Enhance Dynamic Content

[dongilbert]

Q	A
Bug fix?	Y
Enhancement	Y
New feature?
Automated tests included?
Related user documentation PR URL
Related developer documentation PR URL
Issues addressed (#s or URLs)
BC breaks?
Deprecations?

Description:

Dynamic Web Content was slow to load due to always initializing after the page hit event being fired, which could take upwards of 1.5s. This PR moves the request for DWC to just before the page hit event being fired, but includes all the same parameters as the page hit event as well as the request for DWC. In this way, we can properly identify the contact and render the DWC on the page without having to wait for the page hit event to finish. In my testing, this resulted in a 76% increase in DWC rendering time (down to ~600ms from ~2500 ms)

Additionally, we now set the Access-Control-Max-Age header on response to OPTIONS requests made using MauticJS.makeCORSRequest(). This will save ~ 200ms during the page load on external pages that make CORS requests to Mautic, as the browser will now cache the OPTIONS response for 10 min (a hard limit set by Chrome). Previously, it was caching the response for 5s.

Additionally, a bug is fixed where Campaign events were being triggered and logged for non-campaign based DWC. Previously we were checking that a campaign "Request Dynamic Content" decision applied to the requested DWC slot name, and just bypassing it if it did not match. (If you were requesting a slot named blog and your campaign served a slot named something-else, the something-else decision would be logged in the campaign_lead_event_log for the active contact.) This PR fixes that by setting the event status to false and returning false in the check, to prevent going further down the campaign path.

Steps to test this PR:

1. Before applying PR, set up a non-campaign based dynamic content and embed it on an external page where you mtc.js is present.
2. Load the page with your browser dev tools open, and note the response times and visual render time for the dynamic content on your page.
3. Apply PR, clear cache, then navigate to any page in your admin (to warm the Symfony cache).
4. Revisit the page on which you embedded the dynamic content. Have your developer tools open and refresh the page again and not the response times and visual render time. It should be noticeably faster.

[Hadamcik]

Works for me, dynamic content is being loaded right after mtc.js is loaded without further delay