Bounce email handling mailbox full using salesforce triggers - salesforce

Question

I'm trying to solve the bouncing email issue based on "Mail box full" by creating a trigger that resends the message if the message contains "mail box full".
The issue I'm facing is that I need to limit the number of resend to 3 times.
What I have now keeps resending the email as soon as a bounced email is received.
My trigger is
trigger trgBouncedEmails on EmailMessage (after insert) {
for(EmailMessage myEmail: trigger.New) {
//mail box full bounced email
if (myEmail.HtmlBody.contains('full'))
{
Case[] parentCase = [Select c.Id from Case c where c.Id =: myEmail.ParentId];
if (myEmail.Subject.contains('Financial Review'))
parentCase[0].Resend_Email_Send__c = true; // this will trigger a workflow to send the email again.
Update parentCase;
}
}
}
How can I limit the resending, is there a way I can set a wait time before I do the "Update parentCase"
Is there a better way to solve this issue, knowing that I have different types of emails, each one has a different template and a different purpose.
EDIT
The system should automatically re-send the email 3 times in the frequency of 24hours, and then stops resending after 24hrs. My trigger keeps resending indefinitely and I'm trying to find a way to put a wait so it can only send 3 times in 24hrs period, like once every 8hrs.

Answer 1

#grigriforce beat me to the punch - I would also suggest using a field to count the number of retries, rather than a simple boolean value. Here's a "bulkified" trigger with essentially the same logic as the one you posted:
trigger trgBouncedEmails on EmailMessage (after insert) {
List<Id> parentCaseIds = new List<Id>();
for ( EmailMessage myEmail : trigger.New ) {
// mail box full bounced email for Financial Review emails
if ( myEmail.HtmlBody.contains('full') && myEmail.Subject.contains('Financial Review') )
parentCaseIds.add(myEmail.ParentId);
}
Case[] parentCases = [select c.Id from Case c where c.Id in :parentCaseIds];
for ( Case c : parentCases ) {
c.Resend_Email_Count__c += 1; // this will trigger workflow to send the email again
c.Resend_Email_Time__c = System.now(); // keep track of when it was last retried
}
update parentCases;
}
Update to space emails out evenly over a 24-hour period:
Rework your workflow to make sure it has been 8 hours since Resend_Email_Time__c was last set, and then schedule an Apex job to run every hour to pick up eligible Cases that need to have their emails resent, and call update on them to make sure the workflow doesn't go too long without firing:
global class ResendCaseEmails implements Schedulable {
global void execute(SchedulableContext sc) {
Contact[] cs = [select id, Resend_Email_Count__c, Resend_Email_Time__c from Contact where Resend_Email_Count__c < 4];
List<Contact> ups = new List<Contact>();
for ( Contact c : cs ) {
if ( c.Resend_Email_Time__c != null && c.Resend_Email_Time__c.addHours(8) < System.now() )
ups.add(c);
}
update ups;
}
}
**note that it's not a best practice to have this code in the class that implements Schedulable - this code would ideally be in another class that is called by the ResendCaseEmails class.
You can schedule this job to run once an hour by calling this code from the developer console:
ResendCaseEmails sched = new ResendCaseEmails();
String cron = '0 0 * * * ?';
System.schedule('Resend Case Email Job', cron, sched);

Answer 2

You could simply change the resend boolean on the case to an integer count of the send attempts and have your workflow rule re-send only while that count is less than 3.
Case[] parentCase = [Select c.Id, c.Resend_Email_Count__c from Case c where c.Id =: myEmail.ParentId];
if (myEmail.Subject.contains('Financial Review'))
parentCase[0].Resend_Email_Count__c += 1; // this will trigger a workflow to send the email again.
Update parentCase;
Also, I assume that you simplified the trigger to show the problem but if not you really need to bulkify it.

Answer 3

So, here's what you'd like to happen (feel free to correct me if I am wrong). You send an email, and if it bounces you'd like to re-send an email every 8 hours. The number of resends should be 3 max.
I would not use only triggers for this scenario. I'd instead design a solution using a Trigger, Scheduler, and maybe a custom table to keep track of the bounced email(s).
Let's call this table/object "Bounce Email Tracker". It'll have the following 3 fields:
Email Name (some unique description of email)
Email status (Sent, Bounced, ReSent, Failed)
Resend Count
Sent email Timestamp
If and when an email is sent you'd create an entry in this table using a trigger with the status set to "Sent" and the "Sent email . If the email bounces, another trigger would "update" the entry in the table to change the status of the record to "Bounced".
A scheduler will run regularly which will retrieve all records from this new table where status equals "Bounced", and check the last time the email was sent using the value in the "Sent Email Timestamp". It will do the following actions depending on the time sent, and resend count.
If the resend count is less than 3, and if the last email was sent more than or equal to 8 hours ago, send another email from the scheduler. Change the status of the record to "Sent".
If the resend count is more than 3, and the status is "Bounced", change the status to "Failed".
If the resend count it less than 3 but the last email was sent less than 8 hours ago, don't do anything.
I know this is a lot of effort, and I am sure it probably needs more thought, but this will provide a robust framework to track and resend bounced emails.
Hope this helps!
Anup