In this example below, we have some traffic that has a web page that contains on email. I have created a Traffic analysis configuration which knows how to look for the email, pulls it off the page, and stores it into a custom field. This is quite similar to many user websites. (That custom field is configured at the Session level, so it is available from any Hit within that containing Session.)
Attached are a bunch of screenshots that illustrate the above. Screenshot1 shows where I created a custom field (Dec07_2017property) in my Hit Analyzer.
Screenshot2 shows you how/where I configured the 'Extraction Expression'. The email address shows up in the webpage, in the 'Response Content' so I chose that as the 'Value Source'. For the web page that it appears in, below is snippet of the relevant section of html code:
<td><input name="p$lt$ctl08$wPP$p$lt$ctl01$wPL$p$lt$ctl00$wSC$cartElem$wzdStep1$txtEditEmail" type="text" value="firstname.lastname@example.org" maxlength="100" id="p_lt_ctl08_wPP_p_lt_ctl01_wPL_p_lt_ctl00_wSC_cartElem_wzdStep1_txtEditEmail" class="TextBoxField" /><span id="p_lt_ctl08_wPP_p_lt_ctl01_wPL_p_lt_ctl00_wSC_cartElem_wzdStep1_lblMark14"></span></td>
So basically, the APM system looks through that html code for the variable 'txtEditEmail' and grabs the text that comes after it. That is the email address.
In screenshot3, we see a search upon that Hit Filter in which the custom field has been configured. There's been quite a few instances of this. Quite a few Hits.
In screenshot4, I have clicked on one of those Hits and have opened up the session containing that Hit for replay. You can see the actual page as it appears to the End User, with the 'E-mail' field populated.
In screenshot5, it is the same Hit but viewed in 'Display mode' "Response Source" instead of "Response Replay". This is simply the entire HTML code of that page, including that snippet around the email, shown above.
Screenshot6, shows me testing out the RegEx expression, the 'Extraction Expression'. I copied/pasted the entire text, the entire web page, from the "Response Source" above into the 'Sample Text' field. and the 'Test Results' come back finding a match. and the value extracted is "email@example.com". That's what I want. Perfect.
In screenshot7, it is showing where this value is displayed as a 'Custom Field' in the 'Session Details' of a session that contains that Hit. Get here by clicking on 'Session Details' link in the Response Replay page, screenshot4.
Screenshot 8 shows that in the 'Search Sessions' screen, when I search for sessions that match the 'Hit Analyzer' "SampleECommerceRegistrationCheck" (where the custom field is configured) the values for that custom field are shown in their own column in the search results. The value is always just "firstname.lastname@example.org" because that is the only email in the traffic. I was the only user accessing those web pages. In real life, it would have various other email addresses from various other people.
I trust that you find this useful to help you configure your Traffic Analysis configuration on your own APM system.