Hello Everyone,
A Custom function is a user-written set of code to achieve a specific requirement. Set the required conditions needed as when to trigger using the Workflow rules (be it Tasks / Project) and associate the custom function to it.
Requirement:
One of our customers has created four custom currency fields at the Task level and a related set of four custom currency fields at the Project level. Their requirement is to roll up the cumulative values from the Task-level fields and automatically sync them to the corresponding Project-level fields. This requirement was successfully achieved using Custom Function along with Workflow rules.

This approach ensures that project level data stays accurate and up to date without the need for manual consolidation.
Custom function code:
totalMilestoneRev = 0;
totalActualRev = 0;
totalMilestoneGP1 = 0;
totalActualGP1 = 0;
indexValue = 1;
rangeValue = 100;
loop = {1,2,3};
// This loop fetches up to 300 tasks. Increase the count as needed, e.g., loop = {1,2,3,4,5}; to fetch 500 tasks.
for each i in loop
{
taskParameter = Map();
taskParameter.put("index",indexValue);
taskParameter.put("range",rangeValue);
// info taskParameter;
taskResponse = zoho.projects.getRecords(portalId,projectId,"tasks",taskParameter,0,"XXXXX");
// info taskResponse;
if(taskResponse.containKey("tasks"))
{
for each task in taskResponse.get("tasks")
{
if(task.containsKey("custom_fields"))
{
customFields = task.get("custom_fields");
for each customField in customFields
{
if(customField.get("label_name").equalsIgnoreCase("Milestone Rev"))
{
milestoneRev = customField.get("value");
if(milestoneRev.equalsIgnoreCase("-"))
{
milestoneRev = 0;
}
totalMilestoneRev = totalMilestoneRev + milestoneRev.remove(",").toDecimal();
}
if(customField.get("label_name").equalsIgnoreCase("Actual Rev"))
{
actualRev = customField.get("value");
if(actualRev.equalsIgnoreCase("-"))
{
actualRev = 0;
}
totalActualRev = totalActualRev + actualRev.remove(",").toDecimal();
}
if(customField.get("label_name").equalsIgnoreCase("Milestone GP1"))
{
milestoneGP1 = customField.get("value");
if(milestoneGP1.equalsIgnoreCase("-"))
{
milestoneGP1 = 0;
}
totalMilestoneGP1 = totalMilestoneGP1 + milestoneGP1.remove(",").toDecimal();
}
if(customField.get("label_name").equalsIgnoreCase("Actual GP1"))
{
actualGP1 = customField.get("value");
if(actualGP1.equalsIgnoreCase("-"))
{
actualGP1 = 0;
}
totalActualGP1 = totalActualGP1 + actualGP1.remove(",").toDecimal();
}
}
}
}
indexValue = indexValue + 100;
}
else
{
break;
}
}
/*Rollup to project*/
projectParams = Map();
projectParams.put("baseline_revenue",{"amount":totalMilestoneRev.round(2)});
projectParams.put("projects_cf_0002",{"amount":totalActualRev.round(2)});
projectParams.put("baseline_gp1",{"amount":totalMilestoneGP1.round(2)});
projectParams.put("actual_gp1",{"amount":totalActualGP1.round(2)});
info projectParams;
updateProject = invokeurl
[
url :projectsv3APIEndPoint + "/portal/" + portalId + "/projects/" + projectId
type :PATCH
parameters:projectParams.toString()
connection:"XXXXX"
];
info updateProject;
return "success";
Make sure to replace XXXXX with Zoho Projects connection link name along with scopes: ZohoProjects.projects.ALL, ZohoProjects.Tasks.ALL and the custom fields based on your requirement. Please find the screenshot of the list of parameters to be mapped for reference.
We hope you found this post useful. If you have any questions, feel free to share them in the comments below.