them are available in any trigger for individual hits:

First Hit of Session
Every Hit
1. Every Step
2. After Every Step
  Note: Step-based eventing captures events submitted from one of Discover's client-side capture solutions. See "Step-Based Eventing" in the Unica Discover Event Manager Manual.
After Every Hit
Last Hit

Note: In the End of Session trigger, hit attributes and their values are not available for evaluation. Report groups containing dimensions populated by hit attributes can be used by end of session events, but the hit attribute value is not recorded for that dimension.