Opportunity Contact Role "Trigger"

Among the many limitations of the standard OpportunityContactRole object in Salesforce is the inability to put a trigger on it.  The use case I wanted to solve was to aggregate and copy the contact information related to certain roles to the parent opportunity.  Some options I considered:

1. Create a batch job to query OCR nightly and update the parent opportunity
2. Create a trigger on Opportunity updates to fetch the OCR data
3. A combination of 1 and 2
4. Replace the standard OCR with a custom OCR and create the necessary trigger

I finally came across this blog post, and with some tinkering, found that it worked for our use-case. The idea is to hide a inline visualforce page within the standard layout and use that vf page's action property to run some code.  The author chose an asynchronous opportunity update whereas I went with a synchronous update.  The action property on the page tag is generally used for redirects, but could certainly be used for defaulting data as well.

Some issues I came across:

1. Since visualforce is served up from a different domain, I was seeing my page redirected by a servlet to a "page not found".  I was able to stop this by returning a non null page reference.
2. The js console in chrome logs some refusal errors due to the different domains.  This went away with the resolution to #1.
3. I was unable to refresh the parent page from the inline vf page after the update, so the user has to manually refresh the opportunity to see the effect.  This is still the case but our users were ok with it.
4. The hidden vf page's controller is trying to execute a DML.  This is usually followed by a page refresh.  The problem is that the page refresh is occurring within the inline VF, which,when it renders, again executes the controller's action.  This can cause some serious looping, which is why it is imperative for the action method to check whether an update is required or not.