Dataverse: Create GetLastDateOfMonth Function in Custom Connector

Do you know we can write Code (Preview) in Custom Connector? In this blog post, we will make a simple function that will return the last date of the month to try the feature. Without further ado here are the steps!

Go to make.powerapps.com > Dataverse> Custom Connectors> on the top right hit + New custom connector > Create from blank option:

Create a Blank Custom Connector

Then we need to fill in the General Information below:

General tab

I put the host as  temmyraharjo.wordpress.com. This Host URL will be replaced automatically. So you can put any URL that you want.

The next is the Security tab. Here I am following the official documentation which uses API Key:

Security tab

In the Definition tab, you can create the Action/API Method that you want to create. For this example, I named it as GetlastDateOfMonth. Once you define the action, you need to define the Request and Response also.

Definition-Request

Here is my Request (asking for a parameter date):

api/getlastdateofmonth?date=4/9/2022

Then for the Response, I designed that the API can return two properties (Result and Error):

Definition-Response

The Response Sample:

{
  "Result": "4/9/2022",
  "Error": "Error"
}

And here is the fun part! Where do we need to create the code? For now, I don't know how we can write the code efficiently. But when I wrote this code, I depended on the sample that was being generated automatically and in this GitHub code.

public class Script : ScriptBase
{
    public override async Task<HttpResponseMessage> ExecuteAsync()
    {	var query = HttpUtility.ParseQueryString(this.Context.Request.RequestUri.Query);	var inputDateString = query.Get("date");	if(string.IsNullOrEmpty(inputDateString)) return CreateHttpResponseMessage(HttpStatusCode.BadRequest, 		"{\"Error\": \"Date QueryString is empty.\"}");		
        if (!DateTime.TryParse(inputDateString, out DateTime inputDate))	{		return CreateHttpResponseMessage(HttpStatusCode.BadRequest, 			"{\"Error\": \"Bad Format\"}");	}		var lastDay = DateTime.DaysInMonth(inputDate.Year, inputDate.Month);	var lastDayOfTheMonth = new DateTime(inputDate.Year, inputDate.Month, lastDay);	return CreateHttpResponseMessage(HttpStatusCode.OK, "{\"Result\": \"" + lastDayOfTheMonth.ToShortDateString() + "\"}");
    }private HttpResponseMessage CreateHttpResponseMessage(HttpStatusCode statusCode, string content){	return new HttpResponseMessage(statusCode)	{		Content = CreateJsonContent(content)	};}
}

Then you need to check the Code Enabledand paste the code above, create the Connector and the last part was to create Connection.

The code 😁

Once you do it, you can test it from the page. But the Test functionality will automatically encode the input. So in the end I tested it using Postman with the below request:

Success Result

Here is the result if we don't put the date QueryString:

Validation 1

And the last one if we put the wrong date string:

Validation 2

You also need to read the FAQ for the supported namespace (still limited and still got lots of improvement here).

Happy CRM-ing!