Recursion-Reduction Tips For Apex Trigger Code

I wanted to share with you some lessons I learned while working on a trigger.

---

Because a trigger against a "just-saved" record can kick off another "save" operation on that record (typically the point of a trigger), the very same trigger can get re-fired during what's known as the same "execution context."

In Apex trigger programming, it's considered best-practice to make sure that any subsequent re-firings of the same trigger against the same record don't waste valuable CPU cycles when this happens (because Salesforce limits them within an "execution context").

Therefore, when writing a trigger that "does ____ for a just-saved record," it's important to make sure that, at some point, the trigger saves the ID of that record into a "I already did _____ on all of these records" flag that's viewable across all of these recursions (usually a class-level "Static"-flagged "Set<Id>"-typed variable in the trigger handler).

And, of course, you need to program your trigger to pay attention to its own flags and avoid running expensive "consider doing ____" code against records already in that "already-did-____" set of IDs.

---

The interesting question is: When do you set the "I already did _____" flag?
 

• In certain cases, one can trust that all field-values contributing to a trigger's yes/no decision of "should I do _____ to this just-saved record?" will be set the moment that the record is first saved.
   
  In those cases, the most efficient place in your trigger code to set the "I already did _____ on this record" flag is "as soon as the trigger has seen the record for the first time, no matter whether it ends up qualifying for 'doing ____' or not."
   
  That's how I usually write my triggers if I can, since it's the most efficient way to write the trigger.
   
   
• However, in certain cases (often discovered when people test your newly-written trigger and tell you that it fails under normal usage circumstances through 3rd-party record-editing environments like external portals), the values contributing to the answer to "should I do ____ to this record?" change so that the answer goes from "no" to "yes" in the middle of the "execution context."
   
  For example, other "triggers" or equivalent pieces of code do some post-processing to the just-saved record, and it's only after those pieces of code re-save the record that the answer flips to "yes."
   
  In those cases, the most efficient place in your trigger code to set the "I already did ______" on this record" flag is "as soon as the trigger has determined that it needs to do ______ to the record."
   
  This, unfortunately, will make the trigger run "Should I do _____?" checks all the way through the execution context for records that remain "no" throughout. That's why it's less efficient.
   
  But sometimes, it's simply necessary in cases where the answer can flip from "no" to "yes" mid-execution-context.
   
   

---

If one is comfortable authoring / editing the triggers/processes/workflows that are responsible for such impactful mid-execution-context value-changes, sometimes it's possible to refactor them so that they're simply part of the same "trigger handler" code as the one you're in the middle of writing.
You could precisely control the order of code execution "after a record is saved" and author these actions in a way that ensure there will never be any "mid-execution-context surprise value-changes."
That might let you use the more efficient recursion-reduction pattern instead.

Sometimes, though, there's nothing you can do but choose the 2nd option.

Python for Salesforce Developers: "Just Push Play" Run-Specified-Tests Code Deployment

Warning: the attached Python script makes you put a password straight into the code and helps you make an end-run around all sorts of change-management best practices.

Basically, if you're not a little horrified to see this script publicly shared, you probably don't understand what it's capable of enough to be using it -- so please dont!

That said, for circumstances in which you were going to ignore a lot of change-management issues anyway, or just want to do a "check only" deploy of code to a Salesforce org, etc., this code basically lets you type a handful of classes / pages / etc. into a Python script, type in your username & password, say which tests you want to run and how you want to deploy it, and see the results really quickly.

The idea is to be almost as handy, to a developer, for small changes, as right-clicking on code files in Eclipse and "deploying" from there -- the problem with Eclipse being that it doesn't have a "Run Specified Tests" option.

At some point I might create something similar to this that lets you log into two Salesforce orgs, download a smattering of code from one to your local hard drive (instead of already having to have downloaded it with Eclipse), and proceed with the deploy from there. That really feels like playing with laziness/sloppiness fire, though (somehow seems to take out the "Would I really have deployed this just with Eclipse, anyway?" factor).

This code is probably best just for "checkOnly=TRUE" deploys. For real deploys, it's probably still best to Run All Tests, and using a "Change Set" is a lot better for anyone else who might have to stumble into your org a few weeks later and see what's been happening as far as code deploys. (And that's just a bare minimum of version control for simply-maintained orgs.)

A few notes on the code:

• Change "#'''" to "'''" around blocks of code to quickly toggle them off (no point, for example, re-logging in if your Python IDE already has your session ID in memory, and you don't want to fire up a new "deploy" just to run the "check deployment status" code again).
• "thingsToAdd" is where most of the "what you need to type" exists.
• You'll also need to set "username" & "password" values (including your security token appended to your password) in "toOrgLoginEnvelope" -- I recommend remembering to change it back by saving this script to your hard drive (if you do save it) with a filename that includes something like "INCLUDES PASSWORD" so, as you exit the IDE, you remember to change things back.
• "inputstr" will need the actual path to where you've used Eclipse to download the files you have "ready to deploy" to on your hard drive.
• "outpbase" should be somewhere easy to find and delete later, like a sub-folder on your desktop.
• "deployEnvelope" will need "checkOnly" set inside the XML itself, "testLevel" set just above it, and a (brackets-and-comma-delimited) list of tests to run towards the end of the "runtests" parameter inside the parentheses that follow the XML (if n/a, use "[]").

import os
import shutil
import base64
from xml.etree import ElementTree
import xml.dom.minidom
import requests
import re   

def getUniqueElementValueFromXmlString(xmlString, elementName):
    #Extracts an element value from an XML string.
    #For example, invoking getUniqueElementValueFromXmlString('<?xml version="1.0" encoding="UTF-8"?><foo>bar</foo>', 'foo') should return the value 'bar'.
    elementsByName = xml.dom.minidom.parseString(xmlString).getElementsByTagName(elementName)
    elementValue = None
    if len(elementsByName) > 0: elementValue = elementsByName[0].toxml().replace('<' + elementName + '>', '').replace('</' + elementName + '>', '')
    return elementValue

metadataAPIVer = '40.0'

#'''
toOrgLoginEnvelope = """<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"><soapenv:Body><login xmlns="urn:partner.soap.sforce.com"><username>{username}</username><password>{password}</password></login></soapenv:Body></soapenv:Envelope>""".format(
username='username', password='password')
tor = requests.post('https://login.salesforce.com/services/Soap/u/'+metadataAPIVer, toOrgLoginEnvelope, headers={'content-type':'text/xml','charset':'UTF-8','SOAPAction':'login'})
tosessid = getUniqueElementValueFromXmlString(tor.content, 'sessionId')
tohost = getUniqueElementValueFromXmlString(tor.content, 'serverUrl').replace('http://', '').replace('https://', '').split('/')[0].replace('-api', '')
toorgid = re.sub(r'^.*/([a-zA-Z0-9]{15})$', r'\1', getUniqueElementValueFromXmlString(tor.content, 'serverUrl'))
toapiver = re.sub(r'^.*/([0-9.]+)/[a-zA-Z0-9]{15}$', r'\1', getUniqueElementValueFromXmlString(tor.content, 'serverUrl'))
#'''

# EXAMPLE CODE:  thingsToAdd = {'classes':[''],'pages':['']}
thingsToAdd = {'classes': {'singCaps':'ApexClass','ext':'cls','toUpl':['OpportunityETLHandler','OpportunityETLTest']}, 'pages': {'singCaps':'ApexPage','ext':'page','toUpl':['OpportunityETLPage']}}
inputstr = 'C:\\EXAMPLEFOLDER\\EclipseWorkspace\\My Sandbox\\src\\'
outpbase = 'C:\\EXAMPLETEMPFOLDER\\temppkgtouploadfromeclipse\\'
outpfiles = outpbase + '\\filesbeforezip\\'
outpzip = outpbase + 'uploadme'

#'''
# BEGIN:  Code to create package
if not os.path.exists(outpbase): os.makedirs(outpbase)
if not os.path.exists(outpfiles): os.makedirs(outpfiles)
pkgroot = ElementTree.Element('Package', attrib={'xmlns':'http://soap.sforce.com/2006/04/metadata'})
for folder in thingsToAdd.keys():
    innerDict = thingsToAdd[folder]
    typesElem = ElementTree.Element('types')
    if not os.path.exists(outpfiles+folder+'\\'): os.makedirs(outpfiles+folder+'\\')
    for item in innerDict['toUpl']:
        membersElem = ElementTree.Element('members')
        membersElem.text = item
        typesElem.append(membersElem)
        shutil.copy(inputstr+folder+'\\'+item+'.'+innerDict['ext'], outpfiles+folder+'\\'+item+'.'+innerDict['ext'])
        shutil.copy(inputstr+folder+'\\'+item+'.'+innerDict['ext']+'-meta.xml', outpfiles+folder+'\\'+item+'.'+innerDict['ext']+'-meta.xml')
    namesElem = ElementTree.Element('name')
    namesElem.text = innerDict['singCaps']
    typesElem.append(namesElem)
    pkgroot.append(typesElem)
verElem = ElementTree.Element('version')
verElem.text = metadataAPIVer
pkgroot.append(verElem)
with open(outpfiles+'package.xml', 'w', newline='') as fw:
    dom_string = xml.dom.minidom.parseString(ElementTree.tostring(pkgroot)).toprettyxml(encoding='UTF-8', indent='    ')
    dom_string = '\n'.join([s for s in dom_string.decode('UTF-8').splitlines() if s.strip()]) + '\n'
    fw.write(dom_string)
# END:  Code to create package
#'''

#'''
# BEGIN:  Code to create ZIP
shutil.make_archive(base_name=outpzip, format='zip', root_dir=outpfiles, base_dir='./')
zipString = None
with open(outpzip+'.zip', 'rb') as f: zipString = base64.b64encode(f.read()).decode('UTF-8')
# END:  Code to create ZIP
#'''

# TO DO:  Figure out how to run several tests.  Maybe it's just a comma-separation?  I think it it's that in the point-and-click Change Set UI.

#'''
# BEGIN:  Code to deploy ZIP
testLevel = 'RunSpecifiedTests' # Most common values will be 'RunSpecifiedTests' or 'RunLocalTests'
deployEnvelope = """<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:met="http://soap.sforce.com/2006/04/metadata">
      <soapenv:Header>
         <met:SessionHeader>
            <met:sessionId>{sessionid}</met:sessionId>
         </met:SessionHeader>
      </soapenv:Header>
      <soapenv:Body>
         <met:deploy>
             <met:zipFile>{zipfile}</met:zipFile>
             <met:deployOptions>
                 <met:checkOnly>true</met:checkOnly>
                 <met:rollbackOnError>true</met:rollbackOnError>
                 {runtests}
                 <met:singlePackage>true</met:singlePackage>
                 <met:testLevel>{testlev}</met:testLevel>
             </met:deployOptions>
         </met:deploy>
      </soapenv:Body>
      </soapenv:Envelope>""".format(sessionid=tosessid, zipfile=zipString, testlev=testLevel, runtests=''.join(['<met:runTests>'+x+'</met:runTests>' for x in ['OpportunityETLTest1','OpportunityETLTest2']]) if testLevel=='RunSpecifiedTests' else '')
deploytor = requests.post('https://'+tohost+'/services/Soap/m/'+toapiver+'/'+toorgid, deployEnvelope, headers={'content-type': 'text/xml', 'charset': 'UTF-8', 'SOAPAction': 'deploy'})
# END:  Code to deploy ZIP
#'''

#'''
# BEGIN:  Code to check deploy
checkDeployStatusEnvelope = """<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:met="http://soap.sforce.com/2006/04/metadata">
      <soapenv:Header>
         <met:SessionHeader>
            <met:sessionId>{sessionid}</met:sessionId>
         </met:SessionHeader>
      </soapenv:Header>
      <soapenv:Body>
         <met:checkDeployStatus>
             <met:asyncProcessId>{process_id}</met:asyncProcessId>
             <met:includeDetails>true</met:includeDetails>
         </met:checkDeployStatus>
      </soapenv:Body>
      </soapenv:Envelope>""".format(sessionid=tosessid, process_id=getUniqueElementValueFromXmlString(deploytor.content, 'id'))

checkdeploytor = requests.post('https://'+tohost+'/services/Soap/m/'+toapiver+'/'+toorgid, checkDeployStatusEnvelope, headers={'content-type': 'text/xml', 'charset': 'UTF-8', 'SOAPAction': 'checkDeployStatus'})

#print(checkdeploytor.content)
#print()
print('Id: ', getUniqueElementValueFromXmlString(checkdeploytor.content, 'id'))
print('Done: ', getUniqueElementValueFromXmlString(checkdeploytor.content, 'done'))
print('Success: ', getUniqueElementValueFromXmlString(checkdeploytor.content, 'success'))
print('Status: ', getUniqueElementValueFromXmlString(checkdeploytor.content, 'status'))
print('Problem: ', getUniqueElementValueFromXmlString(checkdeploytor.content, 'problem'))
print('NumberComponentsTotal: ', getUniqueElementValueFromXmlString(checkdeploytor.content, 'numberComponentsTotal'))
print('RunTestResult: ', getUniqueElementValueFromXmlString(checkdeploytor.content, 'runTestResult'))
print('NumberTestsTotal: ', getUniqueElementValueFromXmlString(checkdeploytor.content, 'numberTestsTotal'))
#print(getUniqueElementValueFromXmlString(checkdeploytor.content, 'details'))
# END:  Code to check deploy
#'''

DemandTools MassImpact equivalent of UPDATE...SET...WHERE SQL

The CRMFusion company makes powerful Salesforce-record-editing software called DemandTools.

Below are some screenshots of setting up its "MassImpact" (single-table-editing) module to do a job equivalent to running an "UPDATE...SET...WHERE" DML SQL statement against a traditional database, for data cleansing within a specific single table.

For example, to turn all values of table Contact, field Home_Phone__c that are filled with nothing but 10 digits in a row, no punctuation, into a properly formatted US phone number, you might traditionally use the following Oracle-database-friendly DML SQL:

UPDATE Contact
SET Home_Phone__c = REGEXP_REPLACE(Home_Phone__c,'^(\d{3})(\d{3})(\d{4})$','(\1) \2-\3')
WHERE REGEXP_LIKE(Home_Phone__c,'^(\d{3})(\d{3})(\d{4})$')

In DemandTools, you would set up a MassImpact "scenario" as follows:

• Step 1: Tell DemandTools that you want to operate on the "Contact" object/table, and say which fields you want to be able to see the values of while you screen go/no-go on potential updates in the 3rd step.
  
  
  
   
• Step 2: Tell DemandTools that you want to potentially-update all records where "Home_Phone__c" isn't null (unfortunately, you can't use a regular expression in the "WHERE" with DemandTools – but step 3 has some dummy-proofing to get around too wide a selection),
  and say that you want to propose a parentheses-and-dashes-formatted replacement value for any of the returned values that consist of nothing but a string of 10 bare digits in Home_Phone__c.
  
  
  
   
• Step 3: Ensure that you aren't pushing "UPDATE" calls for any records where there is no change to the value of Home_Phone__c, or where the new value of Home_Phone__c would be blank,
  and skim the records to make sure your logic is doing what you thought it would,
  and click "Update Records."
  
  
  
  

---

P.S. Just for geekiness, and to compare ease of use, here's some "Execute Anonymous" Salesforce Apex code along the same idea.
(Note: not tested at scale. Depending on your trigger/workflow/process builder load, might not actually work since it probably all runs in 1 "execution context" of post-DML CPU usage "governor limits," whereas DemandTools will run in truly separate "execution contexts" per 200 records to UPDATE.)

Map<Integer, List<Contact>> csToUpdate = new Map<Integer, List<Contact>>();
Integer csToUpdateCount = 0;
Integer currentBatch = 0;
List<Contact> cs = [SELECT Phone FROM Contact WHERE Phone <> null];
Pattern p = Pattern.compile('^(\\d{3})(\\d{3})(\\d{4})$');
for (Contact c : cs) {
 Matcher m = p.matcher(c.Phone);
 if(m.matches() == true) {
        csToUpdateCount++;
        currentBatch = (csToUpdateCount/200)+1;
        if (!csToUpdate.containsKey(currentBatch)) { csToUpdate.put(currentBatch, new List<Contact>()); }
        c.Phone = m.replaceFirst('($1) $2-$3');
        (csToUpdate.get(currentBatch)).add(c);
 }
}
if (csToUpdate.size() > 0) {
    for (List<Contact> csToU : csToUpdate.values()) {
        UPDATE csToU;
    }
}